Rule2022-25214
Endangered and Threatened Wildlife and Plants; Lesser Prairie-Chicken; Threatened Status With Section 4(d) Rule for the Northern Distinct Population Segment and Endangered Status for the Southern Distinct Population Segment
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
November 25, 2022
Effective
January 24, 2023
Issuing agencies
Interior DepartmentFish and Wildlife Service
Abstract
We, the U.S. Fish and Wildlife Service (Service), are listing two Distinct Population Segments (DPSs) under the Endangered Species Act of 1973 (Act), as amended, for the lesser prairie-chicken (Tympanuchus pallidicinctus), a grassland bird known from southeastern Colorado, western Kansas, eastern New Mexico, western Oklahoma, and the Texas Panhandle. We determine threatened status for the Northern DPS and endangered status for the Southern DPS. This rule adds the DPSs to the List of Endangered and Threatened Wildlife. We also finalize a rule under the authority of section 4(d) of the Act that provides measures that are necessary and advisable to provide for the conservation of the Northern DPS.
Full Text
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[Federal Register Volume 87, Number 226 (Friday, November 25, 2022)]
[Rules and Regulations]
[Pages 72674-72755]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-25214]
[[Page 72673]]
Vol. 87
Friday,
No. 226
November 25, 2022
Part III
Department of the Interior
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Fish and Wildlife Service
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50 CFR Part 17
Endangered and Threatened Wildlife and Plants; Lesser Prairie-Chicken;
Threatened Status With Section 4(d) Rule for the Northern Distinct
Population Segment and Endangered Status for the Southern Distinct
Population Segment; Final Rule
Federal Register / Vol. 87 , No. 226 / Friday, November 25, 2022 /
Rules and Regulations
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2021-0015; FF09E21000 FXES1111090FEDR 234]
RIN 1018-BB27
Endangered and Threatened Wildlife and Plants; Lesser Prairie-
Chicken; Threatened Status With Section 4(d) Rule for the Northern
Distinct Population Segment and Endangered Status for the Southern
Distinct Population Segment
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Final rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are listing
two Distinct Population Segments (DPSs) under the Endangered Species
Act of 1973 (Act), as amended, for the lesser prairie-chicken
(Tympanuchus pallidicinctus), a grassland bird known from southeastern
Colorado, western Kansas, eastern New Mexico, western Oklahoma, and the
Texas Panhandle. We determine threatened status for the Northern DPS
and endangered status for the Southern DPS. This rule adds the DPSs to
the List of Endangered and Threatened Wildlife. We also finalize a rule
under the authority of section 4(d) of the Act that provides measures
that are necessary and advisable to provide for the conservation of the
Northern DPS.
DATES: This rule is effective January 24, 2023.
ADDRESSES: This final rule is available on the internet at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Comments and materials we received, as well as
supporting documentation we used in preparing this rule, are available
for public inspection at <a href="https://www.regulations.gov">https://www.regulations.gov</a> at Docket No. FWS-
R2-ES-2021-0015.
FOR FURTHER INFORMATION CONTACT: Beth Forbus, Regional ES Program
Manager, Southwest Regional Office, 500 Gold Ave SW, Albuquerque, NM
87102; telephone 505-318-8972. Individuals in the United States who are
deaf, deafblind, hard of hearing, or have a speech disability may dial
711 (TTY, TDD, or TeleBraille) to access telecommunications relay
services. Individuals outside the United States should use the relay
services offered within their country to make international calls to
the point-of-contact in the United States.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Act, a species warrants
listing if it meets the definition of an endangered species (in danger
of extinction throughout all or a significant portion of its range) or
a threatened species (likely to become endangered in the foreseeable
future throughout all or a significant portion of its range). If we
determine that a species warrants listing, we must list the species
promptly and designate the species' critical habitat to the maximum
extent prudent and determinable. We have determined that the Northern
DPS of the lesser prairie-chicken meets the definition of a threatened
species and that the Southern DPS of the lesser prairie-chicken meets
the definition of an endangered species; therefore, we are listing them
as such and finalizing a rule under section 4(d) of the Act for the
Northern DPS. Listing a species as an endangered or threatened species
can be completed only by issuing a rule through the Administrative
Procedure Act's rulemaking process.
What this document does. This rule revises the regulations in title
50 of the Code of Federal Regulations to list the Northern DPS of the
lesser prairie-chicken as a threatened species with a rule under
section 4(d) of the Act and the Southern DPS of the lesser prairie-
chicken as an endangered species under the Act.
The basis for our action. Under the Act, we may determine that a
species is an endangered or threatened species because of any of five
factors: (A) The present or threatened destruction, modification, or
curtailment of its habitat or range; (B) overutilization for
commercial, recreational, scientific, or educational purposes; (C)
disease or predation; (D) the inadequacy of existing regulatory
mechanisms; or (E) other natural or manmade factors affecting its
continued existence. We have determined that both the northern and
southern parts of the lesser prairie-chicken's range are discrete and
significant under our DPS Policy and are, therefore, listable entities
under the Act. The Southern DPS includes the Shinnery Oak Ecoregion in
New Mexico and Texas, and the Northern DPS includes the Sand Sagebrush
Ecoregion, the Mixed-Grass Ecoregion, and the Short-Grass/Conservation
Reserve Program (CRP) Ecoregion in Texas, Oklahoma, Colorado, and
Kansas. These two DPSs together encompass the entirety of the lesser
prairie-chicken's range. The primary threat impacting both DPSs is the
ongoing loss of large, connected blocks of grassland and shrubland
habitat. The Southern DPS has low resiliency, redundancy, and
representation and is particularly vulnerable to severe droughts due to
being located in the dryer and hotter southwestern portion of the
range. Because the Southern DPS is currently at risk of extinction, we
are listing it as endangered.
In the Northern DPS, as a result of habitat loss and fragmentation,
resiliency has been much reduced across two of the ecoregions in the
Northern DPS when compared to historical conditions. However, this DPS
still has redundancy across the three ecoregions and genetic and
environmental representation. We expect habitat loss and fragmentation
across the Northern DPS to continue into the foreseeable future,
resulting in even further reduced resiliency. Because the Northern DPS
is at risk of extinction in the foreseeable future, we are listing it
as threatened. The section 4(d) rule for the Northern DPS of the lesser
prairie-chicken generally prohibits the same activities as prohibited
for an endangered species. It includes exceptions from take associated
with continuation of routine agricultural practices on existing
cultivated lands, implementation of prescribed fire for the purposes of
grassland management, and implementation of prescribed grazing
following a grazing management plan developed by a Service-approved
party.
List of Acronyms
We use many acronyms in this rule. For the convenience of the
reader, we define some of them here:
ACEC = Area of Critical Environmental Concern
BLM = Bureau of Land Management
CI = confidence interval
CCAA = candidate conservation agreement with assurances
CCA/CCAA = candidate conservation agreement and candidate
conservation agreement with assurances
CDL = Cropland Data Layer
CHAT = Crucial Habitat Assessment Tool
CPW = Colorado Parks and Wildlife
CRP = Conservation Reserve Program
DOE = Department of Energy
DPS = Distinct Population Segment
EOR = Estimated occupied range
EOR+10 = Estimated occupied range plus a 10-mile buffer
FSA = U.S. Department of Agriculture's Farm Services Agency
KDWP = Kansas Department of Wildlife and Parks (formerly KDWPT:
Kansas Department of Wildlife, Parks, and Tourism)
LPCI = Lesser Prairie-Chicken Initiative
NRCS = Natural Resources Conservation Service
ODWC = Oklahoma Department of Wildlife Conservation
[[Page 72675]]
PECE = Policy for the Evaluation of Conservation Efforts when Making
Listing Decisions
PFW = the Service's Partners for Fish and Wildlife Program
RMPA = Resource Management Plan Amendment
RWP = Lesser Prairie-Chicken Range-wide Conservation Plan
SSA = Species Status Assessment
TPWD = Texas Parks and Wildlife Department
USDA = U.S. Department of Agriculture
USFS = U.S. Forest Service
WAFWA = Western Association of Fish and Wildlife Agencies
LWEG = Land-Based Wind Energy Guidelines
Previous Federal Actions
Please refer to the proposed listing rule for the Northern DPS and
the Southern DPS of the lesser prairie-chicken for a detailed
description of previous Federal actions concerning this species (86 FR
29432, June 1, 2021).
Summary of Changes From the Proposed Rule
Based upon our review of the public comments, State agency
comments, peer review comments, and relevant information that became
available since the proposed rule published, we updated information in
our species status assessment report, including:
<bullet> adding references on the effects of overhead power lines,
<bullet> adding a discussion regarding the effects from competition
with ring-necked pheasants,
<bullet> updating monitoring information related to the
translocation efforts in the Sand Sagebrush Ecoregion,
<bullet> updating information related to conservation banks,
<bullet> updating information related to previous conservation
efforts,
<bullet> adding discussion regarding the Southern Plains Grassland
Program,
<bullet> updating information related to the recent purchase by the
New Mexico Department of Game and Fish of additional lands to be
managed for the lesser prairie-chicken, and
<bullet> updating current population abundance information using
the 2021 aerial survey results.
We also made changes as appropriate in this final rule. In addition
to minor clarifying edits and incorporation of additional information
on the species' biology, populations, and threats, this determination
differs from the proposal in the following ways:
(1) We included updated population trend data, including survey
data made available since the publication of the proposed rule. Some of
these population survey results became available after we finalized the
SSA report. Thus, though the SSA report does not include those results,
we have added them to this final rule and fully considered them in our
determinations on the status of the two DPSs.
(2) We included new and updated conservation actions as submitted
by commenters during the open comment period.
(3) Based on public comments, we expanded our Significant Portion
of the Range analysis to explain why the Sand Sagebrush Ecoregion is
not significant.
(4) Based on comments received from State agencies, local
governments, industry groups, and private citizens, we have updated the
section 4(d) rule to include one new exception from the section 9 take
prohibitions:
The new exception is for take incidental to grazing management when
land managers are following a site-specific grazing plan developed by a
party that has been approved by the Service. When livestock grazing is
managed in ways that are compatible with promoting the maintenance of
the vegetative characteristics needed by the lesser prairie-chicken,
this activity can be an invaluable tool necessary for managing healthy
grasslands benefiting the lesser prairie-chicken. Therefore, we
consider this new exception from prohibitions to be necessary and
advisable to the conservation of the species.
Supporting Documents
A species status assessment (SSA) team prepared an SSA report for
the lesser prairie-chicken. The SSA team was composed of Service
biologists in consultation with other species experts. The SSA report
represents a compilation of the best scientific and commercial data
available concerning the status of the species, including the impacts
of past, present, and future factors (both negative and beneficial)
affecting the species. In accordance with our joint policy on peer
review published in the Federal Register on July 1, 1994 (59 FR 34270),
and our August 22, 2016, memorandum updating and clarifying the role of
peer review of listing actions under the Act, we sought the expert
opinions of six appropriate specialists regarding the SSA. We received
four responses. We also sent the SSA report to the five State fish and
wildlife agencies within the range of the lesser prairie-chicken
(Colorado, Kansas, New Mexico, Oklahoma, and Texas) and the four
primary Federal agencies with whom we work to deliver conservation
actions that could benefit the lesser prairie-chicken: the Bureau of
Land Management (BLM) the U.S. Department of Agriculture's Natural
Resources Conservation Service (NRCS), Farm Service Agency (FSA), and
U.S. Forest Service (USFS). These partners include scientists with
expertise in management of either the lesser prairie-chicken or the
habitat upon which the lesser prairie-chicken depends. We received
responses from USFS, BLM, and all five of the State wildlife agencies.
Comments and feedback from partners and peer reviewers were
incorporated into the SSA report as appropriate and have informed this
final rule.
I. Final Listing Determination
Background
Below is a summary of the taxonomy, life history, and ecology of
the lesser prairie-chicken; for a thorough review, please see the SSA
report (version 2.3; Service 2022, pp. 5-14).
The lesser prairie-chicken is in the order Galliformes, family
Phasianidae, subfamily Tetraoninae; it is generally recognized as a
species separate from the greater prairie-chicken (Tympanuchus cupido
pinnatus) (Jones 1964, pp. 65-73; American Ornithologist's Union 1998,
p. 122).
Most lesser prairie-chicken adults live for 2 to 3 years and
reproduce in the spring and summer (Service 2022, pp. 10-12). Males
congregate on leks during the spring to attract and mate with females
(Copelin 1963, p. 26; Hoffman 1963, p. 730; Crawford and Bolen 1975, p.
810; Davis et al. 1979, p. 84; Merchant 1982, p. 41; Haukos 1988, p.
49). Male prairie-chickens tend to exhibit strong breeding site
fidelity, often returning to a specific lek many times, even in cases
of declining female attendance and habitat condition (Copelin 1963, pp.
29-30; Hoffman 1963, p. 731; Campbell 1972, pp. 698-699, Hagen et al.
2005, entire, Harju et al. 2010, entire). Females tend to establish
nests relatively close to the lek, commonly within 0.6 to 2.4 mile (mi)
(1 to 4 kilometers (km)) (Copelin 1963, p. 44; Giesen 1994, p. 97),
where they incubate 8 to 14 eggs for 24 to 27 days and then raise
broods of young throughout the summer (Boal and Haukos 2016, p. 4).
Some females will attempt a second nesting if the first nest fails
(Johnsgard 1973, pp. 63-64; Merchant 1982, p. 43; Pitman et al. 2006,
p. 25). Eggs and young lesser prairie-chickens are susceptible to
natural mortality from environmental stress and predation. The
appropriate vegetative community and structure is vital to provide
cover for nests and young and to provide food resources as broods
mature into adults (Suminski 1977, p. 32; Riley 1978, p. 36; Riley et
[[Page 72676]]
al. 1992, p. 386; Giesen 1998, p. 9). For more detail on habitat needs
of the lesser prairie-chicken, please see the SSA report (Service 2022,
pp. 9-14).
The lesser prairie-chicken once ranged across the Southern Great
Plains of Southeastern Colorado, Southwestern Kansas, Western Oklahoma,
the Panhandle and South Plains of Texas, and Eastern New Mexico;
currently, it occupies a substantially reduced portion of its presumed
historical range (Rodgers 2016, p. 15). Estimates of the potential
maximum historical range of the lesser prairie-chicken (e.g., Taylor
and Guthery 1980a, p. 1, based on Aldrich 1963, p. 537; Johnsgard 2002,
p. 32; Playa Lakes Joint Venture 2007, p. 1) range from about 64-115
million acres (ac) (26-47 million hectares (ha)). The more recent
estimate of the historical range of the lesser prairie-chicken
encompasses an area of approximately 115 million ac (47 million ha).
Presumably, not all of the area within this historical range was evenly
occupied by lesser prairie-chicken, and some of the area may not have
been suitable to regularly support lesser prairie-chicken populations
(Boal and Haukos 2016, p. 6). However, the current range of the lesser
prairie-chicken has been significantly reduced from the historical
range at the time of European settlement. Estimates as to the extent of
the loss vary from greater than 90 percent reduction (Hagen and Giesen
2005, unpaginated) to approximately 83 percent reduction (Van Pelt et
al. 2013, p. 3).
Lesser prairie-chicken monitoring has been occurring for multiple
decades and has included multiple different methodologies. Estimates of
population abundance prior to the 1960s are indeterminable and rely
almost entirely on anecdotal information (Boal and Haukos 2016, p. 6).
While little is known about precise historical population sizes, the
lesser prairie-chicken was reported to be quite common throughout its
range in the early 20th century (Bent 1932, pp. 280-281, 283; Baker
1953, p. 8; Bailey and Niedrach 1965, p. 51; Sands 1968, p. 454;
Fleharty 1995, pp. 38-44; Robb and Schroeder 2005, p. 13). For example,
prior to 1900, as many as two million birds may have existed in Texas
alone (Litton 1978, p. 1). Information regarding population size is
available starting in the 1960s when the State fish and wildlife
agencies began routine lesser prairie-chicken monitoring efforts.
However, survey methodology and effort have differed over the decades,
making it difficult to precisely estimate trends.
The SSA report and this final rule rely on two main population
estimates. The two methodologies largely cover different time periods,
so we report the results of both throughout this final rule in order to
give the best possible understanding of lesser prairie-chicken trends
both recently and throughout the past decades.
The first of the two studies used historical lek surveys and
population reconstruction methods to calculate historical trends and
estimate male abundance from 1965 through 2016 (Hagen et al. (2017, pp.
6-9). We have concerns with some of the methodologies and assumptions
made in this analysis including survey effort prior to the 1970s,
variation in survey efforts between States, and completeness and
accuracy of source data used. Others have also noted the challenges of
using these data for long-term trends (for example, Zavaleta and Haukos
2013, p. 545; Cummings et al. 2017, pp. 29-30). While these concerns
remain, including the very low sample sizes particularly in the 1960s,
this work represents the only attempt to compile the historical ground
lek count data collected by State agencies to estimate the number of
males at both the range-wide and ecoregional scales, and represents the
best available data for understanding historical population trends.
Following development of aerial survey methods (McRoberts et al.
2011, entire), the second summary of lesser prairie-chicken population
data uses more statistically rigorous estimates of lesser prairie-
chicken abundance (both males and females). This study was designed to
address the shortcomings and limitations associated with ground-based
survey efforts as discussed above. This second study uses data from
aerial line-transect surveys throughout the range of the lesser
prairie-chicken; these results are then extrapolated from the surveyed
area to the rest of the range (Nasman et al. 2022, entire). The results
of these survey efforts should not be taken as precise estimates of the
annual lesser prairie-chicken abundance, as indicated by the large
confidence intervals associated with these estimates. The confidence
intervals are a calculation related to the degree of certainty or
uncertainty that the sampling method results in estimates that
represent the true population abundance.
Due to the lack of confidence in the precision of these population
estimates as reflected by the large confidence intervals, conclusions
regarding current population sizes or population changes should not be
drawn based upon annual fluctuations. In addition to the large
confidence intervals, the lesser prairie-chicken is considered a
``boom-bust'' species with a high degree of annual variation in rates
of successful reproduction and recruitment. These annual and short-term
patterns are largely driven by the influence of seasonal precipitation
patterns. Periods of below-average precipitation and higher spring/
summer temperatures cause less suitable grassland vegetation cover and
less food available, resulting in decreased reproductive output (bust
periods). Periods with above-normal precipitation and cooler spring/
summer temperatures will support favorable habitat conditions and
result in higher reproductive success (boom periods). Thus, annual
population changes are not a measure of population health but instead
largely represent the influence of short-term precipitation cycles
whereas long-term population trends are tied to habitat availability.
Instead of reporting the annual estimates, the best use of this data is
for long-term trend analysis. Thus, in the SSA report and this final
rule, we report the population estimate for the current condition as
the average of the past 5 years of surveys.
The results of the study using ground-based lek data (abundance of
males) indicate that lesser prairie-chicken range-wide abundance (based
on a minimum estimated number of male lesser prairie-chickens at leks)
peaked during 1965-1970 at a mean estimate of about 175,000 males
(figure 1). The estimated mean population maintained levels of greater
than 100,000 males until 1989, after which the population steadily
declined to a low of 25,000 males in 1997 (Garton et al. 2016, p. 68).
The mean population estimates following 1997 peaked again at about
92,000 males in 2006, albeit at a significantly lower value than the
prior peak of 175,000. The mean population estimate subsequently
declined to 34,440 males in 2012 (figure 1).
The aerial survey results from 2012 through 2022 (figure 2)
estimated the lesser prairie-chicken population abundance, averaged
over the most recent 5 years of surveys (2017-2022, no surveys in
2019), at 32,210 (including males and females; 90 percent confidence
interval: 11,489, 64,303) (Nasman et al. 2022, p. 16; table 10).
[[Page 72677]]
[GRAPHIC] [TIFF OMITTED] TR25NO22.029
The preferred habitat of the lesser prairie-chicken is mixed-grass
prairies and shrublands, with the exception of some areas in the
northern extent of the range where shrubs play a lesser role. Lesser
prairie-chickens appear to select areas having a shrub component
dominated by sand sagebrush or sand shinnery oak when those areas are
available (Donaldson 1969, pp. 56, 62; Taylor and Guthery 1980a, p. 6;
Giesen 1998, pp. 3-4). In the southern and central portions of the
lesser prairie-chicken range, small shrubs, such as sand shinnery oak,
are important for summer shade (Copelin 1963, p. 37; Donaldson 1969,
pp. 44-45, 62), winter protection, and as supplemental foods (Johnsgard
1979, p. 112). In some areas in the northern extent of the species'
range, stands of grass that provide adequate vegetative structure
likely serve the same roles. The absence of anthropogenic features as
well as other vertical structures is important, as lesser prairie-
chickens tend to avoid using areas with trees, vertical structures, and
other disturbances in areas with otherwise adequate habitat conditions
(Braun et al. 2002, pp. 11-13; Pruett et al. 2009, pp. 1256, 1258;
Hovick et al. 2014a, p. 1685; Boggie et al. 2017, entire; Lautenbach
2017, pp. 104-142; Plumb et al. 2019, entire).
At the population scale, the most important requirement for the
lesser prairie-chicken is having large, intact, ecologically diverse
grasslands to complete their life history and maintain healthy
populations (Fuhlendorf et al. 2017b, entire). As detailed in chapter 2
of the SSA report, the lesser prairie-chicken requires large
ecologically diverse grasslands to meet specific resource needs, in
terms of microhabitat conditions, which vary to some degree by life
stage and activity (Service 2022, pp. 10-11). Historically, these
ecologically diverse grasslands and shrublands were maintained by the
occurrence of wildfires (keeping woody vegetation restricted to
drainages and rocky outcroppings) and by grazing by bison and other
large ungulates. The lesser prairie-chicken is a species that requires
large, intact grasslands for functional self-sustaining populations
(Giesen 1998, pp. 3-4; Bidwell et al. 2002, pp. 1-3; Hagen et al. 2004,
pp. 71, 76-77; Haukos and Zavaleta 2016, p. 107).
The lesser prairie-chicken now occurs within four ecoregions
(figure 3); these ecoregions were originally delineated in 2012 as part
of the aerial survey designed to monitor long-term trends in lesser
prairie-chicken populations. Each ecoregion is associated with unique
environmental conditions based on habitat and climatic variables and
some genetic differentiation (Boal and Haukos 2016, p. 5; Oyler-McCance
et al. 2016, p. 653). These four ecoregions are the Short-Grass
Prairie/CRP Ecoregion in Kansas; the Sand Sagebrush Prairie Ecoregion
in Colorado, Kansas, and Oklahoma; the Mixed-Grass Prairie Ecoregion in
Kansas, Texas, and Oklahoma; and the Shinnery Oak Prairie Ecoregion of
New Mexico and Texas.
[[Page 72678]]
[GRAPHIC] [TIFF OMITTED] TR25NO22.030
The Shinnery Oak Ecoregion occupies portions of eastern New Mexico
and the South Plains of Texas (McDonald et al. 2012, p. 2). It has a
variable vegetation community that contains a mix of shrubs such as
sand shinnery oak (Quercus havardii) and sand sagebrush (Artemisia
filifolia) as well as mixed and tall grasses and forbs (Grisham et al.
2016a, p. 317). The mean population estimate ranged between about 5,000
to 12,000 males through 1980, increased to 20,000 males in the mid-
1980s and declined to ~1,000 males in 1997 (Hagen et al. 2017, pp. 6-
9). The mean population estimate peaked again to ~15,000 males in 2006
and then declined again to fewer than 3,000 males in the mid-2010s.
While population estimates for the Shinnery Oak Ecoregion have varied
over recent years, the most recent surveys estimate a 5-year average
population size of 2,806 birds (including males and females; 90 percent
confidence intervals (CI): 179, 9,007). Approximately 9 percent of all
lesser prairie-chicken occur in this ecoregion. Lesser prairie-chickens
from the Shinnery Oak Ecoregion are genetically distinct and
geographically isolated from the other three ecoregions by 95 mi (153
km) (figure 3; Oyler-McCance et al. 2016, p. 653). Historically, the
Shinnery Oak Ecoregion was likely connected to the rest of the lesser
prairie-chicken range but as a result of habitat loss and fragmentation
from European settlement the lesser prairie-chicken in the Shinnery Oak
Ecoregion have likely been isolated for over a century (Oyler-McCance
et al. 2016, p. 655).
In New Mexico, the majority of the Shinnery Oak Ecoregion is
privately owned (Grisham et al. 2016a, p. 315), with some portions
owned by the State Game Commission and federally owned BLM lands.
Nearly all of the area in the Texas portion of the ecoregion is
privately owned and managed for agricultural use and petroleum
production (Haukos 2011, p. 110). The remaining patches of shinnery oak
prairie have become isolated, relict communities because the
surrounding grasslands have been converted to row crop agriculture or
fragmented by oil and gas exploration and urban development (Peterson
and Boyd 1998, p. 22). Additionally, honey mesquite (Prosopis
glandulosa) encroachment within this ecoregion has played a significant
role in decreasing available space for the lesser prairie-chicken.
Technological advances in irrigated row crop agriculture have led to
more recent conversion of shinnery oak prairie habitat to row crops in
Eastern New Mexico and West Texas (Grisham et al. 2016a, p. 316).
[[Page 72679]]
The Sand Sagebrush Ecoregion occurs in Southeast Colorado,
Southwest Kansas, and a small portion of Western Oklahoma (McDonald et
al. 2012, p. 2). The vegetation community in this area primarily
consists of sand sagebrush and the associated mixed and tall grass
species that are usually found in the sandier soils adjacent to rivers,
streams, and other drainages in the area. Lesser prairie-chicken from
the Sand Sagebrush Ecoregion show some genetic differentiation from
other ecoregions but have likely contributed some individuals to the
Short-Grass/CRP Ecoregion through dispersal (Oyler-McCance et al. 2016,
p. 653).
Historically, the Sand Sagebrush Ecoregion supported the highest
density of lesser prairie-chicken and was considered the core of the
lesser prairie-chicken range (Haukos et al. 2016, p. 282). A single
flock detected in Seward County, Kansas, was estimated to contain more
than 15,000 birds (Bent 1932, p. 281). The population size is estimated
to have peaked at more than 85,000 males in the 1970s (Garton et al.
2016, p. 62). More recent survey efforts estimate a 5-year average
population size of 1,297 birds (including males and females; 90 percent
CI: 56, 4,881; Nasman et al. 2022, p. 16). Less than 5 percent of all
lesser prairie-chicken occur in this ecoregion (Service 2022, pp. 64-
78). Most of the decline has been attributed to habitat deterioration
and conversion of sand sagebrush to intensive row crop agriculture due
to an increase in center pivot irrigation (Jensen et al. 2000, p. 172).
Environmental conditions in this ecoregion can be extreme, with
stochastic events such as blizzards negatively impacting lesser
prairie-chicken populations.
The Short-Grass/CRP Ecoregion falls within the mixed- and short-
grass prairies of Central and Western Kansas (McDonald et al. 2012, p.
2). As the name implies, much of this ecoregion historically consisted
of short-grass prairie interspersed with mixed-grass prairie as well as
sand sagebrush prairie along some drainages (Dahlgren et al. 2016, p.
260). By the 1980s, large expanses of prairies had been converted from
native grass for crop production in this ecoregion. After the
introduction of the CRP in 1985, landowners began to have enhanced
incentives to convert croplands to perennial grasslands to provide
cover for the prevention of soil erosion. The State of Kansas required
those enrolling in the CRP to plant native mixed- and tall-grass
species, which is notable because the grasses in this area historically
consisted largely of short-grass species, which generally do not
provide adequate habitat for the lesser prairie-chicken. For more
information on the CRP, see the SSA report (Service 2022, pp. 52-54).
Prior to the late 1990s, lesser prairie-chickens in this ecoregion
were thought to be largely absent (or occurred sporadically in low
densities) (Hagen and Giesen 2005, unpaginated; Rodgers 1999, p. 19).
We do not know what proportion of the eastern Short-Grass/CRP Ecoregion
in Kansas was historically occupied by lesser prairie-chicken (Hagen
2003, pp. 3-4), and surveys in this ecoregion only began in earnest in
1999 (Dahlgren et al. 2016, p. 262). The CRP is an idle lands program,
which requires establishment of grass cover and precludes tillage or
agricultural commodity production for the duration of the contract, and
has contractual limits to the type, frequency, and timing of management
activities, such as burning, haying, or grazing of the established
grasses. As a result of these factors, CRP often provides the
vegetative structure preferentially used by lesser prairie-chickens for
nesting. In the State of Kansas, the availability of CRP lands,
especially CRP lands with interseeded or original seed mixture of
forbs, resulted in increased habitat availability for the lesser
prairie-chicken and, thus, an expansion of the known lesser prairie-
chicken range and an increase in the abundance of the lesser prairie-
chicken (Rodgers 1999, pp. 18-19; Fields 2004, pp. 11, 105; Fields et
al. 2006, pp. 931, 937; Sullins et al. 2018, p. 1617).
The Short-Grass/CRP Ecoregion is now estimated to contain the
majority of lesser prairie-chickens compared to the other ecoregions,
with recent survey efforts estimating a 5-year average population size
of 23,083 birds (including males and females; 90 percent CI: 9,653,
39,934), representing approximately 72 percent of the rangewide
population. Recent genetic studies indicate that lesser prairie-
chickens have moved northward largely from the Mixed-Grass Ecoregion
and, to a lesser extent, the Sand Sagebrush Ecoregion into the Short-
Grass/CRP Ecoregion (Oyler-McCance et al. 2016, p. 653).
The northern section of this ecoregion is the only portion of the
lesser prairie-chicken's range where co-occurrence with greater
prairie-chicken occurs. Hybridization rates of up to 5 percent have
been reported (Pitman 2013, p. 5), and that rate seemed to be stable
across multiple years, though sampling is limited where the species co-
occur (Pitman 2013, p. 12). Limited additional work has been completed
to further assess the rate of hybridization. There are concerns about
the implications of genetic introgression (dilution) of lesser prairie-
chicken genes, particularly given that potential effects are poorly
understood (Dahlgren et al. 2016, p. 276). Unresolved issues include
whether hybridization reduces fitness and alters behavior or
morphological traits in either a positive or negative way and the
historical occurrence and rate of hybridization.
The Mixed-Grass Ecoregion for the lesser prairie-chicken lies in
the northeastern panhandle of Texas, the panhandle of northwestern
Oklahoma, and south-central Kansas (McDonald et al. 2012, p. 2). The
Mixed-Grass Ecoregion is separated from the Short-Grass/CRP Ecoregion
in Kansas by the Arkansas River. The vegetation community in this
ecoregion consists largely of a mix of perennial grasses and shrubs
such as sand sagebrush, sand plum (Prunus angustifolia), yucca (Yucca
spp.), and sand shinnery oak (Wolfe et al. 2016, p. 300). Based upon
population reconstruction data, the mean population estimate was around
30,000 males in the 1970s and 1980s followed by a decline in the 1990s
(Hagen et al. 2016, pp. 6-7). The mean population estimate peaked again
in the early 2000s at around 25,000 males, before declining to and
remaining at its lowest levels, less than 10,000 males since 2012
(Hagen et al. 2016, pp. 6-7). Although historical population estimates
in the ecoregion reported some of the highest densities of lesser
prairie-chicken in the range (Wolfe et al. 2016, p. 299), recent aerial
survey efforts estimate a 5-year average population size of 5,024 birds
(including males and females; 90 percent CI: 1,601, 10,481). The recent
survey work indicates that about 15 percent of lesser prairie-chicken
occur in this ecoregion. Lesser prairie-chicken from the Mixed-Grass
Ecoregion are similar in genetic variation with the Short-Grass/CRP
Ecoregion, with individuals likely dispersing from the Mixed-Grass
Ecoregion to the Short-Grass/CRP Ecoregion (Oyler-McCance et al. 2016,
p. 653).
Distinct Population Segment Evaluation
Under the Act, the term ``species'' includes ``any subspecies of
fish or wildlife or plants, and any distinct population segment of any
species of vertebrate fish or wildlife which interbreeds when mature.''
16 U.S.C. 1532(16). To guide the implementation of the distinct
population segment (DPS) provisions of the Act, we and the National
Marine Fisheries Service (National Oceanic and Atmospheric
Administration--Fisheries), published
[[Page 72680]]
the Policy Regarding the Recognition of Distinct Vertebrate Population
Segments Under the Endangered Species Act (DPS Policy) in the Federal
Register on February 7, 1996 (61 FR 4722). Under our DPS Policy, we use
two elements to assess whether a population segment under consideration
for listing may be recognized as a DPS: (1) The population segment's
discreteness from the remainder of the species to which it belongs, and
(2) the significance of the population segment to the species to which
it belongs. If we determine that a population segment being considered
for listing is a DPS, then the population segment's conservation status
is evaluated based on the five listing factors established by the Act
to determine if listing it as either endangered or threatened is
warranted.
As described in Previous Federal Actions, we were petitioned to
list the lesser prairie-chicken either rangewide or in three distinct
population segments. The petition suggested three DPS configurations:
(1) Shinnery Oak Ecoregion, (2) the Sand Sagebrush Ecoregion, and (3) a
segment including the Mixed-Grass Ecoregion and the Short-Grass/CRP
Ecoregion. The petition combined the Mixed-Grass Ecoregion and the
Short-Grass/CRP Ecoregion due to evidence they are linked genetically
and geographically (Molver 2016, p. 18). Genetic studies indicate that
lesser prairie-chicken from the Mixed-Grass Ecoregion are similar in
genetic variation with the Short-Grass/CRP Ecoregion, with individuals
likely dispersing from the Mixed-Grass Ecoregion to the Short-Grass/CRP
Ecoregion (Oyler-McCance et al. 2016, p. 653). Other genetic data
indicate that lesser prairie-chicken from the Sand Sagebrush Ecoregion
and lesser prairie-chicken from the Mixed-Grass and Short-Grass/CRP
Ecoregion also share genetic traits. Genetic studies of neutral markers
indicate that, although lesser prairie-chicken from the Sand Sagebrush
Ecoregion form a distinct genetic cluster from other ecoregions, they
have also likely contributed some individuals to the Short-Grass/CRP
Ecoregion through dispersal (Oyler-McCance et al. 2016, p. 653).
Additionally, these three ecoregions are not geographically isolated
from one another (figure 3). As a result of the shared genetic
characteristics and the geographic connections, we have concluded a
``Northern'' population segment of the species that includes the Sand
Sagebrush Ecoregion, the Mixed-Grass Ecoregion, and the Short-Grass/CRP
Ecoregion is appropriately considered a potential DPS configuration.
Under the Act, we have the authority to consider for listing any
species, subspecies, or, for vertebrates, any distinct population
segment (DPS) of these taxa if there is sufficient information to
indicate that such action may be warranted. We considered whether two
segments meet the DPS criteria under the Act: a ``Southern'' population
segment, including the southernmost ecoregion (Shinnery Oak), and a
``Northern'' population segment, including the three northernmost
ecoregions (Mixed-Grass, Short-Grass/CRP, and Sand Sagebrush).
Discreteness
Under our DPS Policy, a population segment of a vertebrate taxon
may be considered discrete if it satisfies either of the following
conditions: (1) It is markedly separated from other populations of the
same taxon as a consequence of physical, physiological, ecological, or
behavioral factors (Quantitative measures of genetic or morphological
discontinuity may provide evidence of this separation.); or (2) it is
delimited by international governmental boundaries within which
differences in control of exploitation, management of habitat,
conservation status, or regulatory mechanisms exist that are
significant in light of section 4(a)(1)(D) of the Act.
We conclude the two segments satisfy the ``markedly separate''
condition. The two segments are not separated from each other by
international governmental boundaries. The southern population segment
(which includes the Shinnery Oak ecoregion) is separated from the
northern population segment (which includes the three northern
ecoregions) by approximately 95 mi (153 km). Most of this separation
between the two segments is developed or otherwise unsuitable habitat.
There has been no recorded movement of lesser prairie-chickens between
the Shinnery Oak Ecoregion and the three northern ecoregions over the
past several decades. Because there is no connection between the two
population segments, there is subsequently no gene flow between them
(Oyler-McCance et al. 2016, entire).
Therefore, we have determined that both a southern segment and a
northern segment of the lesser prairie-chicken range both individually
meet the condition for discreteness under our DPS Policy.
Significance
Under our DPS Policy, once we have determined that a population
segment is discrete, we consider its biological and ecological
significance to the larger taxon to which it belongs. This
consideration may include, but is not limited to: (1) Evidence of the
persistence of the discrete population segment in an ecological setting
that is unusual or unique for the taxon, (2) evidence that loss of the
population segment would result in a significant gap in the range of
the taxon, (3) evidence that the population segment represents the only
surviving natural occurrence of a taxon that may be more abundant
elsewhere as an introduced population outside its historical range, or
(4) evidence that the discrete population segment differs markedly from
other populations of the species in its genetic characteristics.
For the lesser prairie-chicken, we first considered evidence that
the Shinnery Oak Ecoregion population segment differs markedly from the
other populations of the species, i.e., the ecoregions that constitute
the Northern population segment (Mixed-Grass Ecoregion, Short-Grass/CRP
Ecoregion, and Sand Sagebrush Ecoregion) in its genetic
characteristics. The most recent rangewide genetic study examined
neutral markers in the four ecoregions where the lesser prairie-chicken
occurs. It concluded that there is significant genetic variation across
the lesser prairie-chicken range. The study also concluded that
although there is genetic exchange between the three northern
ecoregions (particularly movement of birds northward from the Mixed-
Grass Ecoregion to the Short-Grass/CRP Ecoregion, and, to a lesser
extent, from the Sand Sagebrush Ecoregion into the Short-Grass/CRP
Ecoregion), lesser prairie-chicken from the Shinnery Oak Ecoregion that
make up the southern population segment) are a group that is
genetically distinct from the remainder of the range, i.e., the
northern population segment (Oyler-McCance et al. 2016, p. 653). The
Shinnery Oak Ecoregion is more distinct from all three ecoregions in
the Northern population segment than those ecoregions are from each
other (Oyler-McCance et al. 2016, table 4). The Shinnery Oak Ecoregion
was likely historically connected to the remainder of the range, but
the two parts have been separated since approximately the time of
European settlement. Therefore, the two segments of the range are
genetically distinct from each other and therefore significant to the
taxon as a whole.
We next considered evidence that loss of the population segment
would result in a significant gap in the range of the taxon. As
discussed above, the southern population segment and the northern
[[Page 72681]]
population segment are separated by approximately 95 mi (153 km). The
loss of the Shinnery Oak Ecoregion would result in the loss of the
entire southern part of the species' range and decrease species
redundancy and ecological and genetic representation, thus decreasing
its ability to withstand demographic and environmental stochasticity.
The loss of the other three ecoregions would result in the loss of 75
percent of the species' range, as well as loss of the part of the range
(the Short-Grass/CRP Ecoregion) that has recently experienced an
expansion of occupied habitat. This would create a large gap in the
northern portion of the species' range, also reducing the species'
ability to withstand demographic and environmental stochasticity.
Therefore, the loss of either part of the range would result in a
significant gap in the range of the lesser prairie-chicken. These
genetic differences and the evidence that a significant gap in the
range of the taxon would result from the loss of either discrete
population segment both individually satisfy the significance criterion
of the DPS Policy. Therefore, under the Service's DPS Policy, we find
that both the southern and northern segments of the lesser prairie-
chicken are significant to the taxon as a whole.
Distinct Population Segment Conclusion
Our DPS Policy directs us to evaluate the significance of a
discrete population in the context of its biological and ecological
significance to the remainder of the species to which it belongs. Based
on an analysis of the best available scientific and commercial data, we
conclude that the northern and southern parts of the lesser prairie-
chicken range are discrete due to geographic (physical) isolation from
the remainder of the taxon. Furthermore, we conclude that both parts of
the lesser prairie-chicken range are significant, because loss of
either part would result in a significant gap in the range of the
taxon, and because the two parts of the range differ markedly from each
other based on neutral genetic markers. Therefore, we conclude that
both the northern and southern parts of the lesser prairie-chicken
range are both discrete and significant under our DPS Policy and are,
therefore, uniquely listable entities under the Act.
Based on our DPS Policy (61 FR 4722; February 7, 1996), if a
population segment of a vertebrate species is both discrete and
significant relative to the taxon as a whole (i.e., it is a distinct
population segment), its evaluation for endangered or threatened status
will be based on the Act's definition of those terms and a review of
the factors enumerated in section 4(a) of the Act. Having found that
both parts of the lesser prairie-chicken range meet the definition of a
distinct population segment, we evaluate the status of both the
Southern DPS and the Northern DPS of the lesser prairie-chicken to
determine whether either meets the definition of an endangered or
threatened species under the Act. The line demarcating the break
between the Northern and Southern DPS lies approximately halfway
between the two DPSs in the unoccupied area between them (figure 4).
[[Page 72682]]
[GRAPHIC] [TIFF OMITTED] TR25NO22.031
Regulatory and Analytical Framework
Regulatory Framework
Section 4 of the Act (16 U.S.C. 1533) and its implementing
regulations (50 CFR part 424) set forth the procedures for determining
whether a species is an endangered species or a threatened species,
issuing protective regulations for threatened species, and designating
critical habitat for threatened and endangered species. In 2019,
jointly with the National Marine Fisheries Service, the Service issued
final rules that revised the regulations in 50 CFR parts 17 and 424
regarding how we add, remove, and reclassify threatened and endangered
species and the criteria for designating listed species' critical
habitat (84 FR 45020 and 84 FR 44752; August 27, 2019). At the same
time the Service also issued final regulations that, for species listed
as threatened species after September 26, 2019, eliminated the
Service's general protective regulations automatically applying to
threatened species the prohibitions that section 9 of the Act applies
to endangered species (collectively, the 2019 regulations).
As with the proposed rule, we are applying the 2019 regulations for
this final rule because the 2019 regulations are currently in effect,
just as they were when we completed the proposed rule. Although there
was a period in the
[[Page 72683]]
interim--between July 5, 2022, and September 21, 2022--when the 2019
regulations became vacated and the pre-2019 regulations therefore
governed, the 2019 regulations are now in effect and govern listing and
critical habitat decisions (see Center for Biological Diversity v.
Haaland, No. 4:19-cv-05206-JST, Doc. 168 (N.D. Cal. July 5, 2022) (CBD
v. Haaland) (vacating the 2019 regulations and thereby reinstating the
pre-2019 regulations)) and In re: Cattlemen's Ass'n, No. 22-70194 (9th
Cir. Sept. 21, 2022) (staying the vacatur of the 2019 regulations and
thereby reinstating the 2019 regulations until a pending motion for
reconsideration before the district court is resolved)).
The Act defines an ``endangered species'' as a species that is in
danger of extinction throughout all or a significant portion of its
range, and a ``threatened species'' as a species that is likely to
become an endangered species within the foreseeable future throughout
all or a significant portion of its range. The Act requires that we
determine whether any species is an endangered species or a threatened
species because of any of the following factors:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
existence.
These factors represent broad categories of natural or human-caused
actions or conditions that could have an effect on a species' continued
existence. In evaluating these actions and conditions, we look for
those that may have a negative effect on individuals of the species, as
well as other actions or conditions that may ameliorate any negative
effects or may have positive effects.
We use the term ``threat'' to refer in general to actions or
conditions that are known to or are reasonably likely to negatively
affect individuals of a species. The term ``threat'' includes actions
or conditions that have a direct impact on individuals (direct
impacts), as well as those that affect individuals through alteration
of their habitat or required resources (stressors). The term ``threat''
may encompass--either together or separately--the source of the action
or condition or the action or condition itself.
However, the mere identification of any threat(s) does not
necessarily mean that the species meets the statutory definition of an
``endangered species'' or a ``threatened species.'' In determining
whether a species meets either definition, we must evaluate all
identified threats by considering the species' expected response and
the effects of the threats--in light of those actions and conditions
that will ameliorate the threats--on an individual, population, and
species level. We evaluate each threat and its expected effects on the
species, then analyze the cumulative effect of all of the threats on
the species as a whole. We also consider the cumulative effect of the
threats in light of those actions and conditions that will have
positive effects on the species, such as any existing regulatory
mechanisms or conservation efforts. The Secretary determines whether
the species meets the definition of an ``endangered species'' or a
``threatened species'' only after conducting this cumulative analysis
and describing the expected effect on the species now and in the
foreseeable future.
The Act does not define the term ``foreseeable future,'' which
appears in the statutory definition of ``threatened species.'' Our
implementing regulations at 50 CFR 424.11(d) set forth a framework for
evaluating the foreseeable future on a case-by-case basis. The term
``foreseeable future'' extends only so far into the future as we can
reasonably determine that both the future threats and the species'
responses to those threats are likely. In other words, the foreseeable
future is the period of time in which we can make reliable predictions.
``Reliable'' does not mean ``certain''; it means sufficient to provide
a reasonable degree of confidence in the prediction. Thus, a prediction
is reliable if it is reasonable to depend on it when making decisions.
It is not always possible or necessary to define foreseeable future
as a particular number of years. Analysis of the foreseeable future
uses the best scientific and commercial data available and should
consider the timeframes applicable to the relevant threats and to the
species' likely responses to those threats in view of its life-history
characteristics. Data that are typically relevant to assessing the
species' biological response include species-specific factors such as
lifespan, reproductive rates or productivity, certain behaviors, and
other demographic factors.
Analytical Framework
The SSA report documents the results of our comprehensive
biological review of the best scientific and commercial data regarding
the status of the species, including an assessment of the potential
threats to the species. The SSA report does not represent our decision
on whether the species should be listed as an endangered or threatened
species under the Act. However, it does provide the scientific basis
that informs our regulatory decisions, which involve the further
application of standards within the Act and its implementing
regulations and policies. The following is a summary of the key results
and conclusions from the SSA report; the full SSA report can be found
at Docket FWS-R2-ES-2021-0015 on <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
To assess lesser prairie-chicken viability, we used the three
conservation biology principles of resiliency, redundancy, and
representation (Shaffer and Stein 2000, pp. 306-310). Briefly,
resiliency supports the ability of the species to withstand
environmental and demographic stochasticity (for example, wet or dry,
warm or cold years), redundancy supports the ability of the species to
withstand catastrophic events (for example, droughts, large pollution
events), and representation supports the ability of the species to
adapt over time to long-term changes in the environment (for example,
climate changes). In general, the more resilient and redundant a
species is and the more representation it has, the more likely it is to
sustain populations over time, even under changing environmental
conditions. Using these principles, we identified the species'
ecological requirements for survival and reproduction at the
individual, population, and species levels, and described the
beneficial and risk factors influencing the species' viability.
The SSA process can be categorized into three sequential stages.
During the first stage, we evaluated the individual species' life-
history needs. The next stage involved an assessment of the historical
and current condition of the species' demographics and habitat
characteristics, including an explanation of how the species arrived at
its current condition. The final stage of the SSA involved making
predictions about the species' responses to positive and negative
environmental and anthropogenic influences. Throughout all of these
stages, we used the best available information to characterize
viability as the ability of a species to sustain populations in the
wild over time. We use this information to inform our regulatory
decision.
Summary of Biological Status and Threats
In this discussion, we review the biological condition of the
species and
[[Page 72684]]
its resources, and the threats that influence the species' current and
future condition, in order to assess the species' overall viability and
the risks to that viability.
We note that, by using the SSA framework to guide our analysis of
the scientific information documented in the SSA report, we have not
only analyzed individual effects on the species, but we have also
analyzed their potential cumulative effects. We incorporate the
cumulative effects into our SSA analysis when we characterize the
current and future condition of the species. To assess the current and
future condition of the species, we undertake an iterative analysis
that encompasses and incorporates the threats individually and then
accumulates and evaluates the effects of all the factors that may be
influencing the species, including threats and conservation efforts.
Because the SSA framework considers not just the presence of the
factors, but to what degree they collectively influence risk to the
entire species, our assessment integrates the cumulative effects of the
factors and replaces a standalone cumulative effects analysis.
Representation
To evaluate representation as a component of lesser prairie-chicken
viability, we considered the need for multiple healthy lesser prairie-
chicken populations within each of the four ecoregions to conserve the
genetic and ecological diversity of the lesser prairie-chicken. Each of
the four ecoregions varies in terms of vegetative communities and
environmental conditions, resulting in differences in abundance and
distribution and management strategies (Boal and Haukos 2016, p. 5).
Despite reduced range and population size, most lesser prairie-chicken
populations appear to have maintained comparatively high levels of
neutral genetic variation (DeYoung and Williford 2016, p. 86). As
discussed in Significance above, recent genetic studies also show
significant genetic variation across the lesser prairie-chicken range
based on neutral markers (Service 2022, figure 2.4), which supports
management separation of these four ecoregions and highlights important
genetic differences between them (Oyler-McCance et al. 2016, p. 653).
While it is unknown how this genetic variation relates to differences
in adaptive capacity between the ecoregions, maintaining healthy lesser
prairie-chicken populations across this range of diversity increases
the likelihood of conserving inherent ecological and genetic variation
within the species to enhance its ability for adaptation to future
changes in environmental conditions.
Resiliency
In the case of the lesser prairie-chicken, we considered the
primary indicators of resiliency to be habitat availability, population
abundance, growth rates, and quasi-extinction risk. Lesser prairie-
chicken populations within ecoregions must have sufficient habitat and
population growth potential to recover from natural disturbance events
such as extensive wildfires, extreme hot or cold events, extreme
precipitation events, or extended local periods of below-average
rainfall. These events can be particularly devastating to populations
when they occur during the late spring or summer when nesting and
brood-rearing are occurring and individuals are more susceptible to
mortality.
The lesser prairie-chicken is considered a ``boom-bust'' species
based on its high reproductive potential with a high degree of annual
variation in rates of successful reproduction and recruitment. These
variations are largely driven by the influence of seasonal
precipitation patterns (Grisham et al. 2013, pp. 6-7), which impact the
population through effects on the quality of habitat. Periods of below-
average precipitation and higher spring/summer temperatures result in
less appropriate grassland vegetation cover and less food available,
resulting in decreased reproductive output (bust periods). Periods with
above-normal precipitation and cooler spring/summer temperatures will
support favorable lesser prairie-chicken habitat conditions and result
in high reproductive success (boom periods). In years with particularly
poor weather conditions, individual female lesser prairie-chicken may
forgo nesting for the year. This population characteristic highlights
the need for habitat conditions to support large population growth
events during favorable climatic conditions so they can withstand the
declines during poor climatic conditions without a high risk of
extirpation.
Historically, the lesser prairie-chicken had large expanses of
grassland habitat to maintain populations. Early European settlement
and development of the Southern Great Plains for agriculture initially,
and for energy extraction later, substantially reduced the amount and
connectivity of the grasslands of this region. Additionally, if
historically some parts of the range were drastically impacted or
eliminated due to a stochastic event, that area could be reestablished
from other populations. Today, those characteristics of the grasslands
have been degraded, resulting in the loss and fragmentation of
grasslands in the Southern Great Plains. Under present conditions, the
potential lesser prairie-chicken habitat is limited to small,
fragmented grassland patches (relative to historical conditions)
(Service 2022, pp. 64-78). The larger and more intact the remaining
grassland patches are, with appropriate vegetation structure, the
larger, healthier, and more resilient the lesser prairie-chicken
populations will be. Exactly how large habitat patches should be to
support healthy populations depends on the quality and intactness of
the patches. Recommended total space needed for a single lesser
prairie-chicken lek ranges from a minimum of about 12,000 ac (4,900 ha)
(Davis 2005, p. 3) up to more than 50,000 ac (20,000 ha), depending on
the quality and intactness of the area (Applegate and Riley 1998, p.
14; Haufler et al. 2012, pp. 7-8; Haukos and Zavaleta 2016, p. 107).
A single lesser prairie-chicken lek is not considered a population
that can persist on its own. Instead, complexes of multiple leks that
interact with each other are required for a lesser prairie-chicken
population to persist over time. These metapopulation dynamics, in
which individuals interact on the landscape to form larger populations,
are dependent upon the specific biotic and abiotic landscape
characteristics of the site and how those characteristics influence
space use, movement, patch size, and fragmentation (DeYoung and
Williford 2016, pp. 89-91). Maintaining multiple, highly resilient
populations (complexes of leks) within the four ecoregions that have
the ability to interact with each other will increase the probability
of persistence in the face of environmental fluctuations and stochastic
events. Because of this concept of metapopulations and their influence
on long-term persistence, when evaluating lesser prairie-chicken
populations, site-specific information can be informative. However,
many of the factors affecting lesser prairie-chicken populations should
be analyzed at larger spatial scales (Fuhlendorf et al. 2002, entire).
Redundancy
Redundancy describes the ability of a species to withstand
catastrophic events. Catastrophes are stochastic events that are
expected to lead to population collapse regardless of population health
and for which adaptation is unlikely. Redundancy spreads the risk and
can be measured through the duplication and distribution
[[Page 72685]]
of resilient populations that are connected across the range of the
species. The larger the number of highly resilient populations the
lesser prairie-chicken has, distributed over a large area within each
ecoregion, the better the species can withstand catastrophic events.
Catastrophic events for lesser prairie-chicken might include extreme
drought; widespread, extended droughts; or a disease outbreak.
Measuring redundancy for lesser prairie-chicken is a difficult task
due to the physiological and biological characteristics of the species,
which make it difficult to survey and limit the usefulness of survey
results. To estimate redundancy for the lesser prairie-chicken, we
estimated the geographic distribution of predicted available habitat
within each of the four ecoregions and the juxtaposition of that
habitat to other habitat and non-habitat. As the amount of large
grassland patches decreases and grassland patches become more isolated
to reduce or preclude lesser prairie-chicken movement between them, the
overall redundancy of the species is reduced. As redundancy decreases
within any representative ecoregion or DPS, the likelihood of
extirpation within that ecoregion or DPS increases. As large grassland
patches, the connectivity of those patches, and the number of lesser
prairie-chicken increase, so does the redundancy within an ecoregion or
a DPS.
Current Condition
In the SSA report, we assessed the current condition of the lesser
prairie-chicken through an analysis of existing habitat; a review of
factors that have impacted the species in the past, including a
geospatial analysis to estimate areas of land cover impacts on the
current landscape condition; a summary of the current potential usable
area based upon our geospatial analysis; and a summary of past and
current population estimates. We also evaluated and summarized the
benefits of the extensive conservation efforts that are ongoing
throughout the lesser prairie-chicken range to conserve the species and
its habitat.
Geospatial Analysis Summary
The primary concern for the lesser prairie-chicken is habitat loss
and fragmentation. We conducted a geographic information system (GIS)
analysis to analyze the extent of usable land cover changes and
fragmentation within the range of the lesser prairie-chicken,
characterizing landscape conditions spatially to analyze the ability of
those landscapes to support the biological needs of the lesser prairie-
chicken. Impacts included in this analysis were the direct and indirect
effects of areas that were converted to cropland; encroached by woody
vegetation such as mesquite and eastern red cedar (Juniperus
virginiana); and developed for roads, petroleum production, wind
energy, and transmission lines. We acknowledge that there are other
impacts, such as power lines or incompatible grazing on the landscape
that can affect lesser prairie-chicken habitat. For those impacts,
either no geospatial data were available, or the available data would
have added so much complexity to our geospatial model that the results
would have been uninterpretable or not explanatory for our purpose.
There are several important limitations to our geospatial analysis.
First, it is a landscape-level analysis, so the results only represent
broad trends at the ecoregional and rangewide scales. Secondly, this
analysis does not incorporate different levels of habitat quality, as
the data do not exist at the spatial scale or resolution needed. Our
analysis considers areas only as either potentially usable or not
usable by lesser prairie-chicken based upon land cover classifications.
We recognize that some habitat, if managed as high-quality grassland,
may have the ability to support higher densities of lesser prairie-
chicken than other habitat that exists at lower qualities.
Additionally, we also recognize that some areas of land cover that we
identified as suitable could be of such poor quality that it is of
limited value to the lesser prairie-chicken. We recognize there are
many important limitations to this landscape analysis, including
variation and inherent error in the underlying data and unavailable
data. We interpreted the results of this analysis with those
limitations in mind.
In this final rule, we discuss effects that relate to the total
potential usable unimpacted acreage for lesser prairie-chicken, as
defined by our geospatial analysis (hereafter, analysis area). A
complete description of the purpose, methodology, constraints, and
additional details for this analysis is provided in the SSA report for
the lesser prairie-chicken (Service 2022, appendix B, parts 1, 2, and
3).
Threats Influencing Current Condition
Following are summary evaluations of the threats analyzed in the
SSA report for the lesser prairie-chicken: effects associated with
habitat degradation, loss, and fragmentation, including conversion of
grassland to cropland (Factor A), petroleum production (Factor A), wind
energy development and transmission (Factor A), woody vegetation
encroachment (Factor A), and roads and electrical distribution lines
(Factor A); other factors, such as livestock grazing (Factor A), shrub
control and eradication (Factor A), collision mortality from fences
(Factor E), predation (Factor C), influence of anthropogenic noise
(Factor E), fire (Factor A); and extreme weather events (Factor E). We
also evaluate existing regulatory mechanisms (Factor D) and ongoing
conservation measures.
In the SSA report, we also considered three additional threats:
hunting and other recreational, educational, and scientific use (Factor
B); parasites and diseases (Factor C); and insecticides (Factor E). We
concluded that, as indicated by the best available scientific and
commercial information, these threats are currently having little to no
impact on lesser prairie-chickens and their habitat, and thus their
overall effect now and into the future is expected to be minimal.
Therefore, we will not present summary analyses of those threats in
this document but will consider them in our overall conclusions of
impacts to the species. For full descriptions of all threats and how
they impact the species, please see the SSA report (Service 2022, pp.
24-49).
Habitat Degradation, Loss, and Fragmentation
The grasslands of the Great Plains are among the most threatened
ecosystems in North America (Samson et al. 2004, p. 6) and have been
impacted more than any other major ecosystem on the continent (Samson
and Knopf 1994, p. 418). Temperate grasslands are also one of the least
conserved ecosystems (Hoekstra et al. 2005, p. 25). Grassland loss in
the Great Plains is estimated at approximately 70 percent (Samson et
al. 2004, p. 7), with nearly 23 million ac (93,000 km\2\; 9.3 million
ha) of grasslands in the United States lost between 1982 and 1997 alone
(Samson et al. 2004, p. 9). The vast majority of the lesser prairie-
chicken range (more than 95 percent) occurs on private lands that have
been in some form of agricultural production since at least the early
1900s. As a result, available habitat for grassland species, such as
the lesser prairie-chicken, has been much reduced and fragmented
compared to historical conditions across its range.
Habitat impacts occur in three general categories that often work
synergistically at the landscape scale: degradation, loss, and
fragmentation. Habitat degradation results in changes to a species'
habitat that reduces its
[[Page 72686]]
suitability to the species, but without making the habitat entirely
unsuitable. Degradation may result in lower carrying capacity, lower
reproductive potential, higher predation rates, or other effects.
Habitat loss may result from the same anthropogenic sources that cause
degradation, but the habitat has been altered to the point where it has
no suitability for the species at all. Habitat fragmentation occurs
when habitat loss is patchy and leaves a matrix of grassland habitat
behind. While habitat degradation continues to be a concern, we focus
our analysis on habitat loss and fragmentation from the cumulative
effects of multiple sources of activities as the long-term drivers of
the species' viability.
Initially, reduction in the total area of available habitat may be
more significant than fragmentation and can exert a much greater effect
on populations (Fahrig 1997, pp. 607, 609). However, as habitat loss
continues, the effects of fragmentation often compound effects of
habitat loss and produce even greater population declines than habitat
loss alone (Bender et al. 1998, pp. 517-518, 525). Spatial habitat
fragmentation occurs when some form of disturbance, usually habitat
degradation or loss, results in the separation or splitting apart of
larger, previously contiguous, functional components of habitat into
smaller, often less valuable, noncontiguous patches (Wilcove et al.
1986, p. 237; Johnson and Igl 2001, p. 25; Franklin et al. 2002,
entire). Habitat loss and fragmentation influence habitat availability
and quality in three primary ways: (1) total area of available habitat
constrains the maximum population size for an area; (2) the size of
habitat patches within a larger habitat area, including edge effects
(changes in population or community structures that occur at the
boundary of two habitats), influences habitat quality and size of local
populations; and (3) patch isolation influences the amount of species
movement between patches, which constrains demographic and genetic
exchange and ability to recolonize local areas where the species might
be extirpated (Johnson and Igl 2001, p. 25; Stephens et al. 2003, p.
101).
Habitat loss, fragmentation, and degradation correlate with the
ecological concept of carrying capacity. Within any given block or
patch of lesser prairie-chicken habitat, carrying capacity is the
maximum number of birds that can be supported indefinitely by the
resources available within that area, that is, sufficient food,
shelter, and lekking, nesting, brood-rearing, and wintering areas. As
habitat loss increases and the size of an area decreases, the maximum
number of birds that can inhabit that particular habitat patch also
decreases. Consequently, a reduction in the total area of available
habitat can negatively influence biologically important characteristics
such as the amount of space available for establishing territories and
nest sites (Fahrig 1997, p. 603). Over time, the continued conversion
and loss of habitat will reduce the capacity of the landscape to
support historical population levels, causing a decline in population
sizes.
Habitat loss not only contributes to overall declines in usable
area for a species but also causes a reduction in the size of
individual habitat patches and influences the proximity and
connectivity of these patches to other patches of similar habitat
(Stephens et al. 2003, p. 101; Fletcher 2005, p. 342), reducing rates
of movement between habitat patches until, eventually, complete
isolation results. Habitat quality for many species is, in part, a
function of patch size and declines as the size of the patch decreases
(Franklin et al. 2002, p. 23). Both the size and shape of the habitat
patch have been shown to influence population persistence in many
species (Fahrig and Merriam 1994, p. 53). The size of the fragment can
influence reproductive success, survival, and movements. As the
distances between habitat fragments increase, the rate of dispersal
between the habitat patches may decrease and ultimately cease, reducing
the likelihood of population persistence and potentially leading to
both localized and regional extinctions (Harrison and Bruna 1999, p.
226; With et al. 2008, p. 3153). In highly fragmented landscapes, once
a species becomes extirpated from an area, the probability of
recolonization is greatly reduced (Fahrig and Merriam 1994, p. 52).
For the lesser prairie-chicken, habitat loss can occur due to
either direct or indirect habitat impacts. Direct habitat loss is the
result of the removal or alteration of grasslands, making that space no
longer available for use by the lesser prairie-chicken. Indirect
habitat loss and degradation is when the vegetation still exists, but
the areas adjacent to a disturbance (the disturbance can be natural or
manmade) are no longer used by lesser prairie-chicken or are used at
reduced rates, or the disturbance negatively alters demographic rates
or behavior in the affected area. In many cases, as discussed in detail
below for specific disturbances, the indirect habitat loss can greatly
exceed the direct habitat loss.
Primarily due to their site fidelity and the need for large,
ecologically diverse landscapes, lesser prairie-chickens appear to be
relatively intolerant to habitat alteration, particularly for
activities that fragment habitat into smaller patches. The birds
require habitat patches with large expanses of vegetative structure in
different successional stages to complete different phases in their
life cycle, and the loss or partial loss of even one of these
structural components can significantly reduce the overall value of
that habitat to lesser prairie-chickens (Elmore et al. 2013, p. 4). In
addition to the impacts on the individual patches, as habitat loss and
fragmentation increases on the landscape, the juxtaposition of habitat
patches to each other and to non-habitat areas will change. This
changing pattern on the landscape can be complex and difficult to
predict, but the results, in many cases, are increased isolation of
individual patches (either due to physical separation or barriers
preventing or limiting movement between patches) and direct impacts to
metapopulation structure, which could be important for population
persistence (DeYoung and Williford 2016, pp. 88-91).
The following sections provide a discussion and quantification of
the influence of habitat loss and fragmentation on the grasslands of
the Great Plains within the lesser prairie-chicken analysis area and
more specifically allow us to characterize the current condition of
lesser prairie-chicken habitat.
Conversion of Grassland to Cropland
Historical conversion of grassland to cultivated agricultural lands
in the late 19th century and throughout the 20th century has been
regularly cited as an important cause in the rangewide decline in
abundance and distribution of lesser prairie-chicken populations
(Copelin 1963, p. 8; Jackson and DeArment 1963, p. 733; Crawford and
Bolen 1976a, p. 102; Crawford 1980, p. 2; Taylor and Guthery 1980b, p.
2; Braun et al. 1994, pp. 429, 432-433; Mote et al. 1999, p. 3).
Because cultivated grain crops may have provided increased or more
dependable winter food supplies for lesser prairie-chickens (Braun et
al. 1994, p. 429), the initial conversion of smaller patches of
grassland to cultivation may have been temporarily beneficial to the
short-term needs of the species as primitive and inefficient
agricultural practices made grain available as a food source (Rodgers
2016, p. 18). However, as conversion increased, it became clear that
landscapes having greater than 20 to 37
[[Page 72687]]
percent cultivated grains may not support stable lesser prairie-chicken
populations (Crawford and Bolen 1976a, p. 102). More recently,
abundances of lesser prairie-chicken increased with increasing cropland
until a threshold of 10 percent was reached; after that, abundance of
lesser prairie-chicken declined with increasing cropland cover (Ross et
al. 2016b, entire). While lesser prairie-chicken may forage in
agricultural croplands, croplands do not provide for the habitat
requirements of the species' life cycle (cover for nesting and
thermoregulation); thus, lesser prairie-chicken avoid landscapes
dominated by cultivated agriculture, particularly where small grains
are not the dominant crop (Crawford and Bolen 1976a, p. 102).
As part of the geospatial analysis completed for the SSA, we
estimated the amount of cropland that currently exists in the four
ecoregions of the lesser prairie-chicken. These percentages do not
equate to the actual proportion of habitat loss in the analysis area
because not all of the analysis area was necessarily suitable lesser
prairie-chicken habitat; they are only the estimated portion of the
total analysis area converted from the native vegetation community,
i.e., grassland, to cropland. About 37 percent of the total area in the
Short-Grass/CRP Ecoregion; 32 percent of the total area in the Sand
Sagebrush Ecoregion; 13 percent of the total area in the Mixed-Grass
Ecoregion; and 14 percent of the total area in the Shinnery Oak
Ecoregion have been converted to cropland in the analysis area of the
lesser prairie-chicken. Rangewide, we estimate about 4,963,000 ac
(2,009,000 ha) of grassland have been converted to cropland,
representing about 23 percent of the total analysis area. We note that
these calculations do not account for all conversion that has occurred
within the historical range of the lesser prairie-chicken but are
limited to the amount of cropland within our analysis area. For further
information, including total acreages impacted, see the SSA report for
the lesser prairie-chicken (Service 2022, appendix E and figure E.1).
The effects of grassland converted to cropland within the
historical range of the lesser prairie-chicken have significantly
impacted the amount of habitat available and how fragmented the
remaining habitat is for the lesser prairie-chicken, leading to overall
decreases in resiliency and redundancy throughout the range of the
lesser prairie-chicken. The impact of cropland has shaped the
historical and current condition of the grasslands and shrublands upon
which the lesser prairie-chicken depends.
Petroleum and Natural Gas Production
Petroleum and natural gas production has occurred over much of the
estimated historical and current range of the lesser prairie-chicken.
As demand for energy has continued to increase nationwide, so has oil
and gas development in the Great Plains. In Texas, for example, one
study noted that from 2002-2012 active oil and gas wells in the lesser
prairie-chicken occupied range increased by more than 80 percent
(Timmer et al. 2014, p. 143). The impacts from oil and gas development
extend beyond the immediate well sites; they involve activities such as
surface exploration, exploratory drilling, field development, and
facility construction, as well as access roads, well pads, and
operation and maintenance. Associated facilities can include compressor
stations, pumping stations, and electrical generators.
Petroleum and natural gas production result in both direct and
indirect habitat effects to the lesser prairie-chicken (Hunt and Best
2004, p. 92). Well pad construction, seismic surveys, access road
development, power line construction, pipeline corridors, and other
activities can all result in direct habitat loss by removal of
vegetation used by lesser prairie-chickens. As documented in other
grouse species, indirect habitat loss also occurs from avoidance of
vertical structures, noise, and human presence (Weller et al. 2002,
entire), which all can influence lesser prairie-chicken behavior in the
general vicinity of oil and gas development areas. These activities
also disrupt lesser prairie-chicken reproductive behavior (Hunt and
Best 2004, p. 41).
Anthropogenic features, such as oil and gas wells, affect the
behavior of lesser prairie-chickens and alter the way in which they use
the landscape (Hagen et al. 2011, pp. 69-73; Pitman et al. 2005,
entire; Hagen 2010, entire; Hunt and Best 2004, pp. 99-104; Plumb et
al. 2019, pp. 224-227; Sullins et al. 2019, pp. 5-8; Peterson et al.
2020, entire). Please see the SSA report for a detailed summary of the
best available scientific information regarding avoidance distances and
effects of oil and gas development on lesser prairie-chicken habitat
use (Service 2022, pp. 27-28).
As part of the geospatial analysis discussed in the SSA report, we
calculated the amount of usable land cover for the lesser prairie-
chicken that has been impacted (both direct and indirect impacts) by
oil and natural gas wells in the current analysis area of the lesser
prairie-chicken, though this analysis did not include all associated
infrastructure as those data were not available. We used an impact
radius of 984 feet (ft) (300 meters (m)) for indirect effects of oil
and gas wells. For details regarding the establishment of the impact
radius, see appendix B, part 2C, of the SSA report (Service 2022).
These calculations were limited to the current analysis area and do not
include historical impacts of habitat loss that occurred outside of the
current analysis area. Thus, the calculation likely underestimates the
rangewide effects of historical oil and gas development on the lesser
prairie-chicken. About 4 percent of the total area in the Short-Grass/
CRP Ecoregion; 5 percent of the total area in the Sand Sagebrush
Ecoregion; about 10 percent of the total area in the Mixed-Grass
Ecoregion; and 4 percent of the total area in the Shinnery Oak
Ecoregion of space that was identified as potential usable or potential
restorable areas have been impacted due to oil and gas development in
the current analysis area of the lesser prairie-chicken. Rangewide, we
estimate about 1,433,000 ac (580,000 ha) of grassland have been lost
due to oil and gas development representing about 7 percent of the
total analysis area. Maps of these areas in each ecoregion are provided
in the SSA report (Service 2022, appendix E, figure E.2).
Oil and gas development directly removes habitat that supports
lesser prairie-chicken, and the effects of the development extend past
the immediate site of the wells and their associated infrastructure,
further impacting habitat and altering behavior of lesser prairie-
chicken throughout both the Northern and the Southern DPS. These
activities have resulted in decreases in population resiliency and
species redundancy.
Wind Energy Development and Power Lines
Wind power is a form of renewable energy increasingly being used to
meet current and projected future electricity demands in the United
States. Much of the new wind energy development is likely to come from
the Great Plains States because they have high wind resource potential,
which exerts a strong, positive influence on the amount of wind energy
developed within a particular State (Staid and Guikema 2013, p. 384).
In 2019, three of the five States within the lesser prairie-chicken
range (Colorado, New Mexico, and Kansas) were within the top 10 States
nationally for fastest growing States for wind generation in the past
year (AWEA 2020, p. 33). There is considerable information (Southwest
Power Pool
[[Page 72688]]
2020) indicating interest by the wind industry in developing wind
energy within the range of the lesser prairie-chicken, especially if
additional transmission line capacity is constructed. As of May 2020,
approximately 1,792 wind turbines were located within the lesser
prairie-chicken analysis area (Hoen et al. 2020). Not all areas within
the analysis area are habitat for the lesser prairie-chicken, so not
all turbines located within the analysis area affect the lesser
prairie-chicken and its habitat.
The average size of installed wind turbines and all other size
aspects of wind energy development continues to increase (DOE 2015, p.
63; AWEA 2020, p. 87-88; AWEA 2014, entire; AWEA 2015, entire; AWEA
2016, entire; AWEA 2017, entire; AWEA 2018, entire; AWEA 2019, entire;
AWEA 2020, entire). Wind energy developments range from 20 to 400
towers, each supporting a single turbine. The individual permanent
footprint of a single turbine unit, about 0.75-1 ac (0.3-0.4 ha), is
relatively small in comparison with the overall footprint of the entire
array (DOE 2008, pp. 110-111). Roads are necessary to access the
turbine sites for installation and maintenance. Depending on the size
of the wind energy development, one or more electrical substations,
where the generated electricity is collected and transmitted on to the
power grid, may also be built. Considering the initial capital
investment and that the service life of a single turbine is at least 20
years (DOE 2008, p. 16), we expect most wind energy developments to be
in place for at least 30 years. Wind repowering is the combined
activity of dismantling or refurbishing existing wind turbines and
commissioning new ones at existing wind energy development sites at the
end of their service life. Wind repowering is increasingly common, with
2,803 megawatts of operating projects partially repowering in 2019
(AWEA 2020, p. 2).
Please see the SSA report for a detailed review of the best
available scientific information regarding the potential effects of
wind energy development on habitat use by the lesser prairie-chicken
(Service 2022, pp. 29-34).
Noise effects to prairie-chickens have been recently explored as a
way to evaluate potential negative effects of wind energy development.
For a site in Nebraska, wind turbine noise frequencies were documented
at less than or equal to 0.73 kilohertz (kHz) (Raynor et al. 2017, p.
493), and reported to overlap the range of lek-advertisement
vocalization frequencies of lesser prairie-chicken, 0.50-1.0 kHz.
Female greater prairie-chickens avoided wooded areas and row crops but
showed no response in space use based on wind turbine noise (Raynor et
al. 2019, entire). Additionally, differences in background noise and
signal-to-noise ratio of boom chorus of leks in relation to distance to
turbine have been documented, but the underlying cause and response
needs to be further investigated, especially since the study of wind
energy development noise on grouse is almost unprecedented (Whalen et
al. 2019, entire).
The effects of wind energy development on the lesser prairie-
chicken must also take into consideration the influence of the
transmission lines critical to distribution of the energy generated by
wind turbines. Transmission lines can traverse long distances across
the landscape and can be both above ground and underground, although
the vast majority of transmission lines are erected above ground. Most
of the impacts to lesser prairie-chicken associated with transmission
lines are with the aboveground systems. Support structures vary in
height depending on the size of the line. Most high-voltage power line
towers are 98 to 125 ft (30 to 38 m) high but can be higher if the need
arises. Local distribution lines, if erected above ground, are usually
much shorter in height but still contribute to fragmentation of the
landscape.
The effect of the transmission line infrastructure is typically
much larger than the physical footprint of transmission line
installation. Information on grouse and power lines is relatively
limited with more studies needed. The available data includes a range
of reported impacts (see Nonne et al. 2013, entire; Dinkins et al.
2014, entire; Hansen et al. 2016, entire; Jarnevich et al. 2016,
entire; Londe et al. 2019, entire; LeBeau et al. 2019, entire; Kohl et
al. 2019, entire; and England and Robert 2021, entire). Transmission
lines can indirectly lead to alterations in lesser prairie-chicken
behavior and space use (avoidance), decreased lek attendance, and
increased predation on lesser prairie-chicken. Transmission lines,
particularly due to their length, can be a significant barrier to
dispersal of prairie grouse, disrupting movements to feeding, breeding,
and roosting areas. Both lesser and greater prairie-chickens avoided
otherwise usable habitat near transmission lines and crossed these
power lines much less often than nearby roads, suggesting that power
lines are a particularly strong barrier to movement (Pruett et al.
2009, pp. 1255-1257). Because lesser prairie-chicken avoid tall
vertical structures like transmission lines and because transmission
lines can increase predation rates, leks located in the vicinity of
these structures may see reduced attendance by new males to the lek, as
has been reported for sage-grouse (Braun et al. 2002, pp. 11-13).
Decreased probabilities of use by lesser prairie-chicken were shown
with the occurrence of more than 0.09 mi (0.15 km) of major roads, or
transmission lines within a 1.2-mi (2-km) radius (Sullins et al. 2019,
unpaged). Additionally, a recent study corroborated numerous authors'
(Pitman et al. 2005; Pruett et al. 2009; Hagen et al. 2011; Grisham et
al. 2014; Hovick et al. 2014a) findings of negative effects of power
lines on prairie grouse and reported a minimum avoidance distance of
1,925.8 ft (587 m), which is similar to other studies of lesser
prairie-chickens (Plumb et al. 2019, entire). LeBeau et al. (2020, p.
24) largely aggregated their findings of wind turbines and a
transmission line on lesser prairie-chicken into effects of ``wind
energy infrastructure,'' but specifically noted evidence that females
selected home ranges farther from transmission lines. Using a
definition for transmission powerlines that included powerlines
transmitting >69 kilovolts, indicated that taller anthropogenic
structures (i.e., transmission powerlines and towers) generally had
larger estimated avoidance response distances of all the studied
features, but also large regional variation (Peterson et al. 2020, p.
9). They found largest estimated avoidance response of 5.6 mi (9 km) in
Northwest Kansas, and the smallest in Oklahoma at approximately 1.8 mi
(3 km). Effects from anthropogenic features, including power lines,
varied by region, and the degree of effect often depended on the
presence of other anthropogenic features (Patten et al. 2021, entire).
As part of our geospatial analysis, we calculated the amount of
otherwise usable land cover for the lesser prairie-chicken that has
been impacted (both direct and indirect impacts) by wind energy
development in the current analysis area of the lesser prairie-chicken.
We used an impact radius of 5,906 ft (1,800 m) for indirect effects of
wind turbines and 2,297 ft (700 m) for indirect effects of transmission
lines. For details regarding the establishment of the impact radius,
see appendix B, part 2C, of the SSA report (Service 2022). Within our
analysis area, the following acreages have been identified as impacted
due to wind energy development: about 2 percent of the total area in
the Short-Grass/CRP, Mixed-Grass, and Shinnery Oak Ecoregions; and no
impacts of wind
[[Page 72689]]
energy development documented currently within the Sand Sagebrush
Ecoregion. Rangewide, we estimate about 428,000 ac (173,000 ha) of
grassland have been impacted by wind energy development, representing
about 2 percent of the total analysis area (Service 2022, appendix E,
figure E.3). These percentages do not account for overlap that may
exist with other features that may have already impacted the landscape.
Additionally, according to our geospatial analysis, the following
acreages within the analysis area have been directly or indirectly
impacted due to the construction of transmission lines: about 7 percent
of the total area in the Short-Grass/CRP Ecoregion; 5 percent of the
total area in the Sand Sagebrush Ecoregion; 7 percent of the total area
in the Mixed-Grass Ecoregion; and 10 percent of the total area in the
Shinnery Oak Ecoregion. Rangewide, we estimate about 1,553,000 ac
(629,000 ha) of grassland have been impacted by transmission lines
representing about 7 percent of the total analysis area (Service 2022,
appendix E, figure E.4).
Wind energy development and transmission lines remove habitat that
supports lesser prairie-chicken. The effects of the development extend
past the immediate site of the turbines and their associated
infrastructure, further impacting habitat and altering behavior of
lesser prairie-chicken throughout both the Northern and the Southern
DPSs. These activities have resulted in decreases in population
resiliency and species redundancy.
Woody Vegetation Encroachment
As discussed in Background, habitat selected by lesser prairie-
chicken is characterized by expansive regions of treeless grasslands
interspersed with patches of small shrubs (Giesen 1998, pp. 3-4);
lesser prairie-chicken avoid areas with trees and other vertical
structures. Prior to extensive Euro-American settlement, frequent fires
and grazing by large, native ungulates helped confine trees like
eastern red cedar to river and stream drainages and rocky outcroppings.
The frequency and intensity of these disturbances directly influenced
the ecological processes, biological diversity, and patchiness typical
of Great Plains grassland ecosystems (Collins 1992, pp. 2003-2005;
Fuhlendorf and Smeins 1999, pp. 732, 737).
Following Euro-American settlement, increasing fire suppression
combined with government programs promoting eastern red cedar for
windbreaks, erosion control, and wildlife cover facilitated the
expansion of eastern red cedar distribution in grassland areas (Owensby
et al. 1973, p. 256; DeSantis et al. 2011, p. 1838). Once a grassland
area has been colonized by eastern red cedar, the trees are mature
within 6 to 7 years and provide a plentiful source of seed so that
adjacent areas can readily become infested with eastern red cedar.
Despite the relatively short viability of the seeds (typically only one
growing season), the large cone crop, potentially large seed dispersal
ability, and the physiological adaptations of eastern red cedar to
open, relatively dry sites help make the species a successful invader
of grassland landscapes (Holthuijzen et al. 1987, p. 1094). Most trees
are relatively long-lived and, once they become established in
grassland areas, require intensive management to remove to return areas
to a grassland state.
Within the southern- and westernmost portions of the estimated
historical and occupied ranges of lesser prairie-chicken in Eastern New
Mexico, Western Oklahoma, and the South Plains and Panhandle of Texas,
honey mesquite is another common woody invader within these grasslands
(Riley 1978, p. vii; Boggie et al. 2017, entire). Mesquite is a
particularly effective invader in grassland habitat due to its ability
to produce abundant, long-lived seeds that can germinate and establish
in a variety of soil types and moisture and light regimes (Lautenbach
et al. 2017, p. 84). Though not as widespread as mesquite or eastern
red cedar, other tall, woody plants, such as redberry or Pinchot
juniper (Juniperus pinchotii), black locust (Robinia pseudoacacia),
Russian olive (Elaeagnus angustifolia), and Siberian elm (Ulmus pumila)
can also be found in grassland habitat historically and currently used
by lesser prairie-chicken and may become invasive in these areas.
Invasion of grasslands by opportunistic woody species causes
otherwise usable grassland habitat no longer to be used by lesser
prairie-chicken and contributes to the loss and fragmentation of
grassland habitat (Lautenbach 2017, p. 84; Boggie et al. 2017, p. 74).
In Kansas, lesser prairie-chicken are 40 times more likely to use areas
that had no trees than areas with 1.6 trees per ac (5 trees per ha),
and no nests occur in areas with a tree density greater than 0.8 trees
per ac (2 trees per ha), at a scale of 89 ac (36 ha) (Lautenbach 2017,
pp. 104-142). Similarly, within the Shinnery Oak Ecoregion, lesser
prairie-chicken habitat use in all seasons is altered in the presence
of mesquite, even at densities of less than 5 percent canopy cover
(Boggie et al. 2017, entire). Woody vegetation encroachment also
contributes to indirect habitat loss and increases habitat
fragmentation because lesser prairie-chicken are less likely to use
areas adjacent to trees (Boggie et al. 2017, pp. 72-74; Lautenbach
2017, pp. 104-142).
Fire is often the best method to control or preclude tree invasion
of grassland. However, to some landowners and land managers, burning of
grassland can be perceived as a high-risk activity because of the
potential liability of escaped fire impacting nontarget lands and
property. Additionally, it is undesirable for optimizing cattle
production and is likely to create wind erosion or ``blowouts'' in
sandy soils. Consequently, wildfire suppression is common, and
relatively little prescribed burning occurs on private land. Often,
prescribed fire is employed only after significant tree invasion has
already occurred and landowners consider forage production for cattle
to have diminished. Preclusion of woody vegetation encroachment on
grasslands of the southern Great Plains using fire requires
implementing fire at a frequency that mimics historical fire
frequencies of 2-14 years (Guyette et al. 2012, p. 330), further
limiting the number of landowners able to implement fire in a manner
that would truly preclude future encroachment. Additionally, in areas
where grazing pressure is heavy and fuel loads are reduced, a typical
grassland fire may not be intense enough to eradicate eastern red cedar
(Briggs et al. 2002a, p. 585; Briggs et al. 2002b, p. 293; Bragg and
Hulbert 1976, p. 19) and will not eradicate mesquite.
As part of our geospatial analysis, we calculated the amount of
woody vegetation encroachment in the current analysis area of the
lesser prairie-chicken. These calculations of the current analysis area
do not include historical impacts of habitat loss that occurred outside
of the current analysis area; thus, it likely underestimates the
effects of historical woody vegetation encroachment rangewide on the
lesser prairie-chicken. An additional limitation associated with this
calculation is that available remote sensing data lack the ability to
detect areas with low densities of encroachment, as well as areas with
shorter trees; thus, this calculation likely underestimates lesser
prairie-chicken habitat loss due to woody vegetation encroachment. The
identified areas of habitat impacted by woody vegetation are: about 5
percent of the total area in the Short-Grass/CRP Ecoregion; about 2
percent of the total area in the Sand Sagebrush Ecoregion;
[[Page 72690]]
about 24 percent of the total area in the Mixed-Grass Ecoregion; and
about 17 percent of the total area in the Shinnery Oak Ecoregion.
Rangewide, we estimate about 3,071,000 ac (1,243,000 ha) of grassland
have been directly or indirectly impacted by the encroachment of woody
vegetation, or about 18 percent of the total area. These percentages do
not account for overlap that may exist with other features that may
have already impacted the landscape. Further information, including
total acres impacted, is available in the SSA report (Service 2022,
appendix B; appendix E, figure E.5).
Woody vegetation encroachment is contributing to ongoing habitat
loss as well as contributing to fragmentation and degradation of
remaining habitat patches. The effects of woody vegetation encroachment
are particularly widespread in the Shinnery Oak Ecoregion that makes up
the Southern DPS as well as the Mixed-Grass Ecoregion of the Northern
DPS. While there are ongoing efforts to control woody vegetation
encroachment, the current level of woody vegetation on the landscape is
evidence that removal efforts are being outpaced by rates of
encroachment; thus, we expect that this threat will continue to
contribute to habitat loss and fragmentation, which has reduced
population resiliency across the range of the lesser prairie-chicken.
Roads and Electrical Distribution Lines
Roads and distribution power lines are linear features on the
landscape that contribute to loss and fragmentation of lesser prairie-
chicken habitat and fragment populations as a result of behavioral
avoidance. Lesser prairie-chickens are less likely to use areas close
to roads (Plumb et al. 2019, entire; Sullins et al. 2019, entire).
Additionally, roads contribute to lek abandonment when they disrupt
important habitat features (such as affecting auditory or visual
communication) associated with lek sites (Crawford and Bolen 1976b, p.
239). Some mammal species that prey on lesser prairie-chicken, such as
red fox (Vulpes vulpes), raccoons (Procyon lotor), and striped skunks
(Mephitis mephitis), have greatly increased their distribution by
dispersing along roads (Forman and Alexander 1998, p. 212; Forman 2000,
p. 33; Frey and Conover 2006, pp. 1114-1115).
Traffic noise from roads may indirectly impact lesser prairie-
chicken. Because lesser prairie-chicken depend on acoustical signals to
attract females to leks, noise from roads, oil and gas development,
wind turbines, and similar human activity may interfere with mating
displays, influencing female attendance at lek sites and causing young
males not to be drawn to the leks. Within a relatively short period,
leks can become inactive due to a lack of recruitment of new males to
the display grounds. For further discussion on noise, please see
Influence of Anthropogenic Noise.
Depending on the traffic volume and associated disturbances, roads
also may limit lesser prairie-chicken dispersal abilities. Lesser
prairie-chickens avoid areas of usable habitat near roads (Pruett et
al. 2009, pp. 1256, 1258; Plumb et al. 2019, entire) and in areas where
road densities are high (Sullins et al. 2019, p. 8). Lesser prairie-
chickens are thought to avoid major roads due to disturbance caused by
traffic volume and perhaps to avoid exposure to predators that may use
roads as travel corridors. However, the extent to which roads
constitute a significant obstacle to lesser prairie-chicken movement
and space use is largely dependent upon the local landscape composition
and characteristics of the road itself.
Local electrical distribution lines are usually much shorter in
height than transmission lines but can still contribute to habitat
fragmentation through similar mechanisms as other vertical features
when erected above ground. In addition to habitat loss and
fragmentation, electrical power lines can directly affect prairie
grouse by posing a collision hazard (Leopold 1933, p. 353; Connelly et
al. 2000, p. 974). There were no datasets available to quantify the
total impact of distribution lines on the landscape for the lesser
prairie-chicken. Although distribution lines are a significant
landscape feature throughout the Great Plains with potential to affect
lesser prairie-chicken habitat, after reviewing all available
information, we were unable to develop a method to quantitatively
incorporate the occurrence of distribution lines into our geospatial
analysis.
As part of our geospatial analysis, we estimated the area impacted
by direct and indirect habitat loss due to roads (Service 2022,
appendix B, part 2). These calculations of the current analysis area do
not include historical impacts of loss; thus, the calculations likely
underestimate the historical effect of roads on rangewide habitat loss
for the lesser prairie-chicken. The results indicate that the total
areas of grassland that have been directly and indirectly impacted by
roads within the analysis area for the lesser prairie-chicken are:
about 17 percent of the total area in the Short-Grass/CRP Ecoregion;
about 14 percent of the total area in the Sand Sagebrush Ecoregion;
about 20 percent of the total area in the Mixed-Grass Ecoregion; and
about 19 percent of the total area in the Shinnery Oak Ecoregion.
Rangewide, we estimate about 3,996,000 ac (1,617,000 ha) of grassland
have been impacted by roads, representing about 18 percent of the total
analysis area (Service 2022, appendix E, figure E.6). We did not have
adequate spatial data to evaluate habitat loss caused solely by
electrical distribution lines, but much of the existing impacts of
power lines occur within the impacts caused by roads. Electrical
distribution lines that fall outside the existing impacts of roads
would represent additional impacts for the lesser prairie-chicken that
are not quantified in our geospatial analysis.
Development of roads and electrical distribution lines directly
removes habitat that supports lesser prairie-chicken, and the effects
of the development extend past the immediate footprint of the
development, further impacting habitat and altering behavior of lesser
prairie-chicken throughout both the Northern and the Southern DPSs.
These activities have resulted in decreases in population resiliency
and species redundancy.
Other Factors
Livestock Grazing
Grazing has long been an ecological driving force throughout the
ecosystems of the Great Plains (Stebbins 1981, p. 84), and much of the
untilled grasslands within the range of the lesser prairie-chicken is
currently grazed by livestock and other animals. Historically, the
interaction of fire, drought, prairie dogs (Cynomys ludovicianus), and
large ungulate grazers created and maintained distinctive plant
communities in the Western Great Plains, resulting in a mosaic of
vegetation structure and composition that sustained lesser prairie-
chicken and other grassland bird populations (Derner et al. 2009, p.
112). As such, grazing by domestic livestock is not inherently
detrimental to lesser prairie-chicken management and, in many cases, is
needed to maintain appropriate vegetative structure.
However, grazing practices that tend to result in overutilization
of forage and decreasing vegetation heterogeneity can produce habitat
conditions that differ in significant ways from the historical
grassland mosaic; these incompatible practices alter the vegetation
structure and composition and degrade the quality of habitat for the
lesser prairie-chicken. The more heavily altered conditions are the
least valuable for the lesser prairie-chicken (Jackson and
[[Page 72691]]
DeArment 1963 p. 733; Davis et al. 1979, pp. 56, 116; Taylor and
Guthery 1980a, p. 2; Bidwell and Peoples 1991, pp. 1-2). In some cases,
these alterations can result in areas that do not contain the
biological components necessary to support the lesser prairie-chicken.
Where grazing regimes leave limited residual cover in the spring,
protection of lesser prairie-chicken nests may be inadequate, and
desirable food resources can be scarce (Bent 1932, p. 280; Cannon and
Knopf 1980, pp. 73-74; Crawford 1980, p. 3; Kraft 2016, pp. 19-21).
Because lesser prairie-chicken depend on medium- and tall-grass species
for nesting, concealment, and thermal cover that are also
preferentially grazed by cattle, these plant species needed by lesser
prairie-chicken can easily be reduced or eliminated by cattle grazing,
particularly in regions of low rainfall (Hamerstrom and Hamerstrom
1961, p. 290). In addition, when grasslands are in a deteriorated
condition due to incompatible grazing and overutilization, the soils
have less water-holding capacity (Blanco and Lal 2010, p. 9), and the
availability of succulent vegetation and insects used by lesser
prairie-chicken chicks is reduced. However, grazing can be beneficial
to the lesser prairie-chicken when management practices produce or
enhance the vegetative characteristics required by the lesser prairie-
chicken.
The interaction of fire and grazing and its effect on vegetation
components and structure is likely important to prairie-chickens
(Starns et al. 2020, entire). On properties managed with patch-burn
grazing regimes, female greater prairie-chickens selected areas with
low cattle stocking rates and patches that were frequently burned,
though they avoided areas that were recently burned (Winder et al.
2017, p. 171). Patch-burn grazing created preferred habitats for female
greater prairie-chickens if the regime included a relatively frequent
fire-return interval, a mosaic of burned and unburned patches, and a
reduced stocking rate in unburned areas avoided by grazers. When
managed compatibly, widespread implementation of patch-burn grazing
could result in significant improvements in habitat quality for
wildlife in the tall-grass prairie ecosystem (Winder et al. 2017, p.
165). In the eastern portion of the lesser prairie-chicken range,
patch-burn grazing resulted in patchy landscapes with variation in
vegetation composition and structure (Lautenbach 2017, p. 20). Female
lesser prairie-chickens' use of the diversity of patches in the
landscape varied throughout their life cycle. They selected patches
with the greatest time-since-fire and subsequently the most visual
obstruction for nesting, and they selected sites with less time-since-
fire and greater bare ground and forbs for summer brooding.
Livestock also inadvertently flush lesser prairie-chicken and
trample lesser prairie-chicken nests (Toole 2005, p. 27; Pitman et al.
2006, pp. 27-29). Brief flushing of adults from nests can expose eggs
and chicks to predation and extreme temperatures. Trampling nests can
cause direct mortality to lesser prairie-chicken eggs or chicks or may
cause adults to permanently abandon their nests, ultimately resulting
in loss of young. Although these effects have been documented, the
significance of direct livestock effects on the lesser prairie-chicken
is largely unknown and is presumed not to be significant at a
population scale.
In summary, domestic livestock grazing (including management
practices commonly used to benefit livestock production) has altered
the composition and structure of grassland habitat, both currently and
historically, used by the lesser prairie-chicken. Much of the remaining
remnants of mixed-grass grasslands, while still important to the lesser
prairie-chicken, exhibit conditions quite different from those prior to
Euro-American settlement. These changes have reduced the suitability of
remnant grassland areas as habitat for lesser prairie-chicken. Grazing
management that has altered the vegetation community to a point where
the composition and structure are no longer suitable for lesser
prairie-chicken can contribute to fragmentation within the landscape,
even though these areas may remain as prairie or grassland. Livestock
grazing, however, is not inherently detrimental to lesser prairie-
chicken provided that grazing management results in a plant community
diversity and structure that is suitable for lesser prairie-chicken.
While domestic livestock grazing is a dominant land use on untilled
range land within the lesser prairie-chicken analysis area, geospatial
data do not exist at a scale and resolution necessary to calculate the
total amount of livestock grazing that is being managed in a way that
results in habitat conditions that are not compatible with the needs of
the lesser prairie-chicken. Therefore, we did not attempt to spatially
quantify the scope of grazing effects across the lesser prairie-chicken
range.
Shrub Control and Eradication
Shrub control and eradication are additional forms of habitat
alteration that can influence the availability and suitability of
habitat for lesser prairie-chicken (Jackson and DeArment 1963, pp. 736-
737). Most shrub control and eradication efforts in lesser prairie-
chicken habitat are primarily focused on sand shinnery oak for the
purpose of increasing forage for livestock grazing. Sand shinnery oak
is toxic if eaten by cattle when it first produces leaves in the spring
and competes with more palatable grasses and forbs for water and
nutrients (Peterson and Boyd 1998, p. 8), which is why it is a common
target for control and eradication efforts by rangeland managers. Prior
to the late 1990s, approximately 100,000 ac (40,000 ha) of sand
shinnery oak in New Mexico and approximately 1,000,000 ac (405,000 ha)
of sand shinnery oak in Texas were lost due to the application of
tebuthiuron and other herbicides for agriculture and range improvement
(Peterson and Boyd 1998, p. 2).
Shrub cover is an important component of lesser prairie-chicken
habitat in certain portions of the range, and sand shinnery oak is a
key shrub in the Shinnery Oak and portions of the Mixed-Grass
Ecoregions. The importance of sand shinnery oak as a component of
lesser prairie-chicken habitat in the Shinnery Oak Ecoregion has been
demonstrated by several studies (Fuhlendorf et al. 2002, pp. 624-626;
Bell 2005, pp. 15, 19-25). In West Texas and New Mexico, lesser
prairie-chicken avoid nesting where sand shinnery oak has been
controlled with tebuthiuron, indicating their preference for habitat
with a sand shinnery oak component (Grisham et al. 2014, p. 18; Haukos
and Smith 1989, p. 625; Johnson et al. 2004, pp. 338-342; Patten and
Kelly 2010, p. 2151). Where sand shinnery oak occurs, lesser prairie-
chicken use it both for food and cover. Sand shinnery oak may be
particularly important in drier portions of the range that experience
more severe and frequent droughts and extreme heat events, as sand
shinnery oak is more resistant to drought and heat conditions than are
most grass species. And because sand shinnery oak is toxic to cattle
and thus not targeted by grazing, it can provide available cover for
lesser prairie-chicken nesting and brood rearing during these extreme
weather events. Loss of this component of the vegetative community
likely contributed to observed population declines in lesser prairie-
chicken in these areas.
While relatively wide-scale shrub eradication has occurred in the
past, geospatial data do not exist to evaluate the extent to which
shrub eradication has contributed to the habitat loss and fragmentation
for the lesser prairie-chicken and, therefore, was not included in our
quantitative analysis.
[[Page 72692]]
While current efforts of shrub eradication are not likely occurring at
rates equivalent to those witnessed in the past, any additional efforts
to eradicate shrubs that are essential to lesser prairie-chicken
habitat will result in additional habitat degradation and thus reduce
redundancy and resiliency.
Influence of Anthropogenic Noise
Anthropogenic noise can be associated with almost any form of human
activity, and lesser prairie-chicken may exhibit behavioral and
physiological responses to the presence of noise. In prairie-chickens,
the ``boom'' call vocalization transmits information about sex,
territorial status, mating condition, location, and individual identity
of the signaler and thus is important to courtship activity and long-
range advertisement of the display ground (Sparling 1981, p. 484). The
timing of displays and frequency of vocalizations are critical
reproductive behaviors in prairie grouse and appear to have developed
in response to unobstructed conditions prevalent in prairie habitat and
indicate that effective communication, particularly during the lekking
season, operates within a fairly narrow set of acoustic conditions.
Prairie grouse usually initiate displays on the lekking grounds around
sunrise, and occasionally near sunset, corresponding with times of
decreased wind turbulence and thermal variation (Sparling 1983, p. 41).
Considering the narrow set of acoustic conditions in which
communication appears most effective for breeding lesser prairie-
chicken and the importance of communication to successful reproduction,
human activities that result in noises that disrupt or alter these
conditions could result in lek abandonment (Crawford and Bolen 1976b,
p. 239). Anthropogenic features and related activities that occur on
the landscape can create noise that exceeds the natural background or
ambient level. When the behavioral response to noise is avoidance, as
it often is for lesser prairie-chicken, noise can be a source of
habitat loss or degradation leading to increased habitat fragmentation.
Anthropogenic noise may be a possible factor in the population
declines of other species of lekking grouse in North America,
particularly for populations that are exposed to human developments
(Blickley et al. 2012a, p. 470; Lipp and Gregory 2018, pp. 369-370).
Male greater prairie-chicken adjust aspects of their vocalizations in
response to wind turbine noise, and wind turbine noise may have the
potential to mask the greater prairie-chicken chorus at 296 hertz (Hz)
under certain scenarios, but the extent and degree of masking is
uncertain (Whalen 2015, entire). Noise produced by typical oil and gas
infrastructure can mask grouse vocalizations, compromise the ability of
female sage-grouse to find active leks when such noise is present, and
affect nest site selection (Blickley and Patricelli 2012, p. 32; Lipp
2016, p. 40). Chronic noise associated with human activity leads to
reduced male and female attendance at noisy leks. Breeding,
reproductive success, and ultimately recruitment in areas with human
developments could be impaired by such developments, impacting survival
(Blickley et al. 2012b, entire). Because opportunities for effective
communication on the display ground occur under fairly narrow
conditions, disturbance during this period may have negative
consequences for reproductive success. Other communications used by
grouse off the lek, such as parent-offspring communication, may
continue to be susceptible to masking by noise from human
infrastructure (Blickley and Patricelli 2012, p. 33).
No data are available to quantify the areas of lesser prairie-
chicken habitat rangewide that have been affected by noise, but noise
is a threat that is almost entirely associated with anthropogenic
features such as roads or energy development. Therefore, through our
accounting for anthropogenic features we may have inherently accounted
for all or some of the response of the lesser prairie-chicken to noise
produced by those features.
Overall, persistent anthropogenic noise could cause lek attendance
to decline, disrupt courtship and breeding activity, and reduce
reproductive success. Noise can also cause abandonment of otherwise
usable habitat and, as a result, contribute to habitat loss and
degradation.
Fire
Fire, or its absence, is understood to be a major ecological driver
of grasslands in the Southern Great Plains (Anderson 2006, entire;
Koerner and Collins 2014, entire; Wright and Bailey 1982, pp. 80-137).
Fire is an ecological process important to maintaining grasslands by
itself and in coupled interaction with grazing and climate. The
interaction of these ecological processes results in increasing
grassland heterogeneity through the creation of temporal and spatial
diversity in plant community composition and structure and associated
response of wildlife (Fuhlendorf and Engle 2001, entire; Fuhlendorf and
Engle 2004, entire; Fuhlendorf et al. 2017a, pp. 169-196).
Following settlement of the Great Plains, fire management generally
emphasized prevention and suppression, often coupled with grazing
pressures that significantly reduced and removed fine fuels (Sayre
2017, pp. 61-70). This approach, occurring in concert with settlement
and ownership patterns that occurred in most of the Southern Great
Plains, meant that the scale of management was relegated to smaller
parcels than historically were affected. This increase in smaller
parcels with both intensive grazing and fire suppression resulted in
the transformation of landscapes from dynamic heterogeneous to largely
static and homogenous plant communities. This simplification of
vegetative pattern due to decoupling fire and grazing (Starns et al.
2019, pp. 1-3) changed the number and size of wildfires and ultimately
led to declines in biodiversity in the affected systems (Fuhlendorf and
Engle 2001, entire).
Changes in patterns of wildfire in the Great Plains have been noted
in recent years (Donovan et al. 2017, entire). While these landscapes
have a long history of wildfire, large wildfires (greater than 1,000 ac
(400 ha)) typically did not occur in recent past decades, and include
an increase in the Southern Great Plains of megafires (greater than
100,000 ac (404 km\2\; 40,468 ha)) since the mid-1990s (Lindley et al.
2019, p. 164). Changes have occurred throughout all or portions of the
Great Plains in number of large wildfires and season of fire
occurrence, as well as increased area burned by wildfire or increasing
probability of large wildfires (Donovan et al. 2017, p. 5990).
Furthermore, Great Plains land cover dominated by woody or woody/
grassland combined vegetation is disproportionately more likely to
experience large wildfires, with the greatest increase in both number
of fires and of area burned (Donovan et al. 2020a, p. 11). Fire
behavior has also been affected such that these increasingly large
wildfires are burning under weather conditions (Lindley et al. 2019,
entire) that result in greater burned extent and intensity. These
shifts in fire parameters and their outcomes have potential
consequences for lesser prairie-chicken, including: (1) larger areas of
complete loss of nesting habitat as compared to formerly patchy
mosaicked burns; and (2) large-scale reduction in the spatial and
temporal variation in vegetation structure and composition affecting
nesting and brood-rearing habitat, thermoregulatory cover, and predator
escape cover.
[[Page 72693]]
Effects from fire are expected to be relatively short term (Donovan
et al. 2020b, entire, Starns et al. 2020, entire), with plant community
recovery time largely predictable and influenced by pre-fire condition,
post-fire weather, and types of management. Some effects from fire,
however, such as the response to changing plant communities in the
range of the lesser prairie-chicken, will vary based on location within
the range and available precipitation. In the eastern extent of the
distribution of sand shinnery oak that occurs in the Mixed-Grass
Ecoregion, fire has potential negative effects on some aspects of the
lesser prairie-chicken habitat for 2 years after the area burns, but
these effects could be longer in duration dependent upon precipitation
patterns (Boyd and Bidwell 2001, pp. 945-946). Effects from fire on
lesser prairie-chicken varied based on fire break preparation, season
of burn, and type of habitat; positive effects included improved brood
habitat through increased forb and grasshopper abundance, but these can
be countered by short-term (2-year) negative effects to quality and
availability of nesting habitat and a reduction in food sources (Boyd
and Bidwell 2001, pp. 945-946). Birds moved into recently burned
landscapes of western Oklahoma for lek courtship displays because of
the reduction in structure from formerly dense vegetation (Cannon and
Knopf 1979, entire).
More recently, research evaluating indirect effects concluded that
prescribed fire and managed grazing following the patch-burn or pyric
herbivory (grazing practices shaped fire) approach will benefit lesser
prairie-chicken through increases in forbs; invertebrates; and the
quality, amount, and juxtaposition of brood habitat to available
nesting habitat (Elmore et al. 2017, entire). The importance of
temporal and spatial heterogeneity derived from pyric herbivory is
apparent in the female lesser prairie-chicken use of all patch types in
the patch-burn grazing mosaic, including greater than 2 years post fire
for nesting, 2-year post fire during spring lekking, 1- and 2-year post
fire during summer brooding, and 1-year post fire during nonbreeding
season (Lautenbach 2017, pp. 20-22). While the use of prescribed fire
as a tool for managing grasslands throughout the lesser prairie-chicken
range is encouraged, current use is at a temporal frequency and spatial
extent insufficient to support large amounts of lesser prairie-chicken
habitat. These fire management efforts are limited to a small number of
fire-minded landowners, resulting in effects to a small percentage of
the lesser prairie-chicken range.
While lesser prairie-chicken evolved in a fire-adapted landscape,
little research (Thacker and Twidwell 2014, entire) has been conducted
on response of lesser prairie-chicken to altered fire regimes. Research
to date has focused on site-specific responses and consequences. Human
suppression of wildfire and the limited extent of fire use (prescribed
fire) for management over the past century has altered the frequency,
scale, and intensity of fire occurrence in lesser prairie-chicken
habitat. These changes in fire parameters have happened simultaneously
with habitat loss and fragmentation, resulting in patchy distribution
of lesser prairie-chicken throughout their range. An increase in size,
intensity, or severity of wildfires as compared to historical
occurrences results in increased vulnerability of isolated, smaller
lesser prairie-chicken populations. Both woody plant encroachment and
drought are additive factors that increase risk of negative
consequences of wildfire ignition, as well as extended post-fire lesser
prairie-chicken habitat effects. The extent of these negative impacts
can be significantly altered by precipitation patterns following the
occurrence of the fire; dry periods will inhibit or extend plant
community response.
Historically, fire served an important role in maintenance and
quality of habitat for the lesser prairie-chicken. Currently, due to a
significant shift in fire regimes in the lesser prairie-chicken range,
fire use for management of grasslands plays a locally important but
overall limited role in most lesser prairie-chicken habitat. This
current lack of prescribed fire use in the range of the lesser prairie-
chicken is contributing to woody plant encroachment and degradation of
grassland quality due to its decoupling from the grazing and fire
interaction that is the foundation for plant community diversity in
structure and composition, which in turn supports the diverse habitat
needs of lesser prairie-chicken. These cascading effects contribute to
greater wildfire risk, and concerns exist regarding the changing
patterns of wildfires (scale, intensity, and frequency) and their
consequences for remaining lesser prairie-chicken populations and
habitat that are increasingly fragmented. Concurrently, wildfire has
increased as a threat rangewide due to compounding influences of
increased size and severity of wildfires and the potential consequences
to remaining isolated and fragmented lesser prairie-chicken
populations.
Extreme Weather Events
Weather-related events such as drought, snow, and hailstorms can
influence habitat quality or result in direct mortality of lesser
prairie-chickens. Although hailstorms typically have only a localized
effect, the effects of snowstorms and drought can often be more
widespread and can affect considerable portions of the lesser prairie-
chicken range. Drought is considered a universal ecological driver
across the Great Plains (Knopf 1996, p. 147). Annual precipitation
within the Great Plains is highly variable (Wiens 1974, p. 391), with
prolonged drought capable of causing local extinctions of annual forbs
and grasses within stands of perennial species; recolonization is often
slow (Tilman and El Haddi 1992, p. 263). Grassland bird species in
particular are impacted by climate extremes such as extended drought,
which acts as a bottleneck that allows only a limited number of
individuals to survive through the relatively harsh conditions (Wiens
1974, pp. 388, 397; Zimmerman 1992, p. 92). Drought also interacts with
many of the other threats impacting the lesser prairie-chicken and its
habitat, such as amplifying the effects of incompatible grazing and
predation.
Although the lesser prairie-chicken has adapted to drought as a
component of its environment, drought and the accompanying harsh,
fluctuating conditions (high temperatures and low food and cover
availability) have influenced lesser prairie-chicken populations.
Widespread periods of drought commonly result in ``bust years'' of
recruitment. Following extreme droughts of the 1930s, 1950s, 1970s, and
1990s, lesser prairie-chicken population levels declined and a decrease
in their overall range was observed (Lee 1950, p. 475; Ligon 1953, p.
1; Schwilling 1955, pp. 5-6; Hamerstrom and Hamerstrom 1961, p. 289;
Copelin 1963, p. 49; Crawford 1980, pp. 2-5; Massey 2001, pp. 5, 12;
Hagen and Giesen 2005, unpaginated). Additionally, lesser prairie-
chicken populations reached near record lows during and after the more
recent drought of 2011 to 2013 (McDonald et al. 2017, p. 12; Fritts et
al. 2018, entire).
Drought impacts prairie grouse, such as lesser prairie-chicken,
through several mechanisms. Drought affects seasonal growth of
vegetation necessary to provide suitable nesting and roosting cover,
food, and opportunity for escape from predators (Copelin 1963, pp. 37,
42; Merchant 1982, pp. 19, 25, 51;
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Applegate and Riley 1998, p. 15; Peterson and Silvy 1994, p. 228;
Morrow et al. 1996, pp. 596-597; Ross et al. 2016a, entire). Lesser
prairie-chicken home ranges will temporarily expand during drought
years (Copelin 1963, p. 37; Merchant 1982, p. 39) to compensate for
scarcity in available resources. During these periods, the adult birds
expend more energy searching for food and tend to move into areas with
limited cover in order to forage, leaving them more vulnerable to
predation and heat stress (Merchant 1982, pp. 34-35; Flanders-Wanner et
al. 2004, p. 31). Chick survival and recruitment may also be depressed
by drought (Merchant 1982, pp. 43-48; Morrow et al. 1996, p. 597;
Giesen 1998, p. 11; Massey 2001, p. 12), which likely affects
population trends more than annual changes in adult survival (Hagen
2003, pp. 176-177). Drought-induced mechanisms affecting recruitment
include decreased physiological condition of breeding females (Merchant
1982, p. 45); heat stress and water loss of chicks (Merchant 1982, p.
46); and effects to hatch success and juvenile survival due to changes
in microclimate, temperature, and humidity (Patten et al. 2005, pp.
1274-1275; Bell 2005, pp. 20-21; Boal et al. 2010, p. 11).
Precipitation, or lack thereof, appears to affect lesser prairie-
chicken adult population trends with a potential lag effect (Giesen
2000, p. 145; Ross et al. 2016a, pp. 6-8). That is, rain levels in one
year promote more vegetative cover for eggs and chicks in the following
year, which influences survival and reproduction.
Although lesser prairie-chicken have persisted through droughts in
the past, the effects of such droughts are exacerbated by human land
use practices such as incompatible grazing and land cultivation
(Merchant 1982, p. 51; Hamerstrom and Hamerstrom 1961, pp. 288-289;
Davis et al. 1979, p. 122; Taylor and Guthery 1980a, p. 2; Ross et al.
2016b, pp. 183-186) as well as the other threats that have affected the
current condition and have altered and fragmented the landscape and
decreased population abundances (Fuhlendorf et al. 2002, p. 617;
Rodgers 2016, pp. 15-19). In past decades, fragmentation of lesser
prairie-chicken habitat was less extensive than it is today,
connectivity between occupied areas was more prevalent, and populations
were larger, allowing populations to recover more quickly. In other
words, lesser prairie-chicken populations were more resilient to the
effects of stochastic events such as drought. As lesser prairie-chicken
population abundances decline and usable habitat declines and becomes
more fragmented, their ability to rebound from prolonged drought is
diminished.
Hailstorms can cause mortality of prairie grouse, particularly
during the spring nesting season. An excerpt from the May 1879 Stockton
News describes a large hailstorm near Kirwin, Kansas, as responsible
for killing prairie-chickens (likely greater prairie-chicken) and other
birds by the hundreds (Fleharty 1995, p. 241). Although such phenomena
are likely rare, the effects can be significant, particularly if they
occur during the nesting period and result in significant loss of eggs
or chicks. Severe winter storms can also result in localized impacts to
lesser prairie-chicken populations. For example, a severe winter storm
in 2006 was reported to reduce lesser prairie-chicken numbers in
Colorado by 75 percent from 2006 to 2007, from 296 birds observed to
only 74. Active leks also declined from 34 leks in 2006 to 18 leks in
2007 (Verquer 2007, p. 2). While populations commonly rebound to some
degree following severe weather events such as drought and winter
storms, a population with decreased resiliency becomes susceptible to
extirpation from stochastic events.
We are not able to quantify the impact that severe weather has had
on the lesser prairie-chicken populations, but, as discussed above,
these events have shaped recent history and influenced the current
condition for the lesser prairie-chicken.
Regulatory Mechanisms
In appendix D of the SSA report (Service 2022), we review in more
detail all of the existing regulatory mechanisms (such as local, State,
and Federal land use regulations or laws) that may impact lesser
prairie-chicken conservation. Here, we present a summary of some of
those regulatory mechanisms. All existing regulatory mechanisms listed
in appendix D of the SSA report were fully considered in our conclusion
about the status of the two DPSs.
All five States in the estimated occupied range (EOR) (Van Pelt et
al. 2013, p. 3) have incorporated the lesser prairie-chicken as a
species of conservation concern and management priority in their
respective State Wildlife Action Plans. While identification of the
lesser prairie-chicken as a species of conservation concern helps
heighten public awareness, this designation provides no protection from
direct take or habitat destruction or alteration. The lesser prairie-
chicken is listed as threatened in Colorado; this listing protects the
lesser prairie-chicken from direct purposeful mortality by humans but
does not provide protections for destruction or alteration of habitat.
Primary land ownership (approximately 5 percent of total range) at
the Federal level is on USFS and BLM lands. The lesser prairie-chicken
is present on the Cimarron National Grassland in Kansas and the
Comanche National Grassland in Colorado; a total of approximately 3
percent of the total acres estimated in the SSA analysis area is on
USFS land. The 2014 Lesser Prairie-Chicken Management Plan for these
grasslands provides a framework to manage lesser prairie-chicken
habitat. The plan provides separate population and habitat recovery
goals for each grassland, as well as vegetation surveys to inform
ongoing and future monitoring efforts of suitable habitat and lek
activities. Because National Grasslands are managed for multiple uses,
the plan includes guidelines for prescribed fire and grazing.
In New Mexico, roughly 41 percent of the known historical and most
of the estimated occupied lesser prairie-chicken range occurs on BLM
land, for a total of 3 percent of the total acres estimated in the
analysis area of the SSA report. The BLM established the 57,522-ac
(23,278-ha) Lesser Prairie-Chicken Habitat Preservation Area of
Critical Environmental Concern (ACEC) upon completion of the Resource
Management Plan Amendment (RMPA) in 2008. The management goal for the
ACEC is to protect the biological qualities of the area, with emphasis
on the preservation of the shinnery oak-dune community to enhance the
biodiversity of the ecosystem, particularly habitats for the lesser
prairie-chicken and the dunes sagebrush lizard. Upon designation, the
ACEC was closed to future oil and gas leasing, and existing leases
would be developed in accordance with prescriptions applicable to the
Core Management Area as described below (BLM 2008, p. 30). Additional
management prescriptions for the ACEC include designation as a right-
of-way exclusion area, vegetation management to meet the stated
management goal of the area, and limiting the area to existing roads
and trails for off-highway vehicle use (BLM 2008, p. 31). All acres of
the ACEC have been closed to grazing through relinquishment of the
permits except for one 3,442-ac (1,393-ha) allotment.
The BLM's approved RMPA (BLM 2008, pp. 5-31) provides some limited
protections for the lesser prairie-chicken in New Mexico by reducing
the number of drilling locations, decreasing the size of well pads,
reducing the number and
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length of roads, reducing the number of power lines and pipelines, and
implementing best management practices for development and reclamation.
The effect of these best management practices on the status of the
lesser prairie-chicken is unknown, particularly considering about
82,000 ac (33,184 ha) have already been leased in those areas (BLM
2008, p. 8). Although the BLM RMPA is an important tool for identifying
conservation actions that would benefit lesser prairie-chicken, this
program does not alleviate all threats acting on the species in this
area.
No new mineral leases will be issued on approximately 32 percent of
Federal mineral acreage within the RMPA planning area (BLM 2008, p. 8),
although some exceptions are allowed on a case-by-case basis (BLM 2008,
pp. 9-11). Within the Core Management Area and Primary Population Area,
as delineated in the RMPA, new leases will be restricted in occupied
and suitable habitat; however, if there is an overall increase in
reclaimed to disturbed acres over a 5-year period, new leases in these
areas will be allowed (BLM 2008, p. 11). In the southernmost habitat
management units outlined in the RMPA, where lesser prairie-chickens
are now far less common than in previous decades (Hunt and Best 2004),
new leases will not be allowed within 1.5 mi (2.4 km) of a lek (BLM
2008, p. 11).
We conclude that existing regulatory mechanisms have minimal
influence on the rangewide trends of lesser prairie-chicken habitat
loss and fragmentation because 97 percent of the lesser prairie-chicken
analysis area occurs on private lands, which are largely unregulated
for the protection of the species and its habitat. The activities
affecting lesser prairie-chicken habitat are largely land use practices
and land development without regulations ameliorating the primary
threats to the lesser prairie-chicken.
Conservation Efforts
Below we include a summary of conservation efforts; for a complete
description of these conservation efforts please see the SSA report
(Service 2022, pp. 49-62). All of the conservation measures discussed
in the SSA report were incorporated into the analysis of the species'
current and future condition. Some programs are implemented across the
species' range, and others are implemented at the State or local level.
Because the vast majority of lesser prairie-chicken and their habitat
occurs on private lands, most of these programs are targeted toward
voluntary, incentive-based actions in cooperation with private
landowners.
At the rangewide scale, plans include the Lesser Prairie-Chicken
Rangewide Conservation Plan, the Lesser Prairie-Chicken Initiative, and
the Conservation Reserve Program. Below is a summary of the primary
rangewide conservation efforts. For detailed descriptions of each
program, please see the SSA report. All existing ongoing conservation
efforts were fully considered in our determination on the status of the
two DPSs.
In 2013, the State fish and wildlife agencies within the range of
the lesser prairie-chicken and the Western Association of Fish and
Wildlife Agencies (WAFWA) finalized the Lesser Prairie-Chicken Range-
wide Conservation Plan (RWP) in response to concerns about threats to
lesser prairie-chicken habitat and resulting effects to lesser prairie-
chicken populations (Van Pelt et al. 2013, entire). The RWP established
biological goals and objectives as well as a conservation targeting
strategy that aims to unify conservation efforts towards common goals.
Additionally, the RWP established a mitigation framework administered
by WAFWA that allows industry participants the opportunity to mitigate
unavoidable impacts of a particular activity on the lesser prairie-
chicken. After approval of the RWP, WAFWA developed a companion oil and
gas candidate conservation agreement with assurances (CCAA), which
adopted the mitigation framework contained within the RWP that was
approved in 2014.
As of August 1, 2020, WAFWA had used incoming funds from industry
participants to place 22 sites totaling 128,230 unimpacted ac (51,893
ha) under conservation contracts to provide offset for industry impacts
that have occurred through the RWP and CCAA (Moore 2020, p. 9). Of
those sites, 35,635 unimpacted ac (14,421 ha) are permanently protected
and 92,595 unimpacted ac (37,472 ha) are being managed under 10-year
term agreements. Landowners who enroll agree to implement actions to
restore or enhance their lands for the lesser prairie-chicken. These
actions may include restoration actions (such as removal of woody
vegetation) or enhancement actions (such as implementation of a grazing
management plan designed for their property). These areas are enrolled
under RWP conservation contracts that will provide mitigation for 1,538
projects, which impacted 48,743 ac (19,726 ha) (WAFWA 2020, table 32,
unpaginated). When enrolling a property, industry participants agree to
minimize impacts from projects to lesser prairie-chicken habitat and
mitigate for all remaining impacts on the enrolled property.
At the end of 2021 in the CCAA, there were 111 active contracts
(Certificates of Inclusion) with 6,226,140 ac (2,519,629 ha) enrolled
(WAFWA 2022, p. 4), and in the WAFWA Conservation Agreement there were
52 active WAFWA Conservation Agreement contracts (Certificates of
Participation) with 599,626 ac (242,660 ha) enrolled (WAFWA 2020, table
5 unpaginated) by industry participants. These acres of industry
enrollment are areas where industry participants have agreed to
implement minimization measures and to pay mitigation fees to offset
the remaining impacts. A recent audit of the mitigation program
associated with the RWP and CCAA identified several key issues to be
resolved within the program to ensure financial stability and effective
conservation outcomes (Moore 2020, appendix E). WAFWA has hired a
consultant who is currently working with stakeholders, including the
Service, to consider available options to address the identified issues
to ensure long-term durability of the strategy.
In 2010, the USDA's Natural Resources Conservation Service (NRCS)
began implementation of the Lesser Prairie-Chicken Initiative (LPCI).
The LPCI provides conservation assistance, both technical and
financial, to landowners throughout the LPCI's administrative boundary
(NRCS 2017, p. 1). The LPCI focuses on maintenance and enhancement of
lesser prairie-chicken habitat while benefiting agricultural producers
by maintaining the farming and ranching operations throughout the
region. In 2019, after annual declines in landowner interest in LPCI,
the NRCS made changes in how LPCI will be implemented moving forward
and initiated conferencing under section 7 of the Act with the Service.
Prior to 2019, participating landowners had to address all threats to
the lesser prairie-chicken present on their property. In the future,
each conservation plan developed under LPCI will only need to include
one or more of the core management practices that include prescribed
grazing, prescribed burning, brush management, and upland wildlife
habitat management. Additional management practices may be incorporated
into each conservation plan, as needed, to facilitate meeting the
desired objectives. These practices are applied or maintained annually
for the life of the practice, typically 1 to 15 years, to treat or
manage habitat for lesser prairie-chicken. From 2010 through 2019, NRCS
worked with 883 private
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agricultural producers to implement conservation practices on 1.6
million ac (647,497 ha) of working lands within the historical range of
the lesser prairie-chicken (NRCS 2020, p. 2). During that time, through
LPCI, NRCS implemented prescribed grazing plans on 680,800 ac (275,500
ha) across the range (Griffiths 2020, pers. comm.). Through LPCI, NRCS
has also removed over 41,000 ac (16,600 ha) of eastern red cedar in the
Mixed-Grass Ecoregion and chemically treated approximately 106,000 ac
(43,000 ha) of mesquite in the Shinnery Oak Ecoregion. Lastly, NRCS has
conducted prescribed burns on approximately 15,000 ac (6,000 ha) during
this time.
The Conservation Reserve Program (CRP) is administered by the
USDA's Farm Service Agency and provides short-term protection and
conservation benefits on millions of acres within the range of the
lesser prairie-chicken. The CRP is a voluntary program that allows
eligible landowners to receive annual rental payments and cost-share
assistance in exchange for removing cropland and certain marginal
pastureland from agricultural production. CRP contract terms are for 10
to 15 years. The total amount of land that can be enrolled in the CRP
is capped nationally by the Food Security Act of 1985, as amended (the
2018 Farm Bill) at 27 million ac (10.93 million ha). All five States
within the range of the lesser prairie-chicken have lands enrolled in
the CRP. The 2018 Farm Bill maintains the acreage limitation that not
more than 25 percent of the cropland in any county can be enrolled in
CRP, with specific conditions under which a waiver to this restriction
can be provided for lands enrolled under the Conservation Reserve
Enhancement Program (84 FR 66813, December 6, 2019). Over time, CRP
enrollment fluctuates both nationally and locally. Within the counties
that intersect the Estimated Occupied Range plus a 10-mile buffer
(EOR+10), acres enrolled in CRP have declined annually since 2007 (with
the exception of one minor increase from 2010 to 2011) from nearly 6
million ac (2.4 million ha) enrolled to current enrollment levels of
approximately 4.25 million ac (1.7 million ha) (FSA 2020a, unpublished
data). The EOR+10 is a 10-mile buffer of the EOR often referenced in
lesser prairie-chicken planning efforts but also contains significant
areas that do not support the biotic and abiotic characteristics
required by the lesser prairie-chicken. More specific to our analysis
area, current acreage of CRP enrollment is approximately 1,822,000 ac
(737,000 ha) within our analysis area. Of those currently enrolled
acres there are approximately 120,000 ac (49,000 ha) of introduced
grasses and legumes dispersed primarily within the Mixed-Grass and
Shinnery Oak Ecoregions (FSA 2020b, unpublished data).
At the State level, programs provide direct technical and financial
cost-share assistance to private landowners interested in voluntarily
implementing conservation management practices to benefit species of
greatest conservation need--including the lesser prairie-chicken.
Additionally, a variety of State-level conservation efforts acquire and
manage lands or incentivize management by private landowners for the
benefit of the lesser prairie-chicken. Below is a summary for each
State within the range of the lesser prairie-chicken. For a complete
description of each, see the SSA report. All conservation measures
discussed in the SSA report were fully considered in this final rule.
Within the State of Kansas, conservation efforts are administered
by the Kansas Department of Wildlife and Parks (KDWP), The Nature
Conservancy, and the Service's Partners for Fish and Wildlife Program
(PFW). KDWP has targeted lesser prairie-chicken habitat improvements on
private lands by leveraging landowner cost-share contributions,
industry and nongovernmental organizations' cash contributions, and
agency funds toward several federally funded grant programs. The KDWP
has implemented conservation measures over 22,000 ac (8,900 ha) through
the Landowner Incentive Program, over 18,000 ac (7,285 ha) through the
State Wildlife Grant Private Landowner Program, 30,000 ac (12,140 ha)
through the Wildlife Habitat Incentives Program, and 12,000 ac (4,855
ha) through the Habitat First Program within the range of the lesser
prairie-chicken. Additionally, KDWP was provided an opportunity through
contributions from the Comanche Pool Prairie Resource Foundation to
leverage additional Wildlife and Sport Fish Restoration funds in 2016
to direct implementation of 19,655 ac (7,954 ha). The Nature
Conservancy in Kansas manages the 18,060-ac (7,309-ha) Smoky Valley
Ranch. The Nature Conservancy also serves as the easement holder for
nearly 34,000 ac (13,760 ha) of properties that are enrolled under the
RWP. The Nature Conservancy is also working to use funds from an NRCS
Regional Conservation Partnership Program that have resulted in nearly
50,000 ac (20,235 ha) on three ranches either with secured or in-
process conservation easements. These easements would restrict future
development and would ensure management is compatible for the
conservation of the lesser prairie-chicken. Our PFW program has
executed 95 private lands agreements with improvements on about 173,000
ac (70,011 ha) of private lands benefitting conservation of the lesser
prairie-chicken in Kansas. The primary activities being implemented on
these acres include: efforts to control and eradicate invasive, woody
plant species such as eastern red cedar; grazing management; and
enhanced use of prescribed fire to improve habitat conditions in native
grasslands.
In 2009, Colorado Parks and Wildlife (CPW) initiated its Lesser
Prairie-Chicken Habitat Improvement Program that provides cost-sharing
to private landowners who participate in practices such as deferred
grazing around active leks, enhancement of fields enrolled in CRP and
cropland-to-grassland habitat conversion. Since program inception, CPW
has completed 37,051 ac (14,994 ha) of habitat treatments. The Nature
Conservancy holds permanent conservation easements on multiple ranches
that make up the Big Sandy complex. Totaling approximately 48,940 ac
(19,805 ha), this complex is managed with lesser prairie-chicken as a
conservation objective and perpetually protects intact sand sagebrush
and short-grass prairie communities. The USFS currently manages the
Comanche Lesser Prairie-Chicken Habitat Zoological Area, as part of the
Comanche and Cimarron National Grasslands, which encompass an area of
10,177 ac (4,118 ha) in Colorado that is managed to benefit the lesser
prairie-chicken (USFS 2014, p. 9). In 2016, CPW and KDWP partnered with
Kansas State University and USFS to initiate a 3-year translocation
project to restore lesser prairie-chicken to the Comanche National
Grasslands (Colorado) and Cimarron National Grasslands (Kansas).
Beginning in the fall of 2016 and concluding with the 2019 spring
lekking season, the partnership trapped and translocated 411 lesser
prairie-chickens from the Short-Grass/CRP Ecoregion in Kansas to the
Sand Sagebrush Ecoregion. During April and May 2020 lek counts,
Colorado and Kansas biologists and technicians found 115 male birds on
20 active leks in the landscape around the Comanche and Cimarron
National Grasslands (Rossi 2020, pers. comm.). During lek counts in
2021, 65 males on 15 leks were documented in the release area (CPW
2021).
In 2013, the FWS issued the Oklahoma Department of Wildlife
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Conservation (ODWC) a 25-year enhancement of survival permit pursuant
to section 10(a)(1)(A) of the Act that included an umbrella CCAA
between the Service and ODWC for the lesser prairie-chicken in 14
Oklahoma counties (78 FR 14111, March 4, 2013). As of 2019, there were
84 participants with a total of 399,225 ac (161,561 ha) enrolled in the
ODWC CCAA, with 357,654 ac (144,737) enrolled as conservation acres
(ODWC 2020). The difference between total acres enrolled and
conservation acres enrolled is because, while a landowner may enroll
their entire property, not all of those acres provide habitat for the
lesser prairie-chicken. Landowners who agree to enroll in the CCAA
agree to implement measures, primarily prescribed grazing, to enhance
or restore habitat for the lesser prairie-chicken. The ODWC owns six
wildlife management areas totaling approximately 75,000 ac (30,351 ha)
in the range of the lesser prairie-chicken, though only a portion of
each wildlife management area can be considered as conservation acres
for lesser prairie-chicken because not all acres of the wildlife
management areas are habitat for the species. Our PFW program has
funded a shared position with ODWC for 6 years to conduct CCAA
monitoring and, in addition, has provided funding for on-the-ground
work in the lesser prairie-chicken range. Since 2017, the Oklahoma PFW
program has implemented 51 private lands agreements on about 10,603 ac
(4,291 ha) for the benefit of the lesser prairie-chicken in Oklahoma.
On these acres conservation measures may include control of eastern red
cedar, native grass planting, and fence marking and removal to minimize
collision mortality. The Nature Conservancy of Oklahoma manages the
4,050-ac (1,640-ha) Four Canyon Preserve in Ellis County for ecological
health to benefit numerous short-grass prairie species, including the
lesser prairie-chicken. In 2017, The Nature Conservancy acquired a
conservation easement on 1,784 ac (722 ha) in Woods County which
restricts future development and ensures sustainable management is
occurring. The Conservancy is seeking to permanently protect additional
acreage in the region through the acquisition of additional
conservation easements.
Texas Parks and Wildlife Department (TPWD) worked with the Service
and landowners to develop the first State-wide umbrella CCAA for the
lesser prairie-chicken in Texas, which was finalized in 2006. The Texas
CCAA covers 50 counties, largely encompassing the Texas Panhandle and
South Plains. Total landowner participation by the close of January
2020 was 91 properties totaling approximately 657,038 ac (265,894 ha)
enrolled in 15 counties (TPWD 2020, entire). On these acres
conservation measures would generally consist of prescribed grazing;
prescribed burning; brush management; cropland and residue management;
range seeding and enrollment in various other Federal or State programs
to provide financial assistance to implement these measures. Our PFW
program and the TPWD have actively collaborated on range management
programs designed to provide cost-sharing for implementation of habitat
improvements for lesser prairie-chicken. In the past the Service
provided funding to TPWD to support a Landscape Conservation
Coordinator position for the Panhandle and Southern High Plains region,
as well as funding to support Landowner Incentive Program projects
targeting lesser prairie-chicken habitat improvements (brush control
and grazing management) in this region. More than $200,000 of Service
funds were committed in 2010, and an additional $100,000 was committed
in 2011.
Since 2008, Texas has used these and other funds to address lesser
prairie-chicken conservation on 14,068 ac (5,693 ha) under the
Landowner Incentive Program. Typical conservation measures include
native plant restoration, control of exotic or invasive vegetation,
prescribed burning, selective brush management, and prescribed grazing.
The PFW program in Texas has executed 66 private lands agreements on
about 131,190 ac (53,091 ha) of privately owned lands for the benefit
of the lesser prairie-chicken in Texas. The Nature Conservancy of Texas
acquired approximately 10,635 ac (4,303 ha) in Cochran, Terry, and
Yoakum Counties. In 2014, The Nature Conservancy donated this land to
TPWD. The TPWD acquired an additional 3,402 ac (1,377 ha) contiguous to
the Yoakum Dunes Preserve creating the 14,037-ac (5,681-ha) Yoakum
Dunes Wildlife Management Area. In 2015, through the RWP process, WAFWA
acquired an additional 1,604 ac (649 ha) in Cochran County, nearly 3 mi
(5 km) west of the Yoakum Dunes Wildlife Management Area. The land was
deeded to TPWD soon after acquisition. In 2016, an additional 320 ac
(129 ha) was purchased by TPWD bordering the WAFWA-acquired tract
creating an additional 1,924-ac (779-ha) property that is being managed
(including prescribed grazing and invasive species control) as part of
the Yoakum Dunes Wildlife Management Area, now at 15,961 ac (6,459 ha).
The BLM's Special Status Species RMPA, which was approved in April
2008, addressed the concerns and future management of lesser prairie-
chicken and dunes sagebrush lizard habitats on BLM lands and
established the Lesser Prairie-Chicken Habitat Preservation Area of
Critical Environmental Concern (BLM 2008, entire). Since the RMPA was
approved in 2008, BLM has closed approximately 300,000 ac (121,000 ha)
to future oil and gas leasing and closed approximately 850,000 ac
(344,000 ha) to wind and solar development (BLM 2008, p. 3). From 2008
to 2020, they have reclaimed 3,500 ac (1,416 ha) of abandoned well pads
and associated roads and required burial of power lines within 2 mi
(3.2 km) of lesser prairie-chicken leks. Additionally, BLM has
implemented control efforts for mesquite on 832,104 ac (336,740 ha) and
has plans to do so on an additional 30,000 ac (12,141 ha) annually. In
2010, BLM acquired 7,440 ac (3,010 ha) of land east of Roswell, New
Mexico, to complete the 54,000-ac (21,853-ha) ACEC for lesser prairie-
chicken, which is managed to protect key habitat.
Following approval of the RMPA, a candidate conservation agreement
(CCA) and CCAA was drafted by a team including the Service, BLM, Center
of Excellence for Hazardous Material Management (CEHMM), and
participating cooperators to address the conservation needs of the
lesser prairie-chicken and the dunes sagebrush lizard. Since the CCA
and CCAA were finalized in 2008, 43 oil and gas companies have enrolled
a total of 1,964,163 ac (794,868 ha) in the historical range of the
lesser prairie-chicken. By enrolling these lands, industry participants
have agreed to implement conservation measures aimed to minimize
impacts of their development activities to the lesser prairie-chicken
and pay fees to offset the remaining impacts. In addition, 72 ranchers
in New Mexico and the New Mexico Department of Game and Fish have
enrolled a total of 2,055,461 ac (831,815 ha). The New Mexico State
Land Office has enrolled a total of 406,673 ac (164,575 ha) in the
historical range of the lesser prairie-chicken. By enrolling, the
Department of Game and Fish, State Land Office, and landowners agree to
follow grazing management standards established in the agreement,
limiting development actions where the landowner has discretion, limit
herbicide use, and other actions as identified in the agreement. The
CCA and CCAA have treated 79,297 ac (32,090 ha) of mesquite and
reclaimed
[[Page 72698]]
154 abandoned well pads and associated roads. CEHMM has also removed
7,564 ac (3,061 ha) of dead, standing mesquite, and has another 12,000
ac (5,000 ha) scheduled in the upcoming 2 years.
The Nature Conservancy owns and manages the 28,000-ac (11,331-ha)
Milnesand Prairie Preserve near Milnesand, New Mexico. Additionally,
the New Mexico Department of Game and Fish (NMDGF) has designated 30
Prairie Chicken Areas (PCAs) specifically for management of the lesser
prairie-chicken ranging in size from 28 to 7,189 ac (11 to 2,909 ha)
and totaling more than 27,262 ac (11,033 ha). More recently, NMDGF
purchased an additional 7,417-ac (3,000-ha) property that connects two
of the previously owned PCAs that will create a 9,817-ac (4,000-ha)
contiguous property. In 2007, the State Game Commission used New Mexico
State Land Conservation Appropriation funding to acquire 5,285 ac
(2,137 ha) of private ranchland in Roosevelt County. Our PFW program in
New Mexico has contributed financial and technical assistance for
restoration and enhancement activities benefitting the lesser prairie-
chicken in New Mexico. In 2016, the PFW program executed a private land
agreement on 630 ac (255 ha) for treating invasive species with a
prescribed burn. In 2020 the PFW program executed a private land
agreement for a prescribed burn on 155 ac (63 ha).
Conditions and Trends
Rangewide Trends
The lesser prairie-chicken estimated historical range encompasses
an area of approximately 115 million ac (47 million ha). As discussed
in Background, not all of the area within this historical range was
evenly occupied by lesser prairie-chicken, and some of the area may not
have been suitable to regularly support lesser prairie-chicken
populations (Boal and Haukos 2016, p. 6). However, the current range of
the lesser prairie-chicken has been significantly reduced from the
historical range, and estimates of the reduction vary from greater than
90 percent (Hagen and Giesen 2005, unpaginated) to approximately 83
percent (Van Pelt et al. 2013, p. 3).
We estimated the current amount and configuration of potential
lesser prairie-chicken usable area within the analysis area using the
geospatial analysis described in the SSA report (Service 2022, section
3.2; appendix B, parts 1, 2, and 3) and considering existing impacts as
described above. The total area of all potential usable (land cover
that may be consistent with lesser prairie-chicken areas that have the
potential to support lesser prairie-chicken use) and potential usable,
unimpacted land cover (that is, not impacted by landscape features)
categories in each ecoregion and rangewide is shown below in table 1.
To assess lesser prairie-chicken habitat at a larger scale and
incorporate some measure of connectivity and fragmentation, we then
grouped the areas of potential usable, unimpacted land cover based on
the proximity of other areas with potential usable, unimpacted lesser
prairie-chicken land cover. To do this, we used a ``nearest neighbor''
geospatial process to determine how much potential usable land cover is
within 1 mi (1.6 km) of any area of potential usable land cover. This
nearest neighbor analysis gives an estimate of how closely potential
usable, unimpacted land cover is clustered together, versus spread
apart, from other potential usable, unimpacted land cover. Areas with
at least 60 percent potential usable, unimpacted land cover within 1 mi
(1.6 km) were grouped. The 60 percent threshold was chosen because
maintaining grassland in large blocks is vital to conservation of the
species (Ross et al. 2016a, entire; Hagen and Elmore 2016, entire;
Spencer et al. 2017, entire; Sullins et al. 2019, entire), and these
studies indicate that landscapes consisting of greater than 60 percent
grassland are required to support lesser prairie-chicken populations.
This approach eliminates small, isolated, and fragmented patches of
otherwise potential usable land cover that are not likely to support
persistent populations of the lesser prairie-chicken. A separate
analysis found that the areas with 60 percent or greater unimpacted
potential usable land cover within 1 mi (1.6 km) captured approximately
90 percent of known leks (Service 2022, appendix B, part 3).
Table 1--Results of Lesser Prairie-Chicken Geospatial Analysis by Ecoregion and Rangewide, Estimating Total Area
in Acres, Potential Usable Area, and Area Calculated by Our Nearest Neighbor Analysis
[All numbers are in acres. Numbers may not sum due to rounding.]
----------------------------------------------------------------------------------------------------------------
Nearest
Ecoregion Ecoregion Potential neighbor % of total
total area usable area analysis area
----------------------------------------------------------------------------------------------------------------
Short-Grass/CRP................................. 6,298,014 2,961,318 1,023,894 16.3
Mixed-Grass..................................... 8,527,718 6,335,451 994,483 11.7
Sand Sagebrush.................................. 3,153,420 1,815,435 1,028,523 32.6
Northern DPS total.............................. 17,979,152 11,112,204 3,046,900 16.9
Shinnery Oak (Southern DPS total)............... 3,850,209 2,626,305 1,023,572 26.6
---------------------------------------------------------------
Rangewide Totals............................ 21,829,361 13,738,509 4,070,472 18.6
----------------------------------------------------------------------------------------------------------------
The results of the nearest neighbor analysis indicate that about 19
percent of the entire analysis area and from 12 percent to 33 percent
within each of the four ecoregions is available for use by the lesser
prairie-chicken. Due to limitations in data availability and accuracy
as well as numerous limitations with the methodology and assumptions
made for this analysis, this estimate should not be viewed as a precise
measure of the lesser prairie-chicken habitat; instead, it provides a
generalized baseline to characterize the current condition and by which
we can then forecast the effect of future changes.
In the SSA report, we also considered trends in populations.
Estimates of population abundance prior to the 1960s are indeterminable
and rely almost entirely on anecdotal information (Boal and Haukos
2016, p. 6). While little is known about precise historical population
sizes, the lesser prairie-chicken was reported to be quite common
throughout its range in the early 20th century (Bent 1932, pp. 280-281,
283; Baker 1953, p. 8; Bailey and Niedrach 1965, p. 51; Sands 1968, p.
454; Fleharty 1995, pp. 38-44; Robb and Schroeder 2005, p. 13). In the
1960s, State fish and wildlife agencies began routine lesser prairie-
chicken monitoring efforts that have largely continued to today.
[[Page 72699]]
In the SSA report and this final rule, we discuss lesser prairie-
chicken population estimates from two studies. The first study
calculated historical trends in lesser prairie-chicken abundances from
1965 through 2016 based on population reconstruction methods and
historical lek surveys (Hagen et al. 2017, pp. 6-9). The results of
these estimates indicate that lesser prairie-chicken rangewide
abundance (based on a minimum estimated number of male lesser prairie-
chicken) peaked from 1965-1970 at a mean estimate of about 175,000
males. The mean population estimates maintained levels of greater than
100,000 males until 1989, after which they steadily declined to a low
of 25,000 males in 1997 (Garton et al. 2016, p. 68). The mean
population estimates following 1997 peaked again at about 92,000 males
in 2006 but subsequently declined to 34,440 males in 2012. This 2006
peak was far below the 1965-1970 estimated peak, demonstrating that the
species did not achieve its prior peak population level. We identified
concerns in the past with some of the methodologies and assumptions
made in this analysis, and the challenges of these data are noted in
other studies (for example, Zavaleta and Haukos 2013, p. 545; Cummings
et al. 2017, pp. 29-30). While these concerns remain, including the
very low sample sizes particularly in the 1960s, this work represents
the only attempt to compile the extensive historical ground lek count
data collected by State agencies to estimate rangewide population
sizes. Approximate distribution of lek locations as reported by WAFWA
for the entire range that were observed occupied by lesser prairie-
chicken at least once between 2015 and 2019 are shown in the SSA report
(Service 2022, appendix E, figure E.7).
Following development of aerial survey methods (McRoberts et al.
2011, entire), more statistically rigorous estimates of lesser prairie-
chicken abundance (both males and females) have been conducted by
flying aerial line-transect surveys throughout the range of the lesser
prairie-chicken and extrapolating densities from the surveyed area to
the rest of the range beginning in 2012 (Nasman et al. 2022, entire).
The aerial survey results from 2012 through 2022 estimated the lesser
prairie-chicken population abundance, averaged over the most recent 5
years of surveys (2017-2022, no surveys in 2019), at 32,210 (90 percent
CI: 11,489, 64,303) (Nasman et al. 2022, p. 16; table 10). The results
of these survey efforts should not be taken as precise estimates of the
annual lesser prairie-chicken population abundance, as indicated by the
large confidence intervals. Thus, the best use of this data is for
long-term trend analysis rather than for conclusions based on annual
fluctuations. As such, we report the population estimate for the
current condition as the average of the past 5 years of surveys.
Table 2--Rangewide and Ecoregional Estimated Lesser Prairie-Chicken Total Population Sizes Averaged From 2017 to
2022, Lower and Upper 90 Percent Confidence Intervals (CI) Over the 5 Years of Estimates, and Percent of
Rangewide Totals for Each Ecoregion (From Nasman et al. 2022, p. 16). No Surveys Were Conducted in 2019.
----------------------------------------------------------------------------------------------------------------
5-Year 5-Year 5-Year
Ecoregion average minimum lower maximum upper Percent of
estimate CI CI total
----------------------------------------------------------------------------------------------------------------
Short-Grass/CRP................................. 23,083 9,653 39,934 72
Mixed-Grass..................................... 5,024 1,601 10,481 15
Sand Sagebrush.................................. 1,297 56 4,881 4
Shinnery Oak.................................... 2,806 179 9,007 9
---------------------------------------------------------------
Rangewide Totals............................ 32,210 11,489 64,303 100
----------------------------------------------------------------------------------------------------------------
We now discuss habitat impacts and population trends in each
ecoregion and DPS throughout the range of the lesser prairie-chicken.
Southern DPS
Using our geospatial analysis, we were able to explicitly account
for habitat loss and fragmentation and quantify the current condition
of the Shinnery Oak Ecoregion. Of the sources of habitat loss and
fragmentation that have occurred, cropland conversion, roads, and
encroachment of woody vegetation had the largest impacts on land cover
in the Southern DPS (Table 3). Based on our nearest neighbor analysis,
we estimated there are approximately 1,023,572 ac (414,225 ha) or 27
percent of the ecoregion and the Southern DPS potentially available for
use by lesser prairie-chicken (table 1).
Table 3--Estimated Areas of Current Direct and Indirect Impacts, by
Impact Source, and the Proportion of the Total Area of the Shinnery Oak
Ecoregion Estimated To Be Impacted (See Table 1 for Totals)
[Impacts are not necessarily cumulative because of overlap of some
impacted areas by more than one impact source.]
------------------------------------------------------------------------
Percent of
Impact Sources Acres ecoregion
------------------------------------------------------------------------
Shinnery Oak Ecoregion (Southern DPS)
------------------------------------------------------------------------
Cropland Conversion..................... 540,120 14
Petroleum Production.................... 161,652 4
Wind Energy Development................. 90,869 2
Transmission Lines...................... 372,577 10
Woody Vegetation Encroachment........... 617,885 16
Roads................................... 742,060 19
-------------------------------
Total Ecoregion/Southern DPS Area... 3,850,209
------------------------------------------------------------------------
[[Page 72700]]
Based on population reconstruction methods, the mean population
estimate ranged between about 5,000 to 12,000 males through 1980,
increased to 20,000 males in the mid-1980s and declined to ~1,000 males
in 1997 (Hagen et al. 2017, pp. 6-9). The mean population estimate
peaked again to ~15,000 males in 2006 and then declined again to fewer
than 3,000 males in the mid-2010s.
Aerial surveys have been conducted to estimate lesser prairie-
chicken population abundance since 2012, and results in the Shinnery
Oak Ecoregion from 2012 through 2022 indicate that this ecoregion has
the third highest population size (Nasman et al. 2022, p. 16) of the
four ecoregions. Average estimates from 2017 to 2022 are 2,806 birds
(90 percent CI: 179, 9,007), representing about 9 percent of the
rangewide total (table 2). Recent estimates have varied between fewer
than 1,000 birds in 2015 to more than 5,000 birds in 2020 and
decreasing to fewer than 1,000 birds again in 2022 (see also Service
2022, appendix E, figure E.7).
Northern DPS
Prairies of the Short-Grass/CRP Ecoregion have been significantly
altered since European settlement of the Great Plains. Much of these
prairies has been converted to other land uses such as cultivated
agriculture, roads, power lines, petroleum production, wind energy, and
transmission lines. Some areas have also been altered due to woody
vegetation encroachment. Within this ecoregion, it has been estimated
that about 73 percent of the landscape has been converted to cropland
with 7 percent of the area in CRP (Dahlgren et al. 2016, p. 262).
According to our GIS analysis, of the sources of habitat loss and
fragmentation that have occurred, conversion to cropland has had the
single largest impact on land cover in this ecoregion (table 4). Based
on our nearest neighbor analysis, we estimated approximately 1,023,894
ac (414,355 ha), or 16 percent of the ecoregion, is potentially
available for use by lesser prairie-chicken (table 1).
Table 4--Estimated Areas of Current Direct and Indirect Impacts, by
Impact Source, and the Proportion of the Total Area of the Short-Grass/
CRP Ecoregion Estimated To Be Impacted (See Table 1 for Totals)
[Impacts are not necessarily cumulative because of overlap of some
impacted areas by more than one impact source.]
------------------------------------------------------------------------
Percent of
Impact sources Acres ecoregion
------------------------------------------------------------------------
Short-Grass/CRP Ecoregion
------------------------------------------------------------------------
Cropland Conversion..................... 2,333,660 37
Petroleum Production.................... 248,146 4
Wind Energy Development................. 145,963 2
Transmission Lines...................... 436,650 7
Woody Vegetation Encroachment........... 284,175 5
Roads................................... 1,075,931 17
-------------------------------
Total Ecoregion Area................ 6,298,014
------------------------------------------------------------------------
Based on population reconstruction methods, the mean population
estimate for this ecoregion increased from a minimum of about 14,000
males in 2001 and peaked at about 21,000 males in 2011 (Hagen et al.
2017, pp. 8-10; see also Service 2022, figure 3.3).
Aerial surveys since 2012 indicate that the Short-Grass/CRP
Ecoregion (figure 3.4) has the largest population size (Nasman et al.
2022, p. 16) of the four ecoregions. Average estimates from 2017 to
2022 are 23,083 birds (90 percent CI: 9,653, 39,934), making up about
72 percent of the rangewide lesser prairie-chicken total (table 2).
Much of the Mixed-Grass Ecoregion was originally fragmented by
home-steading, which subdivided tracts of land into small parcels of
160-320 ac (65-130 ha) in size (Rodgers 2016, p. 17). As a result of
these small parcels, road and fence densities are higher compared to
other ecoregions and, therefore, increase habitat fragmentation and
pose higher risk for collision mortalities than in other ecoregions
(Wolfe et al. 2016, p. 302). Fragmentation has also occurred due to oil
and gas development, wind energy development, transmission lines,
highways, and expansion of invasive woody plants such as eastern red
cedar. A major concern for lesser prairie-chicken populations in this
ecoregion is the loss of grassland due to the rapid westward expansion
of the eastern red-cedar (NRCS 2016, p. 16). Oklahoma Forestry Services
estimated the average rate of expansion of eastern red-cedar in 2002 to
be 762 ac (308 ha) per day (Wolfe et al. 2016, p. 302).
Table 5--Estimated Areas of Current Direct And Indirect Impacts, by
Impact Source, and the Proportion (Percent) of the Total Area of the
Mixed-Grass Ecoregion Estimated To Be Impacted (See Table 1 for Totals)
[Impacts are not necessarily cumulative because of overlap of some
impacted areas by more than one impact source.]
------------------------------------------------------------------------
Percent of
Impact Sources Acres Ecoregion
------------------------------------------------------------------------
Mixed-Grass Ecoregion
------------------------------------------------------------------------
Cropland Conversion..................... 1,094,688 13
Petroleum Production.................... 859,929 10
Wind Energy Development................. 191,571 2
Transmission Lines...................... 576,713 7
Woody Vegetation Encroachment........... 2,047,510 24
Roads................................... 1,732,050 20
-------------------------------
[[Page 72701]]
Total Ecoregion Area................ 8,527,718
------------------------------------------------------------------------
Using our geospatial analysis, we were able to explicitly account
for habitat loss and fragmentation and quantify the current condition
of this ecoregion for the lesser prairie-chicken. Of the sources of
habitat loss and fragmentation that have occurred, encroachment of
woody vegetation had the largest impact, with conversion to cropland,
roads, and petroleum production also having significant impacts on land
cover in this ecoregion (table 5). Based on our nearest neighbor
analysis, we estimated there are approximately 994,483 ac (402,453 ha)
or 12 percent of the ecoregion, that is potentially available for use
by lesser prairie-chicken (table 1).
The Mixed-Grass Ecoregion historically contained the highest lesser
prairie-chicken densities (Wolfe et al. 2016, p. 299). Based on
population reconstruction methods, the mean population estimate for
this ecoregion in the 1970s and 1980s was around 30,000 males (Hagen et
al. 2017, pp. 6-7). Population estimates declined in the 1990s and
peaked again in the early 2000s at around 25,000 males, before
declining and remaining at its lowest levels, fewer than 10,000 males
in 2012, since the late 2000s (Hagen et al. 2017, pp. 6-7).
Aerial surveys from 2012 through 2022 indicate this ecoregion has
the second highest population size of the four ecoregions (Nasman et
al. 2022, p. 16). Average estimates from 2017 to 2022 are 5,024 birds
(90 percent CI: 1,601, 10,481), representing about 15 percent of the
rangewide total (table 2). Results show minimal variation in recent
years.
Prairies of the Sand Sagebrush Ecoregion have been influenced by a
variety of activities since European settlement of the Great Plains.
Much of these grasslands have been converted to other land uses such as
cultivated agriculture, roads, power lines, petroleum production, wind
energy, and transmission lines. Some areas have also been altered due
to woody vegetation encroachment. Only 26 percent of historical sand
sagebrush prairie is available as potential nesting habitat for lesser
prairie-chicken (Haukos et al. 2016, p. 285). Using our geospatial
analysis, we were able to explicitly account for habitat loss and
fragmentation and quantify the current condition of this ecoregion for
the lesser prairie-chicken. Of the sources of habitat loss and
fragmentation that have occurred, conversion to cropland has had the
single largest impact on land cover in this ecoregion (table 6). Based
on our nearest neighbor analysis, we estimated there are approximately
1,028,523 ac (416,228 ha) or 33 percent of the ecoregion, potentially
available for use by lesser prairie-chicken (table 1). In addition,
habitat loss due to the degradation of the rangeland within this
ecoregion continues to be a limiting factor for lesser prairie-chicken,
and most of the existing birds within this ecoregion persist primarily
on and near CRP lands. Drought conditions in the period 2011-2014 have
expedited population decline (Haukos et al. 2016, p. 285).
Table 6--Estimated Areas of Current Direct and Indirect Impacts, by
Impact Source, and the Proportion (Percent) of the Total Area of the
Sand Sagebrush Ecoregion Estimated To Be Impacted (See Table 1 for
Totals).
[Impacts are not necessarily cumulative because of overlap of some
impacted areas by more than one impact source.]
------------------------------------------------------------------------
Percent of
Impact sources Acres ecoregion
------------------------------------------------------------------------
Sand Sagebrush Ecoregion
------------------------------------------------------------------------
Cropland Conversion..................... 994,733 32
Petroleum Production.................... 163,704 5
Wind Energy Development................. 0 0
Transmission Lines...................... 167,240 5
Woody Vegetation Encroachment........... 68,147 2
Roads................................... 446,316 14
-------------------------------
Total Ecoregion Area................ 3,153,420
------------------------------------------------------------------------
Based on population reconstruction methods, the mean population
estimate for this ecoregion peaked at greater than 90,000 males from
1970 to 1975 and declined to its lowest level of fewer than 1,000 males
in recent years.
Aerial surveys from 2012 through 2022 indicate that this ecoregion
has the lowest population size (Nasman et al. 2022, p. 16) of the four
ecoregions. Average estimates from 2017 to 2022 are 1,297 birds (90
percent CI: 56, 4,881) representing about 4 percent of the rangewide
lesser prairie-chicken total (table 2). Recent results have been highly
variable, with 2020 being the lowest estimate reported. Although the
aerial survey results show 171 birds in this ecoregion in 2020 (with no
confidence intervals because the number of detections were too low for
statistical analysis), ground surveys in this ecoregion in Colorado and
Kansas detected 406 birds, so we know the current population is
actually larger than indicated by the aerial survey results (Rossi and
Fricke, pers. comm.
[[Page 72702]]
2020, entire). Aerial surveys for 2021 estimated 440 birds (90 percent
CI: 55, 963) for this ecoregion (Nasman et al. 2022, p. 16).
Table 7 combines the estimated area impacted presented above for
each of the three ecoregions into one estimate for each impact source
for the Northern DPS.
Table 7--Estimated Areas of Current Direct and Indirect Impacts, by
Impact Source, and the Proportion (Percent) of the Total Area of the
Northern DPS Estimated To Be Impacted (See Table 1 For Totals)
[Impacts are not necessarily cumulative because of overlap of some
impacted areas by more than one impact source.]
------------------------------------------------------------------------
Impact Sources Acres Percent of DPS
------------------------------------------------------------------------
Northern DPS
------------------------------------------------------------------------
Cropland Conversion..................... 4,423,081 25
Petroleum Production.................... 1,271,779 7
Wind Energy Development................. 337,534 2
Transmission Lines...................... 1,180,603 7
Woody Vegetation Encroachment........... 2,399,832 13
Roads................................... 3,254,297 18
-------------------------------
Total Northern DPS Area............. 17,979,152
------------------------------------------------------------------------
Future Condition
As discussed above, we conducted a geospatial analysis to
characterize the current condition of the landscape for the lesser
prairie-chicken by categorizing land cover data (into potential usable,
potential restoration, or nonusable categories), taking into account
exclusion areas and impacts to remove nonusable areas. We further
refined the analysis to account for connectivity by use of our nearest
neighbor analysis as described in Rangewide Trends. We then used this
geospatial framework to analyze the future condition for each
ecoregion. To analyze future habitat changes, we accounted for the
effects of both future loss of usable areas and restoration efforts by
estimating the rate of change based on future projections (Service
2022, figure 4.1).
Due to uncertainties associated with both future conservation
efforts and impacts, it is not possible to precisely quantify the
effect of these future actions on the landscape. Instead, we
established five future scenarios to represent a range of plausible
outcomes based upon three plausible levels of conservation (restoration
efforts) and three plausible levels of impacts. To account for some of
the uncertainty in these projections, we combined the levels of impacts
into five different scenarios labeled 1 through 5 (table 8). Scenario 1
represents the scenario with low levels of future impacts and high
levels of future restoration, and Scenario 5 represents the scenario
with high impacts and low restoration. Scenarios 1 and 5 were used to
frame the range of projected outcomes used in our model as they
represent the low and high of likely projected outcomes. Scenarios 2,
3, and 4 are model iterations that fall within the range bounded by
scenarios 1 and 5 and have continuation of the current level of
restoration efforts and vary impacts at low, mid, and high levels,
respectively. These scenarios provide a wide range of potential future
outcomes to consider in assessing lesser prairie-chicken habitat
conditions.
Table 8--Schematic of Future Scenarios for Lesser Prairie-Chicken
Conservation Considering a Range of Future Impacts and Restoration
Efforts
------------------------------------------------------------------------
Levels of future change in usable
area
Scenario ---------------------------------------
Restoration Impacts
------------------------------------------------------------------------
1............................... High.............. Low.
2............................... Continuation...... Low.
3............................... Continuation...... Mid.
4............................... Continuation...... High.
5............................... Low............... High.
------------------------------------------------------------------------
To project the likely future effects of impacts and conservation
efforts to the landscape as described through our land cover model, we
quantified the three levels of future habitat restoration and three
levels of future impacts within the analysis area by ecoregion on an
annual basis. In addition to restoration efforts, we also quantified
those efforts that enhance existing habitat. While these enhancement
efforts do not increase the amount of available area and thus are not
included in the spatial analysis, they are summarized in the SSA report
and considered as part of the overall analysis of the biological status
of the species. We then extrapolated those results over the next 25
years. We chose 25 years as a period for which we had reasonable
confidence in reliably projecting these future changes, and the
timeframe corresponds with some of the long-term planning for the
lesser prairie-chicken. A complete description of methodology used to
quantify projections of impacts and future conservation efforts is
provided in the SSA report (Service 2022, appendix C).
Quantifying future conservation efforts in terms of habitat
restoration allows us to account for the positive impact of those
efforts within our analysis by converting areas of land cover that were
identified as potential habitat in our current condition model to
usable land cover for the lesser prairie-chicken in the future
projections. Explicitly quantifying three levels of impacts in the
future allows us to account for the effect of these impacts on the
lesser prairie-chicken by converting areas identified as usable land
cover in our current condition model to nonusable area that will not be
available for use by the lesser prairie-chicken in the future.
As we did for the current condition to assess habitat connectivity,
after we characterized the projected effects of conservation and
impacts on potential future usable areas, we grouped the areas of
potential usable, unimpacted land cover on these new future landscape
projections using our nearest neighbor analysis (Service 2022, pp. 21-
23; appendix B, parts 1, 2, and 3). Also, as done for the current
condition, we evaluated the frequency of usable area blocks by size in
order to evaluate habitat fragmentation and connectivity in the future
scenarios (Service 2022, figure 4.2).
[[Page 72703]]
Threats Influencing Future Condition
Following are summary evaluations of the expected future condition
of threats analyzed in the SSA for the lesser prairie-chicken: effects
associated with habitat degradation, loss, and fragmentation, including
conversion of grassland to cropland (Factor A), petroleum production
(Factor A), wind energy development and transmission (Factor A), woody
vegetation encroachment (Factor A), and roads and electrical
distribution lines (Factor A); and other factors, such as livestock
grazing (Factor A), shrub control and eradication (Factor A), fire
(Factor A); and climate change (Factor E).
In this final rule, we do not present summary evaluations of the
following threats as we have no information to project future trends,
though we do expect them to have some effect on the species in the
future: predation (Factor C), collision mortality from fences (Factor
E), and influence of anthropogenic noise (Factor E). We also do not
discuss the following threats, as they are having little to no impact
on the species and its habitat currently, nor do we expect them to into
the foreseeable future: hunting and other recreational, educational,
and scientific use (Factor B); parasites and diseases (Factor C); and
insecticides (Factor E).
For the purposes of this assessment, we consider the foreseeable
future to be the amount of time on which we can reasonably determine a
likely threat's anticipated trajectory and the anticipated response of
the species to that threat. For climate change, the time for which we
can reliably project threats and the anticipated response is
approximately 60 years. For many other threats impacting the lesser
prairie-chicken throughout its range, we consider the time for which we
can reliably project threats and the anticipated response to be 25
years. This time period represents our best professional judgment of
the foreseeable future conditions related to conversion of grassland to
cropland, petroleum production, wind energy, and woody vegetation
encroachment, and, as discussed above, is the time period used to
project these threats in our geospatial analysis. For this period, we
had reasonable confidence in projecting these future changes, and the
timeframe corresponds with some of the long-term planning for the
lesser prairie-chicken. For other threats and the anticipated species
response, we can reliably project impacts and the species response for
less than 25 years, such as livestock grazing, roads and electrical
distribution lines, shrub control and eradication, and fire.
Habitat Loss and Fragmentation
As discussed in ``Threats Influencing Current Condition,'' habitat
loss and fragmentation is the primary concern for lesser prairie-
chicken viability. We discuss how each of these activities may
contribute to future habitat loss and fragmentation for the lesser
prairie-chicken and present the outcomes of the projections.
Conversion of Grassland to Cropland
Because much of the lands capable of being used for row crops has
already been converted to cultivated agriculture, we do not expect
future rates
[…truncated; see source link]Indexed from Federal Register on November 25, 2022.
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