Proposed Rule2022-02544
Endangered and Threatened Wildlife and Plants; Endangered Species for Prostrate Milkweed and Designation of Critical Habitat
Primary source
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Published
February 15, 2022
Issuing agencies
Interior DepartmentFish and Wildlife Service
Abstract
We, the U.S. Fish and Wildlife Service (Service), propose to list the prostrate milkweed (Asclepias prostrata), a plant species from Texas, as an endangered species and designate critical habitat under the Endangered Species Act of 1973, as amended (Act). This determination also serves as our 12-month finding on a petition to list the prostrate milkweed. After a review of the best available scientific and commercial information, we find that listing the species is warranted. Accordingly, we propose to list the prostrate milkweed as an endangered species. If we finalize this rule as proposed, it would add this species to the List of Endangered and Threatened Plants and extend the Act's protections to the species. We also propose to designate critical habitat for the prostrate milkweed under the Act. In total, approximately 691.3 acres (279.8 hectares) in Starr and Zapata Counties, Texas, fall within the boundaries of the proposed critical habitat designation. We also announce the availability of a draft economic analysis of the proposed designation of critical habitat for prostrate milkweed.
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[Federal Register Volume 87, Number 31 (Tuesday, February 15, 2022)]
[Proposed Rules]
[Pages 8509-8543]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-02544]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2021-0041; FF09E21000; FXES1111090FEDR 223]
RIN 1018-BE65
Endangered and Threatened Wildlife and Plants; Endangered Species
for Prostrate Milkweed and Designation of Critical Habitat
AGENCY: Fish and Wildlife Service, Interior.
[[Page 8510]]
ACTION: Proposed rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to
list the prostrate milkweed (Asclepias prostrata), a plant species from
Texas, as an endangered species and designate critical habitat under
the Endangered Species Act of 1973, as amended (Act). This
determination also serves as our 12-month finding on a petition to list
the prostrate milkweed. After a review of the best available scientific
and commercial information, we find that listing the species is
warranted. Accordingly, we propose to list the prostrate milkweed as an
endangered species. If we finalize this rule as proposed, it would add
this species to the List of Endangered and Threatened Plants and extend
the Act's protections to the species. We also propose to designate
critical habitat for the prostrate milkweed under the Act. In total,
approximately 691.3 acres (279.8 hectares) in Starr and Zapata
Counties, Texas, fall within the boundaries of the proposed critical
habitat designation. We also announce the availability of a draft
economic analysis of the proposed designation of critical habitat for
prostrate milkweed.
DATES: We will accept comments received or postmarked on or before
April 18, 2022. Comments submitted electronically using the Federal
eRulemaking Portal (see ADDRESSES, below) must be received by 11:59
p.m. Eastern Time on the closing date. We must receive requests for a
public hearing, in writing, at the address shown in FOR FURTHER
INFORMATION CONTACT by April 1, 2022.
ADDRESSES: You may submit comments by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: <a href="https://www.regulations.gov">https://www.regulations.gov</a>. In the Search box, enter the docket number or RIN
for this rulemaking (presented above in the document headings). For
best results, do not copy and paste either number; instead, type the
docket number or RIN into the Search box using hyphens. Then, click on
the Search button. On the resulting page, in the panel on the left side
of the screen, under the Document Type heading, check the Proposed Rule
box to locate this document. You may submit a comment by clicking on
``Comment.''
(2) By hard copy: Submit by U.S. mail to: Public Comments
Processing, Attn: FWS-R2-ES-2021-0041, U.S. Fish and Wildlife Service,
MS: PRB/3W, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
We request that you send comments only by the methods described
above. We will post all comments on <a href="https://www.regulations.gov">https://www.regulations.gov</a>. This
generally means that we will post any personal information you provide
us (see Information Requested, below, for more information).
Availability of supporting materials: The species status assessment
report and the draft economic analysis are available at <a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket No. FWS-R2-ES-2021-0041. For the
critical habitat designation, the coordinates or plot points or both
from which the maps are generated are included in the decision file and
are available at <a href="https://www.fws.gov/southwest/es/TexasCoastal/">https://www.fws.gov/southwest/es/TexasCoastal/</a>, at
<a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket No. FWS-R2-ES-2021-0041, and
at the Texas Coastal Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT). Any additional tools or supporting information
that we may develop for the critical habitat designation will also be
available at the Service website and field office set out above and may
also be included in this preamble and/or at <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
FOR FURTHER INFORMATION CONTACT: Chuck Ardizzone, Field Supervisor,
Texas Coastal Ecological Services Field Office, 17629 El Camino Real,
Suite 211, Houston, TX 77058; telephone 281-286-8282. Persons who use a
telecommunications device for the deaf (TDD) may call the Federal Relay
Service at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Act, if we determine that
a species warrants listing, we are required to promptly publish a
proposal in the Federal Register, unless doing so is precluded by
higher-priority actions and expeditious progress is being made to add
and remove qualified species to or from the List of Endangered and
Threatened Wildlife and Plants. The Service will make a determination
on our proposal within 1 year. If there is substantial disagreement
regarding the sufficiency and accuracy of the available data relevant
to the proposed listing, we may extend the final determination for not
more than six months. To the maximum extent prudent and determinable,
we must designate critical habitat for any species that we determine to
be an endangered or threatened species under the Act. Listing a species
as an endangered or threatened species and designation of critical
habitat can only be completed by issuing a rule.
What this document does. We propose to list the prostrate milkweed
as an endangered species under the Act, and we propose the designation
of critical habitat for the species.
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 competition from
introduced invasive grass; habitat loss and degradations from root-
plowing and conversion of native vegetation to improved buffelgrass
pasture; habitat loss from right of way (ROW) construction and
maintenance from energy development and road and utility construction;
habitat loss from border security development and enforcement
activities (Factor A); and the demographic and genetic consequences of
small population sizes (Factor E) are threats to the prostrate
milkweed.
Section 4(a)(3) of the Act requires the Secretary of the Interior
(Secretary) to designate critical habitat concurrent with listing to
the maximum extent prudent and determinable. Section 3(5)(A) of the Act
defines critical habitat as: (i) The specific areas within the
geographical area occupied by the species, at the time it is listed, on
which are found those physical or biological features (I) essential to
the conservation of the species and (II) which may require special
management considerations or protections; and (ii) specific areas
outside the geographical area occupied by the species at the time it is
listed, upon a determination by the Secretary that such areas are
essential for the conservation of the species. Section 4(b)(2) of the
Act states that the Secretary must make the designation on the basis of
the best scientific data available and after taking into consideration
the economic impact, the impact on national security, and any other
relevant impacts of specifying any particular area as critical habitat.
Information Requested
We intend that any final action resulting from this proposed rule
will be based on the best scientific and commercial data available and
be as accurate and as effective as possible. Therefore, we request
comments or information from other governmental
[[Page 8511]]
agencies, Native American Tribes, the scientific community, industry,
or any other interested parties concerning this proposed rule.
We particularly seek comments concerning:
(1) The species' biology, range, and population trends, including:
(a) Biological or ecological requirements of the species, including
habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range, including distribution patterns;
(d) Historical and current population levels, and current and
projected trends; and
(e) Past and ongoing conservation measures for the species, its
habitat, or both.
(2) Factors that may affect the continued existence of the species,
which may include habitat modification or destruction, overutilization,
disease, predation, the inadequacy of existing regulatory mechanisms,
or other natural or manmade factors.
(3) Biological, commercial trade, or other relevant data concerning
any threats (or lack thereof) to this species and existing regulations
that may be addressing those threats.
(4) Additional information concerning the historical and current
status, range, distribution, and population size of this species,
including the locations of any additional populations of this species.
(5) The reasons why we should or should not designate habitat as
``critical habitat'' under section 4 of the Act (16 U.S.C. 1531 et
seq.), including information to inform the following factors that the
regulations identify as reasons why designation of critical habitat may
be not prudent:
(a) The species is threatened by taking or other human activity and
identification of critical habitat can be expected to increase the
degree of such threat to the species;
(b) The present or threatened destruction, modification, or
curtailment of a species' habitat or range is not a threat to the
species, or threats to the species' habitat stem solely from causes
that cannot be addressed through management actions resulting from
consultations under section 7(a)(2) of the Act;
(c) Areas within the jurisdiction of the United States provide no
more than negligible conservation value, if any, for a species
occurring primarily outside the jurisdiction of the United States; or
(d) No areas meet the definition of critical habitat.
(6) Specific information on:
(a) The amount and distribution of prostrate milkweed habitat;
(b) What areas, that are occupied at the time of listing and that
contain the physical or biological features essential to the
conservation of the species, should be included in the designation and
why;
(c) Any additional areas occurring within the range of the species,
including Starr and Zapata Counties, Texas, that should be included in
the designation because they (1) are occupied at the time of listing
and contain the physical or biological features that are essential to
the conservation of the species and that may require special management
considerations, or (2) are unoccupied at the time of listing and are
essential for the conservation of the species;
(d) Special management considerations or protection that may be
needed in critical habitat areas we are proposing, including managing
for the potential effects of climate change; and
(e) What areas not occupied at the time of listing are essential
for the conservation of the species. We particularly seek comments:
(i) Regarding whether occupied areas are adequate for the
conservation of the species;
(ii) Providing specific information regarding whether or not
unoccupied areas would, with reasonable certainty, contribute to the
conservation of the species and contain at least one physical or
biological feature essential to the conservation of the species; and
(iii) Explaining whether or not unoccupied areas fall within the
definition of ``habitat'' at 50 CFR 424.02 and why.
(7) Land use designations and current or planned activities in the
subject areas and their possible impacts on proposed critical habitat.
(8) Any probable economic, national security, or other relevant
impacts of designating any area that may be included in the final
designation, and the related benefits of including or excluding
specific areas.
(9) Information on the extent to which the description of probable
economic impacts in the draft economic analysis is a reasonable
estimate of the likely economic impacts and any additional information
regarding probable economic impacts that we should consider.
(10) Whether any specific areas we are proposing for critical
habitat designation should be considered for exclusion under section
4(b)(2) of the Act, and whether the benefits of potentially excluding
any specific area outweigh the benefits of including that area under
section 4(b)(2) of the Act, in particular for the critical habitat
units on privately owned lands. If you think we should exclude any
additional areas, please provide credible information regarding the
existence of a meaningful economic or other relevant impact supporting
a benefit of exclusion.
(11) Whether we could improve or modify our approach to designating
critical habitat in any way to provide for greater public participation
and understanding, or to better accommodate public concerns and
comments.
Please include sufficient information with your submission (such as
scientific journal articles or other publications) to allow us to
verify any scientific or commercial information you include.
Please note that submissions merely stating support for, or
opposition to, the action under consideration without providing
supporting information, although noted, will not be considered in
making a determination, as section 4(b)(1)(A) of the Act directs that
determinations as to whether any species is an endangered or a
threatened species must be made ``solely on the basis of the best
scientific and commercial data available.''
You may submit your comments and materials concerning this proposed
rule by one of the methods listed in ADDRESSES. We request that you
send comments only by the methods described in ADDRESSES.
If you submit information via <a href="https://www.regulations.gov">https://www.regulations.gov</a>, your
entire submission--including any personal identifying information--will
be posted on the website. If your submission is made via a hardcopy
that includes personal identifying information, you may request at the
top of your document that we withhold this information from public
review. However, we cannot guarantee that we will be able to do so. We
will post all hardcopy submissions on <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
Comments and materials we receive, as well as supporting
documentation we used in preparing this proposed rule, will be
available for public inspection on <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
Because we will consider all comments and information we receive
during the comment period, our final determinations may differ from
this proposal. Based on the new information we receive (and any
comments on that new information), we may conclude that the species is
threatened instead of endangered, or we may conclude that the species
does not warrant listing as either an endangered species or a
threatened species. For critical habitat, our final designation may not
include all areas proposed, may include some additional areas that meet
the definition
[[Page 8512]]
of critical habitat, and may exclude some areas if we find the benefits
of exclusion outweigh the benefits of inclusion.
Public Hearing
Section 4(b)(5) of the Act provides for a public hearing on this
proposal, if requested. Requests must be received by the date specified
in DATES. Such requests must be sent to the address shown in FOR
FURTHER INFORMATION CONTACT. We will schedule a public hearing on this
proposal, if requested, and announce the date, time, and place of the
hearing, as well as how to obtain reasonable accommodations, in the
Federal Register and local newspapers at least 15 days before the
hearing. For the immediate future, we will provide these public
hearings using webinars that will be announced on the Service's
website, in addition to the Federal Register. The use of these virtual
public hearings is consistent with our regulations at 50 CFR
424.16(c)(3).
Previous Federal Actions
On June 25, 2007, we received a petition, dated June 18, 2007, from
Forest Guardians (now WildEarth Guardians) that included the prostrate
milkweed. On December 16, 2009, we published a 90-day finding (74 FR
66866) that the petition presented substantial information that
prostrate milkweed may be warranted for listing. At that time, we
initiated a status review of the species.
Supporting Documents
A species status assessment (SSA) team prepared an SSA report for
the prostrate milkweed. 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 report. The
Service received two responses. The Service also sent the SSA report to
one partner, a botanist from the Texas Parks and Wildlife Department,
and received a review from this partner.
I. Proposed Listing Determination
Background
A thorough review of the taxonomy, life history, and ecology of the
prostrate milkweed (Asclepias prostrata) is presented in the SSA report
(Service 2020, entire). Prostrate milkweed is an herbaceous, flowering
plant in the Apocynaceae (dogbane) family. It is native to Texas, USA,
and Tamaulipas and eastern Nuevo Le[oacute]n, Mexico.
Prostrate milkweed is a perennial species with cream, yellow,
greenish, or pinkish flowers (Blackwell 1964, p. 178). This species is
distinctive in its prostrate habit; the leaves and stems sprawl outward
along the surface of the ground. It is found in open spaces with full
sun, and with little to no competition from surrounding plants (Poole
and Janssen 1997, p. 117). It occurs in a subtropical, semiarid climate
in sparsely vegetated habitats, including grasslands, savannas, and
open areas of the Tamaulipan shrubland ecological region, on level or
gently sloping uplands (Singhurst et al. 2015, p. 25; Carr 2011, pp.
37-38; Damude and Poole 1990, p. 13; Strong and Williamson 2015, p.
36). Prostrate milkweed occurs primarily in deep, loose, sandy soils
formed over sandstone or indurated caliche (hardened soil layer
cemented by calcium and magnesium carbonates) (Carr 2011, pp. 37-38;
Strong and Williamson 2015, p. 36).
Like all milkweeds, prostrate milkweed flowers have a unique and
complex structure and pollination system. Pollinators are attracted to
the copious nectar produced deep within the flower. To reach the
nectar, insects of a particular size are forced against the flower's
central stalk in such a way that pollinia, which are sack-like
structures full of pollen grains, adhere to their legs. When the insect
visits another flower of the same species, the pollinia are often
wedged against the stigma (the receptive female structure) and detach,
thus delivering a large load of pollen and effecting fertilization. The
closely-related zizotes milkweed, Asclepias oenotheroides, is
effectively pollinated by very large wasps called tarantula hawks
(species of Pepsis and Hemipepsis), and it is likely that these wasps
and large bees also pollinate prostrate milkweed. Due to their
relatively large size and the abundance of nectar produced by the
flowers, these pollinators are able to fly relatively large distances
between nectar sources (Gathman and Tscharntke 2002, entire; Greenleaf
et al. 2007, entire). Hence, it is likely that prostrate milkweed can
reproduce even when individuals are widely distributed at very low
densities, due to the uniquely effective pollination system, large
nectar reward, and large forage range of its pollinators.
Fertilized flowers of prostrate milkweed produce capsules with
about 100 seeds each. The seeds have long, silky, white hairs and are
dispersed by wind (Damude and Poole 1990, pp. 4-5; Richardson and King
2011, p. 76). Seed production of milkweeds is often resource limited
(La Rosa and Conner 2017, p. 151); resources for prostrate milkweed
include rainfall, pollinators, and open, sparsely vegetated habitat.
Prostrate milkweed remains as tubers, up to 12 inches (in) (30
centimeters (cm)) underground that are dormant during long droughts.
New stems are stimulated to emerge from the soil by infrequent, heavy
rainfall, and set seed following wildfire or, historically, a passing
herd of bison has cleared competing grasses and forbs, and the deluges
of tropical storms briefly replenish moisture. The species exists where
competition from other plants is periodically reduced by wildfire or
grazing. These life-history traits allow the species to rebound after
periods of inhospitable conditions, and well-managed livestock grazing,
which simulates the effects of bison, and rangeland management,
including brush thinning and prescribed burning, can return an
unsuitable area to conditions more suitable for prostrate milkweed. As
a result, sufficiently resilient prostrate milkweed populations may be
maintained on well-managed rangelands. Livestock grazing is the primary
economic use of privately-owned land throughout the range of prostrate
milkweed in Texas and northeast Mexico, although the management regime
of these rangelands is unknown. This adaptation also enables prostrate
milkweed to occur along mowed road rights-of-way (ROWs) and in
rangelands where soils are intact. Therefore, while there may be
prostrate milkweed populations on these rangelands, we do not have
evidence that they are present, nor do we have information that the
grazing is managed in such a way as to promote resilient populations.
However, it is unlikely to remain where soils are disturbed by plowing,
bulldozing, or road grading because this destroys the tubers,
preventing any plant regrowth.
In the United States, prostrate milkweed occurs in south Texas from
northwest Zapata County to the vicinity of Roma, in Starr County. All
known U.S. populations are within 8 miles of the Rio Grande (Strong and
Williamson 2015, pp. 34-35). In Mexico, known locations for this
species occur in
[[Page 8513]]
isolated pockets widely scattered in northern Tamaulipas and eastern
Nuevo Le[oacute]n, many over 100 miles (mi) (160 kilometers (km)) from
the Rio Grande (Strong and Williamson 2015, p. 35). The historical
range of prostrate milkweed is unknown; therefore, it is presumed to be
approximately the same as the current range in southern Texas and
northern Mexico. However, the distribution of populations throughout
this range may have been more abundant in the past.
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. 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 expected response by the species,
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 the
Service 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 a decision by
the Service on whether the species should be proposed for listing 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-2021-0041 on <a href="https://www.regulations.gov">https://www.regulations.gov</a> and at <a href="https://www.fws.gov/southwest/es/TexasCoastal/">https://www.fws.gov/southwest/es/TexasCoastal/</a>.
To assess prostrate milkweed 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
[[Page 8514]]
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 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.
For the prostrate milkweed to maintain viability, its populations
or some portion thereof must have sufficient resiliency, redundancy,
and representation. Several factors influence the resiliency of
prostrate milkweed populations, including abundance and recruitment
rate, in addition to elements of the species' habitat that determine
whether prostrate milkweed populations can grow. These resiliency
factors and habitat elements are discussed in detail in the SSA report
and summarized here.
Species Needs
Abundance--Prostrate milkweed abundance is difficult to assess due
to its ability to remain dormant for multiple years until the necessary
environmental conditions occur. Individual plants may emerge only a few
times per decade, and not all plants will emerge at the same time
(Price 2005, pers. comm.; Best 2017, pers. comm.). Therefore, we
considered populations to be extant if plants have been observed within
the past 40 years (Hammerson et al. 2008, entire; Strong 2020, pers.
comm.) and with available habitat (i.e., not paved over) or with
restorable habitat (i.e., nonnative grass could be removed).
Populations of prostrate milkweed must be large enough to have a
high probability of enduring random demographic and environmental
variation. For example, species or populations may be classified as
vulnerable when the probability of persisting 100 years is less than 90
percent (Mace and Lande 1991, p. 151). This metric of population
resilience, called minimum viable population (MVP), refers to the
smallest population size that has a high probability of surviving over
a specified period of time. Calculations of MVP require data that are
not currently available for prostrate milkweed. As a practical
alternative, we estimated the likely MVP range of prostrate milkweed by
comparing it to species with similar life-history traits for which MVPs
have been calculated (Pavlik 1996, p. 137). This method estimates a
highly resilient population of prostrate milkweed has 1,600 or more
adult individuals (Service 2020, p. 38).
Determinations of MVP usually consider the effective population
size, rather than total number of individuals (Pavlik 1996, entire); 10
genetically identical individuals (for example, clones or ramets) would
have an effective population size of one. Because prostrate milkweed is
likely self-incompatible and does not appear to form clonal colonies,
the effective population size is likely to be nearly the same as the
total population size.
Recruitment Rate--A stable or increasing population requires
recruitment rates that equal or exceed mortality rates (Service 2020,
p. 38). All stages of recruitment, from flowering and seed production
to germination and establishment, occur when the soil has available
moisture. The porous soils of prostrate milkweed habitat dry quickly
after a single heavy thunderstorm. Based on observations of other
perennial forbs in this ecosystem, recruitment probably occurs during
periods of extended rainfall, meaning multiple rain events over a
period of several weeks (Service 2020, p. 38). These events are rare in
this semiarid region. Consequently, we expect that successful
recruitment may occur only once or a few times per decade. Similarly,
most mortality probably occurs during years of extended drought. Hence,
both recruitment and mortality would have strong pulses and observed
population sizes would vary widely from year to year, leading to
potentially spurious interpretations of demographic trends (Service
2020, p. 38).
Populations of prostrate milkweed require habitats that also
support healthy populations of large native bees and wasps (Service
2020, p. 38). Native bees in turn require a diversity and abundance of
native forb and shrub species that provide pollen and nectar. Tarantula
hawks (Pepsis spp. and Hemipepsis spp.) may also be important
pollinators of prostrate milkweed; tarantula hawks require healthy
populations of their prey species, tarantulas (Best 2020, pers. comm.).
Prostrate milkweed populations require competition from grasses and
forbs to be periodically reduced (Service 2020, p. 38). This
requirement, which has been observed in other milkweed species, may be
an adaptation to wildfire (Baum and Sharber 2012, pp. 968-971).
Although mowing or livestock grazing can also reduce competition, it is
likely that prostrate milkweed is adapted to grasslands that were
sustained by periodic wildfires (Service 2020, p. 39).
Canopy Cover--Canopy cover refers to shade from trees, shrubs,
prickly pear cactuses, or tall (>1 meter (m)) grass. Resilient
prostrate milkweed populations need an open canopy with little or no
herbaceous cover (Service 2020, p. 3). Therefore, the species may occur
in areas that mimic historical wildfire or grazing, such as along mowed
road rights-of-way (Service 2020, p. 3).
Ground Cover--Ground cover refers to vegetation growing at the
herbaceous layer (approximately <1 m) that would compete with prostrate
milkweed plants for resources. Resilient prostrate milkweed populations
need an open canopy with little or no herbaceous cover, so there is
little competition with other plants (Service 2020, p. 3).
Risk Factors for Prostrate Milkweed
We reviewed the potential risk factors (i.e., threats, stressors)
that may affect prostrate milkweed now and in the future. In this
proposed rule, we will discuss only those factors in detail that could
meaningfully impact the status of the species. Those risks that are not
known to have effects on prostrate milkweed populations, such as
quarrying/mining, hybridization, pollinator decline, and climate
change, are not discussed here but are evaluated in the SSA report. The
primary risk factors (i.e., threats) affecting the status of prostrate
milkweed are: (1) Competition from introduced invasive grasses (Factor
A from the Act); (2) habitat loss from root-plowing and conversion of
native vegetation to pasture (Factor A); (3) habitat loss from ROW
construction and maintenance from energy development and road and
utility construction (Factor A); (4) habitat loss from border security
development and enforcement activities (Factor A); and (5) the
demographic and genetic consequences of small population sizes and
population fragmentation (Factor E).
Competition From Nonnative Invasive Grasses
Nonnative invasive grass species displace native plants by
competing for water, nutrients, and light, and their dense root systems
prevent germination of native plant seeds (Texas Invasives 2019,
unpaginated). Buffelgrass (Pennisetum ciliare) is a perennial
bunchgrass introduced from Africa that is now one of the most abundant
introduced grasses in south Texas, and the most prevalent invasive
grass within the range of prostrate milkweed. Since the 1950s, Federal
and State land management agencies have promoted buffelgrass as a
forage grass in south
[[Page 8515]]
Texas (Smith 2010, p. 113). Buffelgrass is very well-adapted to the
hot, semi-arid climate of south Texas due to its drought resistance and
ability to aggressively establish in heavily grazed landscapes (Smith
2010, p. 113). Buffelgrass continues to be planted in areas affected by
drought and overgrazing to stabilize soils and to increase rangeland
productivity. Buffelgrass often creates homogeneous monocultures by
out-competing native plants for essential resources (Lyons et al. 2013,
p. 8), and it produces phytotoxins in the soil that inhibit the growth
of neighboring native plants (Vo 2013, unpaginated). Furthermore,
prescribed burning used for brush control promotes buffelgrass forage
production in south Texas (Hamilton and Scifres 1982, p. 11).
Most prostrate milkweed plants have been observed where buffelgrass
is absent or at low densities (Eason 2019, pers. comm.; Strong 2019,
pers. comm.). On national wildlife refuge lands, prostrate milkweed was
found in areas where native grass was still dominant, but not where
buffelgrass or woody vegetation was present in dense stands (Best 2005,
p. 3). The unpaved ROWs on private lands in south Texas for oil and gas
wells, wind farms, service roads, pipelines, and powerlines could
benefit prostrate milkweed through the periodic mowing of road margins.
However, disturbed soils along ROWs are rapidly colonized by
buffelgrass.
The Texas Natural Diversity Database (TXNDD) lists invasive
species, primarily buffelgrass, as a pervasive threat of extreme
severity to prostrate milkweed. The TXNDD defines a pervasive threat as
one that affects all or most (71-100 percent) of a species'
populations, occurrences, or extent. An extreme level of severity is
one that is likely to destroy or eliminate occurrences or habitat or
reduce population sizes by 71-100 percent (TXNDD 2016). It is likely
that buffelgrass has negatively impacted all Texas populations (TXNDD
2019-2020, entire; Eason 2019, pers. comm.; Kieschnick 2019, pers.
comm.; Santore 2019, unpaginated). Competition from buffelgrass is the
greatest threat to prostrate milkweed.
Root-Plowing and Conversion of Native Grassland and Savanna
Root-plowing is a brush control method that uses powerful tracked
vehicles to excavate the roots of woody plants with heavy steel subsoil
rippers that dig several feet into the ground. The dead trees and
shrubs are then burned, and the root-plowed soils are planted with
buffelgrass for livestock grazing. Root-plowing and conversion to
buffelgrass pasture is a widely conducted practice in south Texas and
northeast Mexico, occurring in much of the potential habitat of
prostrate milkweed. Extensive areas of recently root-plowed lands can
be identified in aerial photographs. These practices have been and are
still subsidized by the United States Department of Agriculture (USDA)
Natural Resources Conservation Service and its precursor, the USDA Soil
Conservation Service.
Root-plowing temporarily reduces the encroachment of woody plants
into the grassland component of former savannas. The conversion of
native habitats to improved pastures dominated by buffelgrass or other
introduced grasses greatly reduces the abundance and diversity of most
native grass and forb species (Woodin et al. 2010, p. 1). Very few, if
any, prostrate milkweed plants survive following root-plowing and
buffelgrass planting. This is likely due to the excavation and
desiccation of most tubers during root-plowing; subsequently, the few
remaining individuals decline due to competition from dense buffelgrass
cover.
Conversely, prostrate milkweed occurs in well-managed rangelands,
provided that the soil was not previously root-plowed or otherwise
disturbed (Service 2020, p. 53). Most milkweed species are unpalatable
to cattle, and often increase in abundance on grazed lands. Livestock,
including cattle, sheep, and horses, graze preferentially on grasses
and forbs (broad-leaved herbaceous plants), including buffelgrass, and
non-toxic herbaceous plants, and therefore reduce competition with
prostrate milkweed from these plants (Service 2020, p. 41). In addition
to grazing, livestock may also reduce competition with prostrate
milkweed by trampling herbaceous plants (Service 2020, p. 41). Because
prostrate milkweed is often observed in the wheel ruts of dirt roads,
it appears to be unusually tolerant of trampling; thus, the effect of
livestock trampling is minimal (Service 2020, pp. 41-42). Periodic
livestock grazing reduces competition from native and introduced
grasses. In South Texas, over-grazed rangelands typically become
invaded by woody plants, reducing the habitat suitability for prostrate
milkweed. Hence, management practices that promote sustainable grazing
of native grasses are beneficial to prostrate milkweed (Service 2020,
p. 41).
Road and ROW Construction and Maintenance
Oil and gas exploration and wind energy development are occurring
at a rapid pace in Starr and Zapata Counties. Seismic exploration and
the construction of roads and caliche pads for oil and gas wells and
wind turbines can destroy plants and their habitats within the
construction footprint (Reemts et al. 2014, pp. 123 and 125; Leslie
2016, p. 49). Additionally, graded service roads and other permanent
structures may indirectly affect the hydrology of surrounding habitats
by diverting and channeling water through drainage culverts. Invasive
buffelgrass quickly colonizes disturbed roadsides, then invades
adjacent habitats. Heavy vehicle traffic during oil and gas well
drilling and wind farm construction may increase the frequency of road
maintenance, such as grading or widening (Pe[ntilde]a 2019, pers.
comm.). Grading or blading a caliche road involves scraping the road's
surface with a large heavy blade to remove ruts and roadside
vegetation. Increased frequency of road maintenance that removes above-
ground portions of plants could reduce or eliminate prostrate milkweed
flower and fruit production. Conversely, grading or blading of caliche
roads conducted during the milkweed's dormant periods may benefit the
species by temporarily reducing competition from grasses and forbs
(TXNDD 2019, p. 11). TXNDD (2019) ranks road expansion as a pervasive
threat (affects all or most (71-100 percent) of a species' populations,
occurrences, or extent) of extreme severity to prostrate milkweed.
All or parts of nine prostrate milkweed occurrences are in the
margins of improved highway ROWs. All of these highway ROW populations
have declined since they were first observed, likely due to the
frequency of soil disturbance and invasive grass competition (Service
2020, p. 40). In addition, from 2010 to 2012, Texas Department of
Transportation (TxDOT) widened segments of U.S. Highway 83 that
affected at least three known prostrate milkweed sites: Arroyo del
Tigre Grande, Mission Mier a Visita, and Arroyo Roma (Strong and
Williamson 2015, p. 51; Paradise 2019, pers. comm.). TxDOT has also
scheduled additional road widening or construction at five known
prostrate milkweed populations: Arroyo del Tigre Grande, Arroyo del
Tigre Chiquito, Arroyo de los Mudos, Mission Mier a Visita, and Arroyo
Roma (TxDOT 2019, unpaginated). U.S. Customs and Border Protection
(CBP) has scheduled road
[[Page 8516]]
improvements at the prostrate milkweed population site located in the
Arroyo Morteros tract of the Lower Rio Grande Valley National Wildlife
Refuge (NWR) (Vallejo 2019, pers. comm.).
In contrast, all or parts of three prostrate milkweed occurrences
are in the margins of unpaved rural roads. These relatively stable
populations have persisted in narrow strips of native vegetation
between the gravel or caliche roadbeds and the fence lines of adjacent
private properties. The soils in these narrow, naturally vegetated
strips have never been excavated, and they have relatively little
buffelgrass cover.
The installation of natural gas pipelines and fiber-optic cables
has removed prostrate milkweed plants in the Dolores and Arroyo del
Tigre Chiquito populations in the past (Damunde and Poole 1990, p. 32;
Boydston 1993, unpaginated; Campos 1993, unpaginated). In 1995,
Southwestern Bell installed a fiber-optic cable in the Highway 83 ROW,
2.6 miles south of the Webb-Zapata County line, which removed at least
100 individuals at the Dolores population (Service 1995, p. 1). In
1993, prior to the fiber-optic cable installation, this population was
estimated to have 100 to 200 individuals (TXNDD 2019, entire) and was
the largest known population of prostrate milkweed.
In summary, prostrate milkweed faces risks from ROWs and road
construction and maintenance associated with oil and gas activities,
wind energy development, and utility and pipeline corridor
construction.
Border Security Development and Enforcement Activities
All known Texas populations of prostrate milkweed are within 9
miles (14.5 km) of the Texas-Mexico border. To address border security
concerns, additional border barrier construction was proposed in the
Rio Grande Valley, including the Arroyo Morteros tract of the Lower Rio
Grande Valley NWR. Should border wall construction occur, and depending
on the alignment, construction could remove prostrate milkweed plants
that occur within the construction footprint. Additionally, CBP plans
to improve roads across this tract (Vallejo 2019, pers. comm.) and may
also install new drag strips along existing roads. Drag strips are 13-
to 16-foot (ft) (4- to 5-m) -wide swaths cleared of all vegetation and
regularly scraped to keep the soil surface loose, in order to detect
recent foot traffic. Due to the high gypsum content, soils in this area
are extremely vulnerable to gully erosion. Hence, the unvegetated,
continually disturbed drag strips may exacerbate soil erosion and
impact a much wider area. TXNDD ranks drag strip construction within
prostrate milkweed populations as a small threat (defined as a threat
that affects 1-10 percent of the total population or occurrences or
extent) with an extreme level of severity (likely to destroy or
eliminate occurrences or habitat, or reduce population by 71-100
percent) (TXNDD 2016). Consequently, the construction of border
barriers, roads, and drag strips are potential threats of high
magnitude to prostrate milkweed populations, depending on their
alignment, design, and proximity to populations and local topography.
Native plant populations are legally protected on NWRs and, if
listed under the Act, have additional legal protections from federally
funded or regulated actions. However, a provision of the REAL ID Act of
2005 gives the Secretary of Homeland Security authority to waive other
Federal laws, including the Endangered Species Act, in order to
expedite construction of border barriers. Therefore, border barrier
construction on private and public lands is exempt from consultation
with the Service under section 7 of the Act. During the previous phase
of border barrier construction, beginning in 2007, the Department of
Homeland Security (DHS) and the Service coordinated to establish best
management practices for the federally listed plants and animals in the
project impact area (DHS 2008); nevertheless, these best management
practices did not address prostrate milkweed.
Small Population Sizes and Population Fragmentation
Small, isolated populations are more vulnerable to catastrophic
losses caused by random fluctuations in recruitment (demographic
stochasticity) or variations in rainfall or other environmental factors
(environmental stochasticity) (Service 2016, p. 20). Small,
reproductively isolated populations are susceptible to the loss of
genetic diversity, to genetic drift, and to inbreeding (Barrett and
Kohn 1991, pp. 3-30). Due to the small size and isolation of prostrate
milkweed populations, several may already suffer from genetic
bottlenecks, genetic drift, inbreeding, and loss of allelic diversity.
In addition to population size, it is likely that population
density and connectivity also influence population viability (Service
2020, p. 51). Prostrate milkweed is very likely to be an obligate
outcrosser (fertilization between different individuals), as are most
other Asclepias species, which requires that genetically compatible
individuals be clustered within the forage range of the native
pollinators for reproduction to occur (Service 2020, p. 51). While the
specific pollinators of this species have not been revealed, they are
likely to be large bees or wasps, and the forage range could be up to
several kilometers. If this is the case, viable populations of
prostrate milkweed could be dispersed at very low densities over
relatively large areas, provided that they lie within fairly contiguous
habitats that are traversed by pollinating insects. Thus, the small,
isolated clusters of prostrate milkweed that have been documented,
principally along public roads that slice through large expanses of
potential habitat on private lands, may represent only tiny fractions
of larger, highly dispersed populations (Service 2020, p. 51).
Based strictly on the available scientific data, the documented
populations of prostrate milkweed are all far below the estimated MVP
level and may be affected by the demographic and genetic consequences
of small population sizes and by fragmentation of populations.
Summary
Our analysis of the past, current, and future influences on the
needs of prostrate milkweed for long-term viability revealed several
threats that pose a risk to current and future viability: Competition
from introduced invasive grass (buffelgrass); root-plowing of
rangelands; development of new oil and gas wells, wind energy farms,
roads, pipelines, and utility corridors; development of new border
barriers and drag strips; and the demographic and genetic consequences
of small population sizes and population fragmentation. Conversely,
well-managed livestock grazing of rangeland is compatible with
management of prostrate milkweed habitat and may actually benefit this
species.
Species Condition
The current condition of prostrate milkweed takes into account the
current status and risks to its populations. In the SSA report, for
each population, we developed and assigned condition categories for two
demographic factors and two habitat factors that are important for
viability of prostrate milkweed. The condition scores for each factor
were then used to estimate the probability of persistence over the next
30 years. Populations were rated high, moderate, or low when that
probability is greater than 90 percent, between 60 and 90 percent, or
between 10 and 60 percent, respectively. Functionally
[[Page 8517]]
extirpated populations are not expected to persist over 30 years or are
already extirpated.
There are 24 populations of prostrate milkweed remaining in Starr
and Zapata Counties, Texas, and in Tamaulipas and eastern Nuevo
Le[oacute]n, Mexico (see Table 1, below). The species range extends
more than 200 miles (320 kilometers) from northwest to southeast. In
Texas, one population, Dolores, is somewhat isolated in northern Zapata
County, with the nearest known population approximately 25 miles (40
km) away. In Mexico, eight known populations are located in isolated
pockets widely scattered in Tamaulipas and eastern Nuevo Le[oacute]n.
However, botanists have only surveyed a small proportion of the
species' range. Furthermore, the species remains dormant and
undetectable except for short periods of time after infrequent, heavy
rainfall. Consequently, although the species is certainly rare, its
actual abundance is difficult to determine. It is likely that,
historically, populations occurred between these areas, connecting the
populations in Texas and Mexico. Because they are widely separated,
natural gene flow or reestablishment following disturbance is very
unlikely between the 24 known populations. Based upon our analysis of
current conditions of these 24 extant populations, none are in high
condition, 5 are in moderate condition, and 19 are in low condition.
Table 1--Summary of Current Condition for Prostrate Milkweed
------------------------------------------------------------------------
Population name Current condition
------------------------------------------------------------------------
Dolores.................................. Low.
14493.................................... Low.
14491.................................... Low.
Arroyo del Tigre Grande.................. Moderate.
Arroyo del Tigre Chiquito................ Low.
FM 2098.................................. Low.
Falcon................................... Low.
Los Alvaros.............................. Moderate.
Arroyo Morteros Tract.................... Moderate.
Los Arrieros Loop........................ Low.
Arroyo de los Mudos...................... Low.
Mission Mier a Visita.................... Low.
San Juli[aacute]n Road................... Moderate.
FM 3167.................................. Moderate.
Arroyo Roma.............................. Low.
Arroyo Ramirez Tract..................... Low.
Rancho La Coma........................... Low.
Road to Guerrero Viejo................... Low.
Carboneras............................... Low.
Punta de Alambre......................... Low.
Intersection of 101-180.................. Low.
Rio El Cat[aacute]n...................... Low.
Rancho Loreto North...................... Low.
Rancho Loreto South...................... Low.
------------------------------------------------------------------------
The two demographic factors used to analyze resiliency of prostrate
milkweed populations are abundance and recruitment rate. Related to
abundance, a highly resilient population of prostrate milkweed has
1,600 or more adult individuals, a moderately resilient population has
from 800 to 1,600 mature individuals, and a population with less than
800 mature individuals has low resilience (Service 2020, p. 38).
Prostrate milkweed populations have high resiliency if the recruitment
rate is greater than or equal to 25 percent of individuals producing
viable seeds per year. Moderately resilient populations have
recruitment rates of between 15 and 24 percent per year, and
populations with low resiliency have recruitment rates of less than 15
percent per year (Service 2020, p. 57).
The two habitat factors used to analyze resiliency of prostrate
milkweed populations were canopy cover and ground cover. Highly
resilient populations have less than 30 percent canopy cover and have
all bare ground or are sparsely vegetated with mostly native grass and/
or forbs. Moderately resilient populations have between 30 and 60
percent canopy cover and are sparsely vegetated with a mixture of
native and nonnative grasses and/or forbs. Minimally resilient
populations have between 61 and 100 percent canopy cover and a dense
ground cover of native or introduced grasses and forbs and little or no
bare ground (Service 2020, p. 57).
Redundancy is low for this species due to low numbers of
populations in moderate to high condition for resiliency, making
prostrate milkweed populations vulnerable to extirpations from
catastrophic events. Because buffelgrass invasion is prevalent in this
area, ecological diversity among the known populations is limited.
Further, the populations are isolated and widespread across the range,
and therefore gene flow among the populations is limited. As a
consequence of these current conditions, the viability of the prostrate
milkweed now primarily depends on maintaining and restoring the
remaining isolated populations and potentially discovering or
reintroducing new populations where feasible.
As part of the SSA, we also developed three plausible future
scenarios to capture the range of uncertainties regarding future
threats and the projected responses by the prostrate milkweed. Our
scenarios included a continuing conditions scenario, which incorporated
the current risk factors continuing on the same trajectory that they
are on now. We also evaluated a conservation scenario and a scenario
with increased stressors. Because we determined that the current
condition of the prostrate milkweed is consistent with an endangered
species (see Determination of Species Status, below), we are not
presenting the results of the future scenarios in this proposed rule.
Please refer to the SSA report (Service 2020) for the full analysis of
future scenarios.
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.
Determination of Prostrate Milkweed Status
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 meets the definition of an endangered species or a
threatened species. The Act defines endangered species as a species
``in danger of extinction throughout all or a significant portion of
its range,'' and threatened species as a species ``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 a species meets the definition of endangered species or
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.
Status Throughout All of Its Range
After evaluating threats to the species and assessing the
cumulative effect of
[[Page 8518]]
the threats under the section 4(a)(1) factors, we found that, of the 24
known prostrate milkweed populations remaining, 19 are small and
isolated and are low resiliency, and five have moderate resiliency and
connection to other populations, and none have high resiliency. Several
factors pose a threat to prostrate milkweed, including competition from
introduced invasive grass; habitat loss and degradations from root-
plowing and conversion of native vegetation to improved buffelgrass
pasture; habitat loss from ROW construction and maintenance from energy
development and road and utility construction; habitat loss from border
security development and enforcement activities (Factor A from the
Act); and the demographic and genetic consequences of small population
sizes (Factor E).
All the aforementioned threats are currently affecting the known
populations of prostrate milkweed. Buffelgrass has already negatively
impacted all of the Texas populations (TXNDD 2019-2020, entire; Eason
2019, pers. comm.; Kieschnick 2019, pers. comm.; Santore 2019,
unpaginated) and will continue to do so in the future. Habitat loss and
degradation from root-plowing and conversion of native vegetation to
improved buffelgrass pasture has also already been occurring for many
years (Service 2020, p. 40). Habitat loss from ROW construction and
maintenance from energy development and road and utility construction
has already been observed from oil and gas development occurring in
Zapata County. As of November 2019, no wind turbines, oil or gas well
pads, pipelines, or energy service roads have been constructed directly
within known prostrate milkweed populations. However, some Starr County
prostrate milkweed populations are less than 2.0 km (1.2 mi) from
existing wind turbines (Service 2020, pp. 42-43), and a few wind energy
farms are expected to be constructed in the future, which could lead to
additional habitat loss. Habitat loss from border security development
and enforcement activities has occurred in recent years and is expected
to continue into the future. And, finally, the demographic and genetic
consequences of small population sizes is a current threat to the
prostrate milkweed. This situation is not expected to change into the
future.
In addition to the current threats, redundancy and representation
are also limited. There are twenty-four known populations that are
distributed widely across its range, and the majority of those
populations are currently in low condition. Should a catastrophic event
occur, the populations are vulnerable to extirpation because they are
small and isolated from each other. The small, reproductively isolated
populations are also susceptible to the loss of genetic diversity,
genetic drift, and inbreeding due to random fluctuations in recruitment
(demographic stochasticity) or variations in rainfall or other
environmental factors (environmental stochasticity). Because of the
overall species' current resiliency, redundancy, and representation,
prostrate milkweed is currently in danger of extinction throughout all
of its range. We do not find the species meets the definition of a
threatened species because the species has already shown low levels in
current resiliency, redundancy, and representation due to the threats
mentioned above. Thus, after assessing the best available information,
we determine that prostrate milkweed is in danger of extinction
throughout all of its range.
Status Throughout a Significant Portion of Its Range
Under the Act and our implementing regulations, a species may
warrant listing if it is in danger of extinction or likely to become so
in the foreseeable future throughout all or a significant portion of
its range. We have determined that the prostrate milkweed is in danger
of extinction throughout all of its range and accordingly did not
undertake an analysis of any significant portion of its range. Because
the prostrate milkweed warrants listing as endangered throughout all of
its range, our determination is consistent with the decision in Center
for Biological Diversity v. Everson, 2020 WL 437289 (D.D.C. Jan. 28,
2020), in which the court vacated the aspect of the Final Policy on
Interpretation of the Phrase ``Significant Portion of Its Range'' in
the Endangered Species Act's Definitions of ``Endangered Species'' and
``Threatened Species'' (79 FR 37578; July 1, 2014) that provided the
Service does not undertake an analysis of significant portions of a
species' range if the species warrants listing as threatened throughout
all of its range.
Determination of Status
Our review of the best available scientific and commercial
information indicates that the prostrate milkweed meets the definition
of an endangered species. Therefore, we propose to list the prostrate
milkweed as an endangered species in accordance with sections 3(20) and
4(a)(1) of the Act.
Available Conservation Measures
Conservation measures provided to species listed as endangered or
threatened species under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing results in public awareness, and
conservation by Federal, State, Tribal, and local agencies, private
organizations, and individuals. The Act encourages cooperation with the
States and other countries and calls for recovery actions to be carried
out for listed species. The protection required by Federal agencies and
the prohibitions against certain activities are discussed, in part,
below.
The primary purpose of the Act is the conservation of endangered
and threatened species and the ecosystems upon which they depend. The
ultimate goal of such conservation efforts is the recovery of these
listed species, so that they no longer need the protective measures of
the Act. Section 4(f) of the Act calls for the Service to develop and
implement recovery plans for the conservation of endangered and
threatened species. The recovery planning process involves the
identification of actions that are necessary to halt or reverse the
species' decline by addressing the threats to its survival and
recovery. The goal of this process is to restore listed species to a
point where they are secure, self-sustaining, and functioning
components of their ecosystems.
Recovery planning consists of preparing draft and final recovery
plans, beginning with the development of a recovery outline and making
it available to the public within 30 days of a final listing
determination. The recovery outline guides the immediate implementation
of urgent recovery actions and describes the process to be used to
develop a recovery plan. Revisions of the plan may be done to address
continuing or new threats to the species, as new substantive
information becomes available. The recovery plan also identifies
recovery criteria for review of when a species may be ready for
reclassification from endangered to threatened (``downlisting'') or
removal from protected status (``delisting''), and methods for
monitoring recovery progress. Recovery plans also establish a framework
for agencies to coordinate their recovery efforts and provide estimates
of the cost of implementing recovery tasks. Recovery teams (composed of
species experts, Federal and State agencies, nongovernmental
organizations, and stakeholders) are often established to develop
recovery
[[Page 8519]]
plans. When completed, the recovery outline, draft recovery plan, and
the final recovery plan will be available on our website (<a href="https://www.fws.gov/endangered">https://www.fws.gov/endangered</a>), or from our Texas Coastal Ecological Services
Field Office (see FOR FURTHER INFORMATION CONTACT).
Implementation of recovery actions generally requires the
participation of a broad range of partners, including other Federal
agencies, States, Tribes, nongovernmental organizations, businesses,
and private landowners. Examples of recovery actions include habitat
restoration (e.g., restoration of native vegetation), research, captive
propagation and reintroduction, and outreach and education. The
recovery of many listed species cannot be accomplished solely on
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires
cooperative conservation efforts on private, State, and Tribal lands.
If this species is listed, funding for recovery actions will be
available from a variety of sources, including Federal budgets, State
programs, and cost-share grants for non-Federal landowners, the
academic community, and nongovernmental organizations. In addition,
pursuant to section 6 of the Act, the State of Texas would be eligible
for Federal funds to implement management actions that promote the
protection or recovery of the prostrate milkweed. Information on our
grant programs that are available to aid species recovery can be found
at: <a href="https://www.fws.gov/grants">https://www.fws.gov/grants</a>.
Although the prostrate milkweed is only proposed for listing under
the Act at this time, please let us know if you are interested in
participating in recovery efforts for this species. Additionally, we
invite you to submit any new information on this species whenever it
becomes available and any information you may have for recovery
planning purposes (see FOR FURTHER INFORMATION CONTACT).
Section 7(a) of the Act requires Federal agencies to evaluate their
actions with respect to any species that is proposed or listed as an
endangered or threatened species and with respect to its critical
habitat, if any is designated. Regulations implementing this
interagency cooperation provision of the Act are codified at 50 CFR
part 402. Section 7(a)(4) of the Act requires Federal agencies to
confer with the Service on any action that is likely to jeopardize the
continued existence of a species proposed for listing or result in
destruction or adverse modification of proposed critical habitat. If a
species is listed subsequently, section 7(a)(2) of the Act requires
Federal agencies to ensure that activities they authorize, fund, or
carry out are not likely to jeopardize the continued existence of the
species or destroy or adversely modify its critical habitat. If a
Federal action may affect a listed species or its critical habitat, the
responsible Federal agency must enter into consultation with the
Service.
Federal agency actions within the species' habitat that may require
conference or consultation or both as described in the preceding
paragraph include management and any other landscape-altering
activities on Federal lands administered by the U.S. Fish and Wildlife
Service.
The Act and its implementing regulations set forth a series of
general prohibitions and exceptions that apply to endangered plants.
The prohibitions of section 9(a)(2) of the Act, codified at 50 CFR
17.61, make it illegal for any person subject to the jurisdiction of
the United States to: Import or export; remove and reduce to possession
from areas under Federal jurisdiction; maliciously damage or destroy on
any such area; remove, cut, dig up, or damage or destroy on any other
area in knowing violation of any law or regulation of any State or in
the course of any violation of a State criminal trespass law; deliver,
receive, carry, transport, or ship in interstate or foreign commerce,
by any means whatsoever and in the course of a commercial activity; or
sell or offer for sale in interstate or foreign commerce an endangered
plant. Certain exceptions apply to employees of the Service, the
National Marine Fisheries Service, other Federal land management
agencies, and State conservation agencies.
We may issue permits to carry out otherwise prohibited activities
involving endangered plants under certain circumstances. Regulations
governing permits are codified at 50 CFR 17.62. With regard to
endangered plants, a permit may be issued for scientific purposes or
for enhancing the propagation or survival of the species. The statute
also contains certain exemptions from the prohibitions, which are found
in sections 9 and 10 of the Act.
It is our policy, as published in the Federal Register on July 1,
1994 (59 FR 34272), to identify to the maximum extent practicable at
the time a species is listed, those activities that would or would not
constitute a violation of section 9 of the Act. The intent of this
policy is to increase public awareness of the effect of a proposed
listing on proposed and ongoing activities within the range of the
species proposed for listing. Based on the best available information,
the following actions are unlikely to result in a violation of section
9, if these activities are carried out in accordance with existing
regulations and permit requirements; this list is not comprehensive:
(1) Normal agricultural and silvicultural practices, including
herbicide and pesticide use, that are carried out in accordance with
any existing regulations, permit and label requirements, and best
management practices; and
(2) Normal residential landscaping activities on non-Federal lands;
and
(3) Recreational use with minimal ground disturbance.
Based on the best available information, the following activities
may potentially result in a violation of section 9 of the Act if they
are not authorized in accordance with applicable law; this list is not
comprehensive:
(1) Unauthorized handling, removing, trampling, or collecting of
prostrate milkweed on Federal land; and
(2) Removing, cutting, digging up, or damaging or destroying
prostrate milkweed in knowing violation of any law or regulation of the
State of Texas or in the course of any violation of a State criminal
trespass law.
II. Critical Habitat
Background
Critical habitat is defined in section 3 of the Act as:
(1) The specific areas within the geographical area occupied by the
species, at the time it is listed in accordance with the Act, on which
are found those physical or biological features
(a) Essential to the conservation of the species, and
(b) Which may require special management considerations or
protection; and
(2) Specific areas outside the geographical area occupied by the
species at the time it is listed, upon a determination that such areas
are essential for the conservation of the species.
Our regulations at 50 CFR 424.02 define the geographical area
occupied by the species as an area that may generally be delineated
around species' occurrences, as determined by the Secretary (i.e.,
range). Such areas may include those areas used throughout all or part
of the species' life cycle, even if not used on a regular basis (e.g.,
migratory corridors, seasonal habitats, and habitats used periodically,
but not solely by vagrant individuals).
[[Page 8520]]
Additionally, our regulations at 50 CFR 424.02 define the word
``habitat'' as, for the purposes of designating critical habitat only,
``the abiotic and biotic setting that currently or periodically
contains the resources and conditions necessary to support one or more
life processes of a species.''
Conservation, as defined under section 3 of the Act, means to use
and the use of all methods and procedures that are necessary to bring
an endangered or threatened species to the point at which the measures
provided pursuant to the Act are no longer necessary. Such methods and
procedures include, but are not limited to, all activities associated
with scientific resources management such as research, census, law
enforcement, habitat acquisition and maintenance, propagation, live
trapping, and transplantation, and, in the extraordinary case where
population pressures within a given ecosystem cannot be otherwise
relieved, may include regulated taking.
Critical habitat receives protection under section 7 of the Act
through the requirement that Federal agencies ensure, in consultation
with the Service, that any action they authorize, fund, or carry out is
not likely to result in the destruction or adverse modification of
critical habitat. The designation of critical habitat does not affect
land ownership or establish a refuge, wilderness, reserve, preserve, or
other conservation area. Designation also does not allow the government
or public to access private lands, nor does designation require
implementation of restoration, recovery, or enhancement measures by
non-Federal landowners. Where a landowner requests Federal agency
funding or authorization for an action that may affect a listed species
or critical habitat, the Federal agency would be required to consult
with the Service under section 7(a)(2) of the Act. However, even if the
Service were to conclude that the proposed activity would result in
destruction or adverse modification of the critical habitat, the
Federal action agency and the landowner are not required to abandon the
proposed activity, or to restore or recover the species; instead, they
must implement ``reasonable and prudent alternatives'' to avoid
destruction or adverse modification of critical habitat.
Under the first prong of the Act's definition of critical habitat,
areas within the geographical area occupied by the species at the time
it was listed are included in a critical habitat designation if they
contain physical or biological features (1) which are essential to the
conservation of the species and (2) which may require special
management considerations or protection. For these areas, critical
habitat designations identify, to the extent known using the best
scientific and commercial data available, those physical or biological
features that are essential to the conservation of the species (such as
space, food, cover, and protected habitat). In identifying those
physical or biological features that occur in specific occupied areas,
we focus on the specific features that are essential to support the
life-history needs of the species, including, but not limited to, water
characteristics, soil type, geological features, prey, vegetation,
symbiotic species, or other features. A feature may be a single habitat
characteristic or a more complex combination of habitat
characteristics. Features may include habitat characteristics that
support ephemeral or dynamic habitat conditions. Features may also be
expressed in terms relating to principles of conservation biology, such
as patch size, distribution distances, and connectivity.
Under the second prong of the Act's definition of critical habitat,
we can designate critical habitat in areas outside the geographical
area occupied by the species at the time it is listed, upon a
determination that such areas are essential for the conservation of the
species. The implementing regulations at 50 CFR 424.12(b)(2) further
delineate unoccupied critical habitat by setting out three specific
parameters: (1) When designating critical habitat, the Secretary will
first evaluate areas occupied by the species; (2) the Secretary will
only consider unoccupied areas to be essential where a critical habitat
designation limited to geographical areas occupied by the species would
be inadequate to ensure the conservation of the species; and (3) for an
unoccupied area to be considered essential, the Secretary must
determine that there is a reasonable certainty both that the area will
contribute to the conservation of the species and that the area
contains one or more of those physical or biological features essential
to the conservation of the species.
Section 4 of the Act requires that we designate critical habitat on
the basis of the best scientific data available. Further, our Policy on
Information Standards Under the Endangered Species Act (published in
the Federal Register on July 1, 1994 (59 FR 34271)), the Information
Quality Act (section 515 of the Treasury and General Government
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)),
and our associated Information Quality Guidelines provide criteria,
establish procedures, and provide guidance to ensure that our decisions
are based on the best scientific data available. They require our
biologists, to the extent consistent with the Act and with the use of
the best scientific data available, to use primary and original sources
of information as the basis for recommendations to designate critical
habitat.
When we are determining which areas should be designated as
critical habitat, our primary source of information is generally the
information from the SSA report and information developed during the
listing process for the species. Additional information sources may
include any generalized conservation strategy, criteria, or outline
that may have been developed for the species; the recovery plan for the
species; articles in peer-reviewed journals; conservation plans
developed by States and counties; scientific status surveys and
studies; biological assessments; other unpublished materials; or
experts' opinions or personal knowledge.
As the regulatory definition of ``habitat'' reflects (50 CFR
424.02), habitat is dynamic, and species may move from one area to
another over time. We recognize that critical habitat designated at a
particular point in time may not include all of the habitat areas that
we may later determine are necessary for the recovery of the species.
For these reasons, a critical habitat designation does not signal that
habitat outside the designated area is unimportant or may not be needed
for recovery of the species. Areas that are important to the
conservation of the species, both inside and outside the critical
habitat designation, will continue to be subject to: (1) Conservation
actions implemented under section 7(a)(1) of the Act; (2) regulatory
protections afforded by the requirement in section 7(a)(2) of the Act
for Federal agencies to ensure their actions are not likely to
jeopardize the continued existence of any endangered or threatened
species; and (3) the prohibitions found in section 9 of the Act.
Federally funded or permitted projects affecting listed species outside
their designated critical habitat areas may still result in jeopardy
findings in some cases. These protections and conservation tools will
continue to contribute to recovery of the species. Similarly, critical
habitat designations made on the basis of the best available
information at the time of designation will not control the direction
and substance of future recovery plans, habitat conservation plans
(HCPs), or other species conservation planning
[[Page 8521]]
efforts if new information available at the time of those planning
efforts calls for a different outcome.
Prudency Determination
Section 4(a)(3) of the Act, as amended, and implementing
regulations (50 CFR 424.12) require that, to the maximum extent prudent
and determinable, the Secretary shall designate critical habitat at the
time the species is determined to be an endangered or threatened
species. Our regulations (50 CFR 424.12(a)(1)) state that the Secretary
may, but is not required to, determine that a designation would not be
prudent in the following circumstances:
(i) The species is threatened by taking or other human activity and
identification of critical habitat can be expected to increase the
degree of such threat to the species;
(ii) The present or threatened destruction, modification, or
curtailment of a species' habitat or range is not a threat to the
species, or threats to the species' habitat stem solely from causes
that cannot be addressed through management actions resulting from
consultations under section 7(a)(2) of the Act;
(iii) Areas within the jurisdiction of the United States provide no
more than negligible conservation value, if any, for a species
occurring primarily outside the jurisdiction of the United States;
(iv) No areas meet the definition of critical habitat; or
(v) The Secretary otherwise determines that designation of critical
habitat would not be prudent based on the best scientific data
available.
As discussed earlier in this document, there is currently no
imminent threat of collection or vandalism identified under Factor B
for this species, and identification and mapping of critical habitat is
not expected to initiate any such threat. In our SSA and proposed
listing determination for prostrate milkweed, we determined that the
present or threatened destruction, modification, or curtailment of
habitat or range is a threat to prostrate milkweed and that those
threats in some way can be addressed by section 7(a)(2) consultation
measures. We are able to identify areas that meet the definition of
critical habitat where the species occurs in the United States.
Therefore, because none of the circumstances enumerated in our
regulations at 50 CFR 424.12(a)(1) have been met and because the
Secretary has not identified other circumstances for which this
designation of critical habitat would not be prudent, we have
determined that the designation of critical habitat is prudent for
prostrate milkweed.
Critical Habitat Determinability
Having determined that designation is prudent, under section
4(a)(3) of the Act we must find whether critical habitat for the
prostrate milkweed is determinable. Our regulations at 50 CFR
424.12(a)(2) state that critical habitat is not determinable when one
or both of the following situations exist:
(i) Data sufficient to perform required analyses are lacking, or
(ii) The biological needs of the species are not sufficiently well
known to identify any area that meets the definition of ``critical
habitat.''
When critical habitat is not determinable, the Act allows the
Service an additional year to publish a critical habitat designation
(16 U.S.C. 1533(b)(6)(C)(ii)).
We reviewed the available information pertaining to the biological
needs of the species and habitat characteristics where this species is
located. This and other information represent the best scientific data
available and led us to conclude that the designation of critical
habitat is determinable for the prostrate milkweed.
Physical or Biological Features Essential to the Conservation of the
Species
In accordance with section 3(5)(A)(i) of the Act and regulations at
50 CFR 424.12(b), in determining which areas we will designate as
critical habitat from within the geographical area occupied by the
species at the time of listing, we consider the physical or biological
features (PBFs) that are essential to the conservation of the species
and that may require special management considerations or protection.
The regulations at 50 CFR 424.02 define ``physical or biological
features essential to the conservation of the species'' as the features
that occur in specific areas and that are essential to support the
life-history needs of the species, including, but not limited to, water
characteristics, soil type, geological features, sites, prey,
vegetation, symbiotic species, or other features. A feature may be a
single habitat characteristic or a more complex combination of habitat
characteristics. Features may include habitat characteristics that
support ephemeral or dynamic habitat conditions. Features may also be
expressed in terms relating to principles of conservation biology, such
as patch size, distribution distances, and connectivity. For example,
physical features essential to the conservation of the species might
include gravel of a particular size required for spawning, alkaline
soil for seed germination, protective cover for migration, or
susceptibility to flooding or fire that maintains necessary early-
successional habitat characteristics. Biological features might include
prey species, forage grasses, specific kinds or ages of trees for
roosting or nesting, symbiotic fungi, or a particular level of
nonnative species consistent with conservation needs of the listed
species. The features may also be combinations of habitat
characteristics and may encompass the relationship between
characteristics or the necessary amount of a characteristic essential
to support the life history of the species.
In considering whether features are essential to the conservation
of the species, we may consider an appropriate quality, quantity, and
spatial and temporal arrangement of habitat characteristics in the
context of the life-history needs, condition, and status of the
species. These characteristics include, but are not limited to, space
for individual and population growth and for normal behavior; food,
water, air, light, minerals, or other nutritional or physiological
requirements; cover or shelter; sites for breeding, reproduction, or
rearing (or development) of offspring; and habitats that are protected
from disturbance.
Geological Substrate and Soils
Prostrate milkweed grows in well-drained sandy soils of the
Tamaulipan shrubland region of south Texas and northeast Mexico
(Service 2020, pp. 22-26). In Starr and Zapata Counties, Texas, the
soils of documented sites overlie Eocene and Oligocene sandstones and
clays of the Laredo, Yegua, and Jackson geological formations (Stoeser
et al. 2005). In some occupied sites, a stratum of indurated caliche
may also be present; in south Texas, caliche refers to soil strata of
precipitated calcium carbonate formed during the early Pliocene
(Spearing 1998, pp. 258, 398; Baskin and Hulbert, Jr. 2008, p. 93).
Soil types of these occupied sites include deep eolian Hebbronville
sands, Copita fine sandy loam, Brennan fine sandy loam, eroded Maverick
soils, Catarina clay, and Zapata soils (USDA 1972; USDA 2011). Elevated
levels of gypsum are present at some sites.
The climate of the Tamaulipan shrubland region is subtropical and
semi-arid. Much of the region's precipitation occurs during infrequent
periods of heavy rainfall that interrupt prolonged spells of very hot,
dry weather. Rainfall readily infiltrates into the well-drained sandy
soils of prostrate milkweed habitats, but moisture does
[[Page 8522]]
not persist long in these soils. Many occupied sites have underlying
strata of sandstone; these barriers to root growth limit the
establishment of trees and taller shrubs. The growth of many plant
species is also limited by high soil gypsum concentrations in some
occupied sites. The rapid drying of soil, impenetrable rock strata, and
high gypsum are all factors that reduce competition from woody plants,
grasses, and other herbaceous plants.
Prostrate milkweed forms tubers underground that are able to
persist in a dormant condition for one to several years. The species
responds very quickly to rainfall; the tubers sprout new stems that
emerge, flower, and set seed in a matter of weeks, and the plants store
carbohydrates, minerals, and water in tubers. Then the above-ground
portions die back during hot, dry weather. Prostrate milkweed does not
occur in areas of higher rainfall or where moisture persists longer in
deeper silty or clayey soils. The species does not persist when
occupied sites develop a dense shrub overstory or dense cover of
grasses. We conclude that prostrate milkweed is endemic to sites where
it escapes competition from other plants through its unique adaptation
to ephemeral soil moisture, prolonged drought, and tolerance of high
gypsum concentrations.
Therefore, well-drained sandy soil overlying sandstone or indurated
caliche strata is an essential physical feature of prostrate milkweed
critical habitats. A high soil gypsum concentration contributes to the
habitat suitability of some sites by reducing competition, and is an
essential physical feature.
Ecological Community
Within the Tamaulipan shrubland ecological region, prostrate
milkweed inhabits arid subtropical grasslands and shrub savannas. It
requires an open canopy, where there is little or no shade from trees
and shrubs, and relatively little competition from grasses and
herbaceous plants; the estimated combined cover of woody plants,
grasses, and herbaceous plants at a site in Zapata County was less than
30 percent (Damude and Poole 1990, p. 16). It is likely that naturally
occurring wildfires, in the past, maintained the relatively open
structure of these plant communities (Scifres and Hamilton 1993, pp. 8-
21). We have observed an increased abundance of other Texas species of
Asclepias, including antelope horns (A. asperula), Emory's milkweed (A.
emoryi), zizotes milkweed (A. oenotheroides), and wand milkweed (A.
viridiflora), during the first few years after sites have burned; this
fire-following effect has been described for green milkweed (A.
viridis) (Baum and Sharber 2012, entire). Prostrate milkweed, like
other milkweeds, may also be stimulated to grow and flower after
wildfires have reduced competition.
Most Asclepias species require outcrossing for effective
fertilization of flowers. All Asclepias species have highly specialized
pollination mechanisms that require animal pollinators to carry pollen
from one individual to another. Although the effective pollinators of
prostrate milkweed have not been determined, these are likely to
include large bees and wasps. For example, the closely related zizotes
milkweed is effectively pollinated by very large wasps called tarantula
hawks (Pepsis spp. and Hemipepsis spp.) (Service 2020, pp. 17, 35-36).
Therefore, prostrate milkweed habitats must also support populations of
large bees and wasps that, in turn, require abundant, diverse sources
of pollen and nectar. Much like milkweeds, many pollen and nectar
plants are fire followers that are most abundant in sites that burn
periodically, but decline when fires are infrequent.
Buffelgrass is an African grass that is widely planted in south
Texas for livestock forage. Buffelgrass is highly invasive, and
frequently displaces native grasses and herbaceous plants (Best 2009,
pp. 310-311), including prostrate milkweed (Service 2020, pp. 39-40)
and the pollen and nectar plants needed to support pollinator
populations. The majority of prostrate milkweed plants have been
observed in disturbed soils where buffelgrass is absent or at low
densities (Eason 2019, pers. comm.; Strong 2019, pers. comm.).
Prostrate milkweed requires an open canopy with less than 30 percent
cover of native and nonnative grasses and herbaceous plants combined
(Damude and Poole 1990, p. 16); so, assuming nonnative buffelgrass is
more prevalent, we estimate that 20 percent or less cover of
buffelgrass is at a low enough density for prostrate milkweed to
survive. Therefore, prostrated milkweed habitats must also have less
than 20 percent cover of buffelgrass for prostrate milkweed to have
access to sufficient resources such as sunlight.
In summary, the essential biological features of prostrate milkweed
critical habitats are: (1) Open savannas and grasslands of the
Tamaulipan shrubland ecological region; (2) vegetation composition that
includes abundant, diverse pollen and nectar plants and healthy
populations of native bee and wasp species; and (3) less than 20
percent cover of buffelgrass. Periodic prescribed burning may be
necessary to maintain the open structure and diverse composition of the
species' habitats.
Summary of Essential Physical or Biological Features
Additional information can be found in the SSA report (Service
2020, available on <a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket No. FWS-R2-
ES-2021-0041). We have determined that the following physical or
biological features are essential to the conservation of prostrate
milkweed:
(1) Well-drained sandy soil overlying strata of sandstone or
indurated caliche;
(2) High soil gypsum concentration;
(3) Open savannas and grasslands of the Tamaulipan shrubland
ecological region;
(4) Vegetation composition that includes abundant, diverse pollen
and nectar plants and healthy populations of native bee and wasp
species; and
(5) Less than 20 percent cover of buffelgrass.
Special Management Considerations or Protection
When designating critical habitat, we assess whether the specific
areas within the geographical area occupied by the species at the time
of listing contain features that are essential to the conservation of
the species and which may require special management considerations or
protection. The features essential to the conservation of this species
may require special management considerations or protection to reduce
the following threats: Nonnative invasive grass; root-plowing and
conversion of native vegetation to buffelgrass pasture; ROW
construction and maintenance from energy development and road and
utility construction; border security development and law enforcement
activities; and small population sizes. Management activities that
could ameliorate these threats include, but are not limited to:
Prescribed burning, grazing, and/or brush thinning; nonnative invasive
grass control; protection from activities that disturb the soil; and
propagation and reintroduction of plants in restorable areas.
In summary, we find that the occupied areas we are proposing to
designate as critical habitat contain the PBFs that are essential to
the conservation of the species and that may require special management
considerations or protection. Special management considerations or
protection may be required of the Federal action agency to eliminate,
or to
[[Page 8523]]
reduce to negligible levels, the threats affecting the PBFs of each
unit.
Criteria Used To Identify Critical Habitat
As required by section 4(b)(2) of the Act, we use the best
scientific data available to designate critical habitat. In accordance
with the Act and our implementing regulations at 50 CFR 424.12(b), we
review available information pertaining to the habitat requirements of
the species and identify specific areas within the geographical area
occupied by the species at the time of listing and any specific areas
outside the geographical area occupied by the species to be considered
for designation as critical habitat. We are not currently proposing to
designate any areas outside the geographical area occupied by the
species because we have not identified any unoccupied areas that meet
the definition of critical habitat. While prostrate milkweed needs
additional populations to reduce the likelihood of extinction in the
future, we are not able to identify additional locations that may have
a reasonable certainty of contributing to conservation at this time due
to limited access to privately owned lands and information regarding
lands that would be good candidates for introductions in the species'
range.
In summary, for areas within the geographic area occupied by the
species at the time of listing, we delineated critical habitat unit
boundaries using the following criteria. First, using ArcGIS software,
we identified potential habitats in Starr and Zapata Counties that have
the essential features of geology and soils described above. The
geographic information we obtained about the known populations exists
as: (1) Vegetation surveys of entire tracts of land; (2) Element
Occurrence (EO) polygons represented in the TXNDD; or (3) points and
lines represented in the TXNDD. We then adapted methods to delineate
critical habitats for each type of geographic information.
We delineated all of the potential habitats that occur at the
Arroyo Ramirez tract and the Arroyo Morteros tract of the Lower Rio
Grande Valley NWR as proposed critical habitat (Units 2 and 5). The
Lower Rio Grande Valley NWR comprises several disconnected land
parcels, rather than one big land area, and these parcels are referred
to as ``tracts.'' The two tracts that are included in proposed Units 2
and 5 are isolated areas of refuge land. These NWR tracts are managed
for the conservation of native plants and animals, and we have
conducted plant surveys and have extensive knowledge of habitat
suitability of these tracts.
Similarly, we delineated all of the potential habitats that occur
at a private ranch (Unit 6) that is managed for wildlife and plant
conservation as proposed critical habitat. The landowner has granted
access for plant surveys and vegetation studies to researchers from the
Texas Parks and Wildlife Department, academic institutions, and the
Service. Two of the known populations are represented as polygons in
the TXNDD located in the ROWs of unpaved county roads in Starr County.
We have no information about the land uses or habitat suitability of
areas outside these polygons. We delineated all of the potential
habitats that occur within these polygons (Units 4 and 7) as proposed
critical habitat. Three of the known populations are represented as one
or more points or lines in the TXNDD located on privately owned land.
We have no information about the land uses or habitat suitability of
areas outside the points and lines. Because critical habitats must be
areas, not points or lines, we delineated all areas of potential
habitat within a buffer of 50 m (164 ft) from these points and lines as
proposed critical habitat units; we chose the 50-m distance because the
TXNDD also used a 50-m buffer for most of these features to account for
estimated geographic precision. To complete the delineations of
critical habitat areas, we overlaid each critical habitat area
described above on Digital Ortho-Quarter Quad aerial photographs to
identify and exclude any portions of sites that consisted of
unvegetated road beds that are frequently driven and are maintained by
road grading, as well as structures and other developed areas that did
not contain the geological and soil substrates and vegetative cover
that are essential physical and biological features.
We did not include one historical observation that has only
approximate location data and cannot be mapped. We also did not include
any of the populations reported in the U.S. Highway 83 ROW, all of
which have declined since they were first reported. For example, part
of EO 3 (Dolores) along U.S. 83 had about 200 individuals in 1988; four
surveys conducted from 2009 to 2017 found from 0 to 3 individuals. The
degree and frequency of soil disturbance in the ROWs of improved
highways has caused almost complete replacement of the native plant
community with introduced species, such as buffelgrass. Hence, the
essential physical and biological features are no longer present along
this improved highway ROW. For the same reasons, we did not include one
site in the road bed of a Starr County park where the species was last
observed in 1995.
The scale of the maps we prepared under the parameters for
publication within the Code of Federal Regulations may not reflect the
exclusion of such developed lands. Any such lands inadvertently left
inside critical habitat boundaries shown on the maps of this proposed
rule have been excluded by text in the proposed rule and are not
proposed for designation as critical habitat. Therefore, if the
critical habitat is finalized as proposed, a Federal action involving
these lands would not trigger section 7 consultation with respect to
critical habitat and the requirement of no adverse modification unless
the specific action would affect the physical or biological features in
the adjacent critical habitat.
We propose to designate as critical habitat lands that we have
determined are occupied at the time of listing (i.e., currently
occupied) and that contain one or more of the physical or biological
features that are essential to support life-history processes of the
species.
Units are proposed for designation based on one or more of the
physical or biological features being present to support prostrate
milkweed's life-history processes. Some units contain all of the
identified physical or biological features and support multiple life-
history processes. Some units contain only some of the physical or
biological features necessary to support the prostrate milkweed's
particular use of that habitat.
The proposed critical habitat designation is defined by the map or
maps, as modified by any accompanying regulatory text, presented at the
end of this document under Proposed Regulation Promulgation. We include
more detailed information on the boundaries of the critical habitat
designation in the preamble of this document. We will make the
coordinates or plot points or both on which each map is based available
to the public on <a href="https://www.regulations.gov">https://www.regulations.gov</a> at Docket No. FWS-R2-ES-
2021-0041 and on our internet site <a href="https://www.fws.gov/southwest/es/TexasCoastal/">https://www.fws.gov/southwest/es/TexasCoastal/</a>.
Proposed Critical Habitat Designation
We are proposing eight units as critical habitat for prostrate
milkweed. The critical habitat areas we describe below constitute our
current best assessment of areas that meet the definition of critical
habitat for prostrate milkweed. The eight areas we propose as critical
habitat units are all TXNDD EOs: Unit 1 (EO 3), Unit 2 (EO 10), Unit
[[Page 8524]]
3 (EO 11), Unit 4 (EO 12), Unit 5 (EO 15), Unit 6 (EO 16), Unit 7 (EO
17), and Unit 8 (EO 22). Table 2 shows the proposed critical habitat
units and the approximate area of each unit. All units are occupied.
Table 2--Proposed Critical Habitat Units for Prostrate Milkweed
[Area estimates reflect all land within critical habitat unit boundaries]
----------------------------------------------------------------------------------------------------------------
Size of unit
Critical habitat unit Land ownership by type in acres Occupied?
(hectares)
----------------------------------------------------------------------------------------------------------------
1 (EO 3)................................ County Road ROW and 10.51 (4.25) Yes.
Private.
2 (EO 10)............................... Federal--Service.......... 105.43 (42.67) Yes.
3 (EO 11)............................... Private................... 4.0 (1.62) Yes.
4 (EO 12)............................... County Road ROW........... 4.2 (1.7) Yes.
5 (EO 15)............................... Federal--Service.......... 62.49 (25.29) Yes.
6 (EO 16)............................... County Road ROW and 484.32 (196.0) Yes.
Private.
7 (EO 17)............................... County Road ROW and 19.35 (7.83) Yes.
Private.
8 (EO 22)............................... Private................... 1.04 (0.42) Yes.
-----------------------------------------------------------------------
Total............................... .......................... 691.3 (279.8)
----------------------------------------------------------------------------------------------------------------
Note: Area sizes may not sum due to rounding.
We present brief descriptions of all units, and reasons why they
meet the definition of critical habitat for prostrate milkweed below.
Unit 1: EO 3
Unit 1 consists of six areas, totaling 10.51 ac (4.25 ha), east of
highway 83 in northwest Zapata County. This unit is on private land and
unpaved county road ROWs. The unit is occupied by the species and
contains one or more of the PBFs essential to the conservation of
prostrate milkweed. Although we have no recent information on threats
that affect this unit, we conclude that this unit is affected by
invasive nonnative grass (buffelgrass) and road maintenance operations.
Therefore, special management considerations may be required to reduce
invasion of nonnative species and impacts from ROW maintenance.
Unit 2: EO 10
Unit 2 consists of 105.43 ac (42.67 ha) in the 699.4-acre Arroyo
Ramirez tract of Lower Rio Grande Valley NWR. This unit is in
southwestern Starr County adjacent to the Rio Grande on the U.S.-Mexico
border. The entire unit is on land owned and managed by the Service.
The unit is occupied by the species and contains one or more of the
PBFs essential to the conservation of prostrate milkweed. This unit
could be directly impacted by border barrier construction and security
operations (i.e., drag strips), or indirectly impacted by channeling of
runoff along the barrier during heavy rainfall, in addition to invasion
of buffelgrass. Therefore, special management may be required to
mitigate impacts from border security operations and nonnative grass.
Unit 3: EO 11
Unit 3 consists of three areas, totaling 4.0 ac (1.62 ha), on
private land in southwestern Starr County. The unit is occupied by the
species and contains one or more of the PBFs essential to the
conservation of prostrate milkweed. We have no recent information on
threats that affect this unit.
Unit 4: EO 12
Unit 4 consists of 4.2 ac (1.7 ha) along an unpaved county road ROW
in southwestern Starr County. This ROW supports a narrow strip of
diverse native vegetation that has likely not been plowed, bulldozed,
or graded. The unit is occupied by the species and contains one or more
of the PBFs essential to the conservation of prostrate milkweed. This
unit is affected by invasive nonnative grass (buffelgrass) and
maintenance and operation of the county road. Therefore, special
management may be required to reduce invasion of nonnative species.
Unit 5: EO 15
Unit 5 consists of 62.49 ac (25.29 ha) in the 90.8-acre Arroyo
Morteros tract of the Lower Rio Grande Valley NWR. This unit is in
southwestern Starr County adjacent to the Rio Grande on the U.S.-Mexico
border. The entire unit is on land owned and managed by the Service.
The unit is occupied by the species and contains one or more of the
PBFs essential to the conservation of prostrate milkweed. This unit
could be directly impacted by border barrier construction and security
operations (i.e., drag strips), or indirectly impacted by channeling of
runoff along the barrier during heavy rainfall, in addition to invasion
of buffelgrass. Therefore, special management may be required to
mitigate impacts from border security operations and nonnative grass.
Unit 6: EO 16
Unit 6 consists of 484.32 ac (196.0 ha) entirely on the 488.5-acre
private Martinez Ranch and along a county road ROW. This unit is in
southern Starr County. The owner of the Martinez Ranch is a willing
conservation partner in managing the property's native plants and
wildlife. The unit is occupied by the species and contains one or more
of the PBFs essential to the conservation of prostrate milkweed. This
unit is affected by invasive nonnative grass (buffelgrass). Therefore,
special management may be required to reduce invasion of nonnative
species.
Unit 7: EO 17
Unit 7 consists of 19.35 ac (7.83 ha) along both sides of an
unpaved county road ROW and adjacent private land in western Starr
County. This ROW supports a narrow strip of diverse native vegetation
that has likely not been plowed, bulldozed, or graded. The unit is
occupied by the species and contains one or more of the PBFs essential
to the conservation of prostrate milkweed. This unit is affected by
invasive nonnative grass (buffelgrass) and maintenance and operation of
the county road. Therefore, special management may be required to
reduce invasion of nonnative species.
Unit 8: EO 22
Unit 8 consists of 1.04 ac (0.42 ha) on private land in central
Zapata County. The unit is occupied by the species and contains one or
more of the PBFs essential to the conservation of prostrate milkweed.
Although we have no recent information about threats that affect this
unit, we estimate that this unit is
[[Page 8525]]
affected by invasive nonnative grass (buffelgrass) and development and
maintenance of oil and gas wells and utility corridors. Therefore,
special management may be required to reduce invasion of nonnative
species and impacts from ROW construction and maintenance from energy
development and road and utility construction.
Effects of Critical Habitat Designation
Section 7 Consultation
Section 7(a)(2) of the Act requires Federal agencies, including the
Service, to ensure that any action they fund, authorize, or carry out
is not likely to jeopardize the continued existence of any endangered
species or threatened species or result in the destruction or adverse
modification of designated critical habitat of such species. In
addition, section 7(a)(4) of the Act requires Federal agencies to
confer with the Service on any agency action that is likely to
jeopardize the continued existence of any species proposed to be listed
under the Act or result in the destruction or adverse modification of
proposed critical habitat.
We published a final rule revising the definition of destruction or
adverse modification on August 27, 2019 (84 FR 44976). Destruction or
adverse modification means a direct or indirect alteration that
appreciably diminishes the value of critical habitat as a whole for the
conservation of a listed species.
If a Federal action may affect a listed species or its critical
habitat, the responsible Federal agency (action agency) must enter into
consultation with us. Examples of actions that are subject to the
section 7 consultation process are actions on State, Tribal, local, or
private lands that require a Federal permit (such as a permit from the
U.S. Army Corps of Engineers under section 404 of the Clean Water Act
(33 U.S.C. 1251 et seq.) or a permit from the Service under section 10
of the Act) or that involve some other Federal action (such as funding
from the Federal Highway Administration, Federal Aviation
Administration, or the Federal Emergency Management Agency). Federal
actions not affecting listed species or critical habitat--and actions
on State, Tribal, local, or private lands that are not federally
funded, authorized, or carried out by a Federal agency--do not require
section 7 consultation.
Compliance with the requirements of section 7(a)(2) is documented
through our issuance of:
(1) A concurrence letter for Federal actions that may affect, but
are not likely to adversely affect, listed species or critical habitat;
or
(2) A biological opinion for Federal actions that may affect, and
are likely to adversely affect, listed species or critical habitat.
When we issue a biological opinion concluding that a project is
likely to jeopardize the continued existence of a listed species and/or
destroy or adversely modify critical habitat, we provide reasonable and
prudent alternatives to the project, if any are identifiable, that
would avoid the likelihood of jeopardy and/or destruction or adverse
modification of critical habitat. We define ``reasonable and prudent
alternatives'' (at 50 CFR 402.02) as alternative actions identified
during consultation that:
(1) Can be implemented in a manner consistent with the intended
purpose of the action,
(2) Can be implemented consistent with the scope of the Federal
agency's legal authority and jurisdiction,
(3) Are economically and technologically feasible, and
(4) Would, in the Service Director's opinion, avoid the likelihood
of jeopardizing the continued existence of the listed species and/or
avoid the likelihood of destroying or adversely modifying critical
habitat.
Reasonable and prudent alternatives can vary from slight project
modifications to extensive redesign or relocation of the project. Costs
associated with implementing a reasonable and prudent alternative are
similarly variable.
Regulations at 50 CFR 402.16 set forth requirements for Federal
agencies to reinitiate formal consultation on previously reviewed
actions. These requirements apply when the Federal agency has retained
discretionary involvement or control over the action (or the agency's
discretionary involvement or control is authorized by law) and, if
subsequent to the previous consultation: (1) If the amount or extent of
taking specified in the incidental take statement is exceeded; (2) if
new information reveals effects of the action that may affect listed
species or critical habitat in a manner or to an extent not previously
considered; (3) if the identified action is subsequently modified in a
manner that causes an effect to the listed species or critical habitat
that was not considered in the biological opinion; or (4) if a new
species is listed or critical habitat designated that may be affected
by the identified action. In such situations, Federal agencies
sometimes may need to request reinitiation of consultation with us, but
the regulations also specify some exceptions to the requirement to
reinitiate consultation on specific land management plans after
subsequently listing a new species or designating new critical habitat.
See the regulations for a description of those exceptions.
Application of the ``Destruction or Adverse Modification'' Standard
The key factor related to the destruction or adverse modification
determination is whether implementation of the proposed Federal action
directly or indirectly alters the designated critical habitat in a way
that appreciably diminishes the value of the critical habitat as a
whole for the conservation of the listed species. As discussed above,
the role of critical habitat is to support physical or biological
features essential to the conservation of a listed species and provide
for the conservation of the species.
Section 4(b)(8) of the Act requires us to briefly evaluate and
describe, in any proposed or final regulation that designates critical
habitat, activities involving a Federal action that may violate section
7(a)(2) of the Act by destroying or adversely modifying such habitat,
or that may be affected by such designation.
Activities that the Service may, during a consultation under
section 7(a)(2) of the Act, be considered likely to destroy or
adversely modify critical habitat include, but are not limited to:
(1) Actions that would degrade or destroy native plant communities.
Such activities could include, but are not limited to, road building,
land clearing for oil and gas exploration or other purposes,
introducing and encouraging the spread of nonnative species (i.e.,
buffelgrass), and border security operations. However, above-ground
cutting or thinning of woody plants and prescribed burning are
recommended management practices for conservation of prostrate milkweed
and other native grasses and forbs, and would not destroy or adversely
modify critical habitats.
(2) Actions that would mechanically disturb the soil structure.
Such activities could include, but are not limited to, bulldozing,
root-plowing, ripping, excavating, or other mechanical operations that
penetrate deep enough into the soil to cut or remove the tubers of
prostrate milkweed.
(3) Actions that would increase competition from woody plants or
introduced grasses. Such activities could include, but are not limited
to, intentional planting of introduced grass species, such as
buffelgrass, bermudagrass (Cynodon dactylon), or
[[Page 8526]]
Old World bluestems (introduced species of Dichanthium and
Bothriochloa).
Exemptions
Application of Section 4(a)(3) of the Act
Section 4(a)(3)(B)(i) of the Act (16 U.S.C. 1533(a)(3)(B)(i))
provides that the Secretary shall not designate as critical habitat any
lands or other geographical areas owned or controlled by the Department
of Defense (DoD), or designated for its use, that are subject to an
integrated natural resources management plan (INRMP) prepared under
section 101 of the Sikes Act (16 U.S.C. 670a), if the Secretary
determines in writing that such plan provides a benefit to the species
for which critical habitat is proposed for designation. No DoD lands
with a completed INRMP are within the proposed critical habitat
designation.
Consideration of Impacts Under Section 4(b)(2) of the Act
Section 4(b)(2) of the Act states that the Secretary shall
designate and make revisions to critical habitat on the basis of the
best available scientific data after taking into consideration the
economic impact, national security impact, and any other relevant
impact of specifying any particular area as critical habitat. The
Secretary may exclude an area from critical habitat if she determines
that the benefits of such exclusion outweigh the benefits of specifying
such area as part of the critical habitat, unless she determines, based
on the best scientific data available, that the failure to designate
such area as critical habitat will result in the extinction of the
species. In making the determination to exclude a particular area, the
statute on its face, as well as the legislative history, are clear that
the Secretary has broad discretion regarding which factor(s) to use and
how much weight to give to any factor.
Under section 4(b)(2) of the Act, we may exclude an area from
designated critical habitat based on economic impacts, impacts on
national security, or any other relevant impacts. In considering
whether to exclude a particular area from the designation, we identify
the benefits of including the area in the designation, identify the
benefits of excluding the area from the designation, and evaluate
whether the benefits of exclusion outweigh the benefits of inclusion.
If the analysis indicates that the benefits of exclusion outweigh the
benefits of inclusion, the Secretary may exercise discretion to exclude
the area only if such exclusion would not result in the extinction of
the species. We describe below the process that we undertook for taking
into consideration each category of impacts and our analyses of the
relevant impacts.
Consideration of Economic Impacts
Section 4(b)(2) of the Act and its implementing regulations require
that we consider the economic impact that may result from a designation
of critical habitat. To assess the probable economic impacts of a
designation, we must first evaluate specific land uses or activities
and projects that may occur in the area of the critical habitat. We
then must evaluate the impacts that a specific critical habitat
designation may have on restricting or modifying specific land uses or
activities for the benefit of the species and its habitat within the
areas proposed. We then identify which conservation efforts may be the
result of the species being listed under the Act versus those
attributed solely to the designation of critical habitat for this
particular species. The probable economic impact of a proposed critical
habitat designation is analyzed by comparing scenarios both ``with
critical habitat'' and ``without critical habitat.''
The ``without critical habitat'' scenario represents the baseline
for the analysis, which includes the existing regulatory and socio-
economic burden imposed on landowners, managers, or other resource
users potentially affected by the designation of critical habitat
(e.g., under the Federal listing as well as other Federal, State, and
local regulations). Therefore, the baseline represents the costs of all
efforts attributable to the listing of the species under the Act (i.e.,
conservation of the species and its habitat incurred regardless of
whether critical habitat is designated). The ``with critical habitat''
scenario describes the incremental impacts associated specifically with
the designation of critical habitat for the species. The incremental
conservation efforts and associated impacts would not be expected
without the designation of critical habitat for the species. In other
words, the incremental costs are those attributable solely to the
designation of critical habitat, above and beyond the baseline costs.
These are the costs we use when evaluating the benefits of inclusion
and exclusion of particular areas from the final designation of
critical habitat should we choose to conduct a discretionary 4(b)(2)
exclusion analysis.
For this particular designation, we developed an incremental
effects memorandum (IEM) considering the probable incremental economic
impacts that may result from this proposed designation of critical
habitat. The information contained in our IEM was then used to develop
a screening analysis of the probable effects of the designation of
critical habitat for the prostrate milkweed (Industrial Economics, Inc.
(IEc) 2021, entire). We began by conducting a screening analysis of the
proposed designation of critical habitat in order to focus our analysis
on the key factors that are likely to result in incremental economic
impacts. The purpose of the screening analysis is to filter out
particular geographic areas of critical habitat that are already
subject to such protections and are, therefore, unlikely to incur
incremental economic impacts. In particular, the screening analysis
considers baseline costs (i.e., absent critical habitat designation)
and includes any probable incremental economic impacts where land and
water use may be subject to conservation plans, land management plans,
best management practices, or regulations that protect the habitat area
as a result of the Federal listing status of the species. Ultimately,
the screening analysis allows us to focus our analysis on evaluating
the specific areas or sectors that may incur probable incremental
economic impacts as a result of the designation. If the proposed
critical habitat designation contains any unoccupied units, the
screening analysis assesses whether those units require additional
management or conservation efforts that may incur incremental economic
impacts. This screening analysis combined with the information
contained in our IEM constitute what we consider to be our draft
economic analysis (DEA) of the proposed critical habitat designation
for the prostrate milkweed; our DEA is summarized in the narrative
below.
Executive Orders (E.O.s) 12866 and 13563 direct Federal agencies to
assess the costs and benefits of available regulatory alternatives in
quantitative (to the extent feasible) and qualitative terms. Consistent
with the E.O. regulatory analysis requirements, our effects analysis
under the Act may take into consideration impacts to both directly and
indirectly affected entities, where practicable and reasonable. If
sufficient data are available, we assess to the extent practicable the
probable impacts to both directly and indirectly affected entities. As
part of our screening analysis, we considered the types of economic
activities that are likely to occur within the areas likely affected by
the critical habitat designation. In our evaluation of the probable
incremental economic impacts
[[Page 8527]]
that may result from the proposed designation of critical habitat for
the prostrate milkweed, first we identified, in the IEM dated March 11,
2021, probable incremental economic impacts associated with the
following categories of activities: (1) Construction of a new highway;
and (2) potential future border wall construction. We considered each
industry or category individually. Additionally, we considered whether
their activities have any Federal involvement. Critical habitat
designation generally will not affect activities that do not have any
Federal involvement; under the Act, designation of critical habitat
only affects activities conducted, funded, permitted, or authorized by
Federal agencies. If we list the species, in areas where the prostrate
milkweed is present, Federal agencies would be required to consult with
the Service under section 7 of the Act on activities they fund, permit,
or implement that may affect the species. If, when we list the species,
we also finalize this proposed critical habitat designation, our
consultations would include an evaluation of measures to avoid the
destruction or adverse modification of critical habitat.
In our IEM, we attempted to clarify the distinction between the
effects that would result from the species being listed and those
attributable to the critical habitat designation (i.e., difference
between the jeopardy and adverse modification standards) for the
prostrate milkweed's critical habitat. Because the designation of
critical habitat for prostrate milkweed was proposed concurrently with
the listing, it has been our experience that it is more difficult to
discern which conservation efforts are attributable to the species
being listed and those which will result solely from the designation of
critical habitat. However, the following specific circumstances in this
case help to inform our evaluation: (1) The essential physical or
biological features identified for critical habitat are the same
features essential for the life requisites of the species, and (2) any
actions that would result in sufficient harm or harassment to
constitute jeopardy to the prostrate milkweed would also likely
adversely affect the essential physical or biological features of
critical habitat. The IEM outlines our rationale concerning this
limited distinction between baseline conservation efforts and
incremental impacts of the designation of critical habitat for this
species. This evaluation of the incremental effects has been used as
the basis to evaluate the probable incremental economic impacts of this
proposed designation of critical habitat.
The proposed critical habitat designation for the prostrate
milkweed includes eight units totaling 691.3 ac (279.8 ha). All units
are considered occupied by the prostrate milkweed and contain the
physical and biological features essential to the conservation of the
species. We are not proposing to designate any units of unoccupied
habitat. Approximately 24 percent of the proposed designation is
located on Federal land, 4 percent is on county-owned ROWs, and 71
percent is on private land. In these areas, any actions that may affect
the species or its habitat would also affect designated critical
habitat, and it is unlikely that any additional conservation efforts
would be recommended to address the adverse modification standard over
and above those recommended as necessary to avoid jeopardizing the
continued existence of prostrate milkweed. Therefore, the potential
incremental economic effects of the critical habitat designation are
expected to be limited to administrative costs.
While this additional analysis will require time and resources by
both the Federal action agency and the Service, it is believed that, in
most circumstances, these costs would predominantly be administrative
in nature and would not be significant. Nearly all (97 percent) of the
proposed critical habitat overlaps designated critical habitat for the
endangered Zapata bladderpod (Physaria thamnophila). Proposed critical
habitat also overlaps with designated critical habitat for the
endangered ashy dogweed (Thymophylla tephroleuca) and star cactus
(Astrophytum asterias). Because of the overall small size of the
proposed critical habitat, there would likely only be a few
consultations, with minor conservation efforts that would likely result
in relatively low probable economic impacts. It is likely that the
majority of costs would occur on two of the eight proposed critical
habitat units, which are on Federal land (both are owned by the
Service). Any potential future border wall construction has been paused
at this time.
The probable incremental economic impacts of the prostrate milkweed
critical habitat designation are expected to be limited to additional
administrative effort as well as minor costs of conservation efforts
resulting from a small number of future section 7 consultations. This
is due to the fact that all of the proposed critical habitat areas are
considered to be occupied by the species, and incremental economic
impacts of critical habitat designation, other than administrative
costs, are unlikely. The entities most likely to incur incremental
costs are parties to section 7 consultations, including Federal action
agencies and, in some cases, third parties, most frequently State
agencies or municipalities. Activities we expect would be subject to
consultations that may involve private entities as third parties are
residential and commercial development that may occur on private lands.
However, based on coordination efforts with State and local agencies,
the cost to private entities within these sectors is expected to be
relatively minor. We would expect no more than 1 formal consultation,
10 information consultations, and 17 technical assistance efforts to
occur annually over the next year in proposed critical habitat areas
for the prostrate milkweed, with annual costs to the Service and action
agencies of less than $37,800. Thus, the annual administrative burden
is unlikely to reach $100 million, which is the threshold for a
significant regulatory action under E.O. 12866.
We are soliciting data and comments from the public on the DEA
discussed above, as well as on all aspects of this proposed rule and
our required determinations. During the development of a final
designation, we will consider the information presented in the DEA and
any additional information on economic impacts we receive during the
public comment period to determine whether any specific areas should be
excluded from the final critical habitat designation under authority of
section 4(b)(2) and our implementing regulations at 50 CFR 17.90. If we
receive credible information regarding the existence of a meaningful
economic or other relevant impact supporting a benefit of exclusion, we
will conduct an exclusion analysis for the relevant area or areas. We
may also exercise the discretion to evaluate any other particular areas
for possible exclusion. Furthermore, when we conduct an exclusion
analysis based on impacts identified by experts in, or sources with
firsthand knowledge about, impacts that are outside the scope of the
Service's expertise, we will give weight to those impacts consistent
with the expert or firsthand information unless we have rebutting
information. We may exclude an area from critical habitat if we
determine that the benefits of excluding the area outweigh the benefits
of including the area, provided the exclusion will not result in the
extinction of this species.
[[Page 8528]]
Consideration of National Security Impacts
Section 4(a)(3)(B)(i) of the Act may not cover all DoD lands or
areas that pose potential national-security concerns (e.g., a DoD
installation that is in the process of revising its INRMP for a newly
listed species or a species previously not covered). If a particular
area is not covered under section 4(a)(3)(B)(i), then national-security
or homeland-security concerns are not a factor in the process of
determining what areas meet the definition of ``critical habitat.''
However, the Service must still consider impacts on national security,
including homeland security, on those lands or areas not covered by
section 4(a)(3)(B)(i), because section 4(b)(2) requires the Service to
consider those impacts whenever it designates critical habitat.
Accordingly, if DoD, Department of Homeland Security (DHS), or another
Federal agency has requested exclusion based on an assertion of
national-security or homeland-security concerns, or we have otherwise
identified national-security or homeland-security impacts from
designating particular areas as critical habitat, we generally have
reason to consider excluding those areas.
However, we cannot automatically exclude requested areas. When DoD,
DHS, or another Federal agency requests exclusion from critical habitat
on the basis of national-security or homeland-security impacts, we must
conduct an exclusion analysis if the Federal requester provides
credible information, including a reasonably specific justification of
an incremental impact on national security that would result from the
designation of that specific area as critical habitat. That
justification could include demonstration of probable impacts, such as
impacts to ongoing border-security patrols and surveillance activities,
or a delay in training or facility construction, as a result of
compliance with section 7(a)(2) of the Act. If the agency requesting
the exclusion does not provide us with a reasonably specific
justification, we will contact the agency to recommend that it provide
a specific justification or clarification of its concerns relative to
the probable incremental impact that could result from the designation.
If we conduct an exclusion analysis because the agency provides a
reasonably specific justification or because we decide to exercise the
discretion to conduct an exclusion analysis, we will defer to the
expert judgment of DoD, DHS, or another Federal agency as to: (1)
Whether activities on its lands or waters, or its activities on other
lands or waters, have national-security or homeland-security
implications; (2) the importance of those implications; and (3) the
degree to which the cited implications would be adversely affected in
the absence of an exclusion. In that circumstance, in conducting a
discretionary section 4(b)(2) exclusion analysis, we will give great
weight to national-security and homeland-security concerns in analyzing
the benefits of exclusion.
Under section 4(b)(2) of the Act, we also consider whether a
national-security or homeland-security impact might exist on lands
owned or managed by DoD or DHS, or on any other lands. In preparing
this proposal, we have determined that the lands within the proposed
designation of critical habitat for prostrate milkweed are not owned or
managed by DoD or DHS. Although two proposed units of critical habitat
are located along the border, we do not anticipate that there will be
an impact on national security or homeland security. We will work with
CBP to ensure appropriate collaboration in our national security and
conservation efforts. However, if through the public comment period we
receive credible information regarding impacts on national security or
homeland security from designating particular areas as critical
habitat, then as part of developing the final designation of critical
habitat, we will conduct a discretionary exclusion analysis to
determine whether to exclude those areas under authority of section
4(b)(2) and our implementing regulations at 50 CFR 17.90.
Consideration of Other Relevant Impacts
Under section 4(b)(2) of the Act, we consider any other relevant
impacts, in addition to economic impacts and impacts on national
security discussed above. Other relevant impacts may include, but are
not limited to, impacts to Tribes, States, local governments, public
health and safety, community interests, the environment (such as
increased risk of wildfire or pest and invasive species management),
Federal lands, and conservation plans, agreements, or partnerships. To
identify other relevant impacts that may affect the exclusion analysis,
we consider a number of factors, including whether there are permitted
conservation plans covering the species in the area--such as HCPs, safe
harbor agreements (SHAs), or candidate conservation agreements with
assurances (CCAAs)--or whether there are non-permitted conservation
agreements and partnerships that may be impaired by designation of, or
exclusion from, critical habitat. In addition, we look at whether
Tribal conservation plans or partnerships, Tribal resources, or
government-to-government relationships of the United States with Tribal
entities may be affected by the designation. We also consider any
State, local, public-health, community-interest, environmental, or
social impacts that might occur because of the designation.
We have not identified any areas to consider for exclusion from
critical habitat based on other relevant impacts because areas included
in the proposed critical habitat are not covered under any permitted
conservation plans (i.e., SHAs), CCAAs, non-permitted conservation
agreements and partnerships, Tribal conservation plans or partnerships,
or have any State, local, public-health, community-interest,
environmental, or social impacts.
However, during the development of a final designation, we will
consider all information currently available or received during the
public comment period. If we receive credible information regarding the
existence of a meaningful impact supporting a benefit of excluding any
areas, we will undertake an exclusion analysis and determine whether
those areas should be excluded from the final critical habitat
designation under the authority of section 4(b)(2) and our implementing
regulations at 50 CFR 17.90. We may also exercise the discretion to
undertake exclusion analyses for other areas as well, and we will
describe all of our exclusion analyses as part of a final critical
habitat determination.
Summary of Exclusions Considered Under 4(b)(2) of the Act
At this time, we are not considering any exclusions from the
proposed designation based on economic impacts, national security
impacts, or other relevant impacts--such as partnerships, management,
or protection afforded by cooperative management efforts--under section
4(b)(2) of the Act. In this proposed rule, we are seeking credible
information from the public regarding the existence of a meaningful
impact supporting a benefit of excluding any areas that would be used
in an exclusion analysis that may result in the exclusion of areas from
the final critical habitat designation. (Please see FOR FURTHER
INFORMATION CONTACT for instructions on how to submit comments).
[[Page 8529]]
Required Determinations
Clarity of the Rule
We are required by Executive Orders 12866 and 12988 and by the
Presidential Memorandum of June 1, 1998, to write all rules in plain
language. This means that each rule we publish must:
(1) Be logically organized;
(2) Use the active voice to address readers directly;
(3) Use clear language rather than jargon;
(4) Be divided into short sections and sentences; and
(5) Use lists and tables wherever possible.
If you feel that we have not met these requirements, send us
comments by one of the methods listed in ADDRESSES. To better help us
revise the rule, your comments should be as specific as possible. For
example, you should tell us the numbers of the sections or paragraphs
that are unclearly written, which sections or sentences are too long,
the sections where you feel lists or tables would be useful, etc.
Regulatory Planning and Review (Executive Orders 12866 and 13563)
Executive Order 12866 provides that the Office of Information and
Regulatory Affairs (OIRA) in the Office of Management and Budget will
review all significant rules. OIRA has determined that this rule is not
significant.
Executive Order 13563 reaffirms the principles of E.O. 12866 while
calling for improvements in the Nation's regulatory system to promote
predictability, to reduce uncertainty, and to use the best, most
innovative, and least burdensome tools for achieving regulatory ends.
The Executive order directs agencies to consider regulatory approaches
that reduce burdens and maintain flexibility and freedom of choice for
the public where these approaches are relevant, feasible, and
consistent with regulatory objectives. E.O. 13563 emphasizes further
that regulations must be based on the best available science and that
the rulemaking process must allow for public participation and an open
exchange of ideas. We have developed this proposed rule in a manner
consistent with these requirements.
Regulatory Flexibility Act (5 U.S.C. 601 et seq.)
Under the Regulatory Flexibility Act (RFA; 5 U.S.C. 601 et seq.),
as amended by the Small Business Regulatory Enforcement Fairness Act of
1996 (SBREFA; 5 U.S.C. 801 et seq.), whenever an agency is required to
publish a notice of rulemaking for any proposed or final rule, it must
prepare and make available for public comment a regulatory flexibility
analysis that describes the effects of the rule on small entities
(i.e., small businesses, small organizations, and small government
jurisdictions). However, no regulatory flexibility analysis is required
if the head of the agency certifies the rule will not have a
significant economic impact on a substantial number of small entities.
The SBREFA amended the RFA to require Federal agencies to provide a
certification statement of the factual basis for certifying that the
rule will not have a significant economic impact on a substantial
number of small entities.
According to the Small Business Administration, small entities
include small organizations such as independent nonprofit
organizations; small governmental jurisdictions, including school
boards and city and town governments that serve fewer than 50,000
residents; and small businesses (13 CFR 121.201). Small businesses
include manufacturing and mining concerns with fewer than 500
employees, wholesale trade entities with fewer than 100 employees,
retail and service businesses with less than $5 million in annual
sales, general and heavy construction businesses with less than $27.5
million in annual business, special trade contractors doing less than
$11.5 million in annual business, and agricultural businesses with
annual sales less than $750,000. To determine whether potential
economic impacts to these small entities are significant, we considered
the types of activities that might trigger regulatory impacts under
this designation as well as types of project modifications that may
result. In general, the term ``significant economic impact'' is meant
to apply to a typical small business firm's business operations.
Under the RFA, as amended, and as understood in light of recent
court decisions, Federal agencies are required to evaluate the
potential incremental impacts of rulemaking on those entities directly
regulated by the rulemaking itself; in other words, the RFA does not
require agencies to evaluate the potential impacts to indirectly
regulated entities. The regulatory mechanism through which critical
habitat protections are realized is section 7 of the Act, which
requires Federal agencies, in consultation with the Service, to ensure
that any action authorized, funded, or carried out by the agency is not
likely to destroy or adversely modify critical habitat. Therefore,
under section 7, only Federal action agencies are directly subject to
the specific regulatory requirement (avoiding destruction and adverse
modification) imposed by critical habitat designation. Consequently, it
is our position that only Federal action agencies would be directly
regulated if we adopt the proposed critical habitat designation. The
RFA does not require evaluation of the potential impacts to entities
not directly regulated. Moreover, Federal agencies are not small
entities. Therefore, because no small entities would be directly
regulated by this rulemaking, the Service certifies that, if made final
as proposed, the proposed critical habitat designation will not have a
significant economic impact on a substantial number of small entities.
In summary, we have considered whether the proposed designation
would result in a significant economic impact on a substantial number
of small entities. For the above reasons and based on currently
available information, we certify that, if made final, the proposed
critical habitat designation would not have a significant economic
impact on a substantial number of small business entities. Therefore,
an initial regulatory flexibility analysis is not required.
Energy Supply, Distribution, or Use--Executive Order 13211
Executive Order 13211 (Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use) requires
agencies to prepare Statements of Energy Effects when undertaking
certain actions. In our economic analysis, we did not find that this
proposed critical habitat designation would significantly affect energy
supplies, distribution, or use. Therefore, this action is not a
significant energy action, and no Statement of Energy Effects is
required.
Unfunded Mandates Reform Act (2 U.S.C. 1501 et seq.)
In accordance with the Unfunded Mandates Reform Act (2 U.S.C. 1501
et seq.), we make the following finding:
(1) This proposed rule would not produce a Federal mandate. In
general, a Federal mandate is a provision in legislation, statute, or
regulation that would impose an enforceable duty upon State, local, or
Tribal governments, or the private sector, and includes both ``Federal
intergovernmental mandates'' and ``Federal private sector mandates.''
These terms are defined in 2 U.S.C. 658(5)-(7). ``Federal
intergovernmental mandate'' includes a regulation that ``would impose
an enforceable duty upon State, local, or Tribal governments'' with two
exceptions. It
[[Page 8530]]
excludes ``a condition of Federal assistance.'' It also excludes ``a
duty arising from participation in a voluntary Federal program,''
unless the regulation ``relates to a then-existing Federal program
under which $500,000,000 or more is provided annually to State, local,
and Tribal governments under entitlement authority,'' if the provision
would ``increase the stringency of conditions of assistance'' or
``place caps upon, or otherwise decrease, the Federal Government's
responsibility to provide funding,'' and the State, local, or Tribal
governments ``lack authority'' to adjust accordingly. At the time of
enactment, these entitlement programs were: Medicaid; Aid to Families
with Dependent Children work programs; Child Nutrition; Food Stamps;
Social Services Block Grants; Vocational Rehabilitation State Grants;
Foster Care, Adoption Assistance, and Independent Living; Family
Support Welfare Services; and Child Support Enforcement. ``Federal
private sector mandate'' includes a regulation that ``would impose an
enforceable duty upon the private sector, except (i) a condition of
Federal assistance or (ii) a duty arising from participation in a
voluntary Federal program.''
The designation of critical habitat does not impose a legally
binding duty on non-Federal Government entities or private parties.
Under the Act, the only regulatory effect is that Federal agencies must
ensure that their actions do not destroy or adversely modify critical
habitat under section 7. While non-Federal entities that receive
Federal funding, assistance, or permits, or that otherwise require
approval or authorization from a Federal agency for an action, may be
indirectly impacted by the designation of critical habitat, the legally
binding duty to avoid destruction or adverse modification of critical
habitat rests squarely on the Federal agency. Furthermore, to the
extent that non-Federal entities are indirectly impacted because they
receive Federal assistance or participate in a voluntary Federal aid
program, the Unfunded Mandates Reform Act would not apply, nor would
critical habitat shift the costs of the large entitlement programs
listed above onto State governments.
(2) We do not believe that this rule would significantly or
uniquely affect small governments because it will not produce a Federal
mandate of $100 million or greater in any year, that is, it is not a
``significant regulatory action'' under the Unfunded Mandates Reform
Act. The designation of critical habitat imposes no obligations on
State or local governments. Therefore, a Small Government Agency Plan
is not required.
Takings--Executive Order 12630
In accordance with E.O. 12630 (Government Actions and Interference
with Constitutionally Protected Private Property Rights), we have
analyzed the potential takings implications of designating critical
habitat for prostrate milkweed in a takings implications assessment.
The Act does not authorize the Service to regulate private actions on
private lands or confiscate private property as a result of critical
habitat designation. Designation of critical habitat does not affect
land ownership, or establish any closures, or restrictions on use of or
access to the designated areas. Furthermore, the designation of
critical habitat does not affect landowner actions that do not require
Federal funding or permits, nor does it preclude development of habitat
conservation programs or issuance of incidental take permits to permit
actions that do require Federal funding or permits to go forward.
However, Federal agencies are prohibited from carrying out, funding, or
authorizing actions that would destroy or adversely modify critical
habitat. A takings implications assessment has been completed for the
proposed designation of critical habitat for prostrate milkweed, and it
concludes that, if adopted, this designation of critical habitat does
not pose significant takings implications for lands within or affected
by the designation.
Federalism--Executive Order 13132
In accordance with E.O. 13132 (Federalism), this proposed rule does
not have significant federalism effects. A federalism summary impact
statement is not required. In keeping with Department of the Interior
and Department of Commerce policy, we requested information from, and
coordinated development of this proposed critical habitat designation
with, appropriate State resource agencies. From a federalism
perspective, the designation of critical habitat directly affects only
the responsibilities of Federal agencies. The Act imposes no other
duties with respect to critical habitat, either for States and local
governments, or for anyone else. As a result, the proposed rule does
not have substantial direct effects either on the States, or on the
relationship between the national government and the States, or on the
distribution of powers and responsibilities among the various levels of
government. The proposed designation may have some benefit to these
governments because the areas that contain the features essential to
the conservation of the species are more clearly defined, and the
physical or biological features of the habitat necessary for the
conservation of the species are specifically identified. This
information does not alter where and what federally sponsored
activities may occur. However, it may assist State and local
governments in long-range planning because they no longer have to wait
for case-by-case section 7 consultations to occur.
Where State and local governments require approval or authorization
from a Federal agency for actions that may affect critical habitat,
consultation under section 7(a)(2) of the Act would be required. While
non-Federal entities that receive Federal funding, assistance, or
permits, or that otherwise require approval or authorization from a
Federal agency for an action, may be indirectly impacted by the
designation of critical habitat, the legally binding duty to avoid
destruction or adverse modification of critical habitat rests squarely
on the Federal agency.
Civil Justice Reform--Executive Order 12988
In accordance with Executive Order 12988 (Civil Justice Reform),
the Office of the Solicitor has determined that the rule would not
unduly burden the judicial system and that it meets the requirements of
sections 3(a) and 3(b)(2) of the order. We have proposed designating
critical habitat in accordance with the provisions of the Act. To
assist the public in understanding the habitat needs of the species,
this proposed rule identifies the physical or biological features
essential to the conservation of the species. The proposed areas of
designated critical habitat are presented on maps, and the proposed
rule provides several options for the interested public to obtain more
detailed location information, if desired.
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.)
This rule does not contain information collection requirements, and
a submission to the Office of Management and Budget (OMB) under the
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.) is not
required. We may not conduct or sponsor and you are not required to
respond to a collection of information unless it displays a currently
valid OMB control number.
National Environmental Policy Act (42 U.S.C. 4321 et seq.)
It is our position that, outside the jurisdiction of the U.S. Court
of Appeals for the Tenth Circuit, we do not need to
[[Page 8531]]
prepare environmental analyses pursuant to the National Environmental
Policy Act (NEPA; 42 U.S.C. 4321 et seq.) in connection with
regulations adopted pursuant to section 4(a) of the Act. We published a
notice outlining our reasons for this determination in the Federal
Register on October 25, 1983 (48 FR 49244). This position was upheld by
the U.S. Court of Appeals for the Ninth Circuit (Douglas County v.
Babbitt, 48 F.3d 1495 (9th Cir. 1995), cert. denied 516 U.S. 1042
(1996)).
Government-to-Government Relationship With Tribes
In accordance with the President's memorandum of April 29, 1994
(Government-to-Government Relations with Native American Tribal
Governments; 59 FR 22951), Executive Order 13175 (Consultation and
Coordination with Indian Tribal Governments), and the Department of the
Interior's manual at 512 DM 2, we readily acknowledge our
responsibility to communicate meaningfully with recognized Federal
Tribes on a government-to-government basis. In accordance with
Secretarial Order 3206 of June 5, 1997 (American Indian Tribal Rights,
Federal-Tribal Trust Responsibilities, and the Endangered Species Act),
we readily acknowledge our responsibilities to work directly with
Tribes in developing programs for healthy ecosystems, to acknowledge
that Tribal lands are not subject to the same controls as Federal
public lands, to remain sensitive to Indian culture, and to make
information available to Tribes. We have determined that no Tribal
lands fall within the boundaries of the proposed critical habitat for
the prostrate milkweed, so no Tribal lands would be affected by the
proposed designation.
References Cited
A complete list of references cited in this rulemaking is available
on the internet at <a href="https://www.regulations.gov">https://www.regulations.gov</a> and upon request from
the Texas Coastal Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
Authors
The primary authors of this proposed rule are the staff members of
the U.S. Fish and Wildlife Service's Species Assessment Team and the
Texas Coastal Ecological Services Field Office.
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend part 17, subchapter B of chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 1531-1544; and 4201-4245,
unless otherwise noted.
0
2. Amend Sec. 17.12(h) by adding an entry for ``Asclepias prostrata''
to the List of Endangered and Threatened Plants in alphabetical order
under FLOWERING PLANTS to read as follows:
Sec. 17.12 Endangered and threatened plants.
* * * * *
(h) * * *
----------------------------------------------------------------------------------------------------------------
Listing citations and
Scientific name Common name Where listed Status applicable rules
----------------------------------------------------------------------------------------------------------------
Flowering Plants
* * * * * * *
Asclepias prostrata............. Prostrate milkweed. Wherever found.... E [Federal Register
citation when
published as a final
rule]; 50 CFR
17.96(a).\CH\
* * * * * * *
----------------------------------------------------------------------------------------------------------------
0
3. Amend Sec. 17.96(a) by adding an entry for ``Family Apocynaceae:
Asclepias prostrata (Prostrate Milkweed)'' after the entry for ``Family
Apiaceae: Lomatium cookii (Cook's lomatium, Cook's desert parsley)'' to
read as follows:
Sec. 17.96 Critical habitat--plants.
(a) * * *
Family Apocynaceae: Asclepias prostrata (Prostrate Milkweed)
(1) Critical habitat units are depicted for Starr and Zapata
Counties, Texas, on the maps in this entry.
(2) Within these areas, the physical or biological features
essential to the conservation of Asclepias prostrata consist of the
following components:
(i) Well-drained sandy soil overlying strata of sandstone or
indurated caliche;
(ii) High soil gypsum concentration;
(iii) Open savannas and grasslands of the Tamaulipan shrubland
ecological region;
(iv) Vegetation composition that includes abundant, diverse pollen
and nectar plants and healthy populations of native bee and wasp
species; and
(v) Less than 20 percent cover of Pennisetum ciliare (buffelgrass).
(3) Critical habitat does not include manmade structures (such as
buildings, aqueducts, runways, roads, and other paved areas) and the
land on which they are located existing within the legal boundaries on
[EFFECTIVE DATE OF RULE].
(4) Data layers defining map units were created using Texas Natural
Diversity Database (2019-2020) survey data of the documented Asclepias
prostrata locations in the United States to determine the geological
formations and soil types they occupy.
(i) We used the Esri ArcMap software to overlay the geographic
coordinates of populations on a digitized map of Texas surface geology
and a digitized soil survey map. We then clipped those areas of
potential to lands that have documented populations of Asclepias
prostrata.
(ii) The maps in this entry, as modified by any accompanying
regulatory text, establish the boundaries of the critical habitat
designation. The coordinates or plot points or both on which each map
is based are available to the public at the Service's internet site at
<a href="https://www.fws.gov/southwest/es/TexasCoastal/">https://www.fws.gov/southwest/es/TexasCoastal/</a>, at <a href="https://www.regulations.gov">https://www.regulations.gov</a> at Docket No. FWS-R2-ES-2021-0041, and at the field
office responsible for this designation. You may obtain field office
location information by contacting one of the Service regional offices,
the addresses of which are listed at 50 CFR 2.2.
(5) Note: Index map follows:
BILLING CODE 4333-15-P
[[Page 8532]]
[GRAPHIC] [TIFF OMITTED] TP15FE22.016
(6) Unit 1: Zapata County, Texas.
(i) Unit 1 consists of 6 areas totaling 10.51 ac (4.25 ha) east of
highway 83 in northwest Zapata County. This unit is on private land and
a county road right of way.
[[Page 8533]]
(ii) Map of Unit 1 follows:
[GRAPHIC] [TIFF OMITTED] TP15FE22.017
[[Page 8534]]
(7) Unit 2: Starr County, Texas.
(i) Unit 2 consists of 105.43 ac (42.67 ha) in the Arroyo Ramirez
tract of Lower Rio Grande Valley National Wildlife Refuge. This unit is
in southwestern Starr County adjacent to the Rio Grande on the U.S.-
Mexico border. The entire unit is on land owned and managed by the
Service.
[[Page 8535]]
(ii) Map of Unit 2 follows:
[GRAPHIC] [TIFF OMITTED] TP15FE22.018
[[Page 8536]]
(8) Unit 3: Starr County, Texas.
(i) Unit 3 consists of 4.0 ac (1.62 ha) along both sides of a road
right of way on private land in southern Starr County.
(ii) Map of Unit 3 follows:
[[Page 8537]]
[GRAPHIC] [TIFF OMITTED] TP15FE22.019
(9) Unit 4: Starr County, Texas.
(i) Unit 4 consists of 4.2 ac (1.7 ha) along the unpaved right of
way of Los Arrieros Loop, a county road in southwestern Starr County.
[[Page 8538]]
(ii) Map of Unit 4 follows:
[GRAPHIC] [TIFF OMITTED] TP15FE22.020
(10) Unit 5: Starr County, Texas.
(i) Unit 5 consists of 62.49 ac (25.29 ha) in the Arroyo Morteros
tract of the Lower Rio Grande Valley National Wildlife Refuge. This
unit is in western Starr County adjacent to the Rio Grande on the U.S.-
Mexico border. The entire unit is on land owned and managed by the
Service.
(ii) Map of Unit 5 follows:
[[Page 8539]]
[GRAPHIC] [TIFF OMITTED] TP15FE22.021
(11) Unit 6: Starr County, Texas.
(i) Unit 6 consists of 484.32 ac (196.0 ha) entirely on privately
owned land and the adjacent right of way of San
[[Page 8540]]
Julian Road. This unit is in western Starr County.
(ii) Map of Unit 6 follows:
[GRAPHIC] [TIFF OMITTED] TP15FE22.022
[[Page 8541]]
(12) Unit 7: Starr County, Texas.
(i) Unit 7 consists of 19.35 ac (7.83 ha) along both sides of a
right of way and adjacent private land in western Starr County.
(ii) Map of Unit 7 follows:
[GRAPHIC] [TIFF OMITTED] TP15FE22.023
(13) Unit 8: Zapata County, Texas.
(i) Unit 8 consists of 1.04 ac (0.42 ha) on private land in central
Zapata County.
[[Page 8542]]
(ii) Map of Unit 8 follows:
[GRAPHIC] [TIFF OMITTED] TP15FE22.024
[[Page 8543]]
* * * * *
Martha Williams,
Principal Deputy Director, Exercising the Delegated Authority of the
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2022-02544 Filed 2-14-22; 8:45 am]
BILLING CODE 4333-15-C
</pre></body>
</html>Indexed from Federal Register on February 15, 2022.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.