[Federal Register Volume 90, Number 102 (Thursday, May 29, 2025)]
[Rules and Regulations]
[Pages 22650-22670]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-09692]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R6-ES-2022-0093; FXES11130900000-256-FF09E22000]
RIN 1018-BG56
Endangered and Threatened Wildlife and Plants; Removal of
Colorado Hookless Cactus From the List of Endangered and Threatened
Plants
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Final rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are removing
Colorado hookless cactus (Sclerocactus glaucus) from the Federal List
of Endangered and Threatened Plants. Recent taxonomic studies have
indicated that the currently listed entity is actually two species:
Sclerocactus glaucus and Sclerocactus dawsoniae (previously identified
as S. dawsonii in the proposed rule). When we use the common name
``Colorado hookless cactus'' or refer to ``the species'' in this final
rule, we are referring to information or conclusions regarding both
species (S. glaucus and S. dawsoniae) as the currently listed entity.
When we are referring to information or analysis pertaining to one
species, we will use the new scientific names of S. glaucus or S.
dawsoniae. After a review of the best available scientific and
commercial information, we find that delisting Colorado hookless cactus
is warranted. Our review indicates that the threats to the Colorado
hookless cactus have been eliminated or reduced to the point that the
species no longer meets the definition of an endangered or threatened
species under the Endangered Species Act of 1973, as amended (Act).
Accordingly, the prohibitions and conservation measures provided by the
Act, particularly through sections 4 and 7, will no longer apply to the
Colorado hookless cactus.
DATES: This rule is effective June 30, 2025.
ADDRESSES: This final rule is available on the internet at https://www.regulations.gov. Comments and materials we received are available
for public inspection at https://regulations.gov at Docket No. FWS-R6-
ES-2022-0093
Availability of supporting materials: This rule and supporting
documents, including references cited, the 5-year review, the recovery
outline, the species status assessment (SSA) report, the proposed
delisting rule, and the post-delisting monitoring (PDM) plan, are
available at https://www.regulations.gov at Docket No. FWS-R6-ES-2022-
0093.
FOR FURTHER INFORMATION CONTACT: Nathan Darnall, Western Colorado
Supervisor, U.S. Fish and Wildlife Service, Colorado Ecological
Services Field Office, 445 West Gunnison Avenue, Grand Junction, CO
81501; telephone 970-628-7181. Individuals in the United States who are
deaf, deafblind, hard of hearing, or have a speech disability may dial
711 (TTY, TDD, or TeleBraille) to access telecommunications relay
services. Individuals outside the United States should use the relay
services offered within their country to make international calls to
the point-of-contact in the United States.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Act, a species warrants
delisting if it no longer meets the definition of an endangered species
(in danger of extinction throughout all or a significant portion of its
range) or a threatened species (likely to become an endangered species
within the foreseeable future throughout all or a significant portion
of its range). The Colorado hookless cactus is listed as a threatened
species, and we are delisting it. Delisting a species can be completed
only by issuing a rule through the Administrative Procedure Act
rulemaking process (5 U.S.C. 551 et seq.).
What this document does. We are delisting the Colorado hookless
cactus because the species has recovered to the point at which it no
longer meets the definition of an endangered or threatened species.
The basis for our action. Under the Act, we may determine that a
species is an endangered species or a 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. The determination to delist a
species must be based on an analysis of the same factors.
Under the Act, we must review the status of all listed species at
least once every 5 years. We must delist a species if we determine, on
the basis of the best available scientific and commercial data, that
the species is neither a threatened species nor an endangered species.
Our regulations at 50 CFR 424.11(e) identify four reasons why we might
determine a species shall be delisted: (1) The species is extinct, (2)
the species has recovered to the point at which it no longer meets the
definition of an endangered species or a threatened species, (3) new
information that has become available since the original listing
decision shows the listed entity does not meet the definition of an
endangered species or a threatened species, or (4) new information that
has become available since the original listing decision shows the
listed entity does not meet the definition of a species. Here, we have
determined that the Colorado hookless cactus has recovered to the point
at which it no longer meets the definition of an endangered species or
a threatened species; therefore, we are delisting it.
Previous Federal Actions
Please refer to the proposed rule to delist the Colorado hookless
cactus published on April 11, 2023 (88 FR 21582), for a detailed
description of previous Federal actions concerning this species.
Peer Review
A species status assessment (SSA) team prepared the SSA report for
Colorado hookless cactus to inform the 2021 5-year review and updated
it in 2024. 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 and recovery actions under the Act (https://www.fws.gov/sites/default/files/documents/peer-review-policy-directors-memo-2016-08-22.pdf), we solicited independent scientific review of the information
contained in the Colorado hookless cactus SSA report. As discussed in
the proposed rule, we sent the SSA report to five independent peer
reviewers and received three responses. The peer reviews can be found
at https://www.regulations.gov. In preparing the proposed rule, we
incorporated the results of these reviews, as appropriate, into the SSA
report, which was the foundation for the proposed rule and
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this final rule. A summary of the peer review comments and our
responses can be found in the proposed rule (88 FR 21582, April 11,
2023).
Summary of Changes From the Proposed Rule and Draft Post-Delisting
Monitoring Plan
We considered all comments and information we received during the
comment period on our proposed rule to delist Colorado hookless cactus
(88 FR 21582, April 11, 2023). This consideration resulted in the
following changes from the proposed rule and draft post-delisting
monitoring (PDM) plan to this final rule and the updated PDM plan.
In this final rule, we changed the scientific name Sclerocactus
dawsonii to S. dawsoniae based on taxonomic nomenclature standards and
a recently published article establishing it as a new species
(McGlaughlin and Naibauer 2024, entire).
In the proposed rule and SSA version 1.1, we reported a minimum
population estimate of 103,086 plants for Sclerocactus glaucus with a
90 percent lower confidence level estimate of 68,120 plants (88 FR
21582 at 21592, April 11, 2023; Service 2022, p. 14). We now consider
the 90 percent lower confidence value of 68,120 plants to be a better
reflection of the minimum population estimate for the S. glaucus total
population size than the mean estimate of 103,086 plants provided by
the Bureau of Land Management (BLM) (Krening et al. 2021a, p. 8), as
this allows us to be more conservative given the less comprehensive
sampling in the study that produced these estimates (as compared to the
sampling effort from the S. dawsoniae study (see Current Condition;
Service 2025, pp. 20-21)).
Similarly, in the proposed rule and SSA version 1.1, we reported a
minimum population estimate of 31,867 and the 90 percent lower
confidence level estimate of 21,058 plants for Sclerocactus dawsoniae
(88 FR 21582 at 21592, April 11, 2023; Service 2022, p. 14). This
minimum population estimate was derived using S. glaucus macroplot
estimates as a surrogate for S. dawsoniae (Krening et al. 2021a, p. 8).
We have updated in this rule the minimum population estimate for S.
dawsoniae to 17,362 plants based on a BLM technical report that used S.
dawsoniae data to derive the estimate (Krening and Holsinger 2024,
entire). We consider the updated minimum population estimate to better
reflect S. dawsoniae's total population size. We also provide
additional explanation of the BLM methodology to derive population
estimates for both species. We note that the updated minimum population
estimates do not necessarily reflect a change in the species' numbers
per se, but rather an improvement in the accuracy of information about
their population sizes.
In this final rule we have also provided additional information
about protections afforded to BLM sensitive species, and livestock
grazing effects to Colorado hookless cactus, in our pessimistic future
scenario.
In this final rule, we no longer consider or rely on the
protections identified in the 2012 livestock grazing programmatic
biological opinion for Colorado hookless cactus (Service 2012, entire).
Once this final rule goes into effect, the grazing terms and conditions
identified in the biological opinion will not apply to S. glaucus or S.
dawsoniae. Therefore, in this rule we do not mention the protections
afforded to Colorado hookless cactus under the programmatic biological
opinion, as these protections have no bearing on our determination of
the status of the listed entity under the Act.
We have also revised the PDM plan by updating the baseline
densities for both species with 2022 and 2023 trend monitoring data
(Service 2024, entire). We and our partners will use the baseline
densities to track the trend of the species over the PDM timeframe.
Summary of Comments and Recommendations
In the proposed rule published on April 11, 2023 (88 FR 21582), we
requested that all interested parties submit written comments on the
proposal by June 12, 2023. We also contacted appropriate Federal and
State agencies, scientific experts and organizations, and other
interested parties and invited them to comment on the proposal. On
April 10, 2023, we published a press release on our website inviting
the public to comment. Newspaper notices inviting the general public to
comment were published in the Grand Junction Daily Sentinel. We did not
receive any requests for a public hearing. We received 13 public
comments addressing the proposed rule, representing 10 individuals and
3 organizations. All substantive information received during the
comment period has either been incorporated directly into this final
determination or is addressed below.
Comment (1): Several commenters stated that invasive species can
negatively affect survival and recruitment of Colorado hookless cactus
and increase the risk of fire in the species' habitat, and that
invasive species were underrepresented in the current and future
condition analyses of Colorado hookless cactus. One commenter stated
that we relied on optimistic measures to support delisting even though
invasive species could have greater effects in the future.
Response (1): The commenters did not provide information to support
their comment or suggestions for how to better represent the negative
effects of invasive species in our analysis. The BLM Colorado hookless
cactus technical assessment and habitat condition analysis provide the
best scientific and commercial data available to examine current
invasive species levels within Colorado hookless cactus analysis units
(AUs) and potential effects to the species (Krening and Dawson 2020, p.
35; Holsinger and Krening 2021, entire). According to this information,
current invasive species levels do not negatively affect the species or
habitat quality at the AU level. Only individual plants experience
detrimental effects of invasive weeds in localized areas (Service 2025,
pp. 16-21; Krening and Dawson 2020, p. 35). We also evaluated future
increases in effects from invasive species in combination with other
stressors (livestock grazing, off-highway-vehicle (OHV) use, oil and
gas development, utility corridor development and climate change) in
our pessimistic future scenario (see Future Scenarios and Future
Condition).
While fire extent and severity may increase as invasive species
cover increases, wildfires within the range of Colorado hookless cactus
have resulted in only very localized impacts to both species. One
example of a recent fire is the Logan Fire in the Roan Creek AU in 2023
that killed 11 plants (Freitag 2023, pers. comm.; Service 2025, pp. 37-
38); this number represents far less than 1 percent of S. dawsoniae
plants in an AU that has a minimum population estimate of 14,901. The
Logan Fire was small in extent despite the high levels of invasive
plant cover in the area (Service 2025, appendix 1). We expect both
species will continue to experience localized effects from fire in the
future. The majority of their habitat is sparsely vegetated; both
species are widely dispersed across the landscape; and their ranges
contain many barriers such as canyons, roads, and rivers that serve as
firebreaks despite potential future increases in invasive species
cover.
Comment (2): Several commenters stated that the BLM minimum
population size estimates for Colorado hookless cactus are not reliable
because the monitoring plot (macroplot) locations were subjectively
selected by the researchers. One commenter recommended that we
carefully evaluate
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the validity of the study before delisting the species, and another
commenter considered our reliance on the BLM population size estimates
to delist Colorado hookless cactus to be arbitrary and capricious.
Response (2): We disagree with the commenters that the Colorado
hookless cactus minimum population size estimates are arbitrary and
capricious and not reliable. We used the S. glaucus minimum population
size estimates reported in a published peer-reviewed journal article
(Krening et al. 2021a, entire). The sampling methods and analysis in
this study--rather than reliance on census counts--are commonly used
for plants with large populations sizes (Elzinga et al. 1999, pp. 37-
38, 61-88). In this final rule, we relied on the S. dawsoniae minimum
population size estimates reported in a BLM Technical Note with S.
dawsoniae data (Krening and Holsinger 2024, entire) that used the same
methodology as the published study (Krening et al. 2021a, entire) and
received internal peer review.
We consider the BLM methods and population estimates of Krening et
al. 2021a (entire) and Krening and Holsinger 2024 (entire) to be better
and more reliable than earlier methods and population estimates. The
BLM methods have been peer reviewed, were systematically implemented
rangewide, and provide minimum population estimates that are smaller
than the actual population size. Earlier methods were not peer reviewed
and were applied inconsistently across the species' range with data
collected opportunistically from different sources. While macroplots
were placed subjectively for both species, transect locations within
macroplots were randomly selected and represent a variety of habitat
conditions for Colorado hookless cactus according to the BLM's habitat
condition index. We relied on the minimum population estimates that
were conservatively based on the transect data (see Current Condition).
We consider the S. glaucus and S. dawsoniae minimum population
estimates to be reliable and the best scientific information available,
and we are not aware of better estimates of population size for the two
species. Therefore, we continue to rely on the Colorado hookless cactus
minimum population size estimates provided by the studies mentioned
herein (Krening et al. 2021a, entire; Krening and Holsinger 2024,
entire; Holsinger and Krening 2024, entire; Service 2025, pp. 13-14,
24-27). Furthermore, the PDM plan relies on the sampling protocols in
Krening et al. (2021a, entire).
Comment (3): Several commenters stated that the SSA report and
proposed rule downplayed the effects and future risk of oil and gas
development on S. dawsoniae and failed to analyze the cumulative
impacts of this and other stressors. The commenters considered
widespread habitat degradation and a downward trend to be likely for S.
dawsoniae because the entire population is subject to oil and gas
leasing, there are producing wells throughout its range, and over half
of its range is unprotected from development.
Response (3): We review the best scientific and commercial
information available when conducting a threats analysis. The
identification of factors that could impact a species negatively is not
sufficient to compel a finding that listing (or maintaining a currently
listed species) on the Federal Lists of Endangered and Threatened
Wildlife and Plants is appropriate. In determining whether a species
meets the definition of a threatened or endangered species, we must
evaluate all identified threats by considering the species' expected
response and the effects of the threats--in light of those actions and
conditions that will ameliorate the threats--on an individual,
population, and species level, as well as the cumulative effect of the
threats (see Regulatory Framework).
The commenters did not provide additional information to support
their comment. As we discuss below, leased areas do not equate to areas
of surface disturbance; only small subsets of these areas are actively
being explored or developed (see Stressors). We evaluated current and
future scenarios with the SSA framework, which analyzes the cumulative
impact of stressors on the species (see Cumulative Impacts). We
evaluated the potential for increases in oil and gas development, along
with other stressors, in the pessimistic future scenario, and found
that the loss of resiliency for S. dawsoniae AUs will be modest and no
major changes in redundancy or representation are expected (see Future
Scenarios and Future Condition).
Comment (4): Two commenters questioned the protections afforded to
Colorado hookless cactus by its designation as a BLM sensitive species.
The first commenter cited an oil and gas project that resulted in the
loss of 53 plants of another BLM sensitive species, Harrington's
beardtongue (Penstemon harringtonii), as evidence of the limited
protections that designation provides. The first commenter was
concerned that we are considering only the species-level viability when
evaluating the status of Colorado hookless cactus. The second commenter
stated that we do not acknowledge the risk of losing the BLM 200-meter
(m) 656 feet (ft) avoidance buffer for oil and gas development if
Colorado hookless cactus is delisted.
Response (4): We disagree with the first commenter that we can
expect the loss of Colorado hookless cactus populations despite its
designation as a BLM sensitive species. The example provided by the
commenter identifies localized, not population-level, loss of
Harrington's beardtongue. We assess the viability of Colorado hookless
cactus at the population and species levels as described in the
Analytical Framework section, below. We acknowledge that the avoidance
buffer for Colorado hookless cactus on BLM lands will decrease from the
200 m (656 ft) applied to federally listed plant species to 100 m (328
ft) afforded to BLM sensitive species for oil and gas development and
other surface-disturbing activities (see Conservation Efforts and
Regulatory Mechanisms). In addition, BLM has discretion to relocate
proposed energy development projects up to and beyond 200 m (656 ft)
for BLM sensitive species in areas with a controlled surface use
stipulation (see Conservation Efforts and Regulatory Mechanisms,
below).
Comment (5): Several commenters provided a published journal
article about dust effects to a federally listed plant in Utah outside
of Colorado hookless cactus' range that estimated 2.5 tons of dust are
deposited along a road corridor every year (Lewis et al. 2017, p. 431).
Commenters stated that there is no substantive discussion or evaluation
of dust effects to S. dawsoniae in the SSA report and proposed rule.
Response (5): We considered dust effects to both species in the SSA
report as a stressor that is generated from multiple threats, including
oil and gas development, OHV recreational use, and utility corridors.
The best available information indicates that dust is not negatively
impacting S. glaucus or S. dawsoniae at the population or species
levels (Service 2025, pp. 17-18). The Lewis et al. (2017) paper
specifically mentions the estimated dust deposition reported by the
commenters is a generalization and was not measured. We note that the
commenters provided information on dust effects for other species and
locations but did not provide new information on dust within the ranges
of S. glaucus or S. dawsoniae or dust effects specific to the two
species.
Comment (6): Several commenters stated that our analysis in the SSA
report and proposed rule underestimated the effects of livestock
grazing on Colorado hookless cactus and
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ignored the best available science regarding this stressor. Commenters
were concerned that livestock grazing may pose a demographic threat at
the population level for Colorado hookless cactus because cattle can
uproot and crush larger plants crucial to reproduction and cactus
occurrences have been extirpated by concentrated sheep use.
Additionally, several commenters stated that many grazing allotments
within the Colorado hookless cactus' range do not meet BLM land health
assessment standards.
Response (6): We considered the effects of livestock grazing to
both species in the SSA report. Despite some grazing allotments within
the two species' ranges not meeting BLM land health assessment
standards, the best available information indicates that livestock
grazing is not negatively impacting S. glaucus or S. dawsoniae at the
population or species level (see Stressors, below; Service 2025, pp.
16-19). The BLM rangeland health assessment standards are not tailored
to Colorado hookless cactus; rather, they describe specific conditions
needed for public land health, such as the presence of streambank
vegetation and adequate canopy or ground cover (43 CFR part 4100,
subpart 4180). In the pessimistic scenario in the SSA report, we
considered the potential for increased impacts from livestock grazing
into the future. Even in this scenario, we project high or moderate
resiliency in all but one of the S. glaucus AUs and in both S.
dawsoniae AUs. We note that the commenters provided information on
livestock grazing effects for other species and locations but did not
provide new information on livestock grazing within the ranges of S.
glaucus or S. dawsoniae or evidence of livestock grazing effects
specific to the two species.
Comment (7): One commenter stated that BLM would not provide any
restrictions on their lands for livestock grazing if the two
Sclerocactus species were delisted.
Response (7): We disagree with the commenter that BLM would not
provide any restrictions on their lands for livestock grazing if the
two species were delisted. BLM administers special land management
designations called Areas of Critical Environmental Concern (ACECs).
Across the range of S. glaucus and S. dawsoniae, BLM has 11 ACECs,
including 5 totaling 18,093 acres (ac) (7,321 hectares (ha)) where
livestock use is managed or prohibited to benefit listed and BLM
sensitive species in all or part of the management area (the River
Rims, Escalante Canyon, Adobe Badlands, Pyramid Rock, and Atwell Gulch
ACECs; see Stressors). In addition, on lands without special
designations, BLM includes standard permit terms and conditions for
their livestock grazing permits such as seasonal utilization levels,
reductions due to drought or fire, and other restrictions on open
grazing (see Conservation Efforts and Regulatory Mechanisms). These
measures are not dependent on the listed status of Colorado hookless
cactus.
Comment (8): Two commenters stated that we did not consider any
levels of increased livestock grazing in our pessimistic future
scenario or the cumulative impacts from climate change, invasive
species, oil and gas development, and OHV recreation.
Response (8): We included a plausible range of livestock grazing
levels on BLM lands in our future scenarios, including an increase in
effects from livestock grazing on Colorado hookless cactus habitat and
individuals in the pessimistic future scenario. Even in this
pessimistic scenario, S. glaucus is projected to maintain high or
moderate resiliency for all but one AU, and S. dawsoniae is projected
to maintain high or moderate resiliency in both AUs, along with
continued redundancy and representation for both species. Regarding our
evaluation of cumulative effects, see our response to Comment (3),
above.
Comment (9): One commenter stated that we failed to consider the
well-known impacts of livestock grazing on biological soil crusts
(BSCs) that influence water availability, nutrient cycling, and soil
erosion in semi-arid high-elevation deserts; nor did we consider the
severity of future drought conditions caused by climate change.
However, the commenter acknowledged that BSCs are difficult to detect
and their reductions by livestock grazing may not be readily apparent.
The commenter provided supporting published literature on this topic
(Duniway et al. 2018, entire; Belnap and Eldridge 2001, entire).
Response (9): We recognize the function of BSCs to promote soil
stability and nutrient cycling, and we considered the published
literature provided by the commenter. We agree with the commenter that
BSCs may be difficult to detect; the best available information within
Colorado hookless cactus' range identifies the amount of bare ground
and native and invasive plant cover and no information on BSCs. The
commenter does not provide additional information on BSCs' impact to
Colorado hookless cactus, and we have no information to indicate that
BSCs, or the lack thereof, are having lasting population-level effects
for the two species. We evaluated the effects of stressors that impact
BSCs, such as livestock grazing or invasive species, as part of the
habitat condition index metric in our SSA report. We evaluated water
availability during the growing season with a water deficit metric.
These two metrics provide two of the four scores in the current and
future resiliency evaluation.
Comment (10): One commenter considered our cumulative effects
evaluation to be inadequate because we determined that predation,
herbicides, pesticides, and collection and commercial trade were not
AU- or species-level threats, and thus were not addressed in the
current or future resiliency analysis.
Response (10): While some of these threats to the species were
identified in the initial 1979 listing rule or may be threats at a
localized level, all of them are known to impact only individual plants
and are less of a concern than originally suggested. Only threats that
had the potential now or in the future to have AU- or species-level
effects to either species were included in the resiliency analysis. The
threats mentioned by the commenter are limited in magnitude such that
they will not cause a measurable impact to either cactus species
currently or in the future. More information on these stressors and how
we considered them can be found in section 4.1 of the SSA report
(Service 2025, pp. 16-19).
Comment (11): One commenter stated that we did not mention that
Colorado OHV registrations have increased dramatically since 2000,
which would lead to an increase in OHV use in the species' habitat. The
commenter also stated that we did not evaluate the many possible
indirect impacts of OHV use to Colorado hookless cactus. Further, the
commenter stated that the exclusion of non-motorized recreation
(mountain bikes, hiking, camping, etc.) as a stressor is backed with no
direct evidence and may be criticized because the likelihood for these
activities would coincide with OHV recreation.
Response (11): The purpose of the SSA is to gather and compile
information on the status of these species to assess their current
condition and project the species' future condition. The commenter did
not provide information on how OHV use has changed in the species'
range. Moreover, the commenter did not specify or provide information
regarding any other possible indirect impacts of OHV use to the species
that we did not evaluate. We evaluated the effects of OHV use that
include plant loss or
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damage; soil compaction; and increased erosion, sedimentation, and dust
in the SSA report (Service 2025, pp. 17-18). As we stated in our
response to a peer reviewer (Comment 2) in the proposed rule (88 FR
21582 at 21584, April 11, 2023), we did not include non-motorized
recreation (mountain bikes, hiking, camping, etc.) in our resiliency
evaluation due to the relatively small footprint and localized impacts
of these activities, BLM's general avoidance of Colorado hookless
cactus when designing non-motorized trail routes, and the lack of
species- or AU-level effects.
Comment (12): One commenter stated that our assertion in the
proposed rule that collection is not causing population- or species-
level effects to Colorado hookless cactus is counter to the species'
final listing rule and justification for not designating critical
habitat. The commenter claims that we are being arbitrary and
capricious with respect to the threat of collection when we know the
species is ``highly desirable.''
Response (12): We disagree with the commenter's claim that we were
arbitrary and capricious in regard to our evaluation of the threat of
collection for Colorado hookless cactus. As we stated in our response
to a peer reviewer (Comment 8) in the proposed rule (88 FR 21582 at
21585, April 11, 2023), the best available information indicates that
collection has not occurred at the level anticipated at the time of
listing and is not having population- or species-level effects on
either species (Krening and Dawson 2020, p. 36). Furthermore, given the
taxonomic splits since listing between the two Utah Sclerocactus
species and Colorado's S. glaucus and S. dawsoniae, the species
mentioned in the final listing rule (44 FR 58868, October 11, 1979) as
prized by cactus collectors for its beautiful purplish-red flowers is
now known to be Uinta Basin hookless cactus (Sclerocactus wetlandicus),
not S. glaucus or S. dawsoniae. Finally, the Convention on
International Trade in Endangered Species (CITES) is a regulatory
mechanism that helps to prevent and enforce against the illegal
collection and trade of protected species, including Colorado hookless
cactus. CITES protections apply to all members of the cactus family
(Cactaceae), and as such, S. glaucus or S. dawsoniae will receive
protections after delisting under the Act (see Conservation Efforts and
Regulatory Mechanisms).
Comment (13): One commenter stated that we did not demonstrate how
conservation measures to protect Colorado hookless cactus would
continue to be enforced and be effective post-delisting in the BLM
National Conservation Areas (NCAs), Areas of Critical Environmental
Concern (ACECs), and Wilderness Study Areas (WSAs).
Response (13): Protections for Colorado hookless cactus will remain
in NCAs, ACECs, and WSAs regardless of its Federal listing status.
These areas represent approximately 30 percent of the land in S.
glaucus AUs and 41 percent of the land in S. dawsoniae AUs (see
Conservation Efforts and Regulatory Mechanisms). Species-specific
protections are afforded to Colorado hookless cactus in BLM's current
Dominguez-Escalante NCA resource management plan (RMP), and 8 of 11
ACECs across the range of the species specifically reference the
protection of Colorado hookless cactus as a foundational goal.
Likewise, NCAs, ACECs, Wilderness Areas, and WSAs are designed to
protect multiple resources, not only the Colorado hookless cactus. The
1964 Wilderness Act (Pub. L. 88-577) and the Federal Land Policy and
Management Act (FLPMA; 43 U.S.C. 1782) afford protections to wilderness
areas and WSAs and do not allow for permanent disturbances. BLM manages
these areas and will also manage for Colorado hookless cactus as a BLM
sensitive species, affording both species protections.
Comment (14): Several commenters stated that the draft PDM plan's
reliance on 17 macroplots provides insufficient monitoring of the two
species and new or increasing site-specific stressors within their
ranges. The commenters recommended that the PDM plan include rangewide
monitoring of site-specific stressors across the two species' range,
and that monitoring should begin prior to delisting.
Response (14): The PDM plan relies on the sampling protocols used
in Krening et al. (2021a, entire), which are sufficient to detect
rangewide trends for both species (see Comment (2)). We also consider
the PDM sufficient to detect new or increasing stressors within the two
species' ranges because BLM will provide information on newly approved,
permitted, or implemented projects and impacts to Colorado hookless
cactus on an annual basis (Service 2024, pp. 13-15). While the final
PDM plan does not identify a specific mechanism to intervene following
stressor impacts, it identifies actions that may be taken should
monitoring indicate a substantial decline in the Colorado hookless
cactus' density or distribution. These actions include meeting with
conservation partners, extending the monitoring period, modifying
monitoring practices, initiating a rangewide status assessment, or
relisting Colorado hookless cactus, if warranted. During the PDM
monitoring period, we will continue to work with our conservation
partners to develop and implement an effective PDM plan for Colorado
hookless cactus that includes an appropriate duration to detect trends,
identifies potential and increasing stressors, and evaluates the impact
of stressors. The monitoring identified in the PDM plan began before
work began on this rulemaking action, starting in 2011 by BLM and in
2007 by the Denver Botanic Gardens (Krening et al. 2021b, p. 4;
DePrenger-Levin and Hufft 2021, pp. 3-5; Service 2024, entire).
Comment (15): Two commenters were concerned that we relied on an
unpublished genetic study (McGlaughlin and Naibauer 2021, entire) to
inform the proposed delisting rule and noted that the genetic results
have not been recognized by NatureServe.
Response (15): Since the publication of the proposed listing rule,
the authors of the genetic study published their results in a peer-
reviewed journal in December 2023 (McGlaughlin and Naibauer 2023,
entire) and published the official species description for S. dawsoniae
in 2024 (McGlaughlin and Naibauer 2024, entire). Because of the recency
of this taxonomic split, there may be a delay in recognizing the
Colorado hookless cactus (S. glaucus) and Dawson's hookless cactus (S.
dawsoniae), on websites such as NatureServe (https://explorer.natureserve.org) and the Integrated Taxonomic Information
System (https://www.usgs.gov/tools/integrated-taxonomic-information-system-itis). However, the information we relied upon in drafting this
rulemaking action still constitutes the best available scientific
information on these species' taxonomy.
Comment (16): One commenter stated that we should not have
confidence in BLM's ability to prevent livestock grazing from harming
the Colorado hookless cactus because BLM has a long history of ignoring
illegal grazing as identified in a 2016 U.S. Government Accountability
Office (GAO) report.
Response (16): We have no information that illegal grazing is
occurring in the Colorado hookless cactus' range (Lincoln 2025, pers.
comm). The 2016 GAO report identifies 38 incidences of non-compliances
in the State of Colorado, but the report does not identify the
locations where unauthorized grazing is occurring.
[[Page 22655]]
Therefore, we did not include this information in our SSA report. BLM's
management plans allow it to include obligatory stipulations in its
grazing permit renewals that require reductions in the number of
livestock and adjustments to the timing, duration, and season of
livestock use for the benefit of natural resources (see Livestock
Grazing, below). BLM will address impacts to Colorado hookless cactus
from a variety of stressors, including livestock grazing, with
additional monitoring and management interventions, as identified in
the PDM plan (Service 2024, entire).
Background
A thorough review of the taxonomy, life history, and ecology of the
Colorado hookless cactus (S. glaucus and S. dawsoniae) is presented in
the SSA Report Version 1.2 (Service 2025, entire). Colorado hookless
cactus has undergone a series of taxonomic revisions since its original
1979 listing. When listed, the range of Sclerocactus glaucus was
considered to include western Colorado and northeastern Utah (Uinta
Basin hookless cactus complex). A reevaluation of morphological
characteristics, phylogenetic studies, and common garden experiments
led to the determination that the Uinta Basin hookless cactus complex
was in fact three distinct species: Sclerocactus glaucus (Colorado
hookless cactus), Sclerocactus brevispinus (Pariette cactus), and
Sclerocactus wetlandicus (Uinta Basin hookless cactus) (Heil and Porter
2004, pp. 197-207; Hochst[auml]tter 1993, pp. 82-92). Sclerocactus
glaucus was determined to be restricted to the Colorado and Gunnison
River basins in western Colorado, while Sclerocactus brevispinus and
Sclerocactus wetlandicus are limited to the Uinta Basin in eastern
Utah. In 2009, the Service published a final rule recognizing and
accepting this revised taxonomy of the three species and determined
that all three species would continue to be listed as threatened (74 FR
47112, September 15, 2009). Most recently, in 2017, genetic studies
identified three distinct regional groups of Colorado hookless cactus
in Colorado: the northern, Grand Valley, and Gunnison River groups
(Schwabe et al. 2015, p. 447; McGlaughlin and Ramp-Neale 2017, p. 5).
The most recent genetic analyses, using Random Site-Associated DNA
sequencing, determined that the northern group should be recognized as
a distinct species, hereinafter Sclerocactus dawsoniae, or S. dawsoniae
(McGlaughlin and Naibauer 2023, p. 5). The Grand Valley and Gunnison
River groups share connectivity and form a genetically cohesive group,
which represents a second distinct species, hereinafter collectively
referred to as Sclerocactus glaucus, or S. glaucus (McGlaughlin and
Naibauer 2023, p. 5). Because of the recency of this taxonomic split,
the currently listed entity is still considered to be the Colorado
hookless cactus, which encompasses both S. glaucus and S. dawsoniae;
thus, both Sclerocactus glaucus and Sclerocactus dawsoniae are the
subjects of our SSA report and this final delisting rule.
Given the recent nature of this new taxonomic information, most
literature on the species draws conclusions regarding both S. glaucus
and S. dawsoniae without distinguishing between the two. Thus, when we
use the common name ``Colorado hookless cactus'' in this final rule, we
are referring to information or conclusions regarding both species (S.
glaucus and S. dawsoniae). When we are referring to information or
analysis pertaining to one species, we will use the new scientific
names of S. glaucus or S. dawsoniae.
S. glaucus and S. dawsoniae are endemic cactus species found in the
Colorado and Gunnison River basins and their tributary canyons in
Garfield, Mesa, Montrose, and Delta Counties in western Colorado. The
species occur on alluvial benches and colluvial slopes from 1,372 to
2,195 m (4,500 to 7,200 ft) in semi-arid high-elevation desert
(Holsinger 2021, pers. comm.; Service 2025, p. 9). The species display
a patchy, generalist distribution and have been found to grow primarily
in small, discrete colonies of individuals in various upland desert
habitats and communities (Krening and Dawson 2020, p. 18; Service 2025,
p. 9).
For the purposes of analysis in our SSA report, we divided the
ranges of S. glaucus and S. dawsoniae into analysis units (AUs). S.
glaucus occurs in eight AUs in a range that extends approximately 2,802
square kilometers (km\2\) (1,082 square miles (mi\2\)) from the Grand
Valley, through the high desert at the foot of the Grand Mesa, and
along the alluvial terraces of the Gunnison River and the Dominguez and
Escalante Creek drainages to near Montrose. S. dawsoniae occurs over an
area of approximately 505 km\2\ (195 mi\2\) in two AUs along the
Colorado River from DeBeque downstream toward the Grand Valley and
along the Roan and Plateau Creek drainages. BLM owns and manages
approximately 72 percent and 68 percent, respectively, of the land that
comprises the S. glaucus and S. dawsoniae AUs (Service 2025, pp. 19-
22).
S. glaucus and S. dawsoniae are morphologically indistinguishable
from each other and can be identified from one another only by genetic
analysis or location. They are both leafless, flowering, stem-succulent
plants with short, cylindrical bodies usually 3 to 12 centimeters (cm)
(1.2 to 4.8 inches (in)) but up to 30 cm (12 in) tall and 4 to 9 cm
(1.6 to 3.6 in) in diameter (Service 2025, pp. 7-8). The brown coloring
of the spines on mature plants is unique to S. glaucus, S. dawsoniae,
and S. parviflorus, as compared to other cactus species in the area
(Service 2025, p. 7).
Colorado hookless cactus has three life stages: seeds, seedlings,
and mature reproductive adults. Colorado hookless cactus plants are
considered hardy, long-lived perennial species (i.e., high survival
probabilities and low levels of recruitment) (BLM 2018, p. 15). Based
on high observed seedling survival, once a seedling is established,
there is a high probability of an individual persisting to reproductive
stage (BLM 2018, p. 14; Service 2025, p. 13). Pollinator-assisted
outcrossing (xenogamy) is the primary mode of genetic exchange for the
Colorado hookless cactus (Janeba 2009, p. 67; Tepedino et al. 2010, p.
382; Service 2025, p. 8). Plants usually flower in late April and early
May. Plants do not flower until they reach a diameter of more than 4 cm
(1.6 in) (BLM 2018, p. 14); plants are likely at least 4 to 6 years old
before they become reproductive and continue to flower throughout their
relatively long life (DePrenger-Levin 2021, pers. comm.; Service 2025,
p. 13). Colorado hookless cactus can live for many years, but their
exact longevity is unknown.
Recovery Criteria
Section 4(f) of the Act directs us to develop and implement
recovery plans for the conservation and survival of endangered and
threatened species unless we determine that such a plan will not
promote the conservation of the species. Under section 4(f)(1)(B)(ii),
recovery plans must, to the maximum extent practicable, include
objective, measurable criteria which, when met, would result in a
determination, in accordance with the provisions of section 4 of the
Act, that the species be removed from the Lists of Endangered and
Threatened Wildlife and Plants.
Recovery plans provide a roadmap for us and our partners on methods
of enhancing conservation and minimizing threats to listed species, as
well as measurable criteria against which to evaluate progress towards
recovery and assess the species' likely future condition. However, they
are not
[[Page 22656]]
regulatory documents and do not substitute for the determinations and
promulgation of regulations required under section 4(a)(1) of the Act.
A decision to revise the status of a species or to delist a species is
ultimately based on an analysis of the best scientific and commercial
data available to determine whether a species is no longer an
endangered species or a threatened species, regardless of whether that
information differs from the recovery plan.
There are many paths to accomplishing recovery of a species, and
recovery may be achieved without all of the criteria in a recovery plan
being fully met. For example, one or more criteria may be exceeded
while other criteria may not yet be accomplished. In that instance, we
may determine that the threats are minimized sufficiently and that the
species is robust enough that it no longer meets the definition of an
endangered species or a threatened species. In other cases, we may
discover new recovery opportunities after having finalized the recovery
plan. Parties seeking to conserve the species may use these
opportunities instead of methods identified in the recovery plan.
Likewise, we may learn new information about the species after we
finalize the recovery plan. The new information may change the extent
to which existing criteria are appropriate for identifying recovery of
the species. The recovery of a species is a dynamic process requiring
adaptive management that may, or may not, follow all of the guidance
provided in a recovery plan.
A recovery plan for Colorado hookless cactus was not prepared due
to lack of staff capacity; therefore, specific delisting criteria were
not developed for the species. However, we developed a recovery outline
for Colorado hookless cactus in 2010 (Service 2010, entire). A recovery
outline is a succinct document that presents a preliminary recovery
strategy and actions to direct recovery efforts for a newly listed
species until a recovery plan is completed. Additionally, we reviewed
the status of the species in the 2008 and 2021 5-year status reviews
(Service 2008, entire; Service 2021, entire). In the 2008 review, we
identified remaining threats to the species and actions that could be
taken to make progress in addressing those threats and ensuring long-
term management. One such recommendation was to conduct rangewide
inventories and improve population monitoring (Service 2008, p. 4).
Denver Botanic Gardens and BLM have closely monitored Colorado hookless
cactus at multiple sites throughout its range since 2007 (DePrenger-
Levin and Hufft 2021, entire; Krening et al. 2021b, entire). Based on
over a decade of this rich monitoring data, BLM developed a method of
estimating population size and trends in 2021 for S. glaucus (Krening
et al. 2021a, entire) and in 2023 for S. dawsoniae (Krening and
Holsinger 2024, entire), representing the best available scientific and
commercial information for the species regarding total population size
(Krening et al. 2021a, entire; Krening and Holsinger 2024, entire).
The 2010 recovery outline also included an initial action plan for
the species' recovery that included actions such as (1) expanding
comprehensive surveying to improve our understanding of trends; (2)
establishing formal land management designations to provide for long-
term protection of important populations and habitat; (3) directing
development projects to avoid cactus occurrences and incorporate
standard conservation measures; (4) encouraging investigations into
Sclerocactus species' vulnerability to climate change; and (5)
resolving open taxonomic questions for the species. The Service and its
partners have since accomplished all five of these actions.
Since 2010, BLM and the Denver Botanic Gardens have expanded their
annual monitoring program to assess demographic trends and improve
estimation of the species' population sizes; these estimates indicate
there are substantially more Colorado hookless cactus plants on the
landscape than were known at the time of listing and have changed our
understanding of the degree to which the species are resilient to the
threats apparent at the time of listing. As stated previously, BLM has
also established multiple ACECs and an NCA that provide long-term
protection to BLM sensitive plants and habitats. In the past 11 years,
multiple assessments of the species' vulnerability to climate change
have concluded that Colorado hookless cactus has low vulnerability to
future climatic changes (Price 2018, appendix 3 of Krening and Dawson
2020, p. 60; Still et al. 2015, p. 116; Treher et al 2012, pp. 8, 52).
Finally, as discussed at length above in this document, recent genetic
research has determined that Colorado hookless cactus is in fact two
separate species: S. glaucus and S. dawsoniae, thus resolving an open
taxonomic question for the species, as identified by the recovery
outline.
Regulatory and Analytical Framework
Regulatory Framework
Section 4 of the Act (16 U.S.C. 1533) and the implementing
regulations in title 50 of the Code of Federal Regulations set forth
the procedures for determining whether a species is an endangered
species or a threatened species, issuing protective regulations for
threatened species, and designating critical habitat for endangered and
threatened species. On April 5, 2024, jointly with the National Marine
Fisheries Service, the Service issued a final rule that revised the
regulations in 50 CFR part 424 regarding how we add, remove, and
reclassify endangered and threatened species and what criteria we apply
when designating listed species' critical habitat (89 FR 23919). That
final rule is now in effect and is incorporated into the current
regulations. Our analysis for this decision applied our current
regulations. Given that we proposed delisting this species under our
prior regulations (revised in 2019), we have also undertaken an
analysis of whether the decision would be different if we had continued
to apply the 2019 regulations and we concluded that the decision would
be the same. The analyses under both the regulations currently in
effect and the 2019 regulations are available on https://www.regulations.gov.
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
[[Page 22657]]
effects. The determination to delist a species must be based on an
analysis of the same five factors.
We use the term ``threat'' to refer in general to actions or
conditions that are known to or are reasonably likely to negatively
affect individuals of a species. The term ``threat'' includes actions
or conditions that have a direct impact on individuals (direct
impacts), as well as those that affect individuals through alteration
of their habitat or required resources (stressors). The term ``threat''
may encompass--either together or separately--the source of the action
or condition or the action or condition itself.
However, the mere identification of any threat(s) does not
necessarily mean that the species meets the statutory definition of an
``endangered species'' or a ``threatened species.'' In determining
whether a species meets either definition, we must evaluate all
identified threats by considering the species' expected response and
the effects of the threats--in light of those actions and conditions
that will ameliorate the threats--on an individual, population, and
species level. We evaluate each threat and its expected effects on the
species, then analyze the cumulative effect of all of the threats on
the species as a whole. We also consider the cumulative effect of the
threats in light of those actions and conditions that will have
positive effects on the species--such as any existing regulatory
mechanisms or conservation efforts. The Secretary determines whether
the species meets the definition of an ``endangered species'' or a
``threatened species'' only after conducting this cumulative analysis
and describing the expected effect on the species.
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, which is
further described in the 2009 Memorandum Opinion on the foreseeable
future from the Department of the Interior, Office of the Solicitor (M-
37021, January 16, 2009; ``M-Opinion,'' available online at https://www.doi.gov/sites/doi.opengov.ibmcloud.com/files/uploads/M-37021.pdf).
The foreseeable future extends as far into the future as the U.S. Fish
and Wildlife Service and National Marine Fisheries Service (hereafter,
the Services) can make reasonably reliable predictions about the
threats to the species and the species' responses to those threats. We
need not identify the foreseeable future in terms of a specific period
of time. We will describe the foreseeable future on a case-by-case
basis, using the best available data and taking into account
considerations such as the species' life-history characteristics,
threat-projection timeframes, and environmental variability. In other
words, the foreseeable future is the period of time over which we can
make reasonably reliable predictions. ``Reliable'' does not mean
``certain''; it means sufficient to provide a reasonable degree of
confidence in the prediction, in light of the conservation purposes of
the Act.
Analytical Framework
The SSA report documents the results of our comprehensive
biological review of the best scientific and commercial data regarding
the status of the species, including an assessment of the potential
threats to the species. The SSA report does not represent our decision
on whether the species should be delisted. 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. To assess Colorado hookless
cactus' viability, we used the three conservation biology principles of
resiliency, redundancy, and representation (Shaffer and Stein 2000, pp.
306-310). Briefly, resiliency is the ability of the species to
withstand environmental and demographic stochasticity (for example, wet
or dry, warm or cold years); redundancy is the ability of the species
to withstand catastrophic events (for example, droughts, large
pollution events), and representation is the ability of the species to
adapt to both near-term and long-term changes in its physical and
biological environment (for example, climate conditions, pathogens). In
general, species viability will increase with increases in resiliency,
redundancy, and representation (Smith et al. 2018, p. 306). 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 individual species' life-history
needs. The next stage involved an assessment of the historical and
current condition of the species' demographics and habitat
characteristics, including an explanation of how the species arrived at
its current condition. The final stage of the SSA involved making
predictions about the species' responses to positive and negative
environmental and anthropogenic influences. Throughout all of these
stages, we used the best available information to characterize
viability as the ability of a species to sustain populations in the
wild over time, which we then used to inform our regulatory decision.
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-R6-ES-
2022-0093 on https://www.regulations.gov.
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. In addition, the SSA report
(Service 2025, entire) documents our comprehensive biological status
review for the species, including an assessment of the potential
threats to the species.
The following is a summary of this status review and the best
available information gathered since that time that has informed this
decision.
Species Needs
Individuals of both species of Colorado hookless cactus need
certain habitat factors, including shallow exposed sandy or shale soils
of sedimentary parent material or gravelly deposits of river alluvium;
a semi-arid, high-elevation desert climate (elevations from 1,200-2,000
m (3,937-6,561 ft) with 20-30 cm (8-12 in) of rain per year; and a
period of deep cold during winter months to facilitate germination the
following spring (Service 2025, pp. 8, 11-12). To be sufficiently
resilient, populations, referred to as analytical units (AUs) of both
species require survivorship and recruitment at rates that are able to
sustain AUs, in addition to pollinator connectivity between individuals
and clusters of plants within the AU. Adequately resilient AUs also
contain enough individuals across each life stage (seed, seedling, and
mature reproductive adult) to bounce back after experiencing
environmental stressors such as intermediate disturbance, occasional
drought, or intensive grazing.
The number of AUs across the landscape influence redundancy of
Colorado hookless cactus. AUs, synonymous with populations, include
many cactus individuals and were delineated by natural geological and
ecological features and management
[[Page 22658]]
boundaries within each species' range (Service 2025, pp. 6-8). More AUs
across the range of each species increase each species' ability to
withstand catastrophic events. Individuals and AUs inhabiting diverse
ecological settings and exhibiting genetic or phenological variation
add to the level of representation across the species' ranges. The
greater diversity observed in genetics, habitats, and morphology, the
more likely Colorado hookless cactus is to be able to adapt to change
over time. Thus, both species need (1) a sufficient number and
distribution of sufficiently resilient AUs to withstand catastrophic
events (redundancy) and (2) a range of genetic, morphologic, and
habitat variation that allows the species to adapt to changing
environmental conditions (representation) (Service 2025, pp. 15-16).
The SSA report provides additional detail on the species' individual-,
population-, and species-level needs (Service 2025, pp. 10-16).
Stressors
In our SSA, we evaluated stressors and other actions that can
positively or negatively affect Colorado hookless cactus at the
individual, AU (population), or species levels, either currently or
into the future (Service 2025, pp. 16-19). A wide variety of stressors
may influence the resiliency of Colorado hookless cactus, either by
directly affecting individuals or by reducing the quality and quantity
of habitats.
Stressors that have the potential to present AU-level effects for
both species include livestock use, invasive species, oil and gas
development, OHV recreational use, development and maintenance of
utility corridors, and the effects of global climate change (Krening
and Dawson 2020, p. 30; Service 2025, pp. 16-19). We determined that
oil shale deposit development and gold mining, predation, herbicide and
pesticide application, or collection and commercial trade are not
threats to the existence of the species (even though they were
identified as such in the 1979 listing rule), so we do not discuss them
in detail in this rule (Service 2025, pp. 16-19).
Additionally, approximately 30 percent of the land in S. glaucus
AUs and 41 percent of the land in S. dawsoniae AUs have special BLM
land management designations in the form of NCAs, ACECs, a WSA, and a
Wilderness Area. These designations limit or exclude the authorization
of certain land uses, and some designations were specifically created
for the conservation of natural resources. The protections provided by
these management designations are not contingent upon the species'
federally listed status, and these designations help to facilitate the
maintenance and recovery of cactus occurrences because they are areas
where Colorado hookless cactus is not likely to be disturbed or
adversely altered by land-use actions (Krening and Dawson 2020, p. 26).
Eight of 11 ACECs specifically reference the protection of Colorado
hookless cactus as a foundational goal. We discuss the specific
protections each of these areas provides, and the ways in which they
reduce specific stressors, under the relevant stressors below; we also
discuss these conservation measures further under Conservation Efforts
and Regulatory Mechanisms. While the majority of the remaining habitat
is on private lands, approximately 28 percent for S. glaucus and 32
percent for S. dawsoniae, we do not have reliable information for
Colorado hookless cactus on private lands. Since the private lands are
interspersed with BLM lands, we assume that the stressors are the same
on BLM and private lands (Service 2025, pp. 20-22).
Livestock Use
BLM owns and manages approximately 72 percent and 68 percent,
respectively, of the land that comprises S. glaucus and S. dawsoniae
AUs (Service 2025, pp. 19-22). While approximately 5 percent of this
habitat excludes or manages for livestock use for the purposes of
minimizing impacts to Colorado hookless cactus, nearly all habitat that
occurs on BLM lands allows for livestock use. Moderate to heavy
domestic livestock grazing has been observed to cause physical damage
to Sclerocactus plants through trampling; however, on rare occasions do
cattle directly trample or dislodge cactus plants (Service 1990, p.
11). We have no information to indicate that cattle browse on
individual Sclerocactus plants since their spines generally make them
undesirable livestock forage (Dawson 2025, entire; Hornbeck 2025,
entire). A study on another federally listed cactus, S. wrightiae,
found that cacti density increased more rapidly in a fenced plot
excluded from cattle grazing than in an unfenced plot with a reduced
cattle stocking rate (Clark and Clark 2007, p. 21). Overgrazing (the
continued heavy grazing beyond the recovery capacity of forage plants)
by domestic livestock can have a negative impact on North American
xeric (very dry and low humidity) ecosystems (Jones 2000, p. 158). For
example, overgrazing can facilitate the establishment of invasive
species like Bromus tectorum, known as cheatgrass (Masters and Sheley
2001, p. 503; DiTomaso et al. 2016, p. 435), which are difficult to
eradicate and tend to outcompete native vegetation, including cacti.
Currently, BLM manages livestock activities to protect sensitive
plants in the Adobe Badlands, River Rims, and Escalante Canyon ACECs
(BLM 2017, p. 240, p. 258; Krening and Dawson 2020, p. 28; Service
2025, pp. 19-22). In the Atwell Gulch ACEC, BLM excludes livestock
grazing entirely on 2,600 ac (1,052 ha), and in the Pyramid Rock ACEC,
no livestock grazing is allowed (Krening and Dawson 2020, p. 29;
Service 2025, pp. 20-22). BLM monitoring indicates that livestock are
not present in these protected areas (Krening and DePrenger-Levin 2023,
entire). BLM's management plans allow it to include obligatory
stipulations in its grazing permit renewals that require reductions in
the number of livestock and adjustments to the timing, duration, and
season of livestock use for the benefit of natural resources; such
changes in grazing permits would primarily affect future grazing
intensity in the Cactus Park (S. glaucus), Devil's Thumb (S. glaucus),
Gunnison River East (S. glaucus), Roan Creek (S. dawsoniae), and
Plateau Creek AUs (S. dawsoniae).
Currently, livestock use is affecting individual plants in
localized areas and is not resulting in population-level effects based
on stable or increasing population-level trends (Service 2025, pp. 18-
19; Krening and DePrenger-Levin 2023, entire); however, these effects
could increase in the future if no corrective action is taken to
address future problem areas. Thus, we included an analysis in the SSA
to examine the species' potential response to future changes and
increases to this stressor (Service 2025, pp. 28-36).
Invasive Species
Invasive weeds, including Bromus tectorum (cheatgrass) and
Halogeton glomeratus (halogeton), are prevalent on BLM and private
lands within the range of Colorado hookless cactus (Krening and Dawson
2020, p. 35). Invasive weeds alter the ecological characteristics of
cactus habitat, making it less suitable for the species (Service 1990,
p. 11). In addition, invasive annual weeds are often able to outcompete
perennial native species for the essential nutrient nitrogen under
drought conditions (Everard et al. 2010, pp. 85, 93-94). However,
despite their prevalence throughout the range of Colorado hookless
cactus species, individual plants experience extreme
[[Page 22659]]
detrimental effects of invasive weeds only in localized areas (Service
2025, pp. 16-22; Krening and DawsonBLM 2020, p. 35).
Currently, invasive vegetation affects only individual Colorado
hookless cactus plants; invasive species are not causing any broad-
scale reductions in recruitment or survival in entire AUs. However, the
effects of invasive vegetation could increase in the future if
infestations expand or if treatments become less effective. Thus, we
included an analysis in the SSA to examine the species' potential
response to future changes and increases to this stressor (Service
2025, pp. 16-22, 28-36).
Oil and Gas Development
Oil and gas development can also affect Colorado hookless cactus
plants and habitat. Increased surface disturbance from wells, roads,
and pipelines for oil and gas projects can fragment or destroy habitat;
disturb individuals; increase erosion, soil compaction, and
sedimentation; destroy pollinator habitat; increase airborne dust and
subsequent dust accumulation on cacti, which can increase tissue
temperature and reduce photosynthesis, thus decreasing plant growth,
vigor, and water use efficiency; indirectly increase recreational
access to habitat through increased road construction; and increase
invasive vegetation because of the associated surface disturbances
(Service 2010, pp. 6-7).
For S. glaucus, only 5 percent of the AUs (19,365 ac (7,837 ha) of
379,348 total ac (153,517 ha) of habitat) are within BLM lands leased
for oil and gas (BLM 2021, unpaginated). This proportion is higher for
S. dawsoniae; 58 percent of the area within AUs are leased for oil and
gas development on BLM lands (65,384 ac (26,419 ha) of 112,723 total ac
(45,617 ha) of habitat) (BLM 2021, unpaginated). However, leased areas
do not equate to areas of surface disturbance; even if these areas are
leased for oil and gas development, only small subsets of these areas
are actually being actively explored or extracted (Colorado Oil and Gas
Conservation Commission (COGCC) 2022a, unpaginated). Moreover, oil and
gas development does not occur throughout all of the species' ranges;
for S. glaucus, active wells are only in the Devil's Thumb AU (one
active well site), North Fruita Desert AU (10 active well sites),
Whitewater AU (26 active well sites), and a very small portion of the
Palisade AU (one active well site) (COGCC 2022b, unpaginated). For S.
dawsoniae, while oil and gas development occurs in both AUs (Roan Creek
(60 active well sites) and Plateau Creek (51 active well sites)), 42
percent of these AUs are not leased for oil and gas development (COGCC
2022b, unpaginated; BLM 2021, unpaginated). Additionally, there are no
new or pending permits to drill new oil and gas wells within either
species' range; however, as we describe in more detail below,
development could increase within portions of S. dawsoniae's range in
the future (COGCC 2022c, unpaginated; COGCC 2022d, unpaginated).
Additionally, BLM's resource planning documents include
conservation measures to minimize adverse impacts of natural resource
extraction to listed and sensitive species, including the Colorado
hookless cactus; these measures include limiting oil and gas
development within a 100-m (328-ft) buffer around any currently
occupied or historically occupied Colorado hookless cactus habitat,
when possible and with some exceptions (Krening and Dawson 2020, p. 34;
BLM 2015a, p. B-13; BLM 2015b, p. B-22; BLM 2020, p. B-9). While these
limitations and buffers are not obligatory, BLM applies them, with
certain exceptions, to BLM sensitive species, which S. glaucus and S.
dawsoniae will become once Colorado hookless cactus is removed from the
List of Endangered and Threatened Plants (see Conservation Efforts and
Regulatory Mechanisms). Even without the protections given to BLM
sensitive species, based on our analysis of Colorado Oil and Gas
Conservation Commission (COGCC) data, current oil and gas extraction is
relatively limited throughout the range of both species compared to the
amount of occupied habitat (COGCC 2022a, unpaginated; COGCC 2022b,
unpaginated; COGCC 2022c, unpaginated; COGCC 2022d, unpaginated).
Moreover, due to their biology and life history characteristics, both
species are relatively resilient to nearby disturbance (as we discuss
further in our analysis of Current Condition below).
Furthermore, approximately 30 percent of the land in S. glaucus AUs
and 41 percent of the land in S. dawsoniae AUs have special BLM land
management designations in the form of NCAs, ACECs, a WSA, and a
Wilderness Area, which further protect the species from the impacts of
oil and gas development (Service 2025, pp. 16-22). The protections
provided by these management designations are not contingent upon the
species' federally listed status, and these designations help to
facilitate the maintenance and recovery of cactus occurrences because
they are areas where neither the Colorado hookless cactus is likely to
be disturbed nor will its habitat be adversely altered by land-use
actions (Krening and Dawson 2020, p. 26). All 30 percent of the areas
within S. glaucus AUs that have special land management designations
include stipulations that either withdraw lands from oil, gas, and
mineral development, implement ``no-surface-occupancy'' stipulations,
or prohibit surface-disturbing activities (Service 2025, pp. 19-22).
Therefore, no new oil and gas activity is permitted in almost 30
percent of S. glaucus's range (with the exception of portions of the
Devil's Thumb AU); these areas where no new oil and gas activity is
permitted coincide with over half (over 56 percent) of the estimated S.
glaucus occurrences (Service 2025, pp. 14, 21-22). Similarly, all 41
percent of the areas within S. dawsoniae AUs that have special land
management designations include no-surface-occupancy stipulations that
limit oil and gas development in these portions of the species' range.
Thus, currently, oil and gas development is affecting only a small
proportion of individual Colorado hookless cactus plants, due to
limited leasing and development and BLM's protective measures; however,
the effects of oil and gas development could increase in the future.
Nevertheless, given the variable oil and gas potential (none, low,
medium, and high potential) of the area, and the protections outlined
above, the only AUs where oil and gas development could plausibly
increase in the future are the Roan Creek and Plateau Creek AUs (S.
dawsoniae) with high oil and gas potential (BLM 2024, entire; Service
2025, p. 30). Thus, we included an analysis in the SSA to examine the
species' potential response to future changes in this stressor (Service
2025, pp. 28-36).
Off-Highway Vehicle Recreational Use
Off-highway vehicle (OHV) use can cause soil compaction and
erosion, which can physically damage habitat, the surrounding plant
community, and the hydrology of the area. OHVs can also carry invasive
and introduced plants to new sites and present a risk of spilled
contaminants, such as oil spills, gasoline, and grease. OHV use can
also injure or kill above-ground plants or cause direct harm to plants
through accumulation of dust. OHV use can create especially negative
impacts when users travel off designated routes (Service 2025, pp. 16-
19).
The relatively barren nature and other topographical features of
Colorado hookless cactus habitat make it
[[Page 22660]]
desirable to OHV users (Krening and Dawson 2020, p. 38). Even though
OHV recreation is popular and widespread within Colorado hookless
cactus habitat, there is little evidence of direct negative impacts to
plants (Service 2010, p. 8; Krening and Dawson 2020, p. 38).
BLM's resource planning documents include conservation measures to
minimize adverse impacts of land use to listed and sensitive species,
including the Colorado hookless cactus (BLM 2015a, pp. 49, 102-105; BLM
2015b, pp. 26, 101-103, 123, 145, 147, 150; BLM 2015c, p. M-25; BLM
2020, pp. II-87, I-4-I-10). In their Travel Management Plans for the
Grand Junction and Uncompahgre Field Offices, BLM identified multiple
routes for closure to protect sensitive areas (BLM 2015c, p. M-24; BLM
2020, p. I-7). These two travel management plans cover the entirety of
S. glaucus's range and the majority of S. dawsoniae's range. While the
resource management plan for the Colorado River Valley Field Office,
which covers the remainder of S. dawsoniae's range, does not contain a
travel management plan specifically, it includes strategies for
``Comprehensive Trails and Travel Management,'' including limiting
recreational use to designated routes (BLM 2015b, pp. 102-104).
Additionally, as stated previously in this document, approximately 30
percent of the land in S. glaucus AUs and 41 percent of the land in S.
dawsoniae AUs have special BLM land management designations in the form
of NCAs, ACECs, a WSA, and a Wilderness Area, which further protect the
species from the impacts of OHV use by limiting routes within 200 m
(656 ft) of sensitive plants or prohibiting all motorized travel
(Krening and Dawson 2020, pp. 27-29; Service 2025, pp. 19-22). For
example, when the Dominguez-Escalante NCA was created in 2009, which
covers 210,172 ac (85,053 ha) within the Dominguez-Escalante, Gunnison
River East, and Cactus Park AUs, 268 miles of routes were closed to
mechanized and motorized travel, which includes the use of OHVs (BLM
2017, p. 282; Krening and Dawson 2020, p. 27).
As human populations continue to grow in the areas surrounding
Colorado hookless cactus, demand for OHV recreation is likely to
continue to increase. However, BLM would be able to add routes only in
areas outside of the aforementioned ACECs, WSA, and Wilderness Area.
Any increases in designated OHV routes would occur as a result of land
use planning processes that would comply with the stipulations of the
FLPMA and the National Environmental Policy Act (Krening and Dawson
2020, p. 38). Given the protections detailed above, and the
accessibility of certain areas to OHV users, the only AUs where OHV use
could plausibly increase in the future are the North Fruita Desert,
Devil's Thumb, Gunnison Gorge, and Whitewater AUs (S. glaucus) (Service
2025, p. 30). The area represented in these four AUs constitutes
approximately half of S. glaucus' AU range, but it is unlikely that OHV
use would occur across the entire area of these AUs. Through similar
processes, BLM may also choose to close areas to recreation or access
if necessary to protect sensitive resources (Krening and Dawson 2020,
p. 38). It is plausible that implementation of travel management plans
could lead to route closures in S. glaucus AUs (Devil's Thumb, Gunnison
Gorge, Whitewater, Palisade, Dominguez-Escalante, North Fruita Desert)
and S. dawsoniae AUs (Plateau Creek, and Roan Creek AUs).
Thus, currently, OHV use is affecting only a small proportion of
individual Colorado hookless cactus plants; however, the effects of OHV
use could increase in the future if recreational opportunities expand.
Therefore, we included an analysis in the SSA to examine the species'
potential response to future changes in this stressor (Service 2025,
pp. 28-36).
Development and Maintenance of Utility Corridors
The installation and maintenance of utility corridors can result in
damage, loss, or relocation of plants; fragmentation of habitat; and
increases in invasive species (Krening and Dawson 2020, p. 34; Service
2025, pp. 17-19). Multiple transmission lines occur within Colorado
hookless cactus habitat and ``approximately 1,200 plants have been
transplanted in association with these projects'' (Bio-Logic 2008 as
cited in Krening and Dawson 2020, p. 34). While every AU has a utility
corridor within it, most corridors intersect only a small portion of
the AU. Additionally, some of these utility lines are along already-
disturbed corridors (e.g., major highways).
In addition to the limited scope of utility corridor development
and maintenance within Colorado hookless cactus habitat, federally
protected areas further limit the impacts that utility corridor
development can have on the species. Six of the seven ACECs within S.
glaucus' range and all four of the ACECs within S. dawsoniae's range
include right-of-way exclusion or avoidance areas (Service 2025, pp.
19-22).
Based on practical locations for utility corridors, and on these
protections, it is plausible that development could increase in the
energy corridor that intersects the Whitewater, Devil's Thumb, and
Cactus Park AUs and along the I-70 corridor in the Palisade AU (Service
2025, p. 30). It is also plausible that developers could replace an
existing powerline with a larger structure in the Devil's Thumb and
Whitewater AUs to increase capacity, which could cause significant
ground disturbance (Service 2025, p. 30). Finally, developers could
build additional pipelines in the Roan Creek and Plateau Creek AUs
(Service 2025, p. 30).
Thus, currently, development and maintenance of utility corridors
are affecting only individual Colorado hookless cactus plants, partly
due to BLM's avoidance and mitigation measures; however, the effects of
this stressor could increase in the future if development expands.
Therefore, we included an analysis in the SSA to examine the species'
potential response to future changes in this stressor.
Climate Change
Climate change may affect long-term survival of native species,
including Sclerocactus, especially if longer or more frequent droughts
occur. Within the range of Colorado hookless cactus, under lower
emission scenarios, summer maximum temperature is expected to increase
4 [deg]F (2.2 [deg]C) and under higher emission scenarios summer
maximum temperature is expected to increase 10 [deg]F (5.6 [deg]C) by
mid-century, compared to the historical average between 1971 and 2000
(North Central Climate Adaptation Science Center and CIRES 2021,
unpaginated). Extreme droughts, like those that occurred in 2002 and
2018, could also become more frequent by mid-century. Historically,
droughts of this scale did not occur with this frequency within the
range of the species (North Central Climate Adaptation Science Center
and CIRES 2021, unpaginated). By mid-century, under lower emissions
scenarios, these extreme droughts could occur two to three times per
decade or, under higher emissions scenarios, eight to nine times per
decade (North Central Climate Adaptation Science Center and CIRES 2021,
unpaginated).
In addition, invasive annual weeds are often able to outcompete
perennial native species for the essential nutrient nitrogen under
drought conditions (Everard et al. 2010, pp. 85, 93-94). Drought
conditions could further hinder BLM's efforts to control invasive weeds
and restore native vegetation, which is
[[Page 22661]]
already difficult due to the extreme environment of the Colorado and
Gunnison River basins (Service 1990, p. 11).
Climate change vulnerability analyses concluded that Colorado
hookless cactus likely has low vulnerability to climate change (Krening
and Dawson 2020, pp. 43-44); however, these analyses predated the
taxonomic split of Colorado hookless cactus and thus analyzed the range
that contains both S. glaucus and S. dawsoniae. First, NatureServe's
Climate Change Vulnerability Index (CCVI), which evaluates species'
vulnerability to climate change based on multiple factors, indicated
that Colorado hookless cactus was ``not vulnerable'' or ``presumed
stable'' rangewide, meaning the number of plants or range extent is not
likely to increase or decrease considerably by mid-century (Treher et
al. 2012, pp. 8, 52). Second, a combination of CCVI and species
distribution modeling (SDM) methods indicated that Colorado hookless
cactus ``will not be vulnerable to climate change'' within the next 30
years (Still et al. 2015, p. 116). This analysis predicted that the
Colorado hookless cactus' range could shift or increase under projected
changes in climate given the Colorado hookless cactus has no dispersal
constraints and vast areas of suitable habitat beyond known occurrences
(Still et al. 2015, p. 116). Finally, an additional SDM effort, which
aimed to predict changes to the species' range under five different
future climate scenarios, concluded that climate change does not
present a threat, because all but one model indicates that either no
range contraction will occur or that range extent will expand by
midcentury (Price 2018, appendix 3 of Krening and Dawson 2020, p. 60).
Although multiple different models predict the Colorado hookless
cactus has low vulnerability to climate change, Colorado Natural
Heritage Program's (CNHP) CCVI suggested that Colorado hookless cactus
is extremely vulnerable to climate change given ``(1) natural and
anthropogenic barriers to movement; (2) likelihood of short seed
dispersal distances; (3) lack of variation in annual precipitation in
occupied habitat over last 50 years; (4) potential increase in climate
influenced disturbances within its habitat, (5) potential for wind and
solar energy development within its range, and (6) pollinator
specificity'' (CNHP 2015, p. 533). Although the weight of research
indicates both species likely have low vulnerability to climate change,
given the uncertainty that this CNHP study introduced, we included an
analysis in the SSA to examine the species' potential response to
future changes in this stressor.
Conservation Efforts and Regulatory Mechanisms
Positive actions, in the form of conservation efforts such as land
protections and regulations, have reduced sources of habitat
degradation, and multiple agencies, volunteers, and community members
are committed to the conservation and preservation of Colorado hookless
cactus. BLM owns and manages approximately 72 percent and 68 percent,
respectively, of the land that comprises S. glaucus and S. dawsoniae
AUs (Service 2025, pp. 19-22). The majority of the remaining habitat is
privately owned; less than 1 percent is owned by State or local
governments (Service 2025, p. 19).
Within the range of the Colorado hookless cactus, BLM has included
conservation measures in its resource planning documents to minimize
adverse impacts of land use to listed and BLM sensitive species,
including the Colorado hookless cactus (Krening and Dawson 2020, p.
26). For example, BLM RMPs for the Colorado River Valley, Grand
Junction, and Uncompahgre field offices (the three BLM field offices
within the range of the species) include restrictions on surface-
disturbing activities for BLM sensitive species, such as controlled
surface use stipulations 100 m (328 ft) away from occupied habitat, and
the ability to move a project more than 200 m (656 ft) away from
occupied habitat (BLM 2015a, B-39; BLM 2015b, B-30; BLM 2020, B-21). In
addition, the RMPs have motorized recreation restrictions, energy
development restrictions, and grazing management; provisions for
research to aid in better understanding the effects of stressors on the
species and guide conservation efforts; and provisions for habitat
improvements and vegetation management (e.g., reducing encroachment of
woody species, fuels management, closing of livestock allotments, or
maintaining rangeland health standards) (Service 2025, pp. 19-22, 28-
36; BLM 2015a, pp. 41, 68; BLM 2020, p. II-24).
Even without the protections of the Act, both species would remain
BLM sensitive species for at least 10 years (BLM 2008, entire; Dawson
2023, pers. comm.). Beyond this timeframe, they may remain BLM
sensitive species as long as they meet either of the following
criteria: (1) either species has recently undergone, is undergoing, or
is predicted to undergo a downward trend such that the viability of the
species or a distinct population segment of the species is at risk
across all or a significant portion of the species' range; or (2)
either species depends on ecological refugia or specialized or unique
habitats on BLM-administered lands, and there is evidence that such
areas are threatened with alteration such that the continued viability
of the species in the area would be at risk (BLM 2008, entire; Dawson
2023, pers. comm.).
Once delisted, or if S. glaucus or S. dawsoniae are removed from
BLM's sensitive species list, the measures specific to listed and
sensitive species in these RMPs would no longer apply (e.g., buffers
around oil and gas development). However, the majority of measures in
these RMPs are not unique to Colorado hookless cactus, but rather
provide protections for resources in NCAs and ACECs and for other BLM
sensitive species where the species occur. While these conservation
measures are not obligatory, BLM implements them to meet the goals and
objectives identified in RMPs, unless there are waivers, exceptions, or
modifications for a specific project, for effective land management and
rangeland health as required under FLPMA (43 U.S.C. 1701 et seq.).
Continued responsible management of the landscapes in which the
Colorado hookless cactus occurs, even if not directed specifically
towards the species, will still provide benefit.
Further, approximately 30 percent of the land in S. glaucus AUs and
41 percent of the land in S. dawsoniae AUs have special BLM land
management designations in the form of NCAs, ACECs, a WSA, and a
Wilderness Area (Service 2025, pp. 19-22). These designations limit or
exclude the authorization of certain land uses, and some designations
were specifically created for the conservation of natural resources; of
11 ACECs across the species' range, 8 specifically reference the
protection of Colorado hookless cactus as a foundational goal. The
protections provided by these management designations are not
contingent upon the species' federally listed status, and these
designations help to facilitate the maintenance and recovery of cactus
occurrences, because they are areas where Colorado hookless cactus is
not likely to be disturbed or adversely altered by land-use actions
(Krening and Dawson 2020, p. 26). We discuss the specific protections
each of these areas provides under the relevant stressors above.
The BLM RMP for the Dominguez-Escalante NCA identifies Colorado
hookless cactus as a priority species and includes species-specific
protections that will continue into the future under
[[Page 22662]]
the existing RMP. The species-specific protections include controlling
noxious weeds, minimizing livestock use in Escalante Canyon, reducing
route density within 200 m (656 ft) of Colorado hookless cactus
occurrences, and limiting trail development and permitted activities in
known habitat. BLM will continue monitoring and have a conservation
goal that at least 80 percent of populations show evidence of
recruitment. Species-specific restrictions will also be applied within
100 m (328 ft) of any known occurrences for Colorado hookless cactus as
long as it is a BLM sensitive species, in addition to the protections
described above (BLM 2017, pp. II., 34-35). The NCA contains the
Dominguez Canyon WSA and the Dominguez Canyon Wilderness.
BLM designates ACECs under FLPMA (43 U.S.C. 1702(a), 1712(c)(3)).
ACECs do not have an expiration date, and removing an ACEC designation
is not simple. A withdrawal of an ACEC can be made only by the Office
of the Secretary (43 U.S.C. 1714); additionally, the ACECs that include
S. glaucus and S. dawsoniae habitat were designated to protect multiple
species and resources in addition to the Colorado hookless cactus
(Service 2025, table 6, pp. 19-22). Likewise, NCAs, WSAs, and
Wilderness Areas are designated to protect multiple resources, not only
the Colorado hookless cactus (1964 Wilderness Act (Pub. L. 88-577)).
Therefore, it is unlikely that these special management designations
will change in the coming decades.
We describe each of these BLM areas with special management
designations, and the specific protections they provide, in table 6 of
the SSA report (Service 2025, pp. 19-22) and in table 2 of the 5-year
status review (Service 2021, pp. 10-11). The current condition of the
species provides insight into the effectiveness of these protected
areas; all but one of the S. glaucus AUs and both S. dawsoniae AUs have
high resiliency, including moderate to high habitat condition (see
Current Condition, below; Service 2025, pp. 26-27). This conclusion
demonstrates that both due to the species' natural hardiness and to
these land protections and other conservation efforts, stressors are
not currently meaningfully affecting the species' survival and growth.
No regulatory mechanisms or conservation efforts protect Colorado
hookless cactus on private, State, or local lands.
International trade in all Sclerocactus species is regulated by the
Convention on International Trade in Endangered Species of Wild Flora
and Fauna (CITES), an international agreement ratified by most
countries worldwide since 1975. The purpose of CITES is to regulate the
international wildlife trade to safeguard certain species from over-
exploitation. S. glaucus is currently listed as an Appendix I species
under CITES and will remain an Appendix I species after delisting under
the Act. Trade in Appendix I species is permitted only in exceptional
circumstances. Under CITES, exporters must obtain a permit for
international shipment of specimens. Because Appendix I applies to the
cactus family (Cactaceae), S. dawsoniae is also considered an Appendix
I species (CITES 2024, entire; Leuteritz 2024, entire). More
information on CITES can be found at: https://cites.org/eng/disc/how.php.
Cumulative Effects
We note that, by using the SSA framework to guide our analysis of
the scientific information documented in the SSA report, we have
analyzed the cumulative effects of identified threats and conservation
actions on the species. To assess the current and future condition of
the species, we evaluate the effects of all the relevant 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 listed entity, our assessment integrates the cumulative effects
of the factors and replaces a standalone cumulative-effects analysis.
For example, to assess current resiliency, we used a condition
category table (see Current Condition below) to analyze how livestock
use, invasive species, oil and gas development, OHV recreational use,
development and maintenance of utility corridors, and the effects of
global climate change, taken together, may influence habitat condition,
survivorship, population size, and water availability. Similarly, we
analyzed how changes in these stressors, when considered together, may
influence habitat condition, survivorship, population size, and water
availability in the future. We also considered how these same stressors
may affect the species' current and future redundancy and
representation.
Current Condition
In our SSA report, we evaluate current condition by examining
current levels of resiliency in the eight S. glaucus AUs and two S.
dawsoniae AUs, and implications for redundancy and representation.
Here, we summarize our evaluation of current condition for resiliency,
redundancy, and representation. Additional detail regarding our
analysis is provided in the SSA report (Service 2025, pp. 22-28).
Resiliency
We describe the resiliency for each of the 10 AUs in terms of the
habitat and demographic factors needed by the Colorado hookless cactus
(Service 2025, pp. 10-16, 22-28). We developed a categorical model to
calibrate resiliency based on the range of habitat and demographic
conditions in each AU. In a categorical model, we first identify
resource or demographic factors that contribute to the species'
resiliency; typically, these factors align with the individual resource
needs and population-level needs we identified in the SSA analysis. We
then define threshold values for each identified resource or
demographic factor that represent high, moderate, or low levels of that
factor. Finally, we evaluate whether the current levels of each
resource or demographic factor in an AU fall within the predetermined
thresholds for a high, moderate, or low score for the category; we then
average these scores for each category to develop an overall current
resiliency score for each AU.
For Colorado hookless cactus, our categorical model assessed the
resiliency of each AU by evaluating (1) the condition of habitat in
each AU based on an index that evaluates a number of habitat factors
including invasive species cover, bare ground, native perennial cover,
the relative size of the AU, and the probability of occurrence based on
a BLM habitat suitability model (Holsinger and Krening 2021, p. 5); (2)
the summer water deficit, a proxy for drought and soil moisture that
approximates the availability of water; (3) survival rates for each
species, calculated from long-term monitoring data collected by BLM and
the Denver Botanic Gardens; and (4) a minimum population size estimate
for each AU provided by BLM (Service 2025, pp. 22-24). We selected
these habitat and demographic factors based on their importance to the
species' resiliency and because we could evaluate them relatively
consistently across all 10 AUs. We then used this categorical model as
a key to evaluate resiliency for each AU by systematically evaluating
the current condition of each habitat and demographic factor. The AUs
with higher overall resiliency are at less risk from potential
stochastic events, such as climatic variation, than AUs with lower
overall resiliency. Our SSA report provides additional detail
[[Page 22663]]
regarding the methodology we used to evaluate resiliency for each of
the 10 AUs (Service 2025, pp. 22-28).
When measured against the metrics outlined in our categorical model
(Service 2025, pp. 22-24), all but one of the S. glaucus AUs have high
resiliency. This finding is due to the large estimated number of
individuals in each AU, high levels of survivorship, adequate habitat
resources, and a current summer water deficit (averaged over the past
decade) that is similar to the historical average. The only AU that
does not have high resiliency is the Palisade AU, which has moderate
resiliency overall due to its extremely small population size and
moderate score for the habitat condition index. This AU is considerably
smaller in area than the other AUs. A major highway (U.S. Interstate
70) and the Colorado River also cut through this AU, fragmenting the
habitat. Additionally, a high proportion of this AU is on private and
State lands, which contain existing forms of development (e.g., truck
stop, shooting range, power plant) that present additional stressors to
the species and its habitat (Lincoln 2021, pers. comm.).
Both S. dawsoniae AUs have high resiliency (see table 1 below).
This score is due to the high estimated number of individuals in each
AU, high levels of survivorship, high and moderate availability of
habitat features that support the species, and a current summer water
deficit that is similar to the historical average. The stressors
operating in the Plateau Creek AU and the Roan Creek AU are comparable,
but the Plateau Creek AU is geographically smaller, which partly
influences its lower rating for the population size category (Lincoln
2021, pers. comm.).
Rangewide monitoring efforts have demonstrated a stable trend over
recent years and have also provided a detailed understanding of
demographic features and population dynamics. Across their limited
ranges, both species of Colorado hookless cactus are relatively
abundant, which contributes to the high levels of resiliency in all but
one AU. At the time of listing in 1979 (prior to current taxonomic
revisions--See Background for discussion of taxonomy), it was thought
that the combined total for what are now considered to be four separate
species (S. glaucus, S. dawsoniae, S. brevispinus, and S. wetlandicus)
consisted of approximately 15,000 individual plants in both Colorado
and Utah (44 FR 58868, October 11, 1979). After the taxonomic split in
2009, estimates from CNHP suggested there were approximately between
19,000 and 22,000 plants for the total rangewide number of individuals
in both species (S. glaucus and S. dawsoniae), based on observations
within element occurrence records, which do not represent a total count
of plants for the entire range of the species (Service 2025, pp. 13-
14). However, as we discuss below, we now know that there are many more
plants than previously reported.
BLM conducted a novel sampling-based procedure to estimate the
minimum population size of S. glaucus from 16 sampled macroplots across
the species' range that encompass a variety of different habitat
conditions informed by a species-specific habitat index (Krening et al.
2021a, entire). They estimated the total minimum population size for
the taxon by applying the average minimum plant density estimate of the
sampled macroplots to S. glaucus' total rangewide occupied habitat
acreage. To provide a conservative rangewide estimate across all
landownerships (BLM, private, State, and local lands), BLM applied the
90 percent lower confidence level value as the minimum population size
for each AU. Despite their conservative approach, this method produced
a population size estimate for the species that is much higher than
previous estimates (Krening et al. 2021a, entire).
BLM conducted a similar procedure to estimate the minimum
population size for S. dawsoniae (Krening and Holsinger 2024, entire;
Service 2025, pp. 20-21). BLM estimated minimum plant densities in 30
sampled macroplots using the same methods as the S. glaucus study
described above. BLM did not apply the 90 percent lower confidence
level value as the minimum population size for each S. dawsoniae AU
because of the increased sample size and spatially balanced design
(Krening and Holsinger 2024, entire).
Using this sampling-based procedure to determine the minimum number
of plants in each AU, S. glaucus has a minimum population estimate of
at least 68,120 plants (90 percent lower confidence level estimate),
and S. dawsoniae has a minimum population estimate of 17,362 plants
(Service 2025, p. 14; Krening et al. 2021a, p. 8; Krening and Holsinger
2024, entire). Based on the most recent (2023) BLM monitoring report
for the species, both species demonstrate an increasing trend compared
to the baseline density (Krening and DePrenger-Levin 2023, pp. 6-7).
Table 1--Resiliency of S. glaucus and S. dawsoniae
[Based on current demographic, distribution, and habitat conditions in the species' AUs (Service 2025, pp. 26-28).]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Habitat condition Minimum population Summer water Overall AU resiliency
Species Analysis unit index Survivorship size deficit * score
--------------------------------------------------------------------------------------------------------------------------------------------------------
S. glaucus........... Whitewater.......... High.............. High................. High................. High.............. High.
Palisade............ Moderate.......... Low.................. High.............. Moderate.
Dominguez-Escalante. High.............. High................. High.............. High.
North Fruita Desert. Moderate.......... Moderate............. High.............. High.
Devil's Thumb....... High.............. Moderate............. High.............. High.
Cactus Park......... High.............. High................. High.............. High.
Gunnison Gorge...... Moderate.......... Moderate............. High.............. High.
Gunnison River East. High.............. High................. High.............. High.
S. dawsoniae......... Plateau Creek....... Moderate.......... High................. Moderate............. High.............. High.
Roan Creek.......... High.............. High................. High.............. High.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Note: ``High'' in summer water deficit refers to a high resiliency rating, rather than a high water deficit.
Redundancy
Redundancy describes the number and distribution of AUs, such that
the greater the number and the wider the distribution of the AUs, the
better the Colorado hookless cactus can withstand catastrophic events.
The plausibility of catastrophic events also influences species'
redundancy; if catastrophic events are unlikely within the range of the
species, catastrophic risk is inherently lower. We are unaware of any
plausible activity or naturally occurring event that would constitute a
catastrophic event for Colorado hookless cactus. For example, fire is
not a common occurrence in S. glaucus or S. dawsoniae habitat as this
habitat lacks
[[Page 22664]]
the fuels to sustain a burn, though increased invasive species presence
could elevate this risk (Service 2025, p. 28). Additionally, the range
of S. glaucus and S. dawsoniae contains natural and humanmade barriers
(i.e., rivers, canyons, highways) that would constrain the spread of
any catastrophic fire throughout the entire range of Colorado hookless
cactus. Redundancy for narrow endemic species is intrinsically limited;
however, S. glaucus plants are distributed broadly across the range of
the species in eight AUs, providing redundancy throughout its
relatively small geographic range. With only two AUs, S. dawsoniae
redundancy is limited; however, as a narrowly endemic plant, it has
likely always had a small range and limited redundancy, and there has
not been a known decrease in redundancy compared with its historical
range. Additionally, given the lack of plausible catastrophic events
across the range of S. glaucus and S. dawsoniae, even the narrow range
of S. dawsoniae does not introduce appreciable catastrophic risk.
Representation
S. glaucus and S. dawsoniae exhibit some ecological and
morphological variability, coupled with low to moderate genetic
diversity among AUs (McGlaughlin and Naibauer 2021, p. 22). Inbreeding
is not an immediate concern for either species (McGlaughlin and
Naibauer 2021, p. 22). Additionally, S. glaucus demonstrates sufficient
connectivity, which results in ongoing and recent genetic exchange
(McGlaughlin and Naibauer 2021, p. 2). S. dawsoniae is genetically
isolated and diverged from S. glaucus; all genetic analyses support
that S. dawsoniae is a distinct entity (McGlaughlin and Naibauer 2024,
entire).
Future Scenarios and Future Condition
In our SSA report, we forecasted the resiliency of S. glaucus and
S. dawsoniae AUs and their redundancy and representation to mid-century
(the mean of projections for 2040 to 2069) using a range of plausible
future scenarios. After mid-century, the changes in climate conditions
that different climate models and emissions scenarios project begin to
diverge widely (Rangwala et al. 2021, p. 4); in other words, the spread
of potential projected temperature increases broadens substantially
after mid-century. Therefore, we focused our analysis of future
condition on mid-century to avoid the large uncertainty in climate
change at the end of the twenty-first century (Rangwala et al. 2021, p.
4). We also selected this timeframe because we can make reliable
predictions regarding changes in other stressors to S. glaucus and S.
dawsoniae, such as land management. This timeframe encompasses at least
one revision to BLM resource management plans and is biologically
meaningful to S. glaucus and S. dawsoniae for us to begin to understand
the response of ecosystems to those changes.
We used future climate models downscaled to the ranges of S.
glaucus and S. dawsoniae, in combination with forecasted changes in the
location and intensity of stressors, to develop three future scenarios
and evaluate the condition of S. glaucus and S. dawsoniae under each of
those scenarios. By capturing a range of plausible future scenarios, we
can assume that actual future conditions will likely fall somewhere
between these projected scenarios. Detailed descriptions of each
scenario are available in the SSA report (Service 2025, pp. 28-36).
As many of the stressors that affect S. glaucus and S. dawsoniae
occur on BLM lands, future scenarios were developed with input from BLM
about plausible changes in the location and intensity of stressors on
BLM land. Given some level of uncertainty about the conditions that
will occur by mid-century, these scenarios represent three future
conditions--optimistic, continuation, and pessimistic--to capture the
plausible range of future conditions the species may experience.
Therefore, our evaluation of future conditions presents a plausible
range of expected species responses. While the metrics used to assess
the current resiliency of S. glaucus and S. dawsoniae AUs are
quantitative, we do not have a reliable way to quantitatively forecast
these metrics into the future. Instead, future conditions are expressed
qualitatively, using the results of our current condition analysis as
the baseline. Species experts used professional judgment to predict how
the species and their habitats would respond to each future scenario
(Krening 2021, pers. comm.).
Optimistic. In the optimistic scenario, the overall resiliency of
each AU for both species remains the same as the current condition.
Although the overall resiliency of each AU does not change, the
resiliency of the Plateau Creek (S. dawsoniae) and Devil's Thumb (S.
glaucus) AUs increases slightly due to higher ratings for habitat
conditions and population size, respectively. Under this scenario,
decreases in activities such as grazing and OHV use (consistent with
current stipulations in BLM grazing permits and travel management
plans) that degrade S. glaucus and S. dawsoniae habitat allow for
passive restoration, which leads to improved habitat conditions in the
Plateau Creek AU and an increase in population size in the Devil's
Thumb AU. Summer water deficit is expected to slightly decrease,
meaning more water is available for germination, growth, and
reproduction. Redundancy and representation for S. dawsoniae increase
under this scenario, as compared to the current condition, due to an
increase in resiliency in the Plateau Creek AU. Redundancy and
representation of S. glaucus also increase slightly under this scenario
due to an increase in resiliency in the Devil's Thumb AU.
Continuation. In the continuation scenario, we expect resiliency,
redundancy, and representation to remain relatively unchanged from the
current condition. Resiliency of the Palisade AU (S. dawsoniae) is
moderate; resiliency of all other AUs is high. Despite the increase in
water deficit as compared to historical conditions under this scenario
(meaning that less water would be available to the plants), this slight
decrease in water availability would have minimal impact because it is
well within the range of variability that S. glaucus and S. dawsoniae
have historically experienced.
Pessimistic. In the pessimistic scenario, hot and dry conditions
may negatively affect survivorship and recruitment of the species.
Water deficit is more than one standard deviation higher than the
historical mean, meaning that, on average, less water is available to
support germination, growth, and reproduction. Under the pessimistic
scenario, although BLM land management direction and special land
management designations do not change, continued ground disturbance and
habitat degradation may occur. This projection could be driven by
several factors: Livestock grazing without corrective action for
impacts to the range may lead to increased impacts to habitat and plant
communities; and increasing OHV use (due to increased demand from
population growth), increasing demand for oil and gas development and
utility corridor development, and an increase in invasive plant species
may negatively affect the amount and quality of habitat available and
reduce survival rates and overall population sizes, leading to a
decrease in resiliency in the Whitewater, Palisade, North Fruita
Desert, Devil's Thumb, Cactus Park, Gunnison Gorge, and Gunnison River
East AUs (S. glaucus) and in the Plateau Creek AU (S. dawsoniae).
Overall, one S. glaucus AU is in high condition, six
[[Page 22665]]
S. glaucus AUs are in moderate condition, and one is in low condition.
S. dawsoniae has one AU in high condition and one AU in moderate
condition.
Redundancy and representation of S. glaucus decreases slightly in
this scenario due to the decrease in resiliency in all but one AU;
although no AUs are expected to be extirpated, each AU contains
multiple clusters of plants, and some diversity within AUs could be
lost. However, even in the most pessimistic plausible scenario, all but
1 of the 8 AUs are expected to have at least 500 to 10,000 plants,
thereby preserving much of the species' redundancy and representation.
Despite high and moderate resiliency of the two S. dawsoniae AUs,
representation and redundancy are lower than under the optimistic and
continuation scenarios and under current condition due to the Plateau
Creek AU's moderate resiliency; this AU had high resiliency under all
other scenarios. With only two known S. dawsoniae AUs, the loss of one
of these AUs due to catastrophic, natural, or human-caused events would
cause a severe loss of redundancy and representation of the species;
however, loss of either AU is not expected, even under the pessimistic
scenario. As with S. glaucus, some variation within AUs could be
reduced under this scenario; however, ecological, morphological, and
genetic variation will continue to be represented by the multiple AUs
across S. dawsoniae's range.
Determination of Colorado Hookless Cactus (S. glaucus and S. dawsoniae)
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 an ``endangered species'' as a
species in danger of extinction throughout all or a significant portion
of its range, and a ``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 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.
When we listed the Colorado hookless cactus as threatened on
October 11, 1979, we identified the potential development of oil shale
deposits and gold mining (Factor A), off-road vehicle use (Factor A),
collecting pressure (Factor B), livestock grazing (Factor C), and an
inadequacy of existing regulatory mechanisms (Factor D) as threats to
the existence of the species (44 FR 58868, October 11, 1979). In our
SSA, we evaluated these stressors and additional stressors that were
identified after the time of listing. Much more is presently known
about the species' stressors than at the time of listing.
Several of the stressors identified in the original listing
decision are no longer relevant. Given the taxonomic changes, and thus
range extent changes, that the species has undergone in the past 40
years, oil shale and tar sands development and hybridization are no
longer relevant stressors (Service 2025, p. 16). Additionally,
collection from the wild has not occurred at the level anticipated at
the time of listing; collection is not having population- or species-
level effects on either species (Krening and Dawson 2020, p. 36). Thus,
stressors that could influence both species of the Colorado hookless
cactus at the AU or species scale include livestock use (Factor A),
invasive species (Factor A), oil and gas development (Factor A), OHV
recreational use (Factor A), development and maintenance of utility
corridors (Factor A), and the effects of global climate change (Factor
A). Although livestock grazing was categorized as a stressor under
Factor C at the time of listing, we believe that the effects of
livestock grazing are better characterized by Factor A. The spines on
cactus plants generally make them undesirable forage to livestock;
however, livestock can degrade habitat conditions by trailing through
and trampling habitat. Only on rare occasions do cattle directly
trample or dislodge cactus plants.
We also evaluated a variety of conservation efforts and mechanisms
across the 10 AUs of both species that either reduce or ameliorate
stressors or improve the condition of habitats or demographics. These
conservation efforts and mechanisms include five BLM RMPs that, taken
together, cover the range of the species. They include motorized
recreation restrictions, energy development restrictions, and grazing
management; research to aid in better understanding the effects of
stressors on the species and guide conservation efforts; and habitat
improvements and vegetation management (Service 2025, pp. 19-22, 28-
36). With 72 percent of S. glaucus and 68 percent of S. dawsoniae AU
acres occurring on BLM land, BLM's implementation of the regulatory
mechanisms in their resource planning documents on all of their lands
within the range of the species (Factor D) has helped to address the
stressors we identified under Factors A and B. While we cannot
attribute the currently high resiliency of both species (S. glaucus and
S. dawsoniae) to one specific conservation measure, this high
resiliency demonstrates the amelioration of relevant stressors and the
adequacy of the existing regulatory mechanisms, both due to the
combination of conservation measures in place and the hardiness of the
plants (having a demonstrated ability to tolerate nearby disturbance).
In addition to the implementation of measures that minimize impacts
to the Colorado hookless cactus on all BLM lands, approximately 30
percent of the land in S. glaucus AUs and 41 percent of the land in S.
dawsoniae AUs have special BLM land management designations (Factor D),
which further limit or exclude the authorization of certain land uses
and further help to facilitate the maintenance and recovery of cactus
occurrences, because they are areas where Colorado hookless cactus
occurrences are not likely to be disturbed or adversely altered by
land-use actions (Krening and Dawson 2020, p. 26). The protections
provided by these management designations are not contingent upon the
species' federally listed status.
Status Throughout All of Its Range: Sclerocactus glaucus
Currently, seven of the eight S. glaucus AUs have high resiliency,
and one AU has moderate resiliency (Service 2025, pp. 26-28). The
highly resilient AUs have high estimated numbers of individuals, high
levels of survivorship, adequate habitat resources, and a current water
deficit that is similar to the historical average. One AU has moderate
resiliency due to its extremely small population size and moderate
score for the habitat index; this AU covers a considerably smaller area
than the other AUs. Rangewide monitoring has shown a stable trend for
Colorado hookless cactus, with no indication of widespread decline.
This monitoring has also informed our understanding that S. glaucus is
currently much more abundant than originally estimated at the time of
listing in 1979. At the time of listing, and prior to the taxonomic
splits between the 2 Utah Sclerocactus species and Colorado's S.
glaucus and S.
[[Page 22666]]
dawsoniae, it was thought that the combined total for the now 4 species
consisted of approximately 15,000 individual plants in both Colorado
and Utah; now, the minimum population estimate for S. glaucus alone is
68,120 plants (90 percent lower confidence level).
We are unaware of any plausible activity or naturally occurring
event that would constitute a catastrophic event for this species.
Thus, while the species is a narrow endemic with a small range compared
to wide-ranging species, S. glaucus's relatively large range for a
narrow endemic, with eight AUs, and the lack of plausible catastrophic
events reduce catastrophic risk for this species, thereby enhancing
redundancy. The individuals within and among the AUs also exhibit
genetic, ecological, and morphological diversity, contributing to the
species' representation.
Moreover, our understanding of the species' stressors has changed
since the time Colorado hookless cactus was listed. Multiple identified
stressors are no longer relevant to the species, given past taxonomic
changes and subsequent changes in the geographic range of the species
(i.e., oil shale and tar sands development) or because they are not
occurring at a scale anticipated at the time of listing (i.e.,
collection). We also have found that, while OHV use and invasive
species have the potential to detrimentally impact Colorado hookless
cactus, they have caused only minor, localized impacts (Krening and
Dawson 2020, pp. 35, 38). Oil and gas development occurs in only a
small portion of three of the eight S. glaucus AUs.
Since Colorado hookless cactus was listed, the BLM land in the
species' range now includes NCAs, ACECs, a WSA, and a Wilderness Area
(Service 2025, pp. 19-22). These designations limit or exclude the
authorization of certain land uses, and most of these designations
specifically reference the protection of Colorado hookless cactus as a
foundational goal. The protections provided by these management
designations are not contingent upon the species' federally listed
status, and these designations have helped to facilitate the
maintenance and recovery of cactus occurrences, because they are areas
where Colorado hookless cactus is not likely to be disturbed or its
habitat adversely altered by land-use actions (Krening and Dawson 2020,
p. 26). While we cannot attribute the currently high resiliency of all
but one AU to one specific conservation measure, this high resiliency
demonstrates the amelioration of relevant stressors, both due to the
combination of conservation measures in place and the hardiness of the
plant (which has shown an ability to tolerate nearby disturbance).
Given the currently high level of resiliency in seven of the eight
S. glaucus AUs and moderate resiliency of one AU, the additional plants
we now know to occur throughout the species' range, the lack of
significant imminent stressors, and the low likelihood of catastrophic
events, we find that S. glaucus currently has sufficient ability to
withstand stochastic and catastrophic events, and to adapt to
environmental changes.
For the purposes of our analysis of the species' future condition,
we defined the foreseeable future for both S. glaucus and S. dawsoniae
to mid-century (the mean of 2040 to 2069). After mid-century, the
changes in climate conditions that different climate models and
emissions scenarios project begin to diverge widely (Rangwala et al.
2021, p. 4); in other words, after mid-century, there is a wide
variability in temperature projections among different climate models.
This variability makes future conditions beyond the mid-century
difficult to reliably assess. Therefore, we focused our analysis of
future condition on mid-century to avoid the large degree of
uncertainty in how climate change is projected to manifest at the end
of the twenty-first century (Rangwala et al. 2021, p. 4). We also
selected this timeframe because it allows us to reliably predict
changes in species' stressors and land management and is biologically
meaningful to both species for us to begin to understand the response
of ecosystems to those changes.
By mid-century, we anticipate a range of plausible future
conditions for S. glaucus. Under the optimistic scenario, the condition
of the species is likely to improve over the current condition, with
resiliency projected to increase slightly in one S. glaucus AU. BLM's
closure of certain OHV routes and effective implementation of changes
in grazing permit stipulations would lead to decreased grazing and OHV
pressures, causing improved habitat conditions and an increase in the
number of individuals in the AU (Service 2025, pp. 31-32). In the
continuation scenario, we expect resiliency, redundancy, and
representation to remain relatively unchanged from the current
condition, because stressors and conservation efforts would remain very
similar to what the species is currently experiencing.
In the pessimistic scenario, although BLM management planning
documents and special land management designations do not change,
grazing without corrective action for impacts to the range, an increase
in OHV use, increased demand for utility corridor development, an
increase in invasive plant species, and a considerable decrease in
water availability due to climate change may negatively affect the
amount and quality of habitat available, and reduce survival rates and
overall population sizes. This is the only scenario in which the
condition of S. glaucus is projected to decline: One AU's resiliency
remains high, six AUs decrease from high to moderate resiliency, and
one AU decreases to low resiliency. Even under this pessimistic
scenario, the species maintains moderate levels of survival and high or
moderate habitat condition in the majority of AUs, despite increasing
stressors. In all three scenarios, all eight AUs will remain extant,
thereby continuing to contribute to the redundancy and representation
of the species.
Given these future projections of resiliency, redundancy, and
representation to mid-century, S. glaucus could experience a slight
decrease in viability under one of the three future scenarios (the
pessimistic scenario); however, even in this most pessimistic scenario,
all AUs will remain extant and seven of the eight AUs will have
moderate to high resiliency.
Two factors support this consistently moderate to high future
resiliency: BLM conservation actions and the species' biological
characteristics. First, the high to moderate resiliency of S. glaucus
AUs is, in part, due to land protections and regulations implemented by
BLM (Factor D) that will continue to be implemented into the future,
even in the absence of protections afforded by the Act, as described
under Conservation Efforts and Regulatory Mechanisms above. These
protections will continue to limit the potential effects of stressors
on S. glaucus in the future.
Second, independent of future BLM management, the species'
biological characteristics moderate its response to increasing
stressors. S. glaucus is a habitat generalist, which means the species
is not constrained to a specific habitat niche; the species' flexible
resource requirements increase its resiliency to potential future
increases in stressors and its ability to adapt to future change
(representation). This determination is evidenced by S. glaucus' past
ability to maintain high survivorship and resiliency, even in the face
of ongoing stressors that the Service originally determined could lead
to decline (e.g., OHV use, invasive
[[Page 22667]]
species). Additionally, multiple modeling efforts have concluded that
Colorado hookless cactus likely has low vulnerability to climate
change, given its dispersal capabilities and opportunities for
expansion into vast areas of suitable habitat (Krening and Dawson 2020,
pp. 43-44). Although conditions could become considerably drier under
the pessimistic climate scenario, S. glaucus is hardy and already
adapted to arid environments. Individuals of this species live many
decades and have maintained healthy recruitment and survival, even
through droughts and other climatic variation in the past (BLM 2018,
pp. 14-15; Hegewisch and Abatzoglou 2020, entire). These
characteristics allow the species to maintain moderate survivorship and
resiliency, even under the pessimistic scenario.
After evaluating threats to the species and assessing the
cumulative effect of the threats under the Act's section 4(a)(1)
factors, the species currently has sufficient levels of resiliency,
redundancy, and representation, and is anticipated to maintain
sufficient levels under each of the future scenarios, such that S.
glaucus will be able to withstand stochastic events, catastrophic
events, and environmental change now and into the foreseeable future.
Thus, after assessing the best available information, we conclude that
S. glaucus is not in danger of extinction now or likely to become so in
the foreseeable future throughout all of its range.
Status Throughout All of Its Range: Sclerocactus dawsoniae
Currently, both S. dawsoniae AUs have high resiliency (Service
2025, pp. 26-28). The highly resilient AUs have moderate to high
estimated numbers of individuals (i.e., a minimum population estimate
of 17,362 plants total), high levels of survivorship, high and moderate
condition of habitat features, and a current water deficit that is
similar to the historical average. These high current levels of
resiliency reduce the current extinction risk for S. dawsoniae because
they lower the risk to the species from stochastic variation. Rangewide
monitoring has shown a stable trend for S. dawsoniae, with no
indication of widespread decline and greater abundance than originally
estimated. When Colorado hookless cactus was listed in 1979 and prior
to the taxonomic splits between the 2 Utah Sclerocactus species and
Colorado's S. glaucus and S. dawsoniae, it was thought that the
combined total for the now 4 species consisted of approximately 15,000
individual plants in both Colorado and Utah; now, the minimum
population estimate for S. dawsoniae plants alone is 17,362.
Additionally, the two AUs and the individuals within the AUs
exhibit ecological and morphological variability (McGlaughlin and
Naibauer 2021, p. 22), contributing to the representation of the
species. In terms of redundancy, we are unaware of any plausible
activity or naturally occurring event that would constitute a
catastrophic event for this species. Given the lack of plausible
catastrophic events across the range of S. dawsoniae, even its narrow
range (two AUs) does not introduce appreciable catastrophic risk.
Moreover, our understanding of stressors to the Colorado hookless
cactus has changed since the time of the original listing rule (44 FR
58868; October 11, 1979). Multiple identified stressors are no longer
relevant to the species, given past taxonomic changes and subsequent
changes in the geographic range of the species (e.g., oil shale and tar
sands development) or because they are not occurring at a scale
anticipated at the time of listing (i.e., collection). We also have
found that, while OHV use and invasive species had the potential to
detrimentally impact the species, they have caused only minor,
localized impacts (Krening and Dawson 2020, pp. 35, 38).
Since Colorado hookless cactus was listed, NCAs, ACECs, a WSA, and
a Wilderness Area have been designated on BLM land where the species
occurs (Service 2025, pp. 19-22). These designations limit or exclude
the authorization of certain land uses, and most of these designations
specifically reference the protection of Colorado hookless cactus as a
foundational goal. The protections provided by these management
designations are not contingent upon the species' federally listed
status, and these designations have helped to facilitate the
maintenance and recovery of cactus occurrences, because they are areas
where Colorado hookless cactus is not likely to be disturbed or
adversely altered by land-use actions (Krening and Dawson 2020, p. 26).
While we cannot attribute the currently high resiliency of both AUs to
one specific conservation measure, this high resiliency demonstrates
the amelioration of relevant stressors, both due to the combination of
conservation measures in place and the hardiness of the plant (which
has shown an ability to tolerate nearby disturbance).
By mid-century (the foreseeable future), we anticipate a range of
plausible future conditions for S. dawsoniae. Under the optimistic
scenario, the condition of the species improves, with resiliency
expected to increase slightly in one S. dawsoniae AU due to decreased
grazing and OHV pressures, causing improved habitat conditions. In the
continuation scenario, we expect resiliency, redundancy, and
representation to remain relatively unchanged from the current
condition, as stressors and conservation efforts remain very similar to
what the species is currently experiencing. In the pessimistic
scenario, although BLM management planning documents and special land
management designations do not change, continued livestock grazing
without corrective action for impacts to the range, increasing demand
for oil and gas development and utility corridor development, and an
increase in invasive plant species will cause ground disturbance and
habitat degradation that is projected to negatively affect the species,
which would cause a decrease in resiliency in one of the two S.
dawsoniae AUs. Additionally, only under this pessimistic scenario does
water availability drop considerably below the historical average
(i.e., more than one standard deviation). This is the only scenario in
which we foresee resiliency decreasing for either of the species' two
AUs; one AU's resiliency remains high, and one AU decreases to moderate
resiliency. Even in the pessimistic scenario, survivorship in both AUs
remains high. In all three scenarios, both AUs will remain extant,
thereby continuing to contribute to the redundancy and representation
of the species.
Given these future projections of resiliency, redundancy, and
representation to mid-century, S. dawsoniae could experience a slight
increase in extinction risk under one of the three future scenarios;
however, even in the pessimistic scenario, both AUs will remain extant
with moderate to high resiliency. Two factors support this moderate to
high future resiliency: BLM conservation actions and the species'
biological characteristics. First, this high to moderate resiliency of
S. dawsoniae AUs is, in part, due to land protections and regulations
implemented by BLM (Factor D) that will continue to be implemented into
the future even in the absence of protections afforded by the Act, as
described under Conservation Efforts and Regulatory Mechanisms above.
These protections will continue to limit the potential effects of
stressors on S. dawsoniae in the future.
Second, independent of future BLM management, the species'
biological characteristics moderate its response to increasing
stressors. Like S. glaucus, S.
[[Page 22668]]
dawsoniae is a habitat generalist, which means the species is not
constrained to a specific habitat niche; the species' flexible resource
requirements increase its resiliency to potential future increases in
stressors and its ability to adapt to future change (representation).
This finding is evidenced by S. dawsoniae's past ability to maintain
high survivorship and resiliency, even in the face of ongoing stressors
that the Service originally determined could lead to decline (e.g., OHV
use, invasive species). Additionally, multiple modeling efforts have
indicated that Colorado hookless cactus likely has low vulnerability to
climate change, given its dispersal capabilities and opportunities for
expansion into vast areas of suitable habitat (Krening and Dawson 2020,
pp. 43-44). Although conditions could become considerably drier under
the pessimistic climate scenario, S. dawsoniae is hardy and already
adapted to arid environments. Individuals of this species live many
decades and have maintained healthy recruitment and survival, even
through droughts and other climatic variation in the past (BLM 2018,
pp. 14-15; Hegewisch and Abatzoglou 2020, entire). These
characteristics would allow S. dawsoniae to maintain high survivorship
and moderate to high resiliency, even under the pessimistic scenario.
After evaluating threats to the species and assessing the
cumulative effect of the threats under the Act's section 4(a)(1)
factors, the species currently has sufficient levels of resiliency,
redundancy, and representation, and is anticipated to maintain
sufficient levels in each of the plausible future scenarios, such that
S. dawsoniae will be able to withstand stochastic events, catastrophic
events, and environmental change now and within the foreseeable future.
Therefore, after assessing the best available information, we conclude
that S. dawsoniae is not in danger of extinction now or likely to
become so in the foreseeable future 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
within the foreseeable future throughout all or a significant portion
of its range. Having determined that S. glaucus and S. dawsoniae are
not in danger of extinction or likely to become so in the foreseeable
future throughout all of their range, we now consider whether either
may be in danger of extinction (i.e., endangered) or likely to become
so in the foreseeable future (i.e., threatened) in a significant
portion of its range--that is, whether there is any portion of the
species' range for which both (1) the portion is significant; and (2)
the species is in danger of extinction or likely to become so in the
foreseeable future in that portion. Depending on the case, it might be
more efficient for us to address the ``significance'' question or the
``status'' question first. We can choose to address either question
first. Regardless of which question we address first, if we reach a
negative answer with respect to the first question that we address, we
do not need to evaluate the other question for that portion of the
species' range.
In undertaking this analysis for S. glaucus and S. dawsoniae, we
choose to address the status question first. We began by identifying
portions of the range where the biological status of the species may be
different from their biological status elsewhere in their range. For
this purpose, we considered information pertaining to the geographic
distribution of (a) individuals of the species, (b) the threats that
the species face, and (c) the resiliency condition of populations.
For S. glaucus, we evaluated the range of the species to determine
if the species is in danger of extinction now or likely to become so in
the foreseeable future in any portion of its range. The range of a
species can theoretically be divided into portions in an infinite
number of ways. We focused our analysis on portions of the species'
range that may meet the definition of an endangered species or a
threatened species. For S. glaucus, we considered whether the threats
or their effects on the species are greater in any biologically
meaningful portion of the species' range than in other portions such
that the species is in danger of extinction now or likely to become so
in the foreseeable future in that portion. We examined the following
threats: livestock use, invasive species, oil and gas development, OHV
use, development and maintenance of utility corridors, and climate
change, including cumulative effects.
Livestock use, invasive species, OHV use, development and
maintenance of utility corridors, and climate change occur uniformly
across the species' range; there are no portions of the species' range
where these stressors occur more intensely. Oil and gas development is
occurring in only three AUs (North Fruita Desert, Whitewater, and
Palisade AUs), so this threat may be elevated in this area. However,
despite this development activity, the North Fruita Desert and
Whitewater AUs currently have high resiliency and are expected to
maintain this high resiliency under two of three future scenarios.
Under the pessimistic scenario, North Fruita Desert and Whitewater AUs
have moderate resiliency. Oil and gas development is occurring in only
a small portion of the Palisade AU (there is only one active well site
across more than 9,269 ac (3,751 ha)), and, while this AU has moderate
resiliency currently and could drop to low resiliency under the
pessimistic scenario, this possible change is due to the AU's small
size and thus inherently low number of plants, not due to oil and gas
development. Thus, even though oil and gas development may be
concentrated in these AUs, it is not producing a species' response that
would indicate the plants therein are in danger of extinction now or in
the foreseeable future.
Moreover, although the Palisade AU has a low population size and is
the only AU to rank low in resiliency in any future scenario, the AU
occupies the smallest area of any S. glaucus AU and contributes the
least to the species' redundancy and representation. Therefore, this AU
is not considered to be a biologically meaningful portion of the
species' range where threats are impacting individuals differently from
how they are affecting the species elsewhere in its range such that the
status of the species in that portion differs from its status in any
other portion of the species' range.
Overall, we found no biologically meaningful portions of S.
glaucus' range where threats are impacting individuals differently from
how they are affecting the species elsewhere in its range such that the
status of the species in that portion differs from its status in any
other portion of the species' range.
Therefore, we find that the species is not in danger of extinction
or likely to become so within the foreseeable future in any significant
portion of its range. This does not conflict with the courts' holdings
in Desert Survivors v. Department of the Interior, 321 F. Supp. 3d
1011, 1070-74 (N.D. Cal. 2018) and Center for Biological Diversity v.
Jewell, 248 F. Supp. 3d. 946, 959 (D. Ariz. 2017) because, in reaching
this conclusion, we did not apply the aspects 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), including the
definition of ``significant'' that those court decisions held to be
invalid.
For S. dawsoniae, we evaluated the range of the species to
determine if the
[[Page 22669]]
species is in danger of extinction now or likely to become so in the
foreseeable future in any portion of its range. The range of a species
can theoretically be divided into portions in an infinite number of
ways. We focused our analysis on portions of the species' range that
may meet the definition of an endangered species or a threatened
species. For S. dawsoniae, we considered whether the threats or their
effects on the species are greater in any biologically meaningful
portion of the species' range than in other portions such that the
species is in danger of extinction or likely to become so within the
foreseeable future in that portion. We examined the following threats:
livestock use, invasive species, oil and gas development, OHV use,
development and maintenance of utility corridors, and climate change,
including cumulative effects.
Overall, the threats to this species are uniformly distributed
throughout its range, and we did not identify a significant
concentration of threats or the species' response to those threats that
would increase extinction risk in any portion. Oil and gas development
occurs in both AUs, as does livestock use, OHV use, invasive species
infestation, and development and maintenance of utility corridors. The
small range of the species will not experience substantially different
temperature or precipitation changes as a result of climate change.
We found no biologically meaningful portions of S. dawsoniae's
range where threats are impacting individuals differently from how they
are affecting the species elsewhere in its range such that the status
of the species in that portion differs from its status in any other
portion of the species' range.
Therefore, we find that the species is not in danger of extinction
or likely to become so within the foreseeable future in any significant
portion of its range. This finding does not conflict with the courts'
holdings in Desert Survivors v. Department of the Interior, 321 F.
Supp. 3d 1011, 1070-74 (N.D. Cal. 2018) and Center for Biological
Diversity v. Jewell, 248 F. Supp. 3d. 946, 959 (D. Ariz. 2017) because,
in reaching this conclusion, we did not apply the aspects 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),
including the definition of ``significant'' that those court decisions
held to be invalid.
Determination of Status
Based on the best scientific and commercial data available, we
determine that S. glaucus and S. dawsoniae do not meet the definition
of an endangered species or a threatened species in accordance with
sections 3(6) and 3(20) of the Act. In accordance with our regulations
at 50 CFR 424.11(e)(2) currently in effect, S. glaucus and S. dawsoniae
have recovered to the point at which they no longer meet the definition
of an endangered species or a threatened species. Therefore, we are
removing Colorado hookless cactus (S. glaucus and S. dawsoniae) from
the Federal List of Endangered and Threatened Plants.
Effects of This Rule
This rule revises 50 CFR 17.12(h) by removing Colorado hookless
from the Federal List of Endangered and Threatened Plants. On the
effective date of this rule (see DATES, above), the prohibitions and
conservation measures provided by the Act, particularly through
sections 7 and 9, will no longer apply to this species. Federal
agencies will no longer be required to consult with the Service under
section 7 of the Act in the event that activities they authorize, fund,
or carry out may affect Colorado hookless cactus (S. glaucus and S.
dawsoniae).
There is no critical habitat designated for this species, so there
will be no effect to 50 CFR 17.96.
Post-Delisting Monitoring
Section 4(g)(1) of the Act requires us, in cooperation with the
States, to implement a monitoring program for not less than 5 years for
all species that have been recovered. Post-delisting monitoring (PDM)
refers to activities undertaken to verify that a species delisted due
to recovery remains secure from the risk of extinction after the
protections of the Act no longer apply. The primary goal of PDM is to
monitor the species to ensure that its status does not deteriorate, and
if a decline is detected, to take measures to halt the decline so that
proposing it as endangered or threatened is not again needed. If at any
time during the monitoring period data indicate that protective status
under the Act should be reinstated, we can initiate listing procedures,
including, if appropriate, emergency listing.
We have prepared a PDM plan for Colorado hookless cactus (S.
glaucus and S. dawsoniae). We published a notice of availability of a
draft PDM plan with the proposed delisting rule (88 FR 21582, April 11,
2023), and we addressed all comments to the plan under Summary of
Comments and Recommendations and revised the draft PDM plan according
to the information we received. Therefore, we consider the plan final.
As discussed in the proposed rule, the PDM plan: (1) Summarizes the
status of Colorado hookless cactus (S. glaucus and S. dawsoniae) at the
time of proposed delisting; (2) describes frequency and duration of
monitoring; (3) discusses monitoring methods and potential sampling
regimes; (4) defines what potential triggers will be evaluated to
address the need for additional monitoring; (5) outlines reporting
requirements and procedures; (6) proposes a schedule for implementing
the PDM plan; and (7) defines responsibilities. It is our intent to
work with our partners toward maintaining the recovered status of
Colorado hookless cactus (S. glaucus and S. dawsoniae).
Required Determinations
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, May 4, 1994), Executive Order 13175
(Consultation and Coordination with Indian Tribal Governments), the
President's memorandum of November 30, 2022 (Uniform Standards for
Tribal Consultation; 87 FR 74479, December 5, 2022), and the Department
of the Interior's manual at 512 DM 2, we readily acknowledge our
responsibility to communicate meaningfully with federally recognized
Tribes and Alaska Native Corporations on a government-to-government
basis. In accordance with Secretaries' 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 notified the Ute Mountain, Jicarilla Apache Nation, Southern
Ute, Ute Mountain Ute, and Navajo Nation Tribes of our recommendation
to delist the Colorado hookless cactus in our 5-year status review in
2021, and of the proposed delisting rule (88 FR 21582, April 11, 2023).
We did not receive comments from Tribes, and we are not aware of
[[Page 22670]]
any Tribal interests or concerns associated with this final
determination.
References Cited
A complete list of references cited in this rulemaking is available
on the internet at https://www.regulations.gov and upon request from
the Colorado Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
Authors
The primary authors of this rule are the staff members of the Fish
and Wildlife Service's Species Assessment Team and the Colorado
Ecological Services Field Office.
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Plants,
Reporting and recordkeeping requirements, Transportation.
Signing Authority
Paul Souza, Regional Director, Region 8, Exercising the Delegated
Authority of the Director of the U.S. Fish and Wildlife Service,
approved this action on April 24, 2025, for publication. On May 21,
2025, Paul Souza authorized the undersigned to sign the document
electronically and submit it to the Office of the Federal Register for
publication as an official document of the U.S. Fish and Wildlife
Service.
Regulation Promulgation
Accordingly, we 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.
Sec. 17.12 [Amended]
0
2. In Sec. 17.12, amend paragraph (h) by removing the entry for
``Sclerocactus glaucus'' under Flowering Plants from the List of
Endangered and Threatened Plants.
Madonna Baucum,
Regulations and Policy Chief, Division of Policy, Economics, Risk
Management, and Analytics of the Joint Administrative Operations, U.S.
Fish and Wildlife Service.
[FR Doc. 2025-09692 Filed 5-28-25; 8:45 am]
BILLING CODE 4333-15-P