Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To Remove the Bone Cave Harvestman (Texella reyesi) From the List of Endangered and Threatened Wildlife, 30990-30996 [2015-13136]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS–R2–ES–2015–0030;
FF09E42000 156 FXES11130900000]
Endangered and Threatened Wildlife
and Plants; 90-Day Finding on a
Petition To Remove the Bone Cave
Harvestman (Texella reyesi) From the
List of Endangered and Threatened
Wildlife
Fish and Wildlife Service,
Interior.
ACTION: Notice of 90-day petition
finding.
AGENCY:
We, the U.S. Fish and
Wildlife Service (Service), announce a
90-day finding on a petition to remove
the Bone Cave harvestman (Texella
reyesi) from the List of Endangered and
Threatened Wildlife under the
Endangered Species Act of 1973, as
amended (Act). Based on our review, we
find that the petition does not present
substantial scientific or commercial
information indicating that the
petitioned action may be warranted.
Therefore, we are not initiating a status
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SUMMARY:
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review in response to this petition.
However, we ask the public to submit to
us any new information that becomes
available concerning the status of, or
threats to, the Bone Cave harvestman or
its habitat at any time.
DATES: The finding announced in this
document was made on June 1, 2015.
ADDRESSES: Copies of the petition are
available in the docket associated with
this notice at https://
www.regulations.gov and at https://
fws.gov/southwest/es/austintexas/ or
upon request from the Field Supervisor
of the Austin Ecological Services Field
Office, 10711 Burnet Road, Suite 200,
Austin, TX 78758.
FOR FURTHER INFORMATION CONTACT:
Adam Zerrenner, Field Supervisor,
Austin Ecological Services Field Office,
10711 Burnet Road, Suite 200, Austin,
TX 78758; by telephone at 512–490–
0057; or by facsimile at 512–490–0974.
If you use a telecommunications device
for the deaf (TDD), please call the
Federal Information Relay Service
(FIRS) at 800–877–8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Act requires
that we make a finding on whether a
petition to list, delist, or reclassify a
species presents substantial scientific or
commercial information indicating that
the petitioned action may be warranted.
We are to base this finding on
information provided in the petition,
supporting information submitted with
the petition, and information otherwise
available in our files. To the maximum
extent practicable, we are to make this
finding within 90 days of our receipt of
the petition and publish our notice of
the finding promptly in the Federal
Register.
Our standard for substantial scientific
or commercial information within the
Code of Federal Regulations (CFR) with
regard to a 90-day petition finding is
‘‘that amount of information that would
lead a reasonable person to believe that
the measure proposed in the petition
may be warranted’’ (50 CFR
424.14(b)(1)). If we find that substantial
scientific or commercial information
was presented, we are required to
promptly conduct a species status
review, which we subsequently
summarize in a 12-month finding.
Petition History
On June 2, 2014, we received a
petition from John Yearwood, Kathryn
Heidemann, Charles and Cheryl Shell,
the Walter Sidney Shell Management
Trust, the American Stewards of
Liberty, and Steven W. Carothers
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requesting that we remove the
endangered Bone Cave harvestman from
the Federal lists of endangered and
threatened species. The petition clearly
identified itself as a petition and
included the requisite identification
information for the petitioners, as
required in 50 CFR 424.14(a). This
finding addresses the petition.
Previous Federal Actions
The Bone Cave harvestman was
originally listed as endangered on
September 16, 1988 (53 FR 36029). In an
August 18, 1993, Federal Register
document (58 FR 43818), the Service
gave the Bone Cave harvestman
protection under the Act as a separate
species. It had previously been listed as
endangered as a part of the Bee Creek
Cave harvestman (Texella reddelli),
which was subsequently re-classified
into two species, and this final rule set
forth technical corrections to ensure that
the species continued to receive
protection under the Act. On March 14,
1994, we published a 90-day finding (59
FR 11755) on a petition to delist the
Bone Cave harvestman in which we
found that the petition did not present
substantial scientific or commercial
information indicating that the
petitioned action may have been
warranted. A draft recovery plan was
available for public review and
comment on June 7, 1993, and a final
recovery plan was published on August
25, 1994 (Service 1994). On December 4,
2009, we completed a 5-year review of
the Bone Cave harvestman, which
recommended that the species remain
listed as endangered (Service 2009).
Species Information
For information on the biology and
life history of the Bone Cave
harvestman, see the final rule listing
this species (53 FR 36029), the
Endangered Karst Invertebrates
Recovery Plan for Travis and
Williamson Counties (Service 1994),
and the 5-year Status Review for the
Bone Cave Harvestman (Service 2009),
all posted at https://ecos.fws.gov/
speciesProfile/profile/
speciesProfile.action?spcode=J009. For
information on preserve design and
management for karst invertebrate
species conservation, see the Karst
Preserve Design Recommendations
(Service 2012) and the Karst Preserve
Management and Monitoring
Recommendations (Service 2014) posted
at https://www.fws.gov/southwest/es/
AustinTexas/ESA_Sp_KarstInverts.html.
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Evaluation of Information for This
Finding
Under section 3(16) of the Act, we
may consider for listing any species,
including subspecies, of fish, or
wildlife, or plants, and any distinct
population segment (DPS) of any
species of vertebrate fish or wildlife that
interbreeds when mature (16 U.S.C.
1532(16)). Such entities are listed under
the Act if we determine that they meet
the definition of an endangered or
threatened species.
Section 4 of the Act (16 U.S.C. 1533)
and its implementing regulations at 50
CFR 424 set forth the procedures for
adding a species to, or removing a
species from, the lists of endangered
and threatened species. A species may
be determined to be an endangered or
threatened species due to one or more
of the five factors described in section
4(a)(1) of the Act:
(A) The present or threatened
destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial,
recreational, scientific, or educational
purposes;
(C) Disease or predation;
(D) The inadequacy of existing
regulatory mechanisms; or
(E) Other natural or manmade factors
affecting its continued existence.
We must consider these same five
factors in delisting a species. We may
delist a species according to 50 CFR
424.11(d) if the best available scientific
and commercial data indicate that the
species is neither endangered nor
threatened for the following reasons:
(1) The species is extinct;
(2) the species is recovered; or
(3) the original data for classification
were in error. According to 50 CFR
424.11(d)(3), a species may be delisted
when subsequent investigations ‘‘show
that the best scientific and commercial
data available when the species was
listed, or the interpretation of such data,
were in error.’’
In making this 90-day finding, we
evaluated whether the petition
presented substantial information
indicating that the petitioned action
(delisting) may be warranted.
The petition did not assert that the
Bone Cave harvestman is extinct, nor do
we have information in our files
indicating that the species is extinct.
The petition asserted that new
information indicates that the original
data, or our interpretation of the data,
used in the listing of this species were
in error. The petition also states that
significant conservation has been put in
place since the species was listed, such
that the species is recovered.
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In 2009, we conducted a 5-year status
review of the Bone Cave harvestman
(Service 2009). The purpose of a 5-year
status review is to evaluate whether or
not the species’ status has changed since
it was listed (or since the most recent 5year review). Based on a 5-year review,
we recommend whether the species
should be removed from the lists of
endangered and threatened species, be
changed in status from endangered to
threatened, or be changed in status from
threatened to endangered. As part of the
2009 Bone Cave harvestman review, we
evaluated whether the species had met
the recovery criteria laid out in the
species’ recovery plan (Service 1994,
pp. 86–89).
Our recovery handbook (Service 2010)
points out that recovery criteria should
address the biodiversity principles of
resiliency, redundancy, and
representation (Schaffer and Stein
2000).
Resiliency is defined as the ability of
a species to persist through severe
hardships or stochastic events (Tear et
al. 2005, p. 841). A variety of factors
contribute to a species’ resiliency. These
can include how sensitive the species is
to disturbances or stressors in its
environment, how often they reproduce
and how many young they have, and
their specific habitat needs. A species’
resiliency can also be affected by the
resiliency of individual populations and
the number of populations and their
distribution across the landscape.
Protecting multiple populations and
variation of a species across its range
may contribute to its resiliency,
especially if some populations or
habitats are more susceptible or better
adapted to certain threats than others
(Service and NOAA 2011, p. 76994).
The ability of individuals from
populations to disperse and recolonize
an area that has been extirpated may
also influence the species’ resiliency. As
population size and habitat quality
increase, the population’s ability to
persist through periodic hardships also
increases. Healthy populations are more
resilient and better able to withstand
disturbances such as random
fluctuations in birth rates (demographic
stochasticity), and variation in rainfall
and/or temperatures (environmental
stochasticity).
Redundancy is defined as ensuring a
sufficient number of populations to
provide a margin of safety to reduce the
risk of losing a species or certain
representation (variation) within a
species due to catastrophic events or
other threats. Redundancy is essential
for long-term viability (Shaffer and Stein
2000, pp. 307, 309–310; Groves et al.
2002, p. 506). This provides a margin of
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safety for a species to withstand
catastrophic events (Service and NOAA
2011, p. 76994) by decreasing the
chance of any one event affecting the
entire species. Redundancy is about
spreading risk and can be measured
through the duplication and distribution
of resilient populations across the range
of the species.
Representation is defined as
conserving ‘‘some of everything’’ with
regard to genetic and ecological
diversity to allow for future adaptation
and maintenance of evolutionary
potential. Representation and the
adaptive capabilities (Service and
NOAA 2011, p. 76994) of the Bone Cave
harvestman are also important for longterm viability. Because a species’
genetic makeup is shaped through
natural selection by the environments it
has experienced (Shaffer and Stein
2000, p. 308), populations should be
protected in the array of different
environments in which the invertebrate
species occur as a strategy to ensure
genetic representation, adaptive
capability, and conservation of the
species. Generally, the more
representation, or diversity, the species
has, the more it is capable of adapting
to changes (natural or human caused) in
its environment.
The recovery plan for the Bone Cave
harvestman (Service 1994, pp. 86–88)
identifies criteria for reclassification
(from endangered to threatened), but
does not include delisting criteria
because we were uncertain about
prospects for recovery and delisting of
the species. These recovery criteria are
a way of measuring our progress toward
recovery. The recovery plan identifies
two criteria for reclassifying the species
from endangered to threatened:
(1) Three karst fauna areas (if at least
three exist) within each karst fauna
region in its range are protected in
perpetuity. If fewer than three karst
fauna areas exist within a given karst
fauna region, then all karst fauna areas
within that region should be protected.
(2) Criterion (1) has been maintained
for at least 5 consecutive years with
assurances that these areas will remain
protected in perpetuity.
There are six karst fauna regions in
Travis and Williamson Counties that are
known to contain the Bone Cave
harvestman (Service 1994, p. 33): North
Williamson, Georgetown, McNeil/
Round Rock, Cedar Park, Jollyville
Plateau, and Central Austin. These
regions are used as a way to facilitate
conservation of representation and
redundancy (as defined above)
throughout the species’ range.
For the purposes of the recovery plan,
a karst fauna area ‘‘is an area known to
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support one or more locations of a listed
species and is distinct in that it acts as
a system that is separated from other
karst fauna areas by geologic and
hydrologic features and/or processes
that create barriers to the movement of
water, contaminants, and troglobitic
fauna’’ that live their entire lives
underground (Service 1994, p. 76). Karst
fauna areas should be far enough apart
so that if a catastrophic event (for
example, contamination of the water
supply, flooding, disease) were to
destroy one of the areas, that event
would not likely destroy any other area
occupied by that species (Service 1994,
p. 76).
To be considered ‘‘protected,’’ a karst
fauna area must be sufficiently large to
maintain the integrity of the karst
ecosystem on which the species
depends (Service 1994, p. 87). In
addition, these areas must also provide
protection from threats such as red
imported fire ants, habitat destruction,
and contaminants.
The overall recovery strategy for the
Bone Cave harvestman includes the
perpetual protection and management of
an adequate quantity and quality of
habitat (three karst fauna areas in each
karst fauna regions) that spans the
species’ geographic range and provides
a high probability of the species’
recovery and survival over the long
term. Adequate quality (as discussed
below) and quantity of habitat refers to
both size and number of preserved karst
fauna areas that are sufficient for
supporting the karst invertebrates and
the ecosystems upon which they
depend (Service 2011, p. 16). The
recovery plan criteria call for three karst
fauna areas (preserves) in each karst
fauna region. The size of karst fauna
area preserves should be large enough to
ensure resiliency as discussed above
and to protect the environmental
integrity of the karst ecosystems upon
which the species depends. The number
of karst fauna area preserves called for
in the recovery criteria provides
redundancy for the species. A minimal
level of redundancy is essential to
provide a margin of safety for the
species to reduce the risk of losing the
species or representation (variation)
within the species from catastrophic
events or other threats (Shaffer and
Stein 2000 pp. 307, 309–310, Groves et
al. 2002, p. 506). The Bone Cave
harvestman has significant geographic
variability across its range, and loss of
a significant number of locations in part
of its range could result in loss of
genetic and ecological diversity. The
conservation of multiple karst fauna
area preserves across the Bone Cave
harvestman’s range should provide
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representation of the breadth of its
genetic and ecological diversity to
conserve its adaptive capabilities
(Schaffer and Stein 2000, p. 308).
Adequate quality of habitat refers to
(1) the condition and configuration of
preserved lands with respect to the
known localities for the species and (2)
the ability of the species’ needs to be
met to sustain viable populations. Due
to the uncertainty in determining
population viability of the Bone Cave
harvestman, the design of preserves for
its protection should be based on
estimates and assumptions that favor a
high probability for recovery of this
species and the ecosystems upon which
it depends as discussed below.
The Endangered Karst Invertebrates
Recovery Plan for Travis and
Williamson Counties (Service 1994)
calls for protecting karst fauna areas
sufficiently large to maintain the
integrity of the karst ecosystem on
which the species depends. This focus
on the ecosystem is consistent with the
purpose of the Act, which includes ‘‘to
provide a means whereby the ecosystem
upon which endangered species and
threatened species depend may be
conserved.’’ Therefore, we recommend
designing karst fauna area preserves to
protect occupied karst feature(s) and
associated mesocaverns (humanly
impassable voids). For further guidance
on how to provide for adequate quantity
and quality of habitat at specific
invertebrate locations, we have
developed and refer to our Karst
Preserve Design Recommendations
(Service 2012).
According to our preserve design
guidelines (Service 2012, p. 3–5), karst
fauna area preserves should include the
following: (1) Surface and subsurface
drainage basins of at least one occupied
cave or karst feature; (2) a minimum of
16 to 40 hectares (ha) (40 to 100 acres
(ac)) of contiguous, unfragmented,
undisturbed land to maintain native
plant and animal communities around
the feature and protect the subsurface
karst community; (3) 105-meter (m)
(345-feet (ft)) radius undisturbed area
from each cave footprint for cave cricket
foraging (cave crickets are an important
source of nutrient input to the karst
ecosystem) and to minimize deleterious
edge effects; and (4) preserves should be
free of pipelines, storage tanks, or other
facilities (for example, water retention
ponds) that could cause contamination.
In addition, due to the uncertainty in
determining population viability and
habitat requirements of the Bone Cave
harvestman, the design of preserves for
its protection should be based on
estimates and assumptions that favor a
high probability for recovery of the
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species and the ecosystems upon which
it depends. This method follows a
precautionary approach, which provides
guidance to avert irreversible risk when
facing uncertainty (Service 2012,
p. A–1). The best available scientific
information indicates that this species
cannot be reintroduced into existing
habitat. Life-history characteristics of
this species indicate that it requires
stable temperature and humidity (Barr
1968, p. 47, Mitchell 1971, p. 250) and
suggest that this species cannot be
reintroduced because it cannot
withstand surface climatic conditions.
According to anecdotal reports
provided to our field office, limited
efforts to maintain karst invertebrates in
a lab setting have been unsuccessful.
Additionally, captive propagation
techniques have not been developed for
karst invertebrates and may be
challenging to develop because of their
specific adaptations to subterranean
environment. Further, the sample size
that would likely be needed to
reintroduce a population into a new
location cannot be obtained from
existing populations due to the cryptic
nature of this species and the fact that
often only a few individuals are
observed per cave survey. Therefore, an
attempt to re-establish a population after
it has been extirpated is not feasible at
this time. In addition, if a preserve is
later found to be insufficient to support
the species due to surrounding
developments being either too close or
too dense, the potential for adequately
conserving the site is lost.
Because the Bone Cave harvestman
has a relatively long life span and low
requirements for food, a decline in
population size or even the complete
extirpation of the population due to the
influence of development or other
threats may take years or even decades.
Observations of this species over several
years on a preserve that is too small for
perpetual species preservation may not
allow detection of declines that are
actually occurring. If these observations
are used as evidence that a preserve size
was adequate, then the potential for
long-term preservation of the species
may be lost due to irreversible
development surrounding the preserve.
Therefore, preserve sizes should be
established with caution and be large
enough to account for the uncertainty in
area requirements for a population.
According to the petition there are
now more known occupied locations
identified; there were 6 confirmed caves
at listing, 60 confirmed caves at the time
the recovery plan was drafted, and 168
confirmed caves in 2009 when the 5year status review was completed (53
FR 36029, Service 1994, 2009). The
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petition also states that more locations
are likely to be found. We acknowledge
there are more known locations since
the time those documents were
completed and the increase is likely an
increase in our knowledge, not a true
increase in the number of populations
or range; however, species are listed
under the Act based on threats and not
just the number of sites or size of the
range.
In addition, the petition states that 94
karst preserve areas are currently
providing significant conservation.
However, many of the existing protected
areas referenced in the petition are too
small to meet our preserve design
recommendations. As part of the 2009
5-year status review of the Bone Cave
harvestman, we reviewed the status of
all of the known locations of the
harvestman (including 83 of the 94
mentioned in the petition) to assess
whether the criteria from the recovery
plan to reclassify the species from
endangered to threatened had been met
for the Bone Cave harvestman. We
considered the habitat size and
condition to evaluate whether the
locations could meet the preserve
design recommendations (a reflection of
the potential to support a resilient
population) and then also looked at
whether legally binding mechanisms
were in place to provide protection of
these sites over the long term (in
perpetuity).
Of the locations known at the time of
the 5-year review, 21 areas appeared to
have the ability to meet the preserve
design criteria. Our status review refers
to 21 areas, while the petition indicates
that the status review considered 28
sites. This discrepancy is because the
petition considers each individual cave
location, while our status review
considered closely located caves to be
part of the same karst fauna area. Of
these 21 areas, 1 is no longer confirmed
to have the species (Barker Ranch Cave
No. 1), and 5 are now protected karst
fauna areas (Priscilla’s Well, Twin
Springs, Cobbs Cavern, Karankawa, and
Tooth Cave).
In addition, at most of the remaining
locations (of the 21 areas) we are lacking
information to confirm that they meet
the preserve design criteria (such as
surface and subsurface drainage basins,
tract acreage, exact locations of the cave,
and management activities to protect
against threats, such as red imported fire
ants). Also, many of these areas do not
have a legally binding mechanism that
ensures perpetual protection and
management. Hence, we are unsure
whether those areas have adequate
undeveloped acreage, management, or
protection mechanisms to ensure the
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long-term protection and survival of the
Bone Cave harvestman.
Of the five protected karst fauna areas
that meet preserve design criteria, four
occur in the North Williamson County
Karst Fauna Region and one occurs in
the Jollyville Plateau Karst Fauna
Region. However, this species occurs in
six karst fauna regions, and four of these
have no protected karst fauna areas that
are confirmed to meet preserve design
recommendations. Therefore, the best
available information indicates that the
criteria for reclassification from
endangered to threatened for this
species have not been met, nor has
adequate representation and
redundancy (three karst fauna areas in
each karst fauna region) been protected
throughout the species’ range, leaving
the species vulnerable to existing threats
including habitat destruction.
The petition asserts that four
additional locations are known since the
time of the 5-year review. However, the
petition does not provide adequate
information that would support whether
these four additional locations are in a
condition to meet preserve design
recommendations. Based on information
in our files, we are aware of one
additional cave since the 5-year review
that may meet preserve design
recommendations in the North
Williamson Karst Fauna Region;
however, it is privately owned, and we
are unsure about the property acreage
and if the site receives any type of
protection or management. Regardless,
the amount of protected karst fauna area
still falls short of the criteria for
reclassification from endangered to
threatened.
Further, we reviewed 83 of the 94
caves identified in the petition as
receiving some level of protection in the
5-year review. Two of the caves that we
did not review (Cobbs Cavern and
Whitney West Cave) are now in
confirmed karst fauna areas mentioned
above (Cobbs Cavern and Twin Springs),
one (Pond Party Pit) is in the Beard
Ranch Cave area discussed in the 5-year
review, and we have no locality
information or taxonomic verifications
for the remaining caves and this
information was not provided in the
petition.
The petition also asserts that threats
to the species are not as severe as
originally thought. We evaluate that
information, below, in respect to the
five listing factors.
Factor A: The present or threatened
destruction, modification, or
curtailment of the species’ habitat or
range. In the 1988 listing rule (53 FR
36029), we stated that the primary threat
to the Bone Cave harvestman was the
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potential loss of habitat due to
development activities, which could
result in filling in or collapsing of caves;
alteration of drainage patterns; increase
in flow of sediment, pesticides,
fertilizers, and urban run-off into caves;
and increase in human visitation and
vandalism.
We also considered additional
information on threats to the species
when we developed the recovery plan
for the species (Service 1994, pp. 59–65)
and when we conducted the 5-year
status review of the species (Service
2009, p. 2), in which we concluded that
no change in the species’ status (that is,
reclassification to threatened or
delisting) was warranted. We also
reviewed available threat information in
our files and in a 1993 petition when we
made our negative 90-day finding on
that petition to de-list (59 FR 11755).
The current petition asserts that
‘‘Development activities on the surface
may not result in the significant loss or
degradation of habitat for T. reyesi as
originally thought’’ and suggests that
evidence of this is the species
persistence in caves surrounded by
developed areas. Examples given in the
petition are Inner Space Caverns, Sun
City caves, Weldon Cave, Three-Mile
Cave, and Four-Mile Cave. However, the
observation of the species in these
locations does not mean their
populations at these locations are
thriving or can withstand the long-term
impacts from development activities
that are expected to occur to karst
invertebrate populations in developed
areas as discussed in the listing rule,
recovery plan, and 5-year status review
for the Bone Cave harvestman.
Bone Cave harvestman populations
may be declining or threatened even
though they are still observed at a
specific site. Information adequate to
detect population trends for this species
is not readily available and was not
provided in the petition. This species
has life-history strategies that include
characteristics such as low metabolic
and reproductive rates, long life spans,
and inherently low sample sizes, which
make it difficult to detect population
response to possible impacts (Poulson
and White 1969, p. 977, Howarth 1983,
p. 374). We indicated in the 1994 90-day
petition finding (59 FR 11755) that more
time was needed to detect if the species
was declining; however, while more
time has passed, we are still lacking
adequate data to conduct a trend
analysis at most locations, given that it
can take decades to detect population
trends due to small sample sizes, the
difficulty surveying for the species, and
their long life spans.
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In addition, some of the threats from
development are due to the increased
probability of chance events occurring
in the future, such as a contaminant
event like a pipeline leak, which exists
because more contamination sources are
in the vicinity of species’ locations due
to development.
The petition states that several Sun
City caves are examples of areas where
the species can persist in developed
areas. However, the petition failed to
provide data adequate to assess trends
in the karst invertebrate populations
since the development occurred. In
addition, we worked with the Sun City
developers when they designed the
project to develop strategies that we
believed at the time would avoid or
minimize the possibility of ‘‘take’’ to
listed karst species. While we now
believe that most of the Sun City cave
preserves are too small to meet our
preserve design recommendations for
recovery and long-term survival (Service
2012), we expect that the strategies and
measures put in place likely have
reduced the rate of impacts to the
species.
The commercial cave known as Inner
Space Caverns is another example the
petition provided where the Bone Cave
harvestman continues to persist in a
developed area. Although the Bone Cave
harvestman may be present at Inner
Space Caverns, this does not ensure
their populations are robust and secure;
they may still be declining, and are at
risk due to competition with surfacedwelling invertebrates and other threats
associated with development such as
the potential for contamination. This
cave has an overgrowth of blue-green
algae growing near cave lights where the
petition states that this species has been
observed. This type of algae is known as
‘‘lampenflora’’ and favors surfacedwelling invertebrate species that can
out-compete karst invertebrate species
(Mulec and Kosi 2009, p. 109, Culver
1986, p. 438), such as the Bone Cave
harvestman. The petition failed to
provide any data adequate to assess
trends in the karst invertebrate
population in relation to the time
(duration and frequency) that they have
been exposed to the artificial lighting.
Additionally, part of the cave footprint
occurs under a major interstate highway
and train tracks, which both present a
threat of a contaminant spill that could
impact the species in the future.
Weldon Cave was another example in
the petition of a cave occupied by the
Bone Cave harvestman within a
developed area. Based on the best
available information in our files this
cave is surrounded by undeveloped
open space. Other than a small portion
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of the subsurface drainage basin
potentially being impacted by a school
campus, this cave appears to meet our
preserve design recommendations but is
not within a developed area, as asserted
in the petition. Three-Mile Cave and
Four-Mile Cave were also provided in
the petition as examples of developed
caves wherein the Bone Cave
harvestman is known to occur.
According to the petition, surveys
conducted by SWCA in 2008 and 2009
documented the Bone Cave harvestman
at these locations. However, detailed
survey data were not provided by the
petitioners and were not in the SWCA
2009 ‘‘Annual Report of Activities
Involving Endangered Karst
Invertebrates under Threatened and
Endangered Species Permit TE800611–
2.’’
The petition also states that, since the
Bone Cave harvestman uses
mesocaverns, it is protected from
surface development activities because
mesocaverns are ‘‘geologically
protected.’’ We are unclear why the
petition contends that mesocaverns are
protected because mesocaverns are
subject to rapid permeation of surface
water (Cowan et al. 2007, p. 160), and
karst landscapes (including
mesocaverns) are particularly
susceptible to groundwater
contamination because water penetrates
rapidly through bedrock conduits
providing little or no filtration (White
1988, p. 149).
One of the major threats to the Bone
Cave harvestman is habitat loss due to
increasing urbanization. The Bone Cave
harvestman is a troglobite, meaning it
lives its entire life underground. Karst
ecosystems are heavily reliant on
surface plant and animal communities
for nutrient input.
Caves in central Texas that are
occupied by federally listed karst
invertebrates, such as the Bone Cave
harvestman, receive energy (or
nutrients) primarily from (1) detritus
(decomposing organic matter) that falls
or is washed into the caves and (2)
energy brought into the caves by cave
crickets (Ceuthophilus spp.) (Barr 1968,
p. 48; Reddell 1993, p. 2; Lavoie et al.
2007, p. 114; Taylor 2003, p. 3, 2004, p.
2, 2005, p. 97), which are found in most
Texas caves (Reddell 1966, p. 33). Cave
crickets forage widely in the surface
habitat surrounding the cave. Karst
invertebrates feed on the cave cricket
eggs (Mitchell 1971, p. 251), feces (Barr
1968, pp. 51–53, Poulson et al. 1995, p.
226), and directly on the crickets
themselves (Elliott 1994, p. 15).
Development within urbanized areas
can destroy or alter the surface plant
and animal communities on which karst
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invertebrates depend. As development
increases within the cave crickets’
foraging area, there may be dramatic
shifts in the available food supply
within the cave (Taylor et al. 2007, p.
7). The leaf litter and other
decomposing material that make up
most of the detritus from the surface
plant and animal community may also
be reduced or altered, resulting in a
reduction of nutrient and energy flow
into the cave. A study by Taylor et al.
(2007) compared caves in urbanized
areas that were impacted by
development to those in natural areas
and found that, even though a small
area within a largely urbanized
ecosystem may support a cave
community where karst invertebrates
are occasionally seen, these populations
are significantly lower than those found
in caves in more natural, less developed
ecosystems, most likely as a result of
reduced nutrient input. Another study
at Lakeline Cave in Travis County,
Texas, was conducted in association
with the issuance of a habitat
conservation plan and accompanying
section 10(a)(1)(B) permit issued for
Lakeline Mall. That study is based on
data collected from 1992 through 2011,
and it documented a significant decline
during that 20-year timeframe in
another endangered karst invertebrate,
Rhadine persephone, and cave crickets
as development increased (ZARA 2012,
pp. 8, 10, 12). Further, at Lakeline Mall
Cave, no more than three Bone Cave
harvestmen have been observed during
any single survey (ZARA 2012, p. 11).
Also, no Bone Cave harvestmen were
seen during 6 years (1993, 1999, 2001,
2006, 2009, and 2010) and 12 surveys in
Lakeline Mall Cave (ZARA 2012, p. 11).
Available information in our files
supports our projection in the 1988
listing rule that development and
human population would continue to
increase within the range of the species.
The population of the City of Austin
grew from 251,808 people in 1970 to
735,088 people in 2007 (City of Austin
2007). This represents a 192-percent
increase over the 37-year period.
Population projections from the Texas
State Data Center (2012, pp. 496–497),
estimate that Travis County will
increase 94 percent in population from
1,024,266 in 2010, to 1,990,820 in 2050.
The Texas State Data Center also
estimates an increase in human
population in Williamson County from
422,679 in 2010, to 2,015,294 in 2050
representing a 377-percent increase over
a 40-year timeframe. All human
population projections from the Texas
State Data Center presented here are
under a high-growth scenario, which
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assumes that migration rates from 2000
to 2010 will continue through 2050
(Texas State Data Center and the Office
of the State Demographer 2012, p. 9).
Urbanization and human population
growth and development were
identified as a threat in the original
1988 listing rule and continue to
represent a threat to the species.
Factor B: Overutilization for
commercial, recreational, scientific, or
educational purposes. In the 1988
listing rule for the Bone Cave
harvestman, we did not identify any
threats under this factor. Likewise, the
petition and our review of the
information in our files did not identify
any threats under this factor.
Factor C: Disease or predation. In the
1988 listing rule, we stated that
increased human population increases
the threat of predation by and
competition with exotic (non-native)
and native surface-dwelling species,
such as sow bugs, cockroaches, and red
imported fire ants. The petition states
that ‘‘Recent studies suggest that fire
ants may not present as significant or as
lasting of a threat to the species as
originally believed.’’ The information
cited regarding red imported fire ants is
identified in the petition as an article by
Porter and Savignano (1990), which we
previously considered in our finding on
the 1993 petition, and another study by
Morrison (2002). The petition states that
‘‘a subsequent study by Morrison in
2002 revisited the Porter and Savignano
(1990) study area 12 years later and
replicated their study.
Morrison (2002, pp. 2341, 2343–2344)
found that arthropod communities had
rebounded to pre-RIFA [red imported
fire ant]-invasion levels and that all
measures of native ant and other
arthropod species’ diversity had
returned to pre-invasion levels. Red
imported fire ants were still the most
abundant ant species, but not nearly as
abundant as during the initial red
imported fire ants infestation. He
concluded that the impacts to arthropod
communities by red imported fire ants
might be greatest during and shortly
after the initial invasion, but long-term
impacts are likely not as significant as
once believed. However, we note that
Morrison (2002, p. 2342) also states that
‘‘it is quite likely that red imported fire
ants did contribute directly or indirectly
to the disappearance or reduction in
numbers of species’’ and that their study
‘‘should not be interpreted as an
indication that detrimental effects of
invasive ants will simply disappear
with time.’’ In addition, this is not ‘‘new
information’’ as we have already
reviewed these articles and considered
the information they provided in the
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Bexar County Karst Invertebrates
Recovery Plan (Service 2011, p. 12) and
in our Karst Preserve Management and
Monitoring Recommendations (Service
2014, p. 3), which is applicable here as
all central Texas endangered karst
invertebrates have similar life-history
characteristics, and one of the Bexar
County invertebrates is in the same
genus (Texella) as the Bone Cave
harvestman. In addition, red imported
fire ants have been found within and
near many caves in central Texas and
have been observed feeding on dead
troglobites, cave crickets, and other
species within caves (Elliott 1992, p. 13,
1994, p. 15, 2000, pp. 668, 768; Reddell
1993, p. 10; Taylor et al. 2003, p. 3).
Factor D: The inadequacy of existing
regulatory mechanisms. The 1988
listing rule states that ‘‘there are
currently no laws that protect any of
these species or that indirectly address
protection of their habitat.’’
While the petition did discuss some
new ordinances that appear to have
been put in place since the time of
listing, we do not have enough
information to indicate whether or not
these State and local ordinances provide
enough protection from all threats to the
Bone Cave harvestman.
The petition states that ‘‘the
regulatory landscape includes a number
of measures contributing to the
conservation of the species outside of
the protections afforded by the
Endangered Species Act of 1973, as
amended.’’ For example, they say that
protections offered though the City of
Austin are adequate to protect the
species in Austin, Texas. In the course
of our work, we have reviewed these
regulations and understand that most
caves that are defined by the City of
Austin’s Environmental Criteria Manual
as a cave are provided a 46- to 91-m
(150- to 300-ft) set-back area (City of
Austin 2014, p. 13–3). However, a 46-m
(150-ft) or 91-m (300-ft) set-back is not
adequate to meet our preserve design
criteria, does not protect the cave cricket
foraging area, and potentially does not
include the surface and subsurface
drainage basins. Further, it is not
applicable across the range of the Bone
Cave harvestman because the species
occurs in Travis and Williamson
Counties and the City of Austin does not
cover all of those counties.
The petition states that the City of
Georgetown Water Quality Management
Plan for the Georgetown salamander
will offer protection to the Bone Cave
harvestman. They state that this plan
encourages the use of best management
practices to protect water quality at
Georgetown salamander locations.
However, there are few Bone Cave
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30995
harvestman locations that occur near
Georgetown salamander locations, so
any protection offered to the harvestman
would be limited. Further, it is not clear
from the petition whether this
mechanism is voluntary or if it is
regulatory or if it is currently in effect.
In addition, the petition did not provide
enough detail for us to evaluate all
benefits this plan would provide to the
Bone Cave harvestman, and it appears
that participation in this plan is at least
in part voluntary.
The petition states that the Texas
Commission on Environmental Quality
(TCEQ) Edwards Rules provide
protection to recharge features on the
Edwards Plateau and that this provides
protection from pollution to the Bone
Cave harvestman. In a discussion of
Factor D in the Bexar County Karst
Invertebrates Recovery Plan (Service
2011, p. 13), we state that ‘‘the TCEQ
water quality regulations do not provide
much protection to the species’ habitat
(see 65 FR 81419–81433 for more
information). For example, while some
TCEQ practices provide protection from
water quality impacts, others, such as
sealing cave entrances for water quality
reasons, can harm karst invertebrates.’’
Sealing cave entrances can be harmful
by blocking off water (leading to drying)
and nutrient input to the karst
invertebrate habitat. In addition, not all
of the caves and mesocaverns that the
Bone Cave harvestman occurs in are
considered recharge features and,
therefore, would not receive some of the
water quality protection measures. Also,
not all locations of the Bone Cave
harvestman are under the jurisdiction of
the Edwards Rules.
Factor E: Other natural or manmade
factors affecting the continued existence
of the species. In the 1988 listing rule,
we stated that this species is extremely
vulnerable to losses because of its
severely limited range and because of its
naturally limited ability to colonize new
habitats. We also stated that the very
small size of the species habitat units
and the fragile nature of cave
ecosystems make them vulnerable to
even isolated acts of vandalism. The
petition states, ‘‘Inner Space Cavern
demonstrates that the species can
persist in caves with frequent human
visitation and may be more tolerant of
related habitat modification than
originally believed.’’ They also provide
Three-Mile Cave and Four-Mile Cave as
examples of caves that have experienced
human use yet the species persists. The
petition contends that, since the Bone
Cave harvestman exists in Inner Space
Caverns, human visitation is not a
threat. The petition also states that
Three-mile and Four-mile Cave had
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graffiti from the 1890s, 1920s, and
1950s. Yet, no detailed information was
provided to demonstrate if these caves
experienced continued human use. The
petition also indicates that Four-Mile
Cave was inaccessible to humans prior
to 2009 due to boulders blocking the
entrance. In addition, the petition
provided no trend analysis for these
caves. As stated earlier, the observation
of the species in these locations does
not mean the populations at these
locations have not been impacted (in a
way that is short of extirpation) or can
withstand the long-term impacts that are
expected to occur to karst invertebrate
populations in developed areas or from
human visitation.
In the species 5-year status review
(Service 2009, p. 18) we said, ‘‘Although
climate change was not identified as a
threat to T. reyesi in the original listing
document or in the recovery plan, the
species’ dependence on stable
temperatures and humidity levels opens
the possibility of climatic change
impacting this species. Therefore, while
it appears reasonable to assume that T.
reyesi may be affected, we lack
sufficient certainty to know how climate
change will affect this species.’’
The petitioners state that ‘‘the use of
small voids or ‘mesocaverns’ within the
geologic formations known to support
occupied caves mitigates the potential
threat of climate change.’’ We
acknowledge that mesocaverns may
provide some protection from
fluctuations in temperature and
humidity that may be induced by
climate change. However, the presence
of mesocaverns alone will likely not be
sufficient to ameliorate all of the effects
that climate change may pose to this
species. Karst invertebrates depend on
stable temperatures and high humidity
(Barr 1968, p. 47, Mitchell 1971, p. 250).
The temperatures in caves are typically
the average annual temperature of the
surface habitat and vary much less than
the surface environment (Howarth 1983,
p. 372, Dunlap 1995, p. 76). If average
surface temperatures increase, this
could result in increased in-cave
temperatures, which could affect the
Bone Cave harvestman.
Increased and/or more severe storms
as well as prolonged periods of high
temperatures and drought between
rainfall events associated with predicted
climate change effects may also impact
the cave environment. Changes in
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rainfall regimes may affect the
harvestman in several ways, including
directly either through flooding or
indirectly by modifying their habitat or
nutrient availability. Changes in rainfall
regimes could (1) alter the moisture
levels within the caves leaving them
drier between floods, which could lead
to desiccation of the Bone Cave
harvestman and (2) affect the amount
and timing of nutrients washed into a
cave, potentially resulting in longer
periods between nutrient input. These
changes to drier and less suitable
conditions in the caves will likely cause
the Bone Cave harvestman to retreat
farther into mesocaverns and away from
nutrients that are thought to be located
in larger cave passages (Howarth 1987,
pp. 5–7), causing individuals to spend
more energy trying to acquire nutrients
in an already stressed environment. In
addition, caves in arid regions have
been shown to have smaller invertebrate
populations and diversity due to less
moisture and nutrient availability
(George Veni, National Cave and Karst
Research Institute, pers. comm. 2010).
Since the Bone Cave harvestman is also
sensitive to these habitat parameters, it
is reasonable to predict that climate
change could affect its populations in a
similar manner despite the presence of
mesocaverns.
Further, stochastic (random) events
from either environmental factors (for
example, severe weather) or
demographic factors (which come from
the chance events of birth and death of
individuals) exacerbate threats to the
species because of its small population
size (Melbourne and Hastings 2008, p.
100). The risk of extinction for any
species is known to be highly inversely
correlated with population size (Pimm
et al. 1988, pp. 774–775, O’Grady et al.
2004, pp. 516, 518). In other words, the
smaller the population the greater the
overall risk of extinction. Therefore,
threats to the Bone Cave harvestman are
exacerbated by its small population size,
which makes it more vulnerable to
existing threats.
Finding
We have reviewed the petition and
also evaluated readily available, related
information in our files. The petitioners
have based their assessment that the
species can thrive in developed areas on
information that we have already
reviewed (except in 4 caves discovered
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since the 5-year status review and 7 for
which we lack locality information or
taxonomic verifications) while working
on previous documents (Service 2009,
2012) or on observations that lack a
large enough sample size to produce
population trend information for the
Bone Cave harvestman. The petition
provided no trend analysis to indicate
that this species can withstand the
threats associated with development or
climate change over the long term.
Based on our review and evaluation, we
find that the petition does not present
substantial scientific or commercial
information indicating that delisting of
the Bone Cave harvestman may be
warranted due to recovery, extinction,
or error in the original scientific data at
the time the species was classified or in
our interpretation of the data. However,
much progress has been made toward
recovery in the North Williamson and
Jollyville Plateau Karst Fauna Regions.
We encourage interested parties to
continue to gather data and implement
conservation actions across the range of
the Bone Cave harvestman that will
further assist with the conservation of
this species. If you wish to provide
information regarding the Bone Cave
harvestman, you may submit your
information or materials to the Field
Supervisor, Austin Ecological Services
Field Office (see ADDRESSES) at any
time.
References Cited
A complete list of references cited is
available on the Internet at https://
www.regulations.gov and upon request
from the Austin Ecological Services
Field Office (see FOR FURTHER
INFORMATION CONTACT).
Authors
The primary authors of this notice are
staff members of the Austin Ecological
Services Office.
Authority
The authority for this action is the
Endangered Species Act of 1973, as
amended (16 U.S.C. 1531 et seq.).
Dated: May 21, 2015.
Gary Frazer,
Acting Director, U.S. Fish and Wildlife
Service.
[FR Doc. 2015–13136 Filed 5–29–15; 8:45 am]
BILLING CODE 4310–55–P
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[Federal Register Volume 80, Number 104 (Monday, June 1, 2015)]
[Proposed Rules]
[Pages 30990-30996]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-13136]
=======================================================================
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2015-0030; FF09E42000 156 FXES11130900000]
Endangered and Threatened Wildlife and Plants; 90-Day Finding on
a Petition To Remove the Bone Cave Harvestman (Texella reyesi) From the
List of Endangered and Threatened Wildlife
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 90-day petition finding.
-----------------------------------------------------------------------
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
90-day finding on a petition to remove the Bone Cave harvestman
(Texella reyesi) from the List of Endangered and Threatened Wildlife
under the Endangered Species Act of 1973, as amended (Act). Based on
our review, we find that the petition does not present substantial
scientific or commercial information indicating that the petitioned
action may be warranted. Therefore, we are not initiating a status
review in response to this petition. However, we ask the public to
submit to us any new information that becomes available concerning the
status of, or threats to, the Bone Cave harvestman or its habitat at
any time.
DATES: The finding announced in this document was made on June 1, 2015.
ADDRESSES: Copies of the petition are available in the docket
associated with this notice at https://www.regulations.gov and at https://fws.gov/southwest/es/austintexas/ or upon request from the Field
Supervisor of the Austin Ecological Services Field Office, 10711 Burnet
Road, Suite 200, Austin, TX 78758.
FOR FURTHER INFORMATION CONTACT: Adam Zerrenner, Field Supervisor,
Austin Ecological Services Field Office, 10711 Burnet Road, Suite 200,
Austin, TX 78758; by telephone at 512-490-0057; or by facsimile at 512-
490-0974. If you use a telecommunications device for the deaf (TDD),
please call the Federal Information Relay Service (FIRS) at 800-877-
8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Act requires that we make a finding on
whether a petition to list, delist, or reclassify a species presents
substantial scientific or commercial information indicating that the
petitioned action may be warranted. We are to base this finding on
information provided in the petition, supporting information submitted
with the petition, and information otherwise available in our files. To
the maximum extent practicable, we are to make this finding within 90
days of our receipt of the petition and publish our notice of the
finding promptly in the Federal Register.
Our standard for substantial scientific or commercial information
within the Code of Federal Regulations (CFR) with regard to a 90-day
petition finding is ``that amount of information that would lead a
reasonable person to believe that the measure proposed in the petition
may be warranted'' (50 CFR 424.14(b)(1)). If we find that substantial
scientific or commercial information was presented, we are required to
promptly conduct a species status review, which we subsequently
summarize in a 12-month finding.
Petition History
On June 2, 2014, we received a petition from John Yearwood, Kathryn
Heidemann, Charles and Cheryl Shell, the Walter Sidney Shell Management
Trust, the American Stewards of Liberty, and Steven W. Carothers
requesting that we remove the endangered Bone Cave harvestman from the
Federal lists of endangered and threatened species. The petition
clearly identified itself as a petition and included the requisite
identification information for the petitioners, as required in 50 CFR
424.14(a). This finding addresses the petition.
Previous Federal Actions
The Bone Cave harvestman was originally listed as endangered on
September 16, 1988 (53 FR 36029). In an August 18, 1993, Federal
Register document (58 FR 43818), the Service gave the Bone Cave
harvestman protection under the Act as a separate species. It had
previously been listed as endangered as a part of the Bee Creek Cave
harvestman (Texella reddelli), which was subsequently re-classified
into two species, and this final rule set forth technical corrections
to ensure that the species continued to receive protection under the
Act. On March 14, 1994, we published a 90-day finding (59 FR 11755) on
a petition to delist the Bone Cave harvestman in which we found that
the petition did not present substantial scientific or commercial
information indicating that the petitioned action may have been
warranted. A draft recovery plan was available for public review and
comment on June 7, 1993, and a final recovery plan was published on
August 25, 1994 (Service 1994). On December 4, 2009, we completed a 5-
year review of the Bone Cave harvestman, which recommended that the
species remain listed as endangered (Service 2009).
Species Information
For information on the biology and life history of the Bone Cave
harvestman, see the final rule listing this species (53 FR 36029), the
Endangered Karst Invertebrates Recovery Plan for Travis and Williamson
Counties (Service 1994), and the 5-year Status Review for the Bone Cave
Harvestman (Service 2009), all posted at https://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=J009. For
information on preserve design and management for karst invertebrate
species conservation, see the Karst Preserve Design Recommendations
(Service 2012) and the Karst Preserve Management and Monitoring
Recommendations (Service 2014) posted at https://www.fws.gov/southwest/es/AustinTexas/ESA_Sp_KarstInverts.html.
[[Page 30991]]
Evaluation of Information for This Finding
Under section 3(16) of the Act, we may consider for listing any
species, including subspecies, of fish, or wildlife, or plants, and any
distinct population segment (DPS) of any species of vertebrate fish or
wildlife that interbreeds when mature (16 U.S.C. 1532(16)). Such
entities are listed under the Act if we determine that they meet the
definition of an endangered or threatened species.
Section 4 of the Act (16 U.S.C. 1533) and its implementing
regulations at 50 CFR 424 set forth the procedures for adding a species
to, or removing a species from, the lists of endangered and threatened
species. A species may be determined to be an endangered or threatened
species due to one or more of the five factors described in section
4(a)(1) of the Act:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
existence.
We must consider these same five factors in delisting a species. We
may delist a species according to 50 CFR 424.11(d) if the best
available scientific and commercial data indicate that the species is
neither endangered nor threatened for the following reasons:
(1) The species is extinct;
(2) the species is recovered; or
(3) the original data for classification were in error. According
to 50 CFR 424.11(d)(3), a species may be delisted when subsequent
investigations ``show that the best scientific and commercial data
available when the species was listed, or the interpretation of such
data, were in error.''
In making this 90-day finding, we evaluated whether the petition
presented substantial information indicating that the petitioned action
(delisting) may be warranted.
The petition did not assert that the Bone Cave harvestman is
extinct, nor do we have information in our files indicating that the
species is extinct.
The petition asserted that new information indicates that the
original data, or our interpretation of the data, used in the listing
of this species were in error. The petition also states that
significant conservation has been put in place since the species was
listed, such that the species is recovered.
In 2009, we conducted a 5-year status review of the Bone Cave
harvestman (Service 2009). The purpose of a 5-year status review is to
evaluate whether or not the species' status has changed since it was
listed (or since the most recent 5-year review). Based on a 5-year
review, we recommend whether the species should be removed from the
lists of endangered and threatened species, be changed in status from
endangered to threatened, or be changed in status from threatened to
endangered. As part of the 2009 Bone Cave harvestman review, we
evaluated whether the species had met the recovery criteria laid out in
the species' recovery plan (Service 1994, pp. 86-89).
Our recovery handbook (Service 2010) points out that recovery
criteria should address the biodiversity principles of resiliency,
redundancy, and representation (Schaffer and Stein 2000).
Resiliency is defined as the ability of a species to persist
through severe hardships or stochastic events (Tear et al. 2005, p.
841). A variety of factors contribute to a species' resiliency. These
can include how sensitive the species is to disturbances or stressors
in its environment, how often they reproduce and how many young they
have, and their specific habitat needs. A species' resiliency can also
be affected by the resiliency of individual populations and the number
of populations and their distribution across the landscape. Protecting
multiple populations and variation of a species across its range may
contribute to its resiliency, especially if some populations or
habitats are more susceptible or better adapted to certain threats than
others (Service and NOAA 2011, p. 76994). The ability of individuals
from populations to disperse and recolonize an area that has been
extirpated may also influence the species' resiliency. As population
size and habitat quality increase, the population's ability to persist
through periodic hardships also increases. Healthy populations are more
resilient and better able to withstand disturbances such as random
fluctuations in birth rates (demographic stochasticity), and variation
in rainfall and/or temperatures (environmental stochasticity).
Redundancy is defined as ensuring a sufficient number of
populations to provide a margin of safety to reduce the risk of losing
a species or certain representation (variation) within a species due to
catastrophic events or other threats. Redundancy is essential for long-
term viability (Shaffer and Stein 2000, pp. 307, 309-310; Groves et al.
2002, p. 506). This provides a margin of safety for a species to
withstand catastrophic events (Service and NOAA 2011, p. 76994) by
decreasing the chance of any one event affecting the entire species.
Redundancy is about spreading risk and can be measured through the
duplication and distribution of resilient populations across the range
of the species.
Representation is defined as conserving ``some of everything'' with
regard to genetic and ecological diversity to allow for future
adaptation and maintenance of evolutionary potential. Representation
and the adaptive capabilities (Service and NOAA 2011, p. 76994) of the
Bone Cave harvestman are also important for long-term viability.
Because a species' genetic makeup is shaped through natural selection
by the environments it has experienced (Shaffer and Stein 2000, p.
308), populations should be protected in the array of different
environments in which the invertebrate species occur as a strategy to
ensure genetic representation, adaptive capability, and conservation of
the species. Generally, the more representation, or diversity, the
species has, the more it is capable of adapting to changes (natural or
human caused) in its environment.
The recovery plan for the Bone Cave harvestman (Service 1994, pp.
86-88) identifies criteria for reclassification (from endangered to
threatened), but does not include delisting criteria because we were
uncertain about prospects for recovery and delisting of the species.
These recovery criteria are a way of measuring our progress toward
recovery. The recovery plan identifies two criteria for reclassifying
the species from endangered to threatened:
(1) Three karst fauna areas (if at least three exist) within each
karst fauna region in its range are protected in perpetuity. If fewer
than three karst fauna areas exist within a given karst fauna region,
then all karst fauna areas within that region should be protected.
(2) Criterion (1) has been maintained for at least 5 consecutive
years with assurances that these areas will remain protected in
perpetuity.
There are six karst fauna regions in Travis and Williamson Counties
that are known to contain the Bone Cave harvestman (Service 1994, p.
33): North Williamson, Georgetown, McNeil/Round Rock, Cedar Park,
Jollyville Plateau, and Central Austin. These regions are used as a way
to facilitate conservation of representation and redundancy (as defined
above) throughout the species' range.
For the purposes of the recovery plan, a karst fauna area ``is an
area known to
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support one or more locations of a listed species and is distinct in
that it acts as a system that is separated from other karst fauna areas
by geologic and hydrologic features and/or processes that create
barriers to the movement of water, contaminants, and troglobitic
fauna'' that live their entire lives underground (Service 1994, p. 76).
Karst fauna areas should be far enough apart so that if a catastrophic
event (for example, contamination of the water supply, flooding,
disease) were to destroy one of the areas, that event would not likely
destroy any other area occupied by that species (Service 1994, p. 76).
To be considered ``protected,'' a karst fauna area must be
sufficiently large to maintain the integrity of the karst ecosystem on
which the species depends (Service 1994, p. 87). In addition, these
areas must also provide protection from threats such as red imported
fire ants, habitat destruction, and contaminants.
The overall recovery strategy for the Bone Cave harvestman includes
the perpetual protection and management of an adequate quantity and
quality of habitat (three karst fauna areas in each karst fauna
regions) that spans the species' geographic range and provides a high
probability of the species' recovery and survival over the long term.
Adequate quality (as discussed below) and quantity of habitat refers to
both size and number of preserved karst fauna areas that are sufficient
for supporting the karst invertebrates and the ecosystems upon which
they depend (Service 2011, p. 16). The recovery plan criteria call for
three karst fauna areas (preserves) in each karst fauna region. The
size of karst fauna area preserves should be large enough to ensure
resiliency as discussed above and to protect the environmental
integrity of the karst ecosystems upon which the species depends. The
number of karst fauna area preserves called for in the recovery
criteria provides redundancy for the species. A minimal level of
redundancy is essential to provide a margin of safety for the species
to reduce the risk of losing the species or representation (variation)
within the species from catastrophic events or other threats (Shaffer
and Stein 2000 pp. 307, 309-310, Groves et al. 2002, p. 506). The Bone
Cave harvestman has significant geographic variability across its
range, and loss of a significant number of locations in part of its
range could result in loss of genetic and ecological diversity. The
conservation of multiple karst fauna area preserves across the Bone
Cave harvestman's range should provide representation of the breadth of
its genetic and ecological diversity to conserve its adaptive
capabilities (Schaffer and Stein 2000, p. 308).
Adequate quality of habitat refers to (1) the condition and
configuration of preserved lands with respect to the known localities
for the species and (2) the ability of the species' needs to be met to
sustain viable populations. Due to the uncertainty in determining
population viability of the Bone Cave harvestman, the design of
preserves for its protection should be based on estimates and
assumptions that favor a high probability for recovery of this species
and the ecosystems upon which it depends as discussed below.
The Endangered Karst Invertebrates Recovery Plan for Travis and
Williamson Counties (Service 1994) calls for protecting karst fauna
areas sufficiently large to maintain the integrity of the karst
ecosystem on which the species depends. This focus on the ecosystem is
consistent with the purpose of the Act, which includes ``to provide a
means whereby the ecosystem upon which endangered species and
threatened species depend may be conserved.'' Therefore, we recommend
designing karst fauna area preserves to protect occupied karst
feature(s) and associated mesocaverns (humanly impassable voids). For
further guidance on how to provide for adequate quantity and quality of
habitat at specific invertebrate locations, we have developed and refer
to our Karst Preserve Design Recommendations (Service 2012).
According to our preserve design guidelines (Service 2012, p. 3-5),
karst fauna area preserves should include the following: (1) Surface
and subsurface drainage basins of at least one occupied cave or karst
feature; (2) a minimum of 16 to 40 hectares (ha) (40 to 100 acres (ac))
of contiguous, unfragmented, undisturbed land to maintain native plant
and animal communities around the feature and protect the subsurface
karst community; (3) 105-meter (m) (345-feet (ft)) radius undisturbed
area from each cave footprint for cave cricket foraging (cave crickets
are an important source of nutrient input to the karst ecosystem) and
to minimize deleterious edge effects; and (4) preserves should be free
of pipelines, storage tanks, or other facilities (for example, water
retention ponds) that could cause contamination.
In addition, due to the uncertainty in determining population
viability and habitat requirements of the Bone Cave harvestman, the
design of preserves for its protection should be based on estimates and
assumptions that favor a high probability for recovery of the species
and the ecosystems upon which it depends. This method follows a
precautionary approach, which provides guidance to avert irreversible
risk when facing uncertainty (Service 2012, p. A-1). The best available
scientific information indicates that this species cannot be
reintroduced into existing habitat. Life-history characteristics of
this species indicate that it requires stable temperature and humidity
(Barr 1968, p. 47, Mitchell 1971, p. 250) and suggest that this species
cannot be reintroduced because it cannot withstand surface climatic
conditions.
According to anecdotal reports provided to our field office,
limited efforts to maintain karst invertebrates in a lab setting have
been unsuccessful. Additionally, captive propagation techniques have
not been developed for karst invertebrates and may be challenging to
develop because of their specific adaptations to subterranean
environment. Further, the sample size that would likely be needed to
reintroduce a population into a new location cannot be obtained from
existing populations due to the cryptic nature of this species and the
fact that often only a few individuals are observed per cave survey.
Therefore, an attempt to re-establish a population after it has been
extirpated is not feasible at this time. In addition, if a preserve is
later found to be insufficient to support the species due to
surrounding developments being either too close or too dense, the
potential for adequately conserving the site is lost.
Because the Bone Cave harvestman has a relatively long life span
and low requirements for food, a decline in population size or even the
complete extirpation of the population due to the influence of
development or other threats may take years or even decades.
Observations of this species over several years on a preserve that is
too small for perpetual species preservation may not allow detection of
declines that are actually occurring. If these observations are used as
evidence that a preserve size was adequate, then the potential for
long-term preservation of the species may be lost due to irreversible
development surrounding the preserve. Therefore, preserve sizes should
be established with caution and be large enough to account for the
uncertainty in area requirements for a population.
According to the petition there are now more known occupied
locations identified; there were 6 confirmed caves at listing, 60
confirmed caves at the time the recovery plan was drafted, and 168
confirmed caves in 2009 when the 5-year status review was completed (53
FR 36029, Service 1994, 2009). The
[[Page 30993]]
petition also states that more locations are likely to be found. We
acknowledge there are more known locations since the time those
documents were completed and the increase is likely an increase in our
knowledge, not a true increase in the number of populations or range;
however, species are listed under the Act based on threats and not just
the number of sites or size of the range.
In addition, the petition states that 94 karst preserve areas are
currently providing significant conservation. However, many of the
existing protected areas referenced in the petition are too small to
meet our preserve design recommendations. As part of the 2009 5-year
status review of the Bone Cave harvestman, we reviewed the status of
all of the known locations of the harvestman (including 83 of the 94
mentioned in the petition) to assess whether the criteria from the
recovery plan to reclassify the species from endangered to threatened
had been met for the Bone Cave harvestman. We considered the habitat
size and condition to evaluate whether the locations could meet the
preserve design recommendations (a reflection of the potential to
support a resilient population) and then also looked at whether legally
binding mechanisms were in place to provide protection of these sites
over the long term (in perpetuity).
Of the locations known at the time of the 5-year review, 21 areas
appeared to have the ability to meet the preserve design criteria. Our
status review refers to 21 areas, while the petition indicates that the
status review considered 28 sites. This discrepancy is because the
petition considers each individual cave location, while our status
review considered closely located caves to be part of the same karst
fauna area. Of these 21 areas, 1 is no longer confirmed to have the
species (Barker Ranch Cave No. 1), and 5 are now protected karst fauna
areas (Priscilla's Well, Twin Springs, Cobbs Cavern, Karankawa, and
Tooth Cave).
In addition, at most of the remaining locations (of the 21 areas)
we are lacking information to confirm that they meet the preserve
design criteria (such as surface and subsurface drainage basins, tract
acreage, exact locations of the cave, and management activities to
protect against threats, such as red imported fire ants). Also, many of
these areas do not have a legally binding mechanism that ensures
perpetual protection and management. Hence, we are unsure whether those
areas have adequate undeveloped acreage, management, or protection
mechanisms to ensure the long-term protection and survival of the Bone
Cave harvestman.
Of the five protected karst fauna areas that meet preserve design
criteria, four occur in the North Williamson County Karst Fauna Region
and one occurs in the Jollyville Plateau Karst Fauna Region. However,
this species occurs in six karst fauna regions, and four of these have
no protected karst fauna areas that are confirmed to meet preserve
design recommendations. Therefore, the best available information
indicates that the criteria for reclassification from endangered to
threatened for this species have not been met, nor has adequate
representation and redundancy (three karst fauna areas in each karst
fauna region) been protected throughout the species' range, leaving the
species vulnerable to existing threats including habitat destruction.
The petition asserts that four additional locations are known since
the time of the 5-year review. However, the petition does not provide
adequate information that would support whether these four additional
locations are in a condition to meet preserve design recommendations.
Based on information in our files, we are aware of one additional cave
since the 5-year review that may meet preserve design recommendations
in the North Williamson Karst Fauna Region; however, it is privately
owned, and we are unsure about the property acreage and if the site
receives any type of protection or management. Regardless, the amount
of protected karst fauna area still falls short of the criteria for
reclassification from endangered to threatened.
Further, we reviewed 83 of the 94 caves identified in the petition
as receiving some level of protection in the 5-year review. Two of the
caves that we did not review (Cobbs Cavern and Whitney West Cave) are
now in confirmed karst fauna areas mentioned above (Cobbs Cavern and
Twin Springs), one (Pond Party Pit) is in the Beard Ranch Cave area
discussed in the 5-year review, and we have no locality information or
taxonomic verifications for the remaining caves and this information
was not provided in the petition.
The petition also asserts that threats to the species are not as
severe as originally thought. We evaluate that information, below, in
respect to the five listing factors.
Factor A: The present or threatened destruction, modification, or
curtailment of the species' habitat or range. In the 1988 listing rule
(53 FR 36029), we stated that the primary threat to the Bone Cave
harvestman was the potential loss of habitat due to development
activities, which could result in filling in or collapsing of caves;
alteration of drainage patterns; increase in flow of sediment,
pesticides, fertilizers, and urban run-off into caves; and increase in
human visitation and vandalism.
We also considered additional information on threats to the species
when we developed the recovery plan for the species (Service 1994, pp.
59-65) and when we conducted the 5-year status review of the species
(Service 2009, p. 2), in which we concluded that no change in the
species' status (that is, reclassification to threatened or delisting)
was warranted. We also reviewed available threat information in our
files and in a 1993 petition when we made our negative 90-day finding
on that petition to de-list (59 FR 11755).
The current petition asserts that ``Development activities on the
surface may not result in the significant loss or degradation of
habitat for T. reyesi as originally thought'' and suggests that
evidence of this is the species persistence in caves surrounded by
developed areas. Examples given in the petition are Inner Space
Caverns, Sun City caves, Weldon Cave, Three-Mile Cave, and Four-Mile
Cave. However, the observation of the species in these locations does
not mean their populations at these locations are thriving or can
withstand the long-term impacts from development activities that are
expected to occur to karst invertebrate populations in developed areas
as discussed in the listing rule, recovery plan, and 5-year status
review for the Bone Cave harvestman.
Bone Cave harvestman populations may be declining or threatened
even though they are still observed at a specific site. Information
adequate to detect population trends for this species is not readily
available and was not provided in the petition. This species has life-
history strategies that include characteristics such as low metabolic
and reproductive rates, long life spans, and inherently low sample
sizes, which make it difficult to detect population response to
possible impacts (Poulson and White 1969, p. 977, Howarth 1983, p.
374). We indicated in the 1994 90-day petition finding (59 FR 11755)
that more time was needed to detect if the species was declining;
however, while more time has passed, we are still lacking adequate data
to conduct a trend analysis at most locations, given that it can take
decades to detect population trends due to small sample sizes, the
difficulty surveying for the species, and their long life spans.
[[Page 30994]]
In addition, some of the threats from development are due to the
increased probability of chance events occurring in the future, such as
a contaminant event like a pipeline leak, which exists because more
contamination sources are in the vicinity of species' locations due to
development.
The petition states that several Sun City caves are examples of
areas where the species can persist in developed areas. However, the
petition failed to provide data adequate to assess trends in the karst
invertebrate populations since the development occurred. In addition,
we worked with the Sun City developers when they designed the project
to develop strategies that we believed at the time would avoid or
minimize the possibility of ``take'' to listed karst species. While we
now believe that most of the Sun City cave preserves are too small to
meet our preserve design recommendations for recovery and long-term
survival (Service 2012), we expect that the strategies and measures put
in place likely have reduced the rate of impacts to the species.
The commercial cave known as Inner Space Caverns is another example
the petition provided where the Bone Cave harvestman continues to
persist in a developed area. Although the Bone Cave harvestman may be
present at Inner Space Caverns, this does not ensure their populations
are robust and secure; they may still be declining, and are at risk due
to competition with surface-dwelling invertebrates and other threats
associated with development such as the potential for contamination.
This cave has an overgrowth of blue-green algae growing near cave
lights where the petition states that this species has been observed.
This type of algae is known as ``lampenflora'' and favors surface-
dwelling invertebrate species that can out-compete karst invertebrate
species (Mulec and Kosi 2009, p. 109, Culver 1986, p. 438), such as the
Bone Cave harvestman. The petition failed to provide any data adequate
to assess trends in the karst invertebrate population in relation to
the time (duration and frequency) that they have been exposed to the
artificial lighting. Additionally, part of the cave footprint occurs
under a major interstate highway and train tracks, which both present a
threat of a contaminant spill that could impact the species in the
future.
Weldon Cave was another example in the petition of a cave occupied
by the Bone Cave harvestman within a developed area. Based on the best
available information in our files this cave is surrounded by
undeveloped open space. Other than a small portion of the subsurface
drainage basin potentially being impacted by a school campus, this cave
appears to meet our preserve design recommendations but is not within a
developed area, as asserted in the petition. Three-Mile Cave and Four-
Mile Cave were also provided in the petition as examples of developed
caves wherein the Bone Cave harvestman is known to occur. According to
the petition, surveys conducted by SWCA in 2008 and 2009 documented the
Bone Cave harvestman at these locations. However, detailed survey data
were not provided by the petitioners and were not in the SWCA 2009
``Annual Report of Activities Involving Endangered Karst Invertebrates
under Threatened and Endangered Species Permit TE800611-2.''
The petition also states that, since the Bone Cave harvestman uses
mesocaverns, it is protected from surface development activities
because mesocaverns are ``geologically protected.'' We are unclear why
the petition contends that mesocaverns are protected because
mesocaverns are subject to rapid permeation of surface water (Cowan et
al. 2007, p. 160), and karst landscapes (including mesocaverns) are
particularly susceptible to groundwater contamination because water
penetrates rapidly through bedrock conduits providing little or no
filtration (White 1988, p. 149).
One of the major threats to the Bone Cave harvestman is habitat
loss due to increasing urbanization. The Bone Cave harvestman is a
troglobite, meaning it lives its entire life underground. Karst
ecosystems are heavily reliant on surface plant and animal communities
for nutrient input.
Caves in central Texas that are occupied by federally listed karst
invertebrates, such as the Bone Cave harvestman, receive energy (or
nutrients) primarily from (1) detritus (decomposing organic matter)
that falls or is washed into the caves and (2) energy brought into the
caves by cave crickets (Ceuthophilus spp.) (Barr 1968, p. 48; Reddell
1993, p. 2; Lavoie et al. 2007, p. 114; Taylor 2003, p. 3, 2004, p. 2,
2005, p. 97), which are found in most Texas caves (Reddell 1966, p.
33). Cave crickets forage widely in the surface habitat surrounding the
cave. Karst invertebrates feed on the cave cricket eggs (Mitchell 1971,
p. 251), feces (Barr 1968, pp. 51-53, Poulson et al. 1995, p. 226), and
directly on the crickets themselves (Elliott 1994, p. 15).
Development within urbanized areas can destroy or alter the surface
plant and animal communities on which karst invertebrates depend. As
development increases within the cave crickets' foraging area, there
may be dramatic shifts in the available food supply within the cave
(Taylor et al. 2007, p. 7). The leaf litter and other decomposing
material that make up most of the detritus from the surface plant and
animal community may also be reduced or altered, resulting in a
reduction of nutrient and energy flow into the cave. A study by Taylor
et al. (2007) compared caves in urbanized areas that were impacted by
development to those in natural areas and found that, even though a
small area within a largely urbanized ecosystem may support a cave
community where karst invertebrates are occasionally seen, these
populations are significantly lower than those found in caves in more
natural, less developed ecosystems, most likely as a result of reduced
nutrient input. Another study at Lakeline Cave in Travis County, Texas,
was conducted in association with the issuance of a habitat
conservation plan and accompanying section 10(a)(1)(B) permit issued
for Lakeline Mall. That study is based on data collected from 1992
through 2011, and it documented a significant decline during that 20-
year timeframe in another endangered karst invertebrate, Rhadine
persephone, and cave crickets as development increased (ZARA 2012, pp.
8, 10, 12). Further, at Lakeline Mall Cave, no more than three Bone
Cave harvestmen have been observed during any single survey (ZARA 2012,
p. 11). Also, no Bone Cave harvestmen were seen during 6 years (1993,
1999, 2001, 2006, 2009, and 2010) and 12 surveys in Lakeline Mall Cave
(ZARA 2012, p. 11).
Available information in our files supports our projection in the
1988 listing rule that development and human population would continue
to increase within the range of the species. The population of the City
of Austin grew from 251,808 people in 1970 to 735,088 people in 2007
(City of Austin 2007). This represents a 192-percent increase over the
37-year period. Population projections from the Texas State Data Center
(2012, pp. 496-497), estimate that Travis County will increase 94
percent in population from 1,024,266 in 2010, to 1,990,820 in 2050. The
Texas State Data Center also estimates an increase in human population
in Williamson County from 422,679 in 2010, to 2,015,294 in 2050
representing a 377-percent increase over a 40-year timeframe. All human
population projections from the Texas State Data Center presented here
are under a high-growth scenario, which
[[Page 30995]]
assumes that migration rates from 2000 to 2010 will continue through
2050 (Texas State Data Center and the Office of the State Demographer
2012, p. 9). Urbanization and human population growth and development
were identified as a threat in the original 1988 listing rule and
continue to represent a threat to the species.
Factor B: Overutilization for commercial, recreational, scientific,
or educational purposes. In the 1988 listing rule for the Bone Cave
harvestman, we did not identify any threats under this factor.
Likewise, the petition and our review of the information in our files
did not identify any threats under this factor.
Factor C: Disease or predation. In the 1988 listing rule, we stated
that increased human population increases the threat of predation by
and competition with exotic (non-native) and native surface-dwelling
species, such as sow bugs, cockroaches, and red imported fire ants. The
petition states that ``Recent studies suggest that fire ants may not
present as significant or as lasting of a threat to the species as
originally believed.'' The information cited regarding red imported
fire ants is identified in the petition as an article by Porter and
Savignano (1990), which we previously considered in our finding on the
1993 petition, and another study by Morrison (2002). The petition
states that ``a subsequent study by Morrison in 2002 revisited the
Porter and Savignano (1990) study area 12 years later and replicated
their study.
Morrison (2002, pp. 2341, 2343-2344) found that arthropod
communities had rebounded to pre-RIFA [red imported fire ant]-invasion
levels and that all measures of native ant and other arthropod species'
diversity had returned to pre-invasion levels. Red imported fire ants
were still the most abundant ant species, but not nearly as abundant as
during the initial red imported fire ants infestation. He concluded
that the impacts to arthropod communities by red imported fire ants
might be greatest during and shortly after the initial invasion, but
long-term impacts are likely not as significant as once believed.
However, we note that Morrison (2002, p. 2342) also states that ``it is
quite likely that red imported fire ants did contribute directly or
indirectly to the disappearance or reduction in numbers of species''
and that their study ``should not be interpreted as an indication that
detrimental effects of invasive ants will simply disappear with time.''
In addition, this is not ``new information'' as we have already
reviewed these articles and considered the information they provided in
the Bexar County Karst Invertebrates Recovery Plan (Service 2011, p.
12) and in our Karst Preserve Management and Monitoring Recommendations
(Service 2014, p. 3), which is applicable here as all central Texas
endangered karst invertebrates have similar life-history
characteristics, and one of the Bexar County invertebrates is in the
same genus (Texella) as the Bone Cave harvestman. In addition, red
imported fire ants have been found within and near many caves in
central Texas and have been observed feeding on dead troglobites, cave
crickets, and other species within caves (Elliott 1992, p. 13, 1994, p.
15, 2000, pp. 668, 768; Reddell 1993, p. 10; Taylor et al. 2003, p. 3).
Factor D: The inadequacy of existing regulatory mechanisms. The
1988 listing rule states that ``there are currently no laws that
protect any of these species or that indirectly address protection of
their habitat.''
While the petition did discuss some new ordinances that appear to
have been put in place since the time of listing, we do not have enough
information to indicate whether or not these State and local ordinances
provide enough protection from all threats to the Bone Cave harvestman.
The petition states that ``the regulatory landscape includes a
number of measures contributing to the conservation of the species
outside of the protections afforded by the Endangered Species Act of
1973, as amended.'' For example, they say that protections offered
though the City of Austin are adequate to protect the species in
Austin, Texas. In the course of our work, we have reviewed these
regulations and understand that most caves that are defined by the City
of Austin's Environmental Criteria Manual as a cave are provided a 46-
to 91-m (150- to 300-ft) set-back area (City of Austin 2014, p. 13-3).
However, a 46-m (150-ft) or 91-m (300-ft) set-back is not adequate to
meet our preserve design criteria, does not protect the cave cricket
foraging area, and potentially does not include the surface and
subsurface drainage basins. Further, it is not applicable across the
range of the Bone Cave harvestman because the species occurs in Travis
and Williamson Counties and the City of Austin does not cover all of
those counties.
The petition states that the City of Georgetown Water Quality
Management Plan for the Georgetown salamander will offer protection to
the Bone Cave harvestman. They state that this plan encourages the use
of best management practices to protect water quality at Georgetown
salamander locations. However, there are few Bone Cave harvestman
locations that occur near Georgetown salamander locations, so any
protection offered to the harvestman would be limited. Further, it is
not clear from the petition whether this mechanism is voluntary or if
it is regulatory or if it is currently in effect. In addition, the
petition did not provide enough detail for us to evaluate all benefits
this plan would provide to the Bone Cave harvestman, and it appears
that participation in this plan is at least in part voluntary.
The petition states that the Texas Commission on Environmental
Quality (TCEQ) Edwards Rules provide protection to recharge features on
the Edwards Plateau and that this provides protection from pollution to
the Bone Cave harvestman. In a discussion of Factor D in the Bexar
County Karst Invertebrates Recovery Plan (Service 2011, p. 13), we
state that ``the TCEQ water quality regulations do not provide much
protection to the species' habitat (see 65 FR 81419-81433 for more
information). For example, while some TCEQ practices provide protection
from water quality impacts, others, such as sealing cave entrances for
water quality reasons, can harm karst invertebrates.'' Sealing cave
entrances can be harmful by blocking off water (leading to drying) and
nutrient input to the karst invertebrate habitat. In addition, not all
of the caves and mesocaverns that the Bone Cave harvestman occurs in
are considered recharge features and, therefore, would not receive some
of the water quality protection measures. Also, not all locations of
the Bone Cave harvestman are under the jurisdiction of the Edwards
Rules.
Factor E: Other natural or manmade factors affecting the continued
existence of the species. In the 1988 listing rule, we stated that this
species is extremely vulnerable to losses because of its severely
limited range and because of its naturally limited ability to colonize
new habitats. We also stated that the very small size of the species
habitat units and the fragile nature of cave ecosystems make them
vulnerable to even isolated acts of vandalism. The petition states,
``Inner Space Cavern demonstrates that the species can persist in caves
with frequent human visitation and may be more tolerant of related
habitat modification than originally believed.'' They also provide
Three-Mile Cave and Four-Mile Cave as examples of caves that have
experienced human use yet the species persists. The petition contends
that, since the Bone Cave harvestman exists in Inner Space Caverns,
human visitation is not a threat. The petition also states that Three-
mile and Four-mile Cave had
[[Page 30996]]
graffiti from the 1890s, 1920s, and 1950s. Yet, no detailed information
was provided to demonstrate if these caves experienced continued human
use. The petition also indicates that Four-Mile Cave was inaccessible
to humans prior to 2009 due to boulders blocking the entrance. In
addition, the petition provided no trend analysis for these caves. As
stated earlier, the observation of the species in these locations does
not mean the populations at these locations have not been impacted (in
a way that is short of extirpation) or can withstand the long-term
impacts that are expected to occur to karst invertebrate populations in
developed areas or from human visitation.
In the species 5-year status review (Service 2009, p. 18) we said,
``Although climate change was not identified as a threat to T. reyesi
in the original listing document or in the recovery plan, the species'
dependence on stable temperatures and humidity levels opens the
possibility of climatic change impacting this species. Therefore, while
it appears reasonable to assume that T. reyesi may be affected, we lack
sufficient certainty to know how climate change will affect this
species.''
The petitioners state that ``the use of small voids or
`mesocaverns' within the geologic formations known to support occupied
caves mitigates the potential threat of climate change.'' We
acknowledge that mesocaverns may provide some protection from
fluctuations in temperature and humidity that may be induced by climate
change. However, the presence of mesocaverns alone will likely not be
sufficient to ameliorate all of the effects that climate change may
pose to this species. Karst invertebrates depend on stable temperatures
and high humidity (Barr 1968, p. 47, Mitchell 1971, p. 250). The
temperatures in caves are typically the average annual temperature of
the surface habitat and vary much less than the surface environment
(Howarth 1983, p. 372, Dunlap 1995, p. 76). If average surface
temperatures increase, this could result in increased in-cave
temperatures, which could affect the Bone Cave harvestman.
Increased and/or more severe storms as well as prolonged periods of
high temperatures and drought between rainfall events associated with
predicted climate change effects may also impact the cave environment.
Changes in rainfall regimes may affect the harvestman in several ways,
including directly either through flooding or indirectly by modifying
their habitat or nutrient availability. Changes in rainfall regimes
could (1) alter the moisture levels within the caves leaving them drier
between floods, which could lead to desiccation of the Bone Cave
harvestman and (2) affect the amount and timing of nutrients washed
into a cave, potentially resulting in longer periods between nutrient
input. These changes to drier and less suitable conditions in the caves
will likely cause the Bone Cave harvestman to retreat farther into
mesocaverns and away from nutrients that are thought to be located in
larger cave passages (Howarth 1987, pp. 5-7), causing individuals to
spend more energy trying to acquire nutrients in an already stressed
environment. In addition, caves in arid regions have been shown to have
smaller invertebrate populations and diversity due to less moisture and
nutrient availability (George Veni, National Cave and Karst Research
Institute, pers. comm. 2010). Since the Bone Cave harvestman is also
sensitive to these habitat parameters, it is reasonable to predict that
climate change could affect its populations in a similar manner despite
the presence of mesocaverns.
Further, stochastic (random) events from either environmental
factors (for example, severe weather) or demographic factors (which
come from the chance events of birth and death of individuals)
exacerbate threats to the species because of its small population size
(Melbourne and Hastings 2008, p. 100). The risk of extinction for any
species is known to be highly inversely correlated with population size
(Pimm et al. 1988, pp. 774-775, O'Grady et al. 2004, pp. 516, 518). In
other words, the smaller the population the greater the overall risk of
extinction. Therefore, threats to the Bone Cave harvestman are
exacerbated by its small population size, which makes it more
vulnerable to existing threats.
Finding
We have reviewed the petition and also evaluated readily available,
related information in our files. The petitioners have based their
assessment that the species can thrive in developed areas on
information that we have already reviewed (except in 4 caves discovered
since the 5-year status review and 7 for which we lack locality
information or taxonomic verifications) while working on previous
documents (Service 2009, 2012) or on observations that lack a large
enough sample size to produce population trend information for the Bone
Cave harvestman. The petition provided no trend analysis to indicate
that this species can withstand the threats associated with development
or climate change over the long term. Based on our review and
evaluation, we find that the petition does not present substantial
scientific or commercial information indicating that delisting of the
Bone Cave harvestman may be warranted due to recovery, extinction, or
error in the original scientific data at the time the species was
classified or in our interpretation of the data. However, much progress
has been made toward recovery in the North Williamson and Jollyville
Plateau Karst Fauna Regions. We encourage interested parties to
continue to gather data and implement conservation actions across the
range of the Bone Cave harvestman that will further assist with the
conservation of this species. If you wish to provide information
regarding the Bone Cave harvestman, you may submit your information or
materials to the Field Supervisor, Austin Ecological Services Field
Office (see ADDRESSES) at any time.
References Cited
A complete list of references cited is available on the Internet at
https://www.regulations.gov and upon request from the Austin Ecological
Services Field Office (see FOR FURTHER INFORMATION CONTACT).
Authors
The primary authors of this notice are staff members of the Austin
Ecological Services Office.
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: May 21, 2015.
Gary Frazer,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2015-13136 Filed 5-29-15; 8:45 am]
BILLING CODE 4310-55-P
