[Federal Register Volume 67, Number 157 (Wednesday, August 14, 2002)]
[Rules and Regulations]
[Pages 52879-52889]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-20339]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
RIN 1018-AI19
Endangered and Threatened Wildlife and Plants; Determination of
Endangered Status for the Tumbling Creek Cavesnail
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Final rule.
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SUMMARY: We, the Fish and Wildlife Service (Service), determine the
Tumbling Creek cavesnail (Antrobia culveri) to be an endangered species
under the Endangered Species Act of 1973, as amended (Act). This
species is known to occur in one cave in Missouri. The distribution of
this species in Tumbling Creek has decreased by 90 percent since 1974.
Although cavesnail numbers fluctuated seasonally and annually between
1996 and 2000, the species was not found in the monitored section of
the cave stream during six surveys in 2001 and two surveys in 2002.
Small numbers of individuals continue to exist in other portions of the
cave stream. Because the sudden population decline demonstrates a
significant and imminent risk to the well-being of the Tumbling Creek
cavesnail, we find that listing this species is necessary to provide
Federal protection pursuant to the Act.
DATES: This final rule is effective August 14, 2002.
ADDRESSES: The complete file for this rule is available for inspection,
by appointment, during normal business hours at the U.S. Fish and
Wildlife Service, Columbia Field Office, 608 E. Cherry St., Room 200,
Columbia, MO 65201-7712.
FOR FURTHER INFORMATION CONTACT: Paul McKenzie, Ph.D., Columbia Field
Office (see ADDRESSES) (telephone: 573-876-1911, ext. 107; e-mail:
[email protected]; facsimile: 573-876-1914). Individuals who are
hearing-impaired or speech-impaired may call the Federal Relay Service
at 1-800-877-8337 for TTY assistance.
SUPPLEMENTARY INFORMATION:
Background
The Tumbling Creek cavesnail (Antrobia culveri) was described as a
new species by Hubricht (1971) from specimens taken by David Culver,
Thomas Aley, and Leslie Hubricht in 1969 and 1970. Antrobia culveri is
the type species for the genus Antrobia, also described new to science
in 1971 by Hubricht. Hershler and Hubricht (1988) examined specimens of
A. culveri and confirmed the taxonomic placement of this species in the
subfamily Littoridininae of the Gastropod family Hydrobiidae. They also
noted the similarity of the genus Antrobia to, but distinguished it
from, the genus Fontigens, which contains cave-adapted snails found in
other caves and springs of the Ozark Plateau in Missouri and Arkansas.
The Tumbling Creek cavesnail is a small, white, blind, aquatic snail.
Hubricht (1971) provided the following measurements of the type
specimen: height 2.3 millimeters (mm) (0.09 inches (in)); diameter 2.0
mm (0.08 in); aperture height 1.2 mm (0.05 in); aperture diameter 1.1
mm (0.04 in); with a small, conical, well-rounded, pale-yellow shell
containing about 3.5 whorls (Hubricht 1971). The Tumbling Creek
cavesnail is restricted to a single cave stream in Tumbling Creek Cave
in Taney County, southwestern Missouri.
Greenlee (1974) provided the first information on the habitat of
the species. He reported that the species was found primarily on ``3
inch gravel substrate'' (presumably meaning small stones or cobble of
3-inch (7.5 cm) diameter), with a few individuals observed using the
recesses of a solid rock stream bottom. Greenlee's use of a Surber
Sampler, however, may have biased his survey to search for rocks
smaller than 25 cm (10 in) in diameter (Julian J. Lewis, J. Lewis &
Associates, Clarksville, IN; in litt., January 27, 2002). Greenlee
(1974) did not note whether the snails used the upper or lower surface
of the 3-inch gravel he observed them on, or whether the species was
ever observed using larger rocks within the cave stream. Subsequent
surveyors, however, have failed to document A. culveri using a solid
rock bottom, and the species is usually observed on the undersurface of
rocks and gravel of various sizes (Ashley unpub. data; McKenzie in
litt., September 16, 1996; Ashley and McKenzie, pers. obs.). Although
Greenlee (1974) stated that the Tumbling Creek cavesnail was absent
from areas of the stream that contained bat guano, subsequent observers
(Ashley 2001a; Ashley and McKenzie, pers. obs.) have noted A. culveri
in portions of
[[Page 52880]]
Tumbling Creek where bat guano occurs. Greenlee (1974) noted that the
species appears to prefer areas of the stream that lack silt, but
Ashley (2000) found no significant differences in snail populations
between habitats having silt and those lacking silt. There is
insufficient data currently available to determine if silt is
detrimental to the Tumbling Creek cavesnail. Tom and Cathy Aley
suggested (pers. comm., August 30, 2001) that silt deposition in recent
years in the stream has ``cemented'' smaller rocks to the stream bottom
making their undersurface unavailable to cavesnails. This hypothesis is
supported by observations made by researchers while conducting
cavesnail surveys (e.g., Ashley and McKenzie, pers. obs.).
Although little is known regarding the biology of this cavesnail,
Greenlee (1974) postulated that the species feeds on aquatic
microfauna. Because Tumbling Creek cavesnails have been concentrated in
sections of Tumbling Creek Cave that are usually adjacent to large
deposits of bat guano, it has been postulated that Antrobia culveri is
indirectly dependent upon these deposits for food (Greenlee 1974).
Other life history aspects of this species, including its reproductive
behavior, are unknown. Although nothing is known about the longevity or
movements of this species, some limited information is available on the
frequency of shell sizes within the population across different
seasons. Ashley (2000) examined shell length data collected between
1996 and 2000 and noted that the average length of A. culveri shells
exhibited a slight peak during summer months but further noted that the
difference was not statistically significant. Ashley (2000) also
analyzed the frequency distribution of cavesnail shell lengths from
fall data collected between 1997 and 2000 and noted a decrease in the
frequency of smaller shells over that period. Ashley (2000) concluded
that both fewer snails and fewer smaller snails in the younger age
classes were observed in the more recent fall visits conducted from
1997 through 2000. This suggests that there has been a reduction in
recruitment of younger age classes into the population between 1997 and
2000.
The fauna of Tumbling Creek Cave is highly diverse (Thomas Aley,
Ozark Underground Laboratory (OUL), in litt. 1978; Cecil Andrus, USDI,
in litt. 1980). In addition to one species included in the Missouri
Department of Conservation's (MDC) Checklist of Species of Conservation
Concern (Missouri Natural Heritage Program 2001) (i.e., a cave
millipede (Scoterpes dendropus)), Antrobia culveri is associated with
at least three, and possibly as many as six, species that are new to
science but have not yet been formally described: a millipede
(Chaetaspis sp.), a terrestrial isopod (Caucasonethes sp.), an amphipod
(Stygobromus sp.), a dipluran (Plusiocampa sp.), a phalangodid
harvestman (Phalangium sp.), and a cave spider (Islandiana sp.).
Tumbling Creek Cave also provides habitat for a large maternity colony
of federally listed gray bats (Myotis grisescens), with a recent
estimated breeding population of 12,400 in 1998 (Dr. William Elliott,
MDC, in litt. October 9, 2001). Historically, the gray bat breeding
population included an estimated 50,000 individuals (MDC 1992, Missouri
Natural Heritage Program 2000). The Gray Bat Recovery Plan lists
Tumbling Creek Cave as a ``Priority 1'' cave. Priority 1 gray bat caves
have the highest level of biological significance for a gray bat
maternity site (i.e., a cave deemed to be ``absolutely essential'' in
preventing the extinction of the endangered gray bat) (U.S. Fish and
Wildlife Service 1982). There have also been historical observations of
a very small hibernating population of the federally listed Indiana bat
(Myotis sodalis). However, the Indiana bat has not been documented at
the site since 1989 (Missouri Natural Heritage Program 2000).
Tumbling Creek Cave is owned by Tom and Cathy Aley of Protem, MO.
Because of its rich cave fauna, the large maternity colony for the
endangered gray bat, and its diverse physical features, Tumbling Creek
Cave was designated as a National Natural Landmark and approved for
inclusion on the National Registry of Natural Landmarks under the
authority of the Historic Sites Act of 1935 (49 Stat. 666; 16 U.S.C.
461 et seq.) (Cecil Andrus, USDI, in litt., 1980; 48 FR 8693). Tumbling
Creek Cave and approximately 395 acres surrounding the cave were
embodied in the designation, including about 140 surface acres owned by
the Aleys and about 255 surface acres owned by two adjacent property
owners.
Status and Distribution
Antrobia culveri is known only from Tumbling Creek Cave in Taney
County, southwestern Missouri. In an extensive survey of publicly and
privately owned Missouri caves, no additional populations of this
cavesnail were discovered (Gardner 1986). Recent surveys conducted in
nearby caves and springs by Dr. David Ashley of Missouri Western State
College, St. Joseph, MO, have also failed to locate this species at any
other sites (David Ashley, in litt. November 2001). The fact that no
additional populations were found in springs in close proximity to
Tumbling Creek Cave supports the long-held contention that Tumbling
Creek cave is the only location where this species occurs.
Antrobia culveri was historically known from an estimated area of
1,016 square meters (m2) (10,900 square feet
(ft2) or 0.25 acres) of Tumbling Creek along approximately
229 meters (m) (750 feet (ft)) of the stream in the middle one-third of
the lower stream passage in Tumbling Creek Cave (Greenlee 1974). Based
on a survey of approximately 630 m2 (6,800 ft2)
of suitable habitat within the 457 m (1,500 ft) of human-accessible
cave-stream habitat, Greenlee (1974) estimated the population of
Tumbling Creek cavesnails at 15,118 individuals.
In 1995, we reviewed the status of the species, including the
survey methodology originally established by Greenlee (1974), and
determined that an inadequate description of the survey methods made it
difficult to determine the number of plots taken. Our lack of knowledge
on the number of plots sampled by Greenlee made it difficult to
interpret his population estimates and impossible to duplicate his
survey methods. Therefore, we concluded that a new and more rigorous
statistical survey design would be necessary to establish population
trends for the species. Following meetings with Dr. Pam Haverland of
the U.S. Geological Survey, Columbia Environmental Research Center in
Columbia, MO, and Mr. Tom Aley, President of Ozark Underground
Laboratory (OUL) and owner of Tumbling Creek Cave, a sampling protocol
was established within an approximate 75 m (247 ft) section of Tumbling
Creek that was known to be inhabited by Antrobia culveri but that would
minimize any potential impacts to the federally endangered gray and
Indiana bats.
Following the establishment of sampling stations within Tumbling
Creek Cave, and an initial September 1996 survey using those stations
(McKenzie, in litt. 1996), we contracted Dr. David Ashley, of Missouri
Western State College, St. Joseph, MO, to monitor population trends of
the Tumbling Creek cavesnail. Ashley completed 19 separate monitoring
trips between September 3, 1997, and March 23, 2002 (Ashley 2000,
2001a, 2001b, 2001c, 2002). Ashley (2000, 2001a, 2001b, 2001c, 2002)
determined that population estimates of Antrobia culveri within the
monitoring stations fluctuated both seasonally and annually, and ranged
from a high of 1,166
[[Page 52881]]
individuals on September 3, 1997, to a low of 0 individuals on January
11, March 17, May 8, July 16, August 31, and November 2, 2001, and
January 9 and March 23, 2002. Ashley concluded that a significant
decrease in the numbers of cavesnails had occurred between September 9,
1996, and March 23, 2002 (Ashley 2002).
Although the 2001 and 2002 surveys failed to document the presence
of any cavesnails within the established monitoring stations, 40
individuals were discovered upstream of the sampling stations in March
2001. During March 16-18, 2001, Ashley and others surveyed the entire
human-accessible 457 m (1,500 ft) of Tumbling Creek, including a small
tributary that has approximately 9 additional meters (30 ft) of
accessible habitat. A total of 39 person-hours was expended in
searching a total of 1,054 rocks in the 466 m (1,530 ft) of available
habitat. A total of 39 cavesnails were located in a 14-m (45-ft)
section of the stream upstream from the monitoring stations, and
another cavesnail was found in the tributary (Ashley 2001a). Subsequent
surveys in May, July, September, and November, 2001, and January, 2002,
documented the presence of cavesnails only in this 14-m section
upstream of the established sampling stations. The small tributary
stream was not searched during those subsequent surveys. A more
thorough search was not conducted in either the tributary or the area
upstream from the sampling stations in order to minimize disturbance to
cavesnails in those areas. Observations made between September 1997 and
March 2002 suggest that the numbers of Antrobia culveri have declined
significantly from estimates obtained by Greenlee (1974); however,
differing sampling methods make it impossible to directly compare
Ashley's estimates with those of Greenlee.
In addition to Greenlee's 1974 survey and the standardized surveys
conducted between 1996 and 2002, other attempts have been made to
monitor the species' status and derive estimates of its abundance. A
June 1991 survey conducted by Tom Aley, Paul McKenzie (Service,
Columbia, MO), and Dennis Figg (MDC, Jefferson City, MO) located 42
individuals after a 9 person-hour search (McKenzie, pers. obs.). A June
1993 survey conducted by Monty Holder (a high school biology
instructor) of Sedalia, MO, and three assistants located 21 individuals
during 6 person-hours of search effort (Tom Aley, in litt. 1993), but
the number of plots sampled is unknown. On August 29, 1995, Paul
McKenzie and Cathy Aley searched for the species and attempted to
estimate the number of cavesnails discovered per 0.3 m2 (1
ft2) plot. This survey yielded 6 cavesnails in 22 plots or
0.27 cavesnails per plot (McKenzie, unpubl. data). This compares to an
estimated 2.16 cavesnails per plot observed by Greenlee (1974) when
equivalent plot sizes were calculated for analysis purposes. Although
it is impossible to determine the exact number of plots sampled by
Greenlee (1974), he did record the average number of snails per plot,
and this can be compared to the same variable measured in 1995. A
decrease from 2.16 cavesnails per plot to 0.27 cavesnails per plot
would represent an approximate 88 percent decrease in the species'
density over the 22-year period between 1974 and 1995.
Previous Federal Action
On January 6, 1989, the Service published an Animal Notice of
Review (54 FR 54554-54579) which included the Tumbling Creek cavesnail
as a category 2 candidate species for possible future listing as
threatened or endangered. Category 2 candidates were those taxa for
which information contained in the Service's files indicated that
listing may be appropriate but for which additional data were needed to
support a listing proposal. On November 21, 1991, the Service published
an Animal Candidate Notice of Review (56 FR 58804-58836), which
elevated the Tumbling Creek cavesnail to category 1 status. Category 1
candidates were those taxa for which the Service had on file sufficient
information on biological vulnerability and threats to support
preparation of listing proposals. In the subsequent February 28, 1996,
Candidate Notice of Review (61 FR 7596-7613), we indicated that the
category 2 candidate species list was being discontinued, and that
henceforth the term ``candidate species'' would be applied only to
those taxa that would have earlier fit the definition of the former
category 1 candidate taxa, that is, those species for which we had on
hand sufficient information to support a listing proposal. Antrobia
culveri was retained as a candidate species in that notice.
In 1996, we initiated a 5-year set of standardized surveys designed
to better assess and quantify the decline in the species' population
that was apparent from the earlier data. In January 2001, Ashley (pers.
comm. January 14, 2001) notified the Service that no cavesnails were
observed within the established monitoring stations during the January
11 survey. He further reported that an analysis of 5 years of data
collected between September 1996 and March 2001 indicated that the
population of the species had exhibited an alarming decline (Ashley
2001b). Based on this information, the Service determined that it was
necessary to more closely monitor the species by having surveys
conducted once every two months. Surveys conducted every two months
between March 2001 and March 2002 have yielded the same results--no
cavesnails have been found within the established sampling section of
Tumbling Creek (Ashley 2002).
Recognizing the need for prompt additional conservation actions for
the species, on January 30, 2001, Region 3 of the Service recommended
changing the listing priority number for the Tumbling Creek cavesnail
from 7 to 1 based upon the mid-January monitoring that failed to locate
any cavesnails (Service 2001). Region 3 also recommended pursuing an
emergency listing of the species and simultaneously publishing a
proposal for long-term listing as endangered under the Act as soon as
funding became available. On October 30, 2001, we published an updated
Candidate Species Notice of Review (66 FR 54808) that formally changed
the listing priority number for Antrobia culveri from 7 to 1,
reflecting our increased concern for the survival of the species.
On August 29, 2001, the U.S. Department of the Interior reached an
agreement with several conservation organizations regarding a number of
listing actions that had been delayed by court-ordered critical habitat
designations and listing actions for other species. That agreement was
subsequently approved by the U.S. District Court for the District of
Columbia. Under the agreement, the Service and the organizations agreed
to significantly extend the existing court-approved deadlines for the
actions on the other species, thereby making funds available for a
number of listing actions judged to be higher priority by the Service.
Those higher priority listing actions included the emergency listing of
the Tumbling Creek cavesnail.
On December 27, 2001 (66 FR 66803), we listed Antrobia culveri on
an emergency basis for 240 days through August 26, 2002. On the same
date (66 FR 66868), we published a proposal to list the Tumbling Creek
cavesnail as an endangered species under the standard listing
provisions of the Act, and solicited comments on the proposed rule. The
comment period was opened for 60 days and closed February 25, 2002.
[[Page 52882]]
Summary of Peer Review and Public Comments
In the December 27, 2001, proposed rule, we requested all
interested parties to submit factual reports or information that might
contribute to the development of a final rule. We also provided a
notice indicating that a request for a public hearing could be made by
February 11, 2002. We contacted appropriate Federal and State agencies,
county governments, scientific organizations, and interested parties
and requested their comments. We published notices inviting public
comment in the Springfield, MO, News Leader and the Branson, MO, Tri-
Lakes Daily News. In accordance with our July 1, 1994, Interagency
Policy on Peer Review (59 FR 34270), we requested the expert opinions
of independent specialists regarding pertinent scientific or commercial
data and assumptions relating to the supportive biological and
ecological information in the proposed rule. The purpose of such review
is to ensure that the listing decision is based on scientifically sound
data, assumptions, and analyses, including input of appropriate experts
and specialists.
We requested scientific peer review of our proposed endangered
listing from four invertebrate zoologists who possess expertise on the
cavesnail or other invertebrates, and also solicited comments from one
research fisheries biologist who has expertise on the potential impacts
of contaminants on aquatic invertebrates. We received a written
response and comments from all five of these experts; we also received
comments from five private land owners within the recharge area for
Tumbling Creek Cave during the open comment period. No requests for a
public hearing were received. All species experts and private
landowners strongly supported the listing proposal and agreed that this
species is in need of Federal protection as an endangered species. Four
of the five peer reviewers commented that the data on changes in
cavesnail numbers were very thorough and that there was clear
scientific evidence for listing the species as endangered. The fifth
peer reviewer did not comment on adequacy of the data.
A. Technical and Editorial Comments
Several technical and editorial comments and corrections were
provided by two peer reviewers. Clarification of biological
terminology, enhanced explanations of information cited from several
references, and the inclusion of additional literature citations to
strengthen Factors A through D, discussed below, were recommended. We
have incorporated the majority of the recommended changes, as
appropriate. In a few cases, suggested changes were not made if we
determined that incorporating the change in text would not improve the
clarity of the discussion.
B. Suggestions Related to Recovery Actions
Three peer reviewers and two private land owners suggested various
recovery actions that could benefit the cavesnail or its habitat. We
will prepare a recovery plan for the cavesnail following the
publication of the final rule, and these comments will be considered
for incorporation into the recovery plan at that time. They are not
discussed in this document, because they are not germane to this
listing decision.
C. Specific Comments
All peer reviewers commented on the possible reasons for the recent
decline in cavesnail numbers. With the exception of the introduction of
a few new suggestions discussed below, most of the reasons provided by
the peer reviewers are identical to those outlined in the December 27,
2001, emergency rule. All peer reviewers reaffirmed the supposition
that siltation from erosion problems, overgrazing, poor land
management, deforestation, or the sudden appearance and population
explosion of limpets probably contributed to the decline in the
species. Other reasons presented by peer reviewers that were previously
provided in the Service's emergency rule were: eutrophication or
nutrient runoff from livestock operations within the recharge area;
disease; depressed dissolved oxygen levels; and degraded water quality
from various waterborne contaminants. Two private landowners also
believed that silt deposited into Tumbling Creek cave was a major
contributor to habitat loss of the species. Newly suggested reasons
given by peer reviewers for the decline in cavesnail numbers that were
not addressed in the emergency rule were: residual toxins in the
surrounding substrate that could adversely affect the water quality of
the cave stream and cause changes in water chemistry (e.g., change in
pH or imbalances in the anion/cation exchange).
Four of the five private landowners who provided comments stated
their belief that the listing of Tumbling Creek cavesnail as an
endangered species would not impact their property rights. The fifth
landowner did not comment on this issue. Two respondents indicated that
the declining population of Antrobia culveri served as a barometer on
the quality of water important to area land owners and further noted
that listing the species was important in preserving the rich
biological diversity of the Ozarks on esthetic and ecological grounds.
One peer reviewer and two land owners recommended that the entire
recharge area of Tumbling Creek cave be designated as critical habitat.
Comments related to the issue of critical habitat for this species are
addressed below.
Summary of Factors Affecting the Species
After a thorough review and consideration of all information
available, we determine that the Tumbling Creek cavesnail should be
classified as an endangered species. We followed procedures found in
section 4 of the Act (16 U.S.C. 1533) and regulations (50 CFR part 424)
promulgated to implement the listing provisions of the Act. We may
determine a species to be endangered or threatened due to one or more
of the five factors described in section 4(a)(1) of the Act. These
factors and their application to the Tumbling Creek cavesnail (Antrobia
culveri) are as follows:
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
Antrobia culveri has exhibited a large decline in numbers since the
first estimate was made by Greenlee (1974) (see Status and
Distribution, above). Systematic sampling within various sections of
Tumbling Creek was initiated in 1996 (McKenzie in litt. 1996).
Placement of sampling quadrats was done by inspecting the area within
each of the sampling sections and arbitrarily placing the sampling
squares approximately equidistant along each section. Ashley reported a
statistically significant decline in the snail population over the
period between 1996 and the first quarter of 2002 (Ashley 2001c, 2002).
Additionally, no cavesnails have been located at established monitoring
stations during the last eight surveys (Ashley 2001a, 2001b, 2001c,
2002).
We also have documented a large reduction in the portion of the
cave stream occupied by the cavesnail. Antrobia culveri was
historically known from an estimated 229 m (750 ft) of Tumbling Creek
(Greenlee 1974). The 229 m of occupied habitat in 1974 constituted 50
percent of the 457 m (1,500 ft) of human-accessible cave-stream habitat
that is believed to be
[[Page 52883]]
suitable for the cavesnail. The entire accessible 457 m (1,500 ft) of
Tumbling Creek, including a small tributary that has approximately 9
additional meters (30 ft) of accessible suitable habitat, was surveyed
in March 2001. Cavesnails were found solely in one small (14-m) (45-ft)
section of the stream and in the small tributary (Ashley 2001a).
Observations between March and August 2001 suggest that A. culveri is
now restricted to 23 m of available stream habitat or approximately 5
percent of the 457 m of accessible suitable habitat. These figures
indicate that distribution of this species in Tumbling Creek Cave has
decreased by 90 percent.
Species such as the Tumbling Creek cavesnail, which spend all of
their life cycle in subterranean waters, are highly vulnerable to
changes in the quality and quantity of that water. In turn, the quality
and quantity of the subsurface water is highly dependent upon
conditions and human activities on the land surface. Water feeds into
losing streams and sinkholes that drain into underground karst
conduits. Surface water moves into the subsurface system by a number of
mechanisms, including sinkholes, percolation through sandy or gravelly
soils and stream bottoms, and seepage and flowage into crevices. As
water moves from the surface to the subsurface system, it carries the
chemicals and particulate matter from the surface (Gines and Gines
1992). The land surface that feeds water into a particular cave stream
is referred to as the ``recharge area'' for that cave stream. Because
recharge areas may be large and may consist of all or parts of several
surface watersheds, it is critically important to accurately determine
the boundaries of the recharge area with reliable hydrogeological
methods. Only when the recharge area is accurately delineated can water
quality threats be successfully addressed (Aley and Aley 1991).
The recharge area that feeds water into Tumbling Creek Cave has
been recently delineated by the cave owner, Mr. Thomas Aley of the OUL,
who is also a recognized cave specialist and expert karst
hydrogeologist (Aley and Aley 2001). Pending the results of additional
recharge delineation studies currently being conducted by Aley on a
tract of land recently purchased by him and Cathy Aley (Tom Aley, pers.
comm., September 24, 2001), he estimated the recharge area to be
approximately 2,349 hectares (5,804 acres or 9.07 square miles). Land
ownership based on current data within the recharge area is: (1) Tom
and Cathy Aley own approximately 1,550 acres, or 25 percent of the
total; (2) employees of Ozark Underground Laboratory and other private
individuals, who manage their property to protect water quality and
benefit the species, own approximately 1,268 acres or 22 percent; (3)
an estimated 1,300 acres or 23 percent is within Mark Twain National
Forest; (4) the U.S. Army Corps of Engineers (CE) owns an estimated 100
acres or 2 percent; and (5) other private landowners, whose land use
practices and knowledge of the cavesnail are currently unknown to us,
own approximately 1,636 acres or 28 percent. Thus, within the
delineated recharge area for Tumbling Creek Cave, roughly 4,168 acres
or approximately 72 percent is either in public or private ownership by
entities who can be expected to manage their land to benefit the
species. This includes 920 acres recently purchased by Tom and Cathy
Aley, or about 22 percent of the total conservation ownership. However,
most of this recently purchased land was subject to land use practices
(e.g., over-grazing and removal of riparian vegetation) by the previous
owner that resulted in heavy soil erosion that probably continues to
contribute to deteriorating water quality in Tumbling Creek Cave.
Remediation and restoration of these lands are planned and will require
considerable funds, effort, and time.
The Tumbling Creek cavesnail is likely threatened by habitat
degradation through diminished water quality from upstream locations
within the unprotected or improperly managed areas within the cave's
delineated recharge zone. The dramatic decrease in the population and
area occupied by this species is probably attributable to degraded
water quality from these sources. In recent years, there has been a
noticeable increase in water turbidity in Tumbling Creek; the increased
turbidity has probably had an adverse effect on the water quality in
the cave's stream (Tom and Cathy Aley, pers. comm., August 30, 2001).
Increased silt loads within Tumbling Creek could adversely affect the
cavesnail by hampering reproduction and recruitment by suffocating
juvenile cavesnails (Ashley 2000). Several authors (e.g., Poulson 1996,
Elliott 2000, Taylor et al. 2000) have noted that high sediment loads
usually have a negative impact on aquatic species. Tom and Cathy Aley
have also observed that clay particles within deposited silt have
settled between gravel and rocks and cemented them together and to the
stream bottom (Tom and Cathy Aley, pers. comm., August 2001). Such
cementing decreases habitat available to cavesnails, especially
interstitial areas, because the species is generally restricted to the
undersurface of gravel and rocks. Coineau and Boutin (1992)
demonstrated that interstitial habitats are critically important to the
dispersal capabilities of animals with limited movements. Comacho
(1992) suggested that the size, porosity, and compaction of sediment
grains (e.g., clay vs. sand) was a limiting factor in the availability
of interstitial habitats to aquatic cave organisms. Interestingly,
Ashley (2000) determined that some Tumbling Creek cavesnails use silt-
covered substrates. This is different from the observations made by
Greenlee (1974) who noted that cavesnails were not observed in areas of
the stream where fine silt was deposited. Ashley's observations may be
due to a reduction in the amount of silt-free substrates preferred by
cavesnails which could force the species to use less favorable
habitats. Although silt has been a component of Tumbling Creek since
Greenlee's initial survey in 1974, it has apparently increased since
that date (Tom and Cathy Aley, pers. comm., August 2001).
Silt could also be harmful to Antrobia culveri indirectly due to
the interrelationship between various harmful bacteria or viruses and
some sediment mediums. Taylor and Webb (2000) reported that the
survival of some bacteria and viruses may increase when they become
attached to the surface of silt and clay particles and organic matter.
Additionally, they noted that such harmful bacteria as coliform and
fecal coliform bacteria ``may persist and reach much higher
concentrations in aquatic sediments (especially in the presence of
organic nutrients) than in the water column.'' Consequently, an
increase of silt into Tumbling Creek could exacerbate the potential
problems from bacteria and viruses originating from livestock wastes
entering Tumbling Creek. Additional research is needed to determine the
degree of silt deposition within Tumbling Creek and if the deposition
of silt into the cave is adversely impacting the species, especially
smaller and younger individuals (Ashley 2000).
Potential sources of silt within the cave's recharge area have been
identified on the two tracts recently purchased by Tom and Cathy Aley,
including an earthen dam that burst, as well as severely degraded and
eroded pastureland due to overgrazing. In the latter case, soil erosion
has been exacerbated in the last six years by the removal of nearly all
vegetation by bulldozing equipment within the riparian corridors of all
semi-permanent
[[Page 52884]]
and intermittent streams on one of those parcels. Tree removal
activities associated with pasture expansion have increased soil
erosion and resulted in the subsequent movement of silt into the cave
system (Aley, Ashley, and McKenzie, pers. obs.). Harvey (1980)
concluded that ``accelerated erosion and sediment transport'' was a
problem within drainage basins that have ``excessive slopes,'' and
identified ``timber cutting and land clearing for raising livestock,
extending urban sprawl, and highway building'' as potential sources of
``accelerated erosion.'' In addition to these sources, the construction
of fire lanes associated with controlled burning on Forest Service
property within the recharge area may increase the threat of soil
erosion with a resulting decrease in water quality in Tumbling Creek.
Other factors within the recharge area of Tumbling Creek Cave that
could contribute to the deterioration of the water quality of Tumbling
Creek include: (1) Nutrient enrichment from livestock feedlots or from
fertilizers used for crop production or pasture improvement within the
recharge area that could reduce dissolved oxygen levels in Tumbling
Creek or become toxic to aquatic organisms at high concentrations; (2)
chemicals used for highway maintenance or from accidental spills; (3)
contaminants from different types of trash or hazardous waste materials
deposited into sinkholes, ravines, and depressions; and (4)
contamination from hormones, antibiotics, disinfectants, or other
chemicals found in human and livestock wastes (Koplin et al. 2002).
Contaminants presumably from crop fertilizers were detected at levels
high enough in cave streams within the Perryville Karst Region of
southeastern Missouri to be detrimental to aquatic life (Vandike 1985;
Burr et al. 2001). Contamination of groundwater has occurred due to
spills associated with traffic accidents in the Mammoth Cave area of
Kentucky (U.S. Department of Interior 1983; U.S. Fish and Wildlife
Service 1988; Taylor et al. 2000). Because portions of Routes 160 and
125 occur within the recharge area for Tumbling Creek Cave, accidental
spills resulting from traffic accidents could potentially occur. Taylor
and Webb (2000) summarized the deleterious effects of various inorganic
ions on the distribution and abundance of different aquatic cave
isopods and amphipods. Taylor et al. (2000) suggested that several
parameters, including depressed oxygen levels, improper pH levels, and
the presence of metals, pesticides, and harmful bacteria may all
contribute to the persistence or decline of aquatic cave organisms.
Burr et al. (2001) reported that ``no less than one-half of sinkholes
in Perry County, MO, contain anthropomorphic refuse, ranging from
household cleansers and sewage to used pesticide and herbicide
containers.'' Some unidentified point source pollution that was
apparently dumped accidentally into Running Bull Cave in Perry County,
MO, resulted in a mass mortality of cave-dwelling grotto sculpin (Burr
et al. 2001). Eliott (2000) summarized the documented impact of various
chemical pollutants into cave systems including sewage, contaminants
from old batteries, nitric acid, leaks from petroleum products, brine
pollution, herbicides, pesticides, solvents, fertilizers, milk, cream,
tobacco waste products, and medical waste. Kolpin et al. (2002) sampled
139 streams across 30 States, including Missouri, and documented the
presence of human and livestock antibiotics, human prescription and
nonprescription drugs, steroid compounds including several biogenic and
synthetic reproductive compounds, and 30 different organic wastewater
contaminants in 80 percent of the streams sampled. Although there are
no waste water treatment facilities within the recharge area for
Tumbling Creek cave, livestock antibiotics, hormones, and chemical
treatments for controlling insect pests could originate from livestock
facilities that occur within the cave's recharge area. The extent to
which any of these factors have contributed to the decline of the
Tumbling Creek cavesnail remains to be determined. Refer to Factor E
for further discussion of these potential threats.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Because access to Tumbling Creek Cave is controlled by the cave
owners, all collection of and research on Antrobia culveri is strictly
controlled. Consequently, there is no evidence, and very little
likelihood, of overutilization of this species for commercial,
recreational, scientific, or educational purposes. There is also no
evidence that disturbance associated with conducting regular surveys is
adversely affecting the species. Rocks that are examined for cavesnails
are carefully replaced in the location from which they were removed,
any specimens discovered are disturbed as little as possible and kept
moist to reduce stress, and only a small percentage of the available
habitat is sampled during each survey.
C. Disease or Predation
The direct effect of disease on the Tumbling Creek cavesnail is not
known and such risks to the species have not been determined. Because
the Tumbling Creek cavesnail is known to inhabit only a single
location, disease must be considered a potential significant threat to
the survival of the species. Certain species of salamanders have been
shown to be adversely impacted by the bacterium Acinetobacter that
flourished due to increasing levels of nitrogen associated with the
overstocking of livestock (Worthylake and Hovingh 1989). Similarly,
Lefcort et al. (1997) and Kiesecker and Blaustein (1997) found that
amphibians exposed to high levels of silt are susceptible to infection
by different species of water mold of the genus Saprolegnia.
Saprolegnia spp. are widespread in natural waters and commonly grow on
dead organic material (Wise et al. 1995). Speer (1995) stated that some
species of Saprolegnia are parasitic on aquatic invertebrates such as
rotifers, nematodes, diatoms, and arthropods. High nitrogen and silt
levels from overgrazing or other agricultural or urban runoff may
increase the cavesnail's susceptibility to disease and may act
synergistically with other risk factors (e.g., competition from
limpets, discussed below) to jeopardize the survival of the remaining
individuals. Whether the Tumbling Creek cavesnail is being adversely
affected by bacteria or water molds associated with increased loads of
nitrogen or silt into Tumbling Creek is unknown but warrants further
investigation.
During the December 6, 1997, survey, a few individuals of an
unknown species of limpet (Ferrissia sp.) were discovered for the first
time on the same substrates used by Antrobia culveri within the
established monitoring stations (Ashley, pers. comm., September 10,
2001). Limpets were not observed again until the January 11, 2001,
survey, after which their numbers began to increase. By the August 31,
2001, survey, limpet numbers had increased explosively, and the
presence of many small limpets, as well as larger limpets with visible,
developing embryos, indicated that reproduction was taking place
(Ashley, pers. comm., September 10, 2001; McKenzie pers. obs.) The
reasons that caused these organisms to appear and increase in numbers
within Tumbling Creek are unknown; it is also unknown whether they
compete with the cavesnails for food, breeding substrates, or other
necessary resources. Dr. Julian J. Lewis documented that the
disappearance of
[[Page 52885]]
the rare isopod crustacean Caecidotea rotunda coincided with the
appearance of limpets in a cave in southern Indiana (J. Lewis, in
litt., January 27, 2002). Numerous investigations by David Culver and
others (e.g., Culver 1970, 1975) have demonstrated that interspecific
competition between aquatic cave invertebrates may reduce the
availability of important niche habitats. Other cave invertebrates
(e.g., a troglobitic isopod, Caecidota antricola.; a troglobitic
amphipod, Stygobromus sp.; and a troglophilic amphipod, Gammarus sp.)
coexist with A. culveri, often on the same rocks, but it is unknown if
these species compete with the cavesnail in any way. Additional
research is needed to determine if local environmental changes have
provided a competitive advantage for one or more of these species over
the Tumbling Creek cavesnail.
D. The Inadequacy of Existing Regulatory Mechanisms
The primary cause of the decline of the Tumbling Creek cavesnail is
unknown but is believed to be associated with factors within the 2,349-
hectare (5,804-acre) delineated recharge area that have adversely
affected the water quality of Tumbling Creek. Federal, State, and local
laws have not been sufficient to prevent past and ongoing impacts to
areas within the cave's delineated recharge area. Antrobia culveri is
listed as critically imperiled globally (G1) by The Nature Conservancy,
as well as critically imperiled in the State (S1) on the Missouri
Species of Conservation Concern Checklist (Missouri Natural Heritage
Program 2001). The designation as G1/S1 on this checklist, however,
provides no legal protection, but is simply utilized for planning and
communication purposes (Missouri Natural Heritage Program 2001).
Nonetheless, the species currently receives some protection under the
Wildlife Code of Missouri (Wildlife Code) (Missouri Department of
Conservation 2001) as a ``biological diversity element'' (Missouri
Natural Heritage Program 2001). ``Biological diversity elements'' are
protected under the following general prohibitions of chapter 4 of the
Wildlife Code (3CSR10-4.110): ``(1) No bird, fish, amphibian, reptile,
mammal or other form of wildlife, including their homes, dens, nests
and eggs in Missouri shall be molested, pursued, taken, hunted,
trapped, tagged, marked, enticed, poisoned, killed, transported,
stored, served, bought, imported, exported or liberated to the wild in
any manner, number, part, parcel or quantity, at any time, except as
specifically permitted by these rules and any laws consistent with
Article IV, sections 40-46 of the Constitution of Missouri. (2) Except
as otherwise provided in this Code, wildlife may be taken only by
holders of the prescribed permits and in accordance with prescribed
methods. (3) No person, corporation, municipality, county, business or
other public or private entity shall cause or allow any deleterious
substance to be placed, run or drained into any of the waters of this
State in quantities sufficient to injure, stupefy or kill fish or other
wildlife which may inhabit such waters.''
Under the Section 6 Cooperative Agreement between MDC and the
Service, if a species is listed as endangered under the Act, the
Conservation Commission of Missouri shall list the species as State
endangered. The protection of all species in Missouri is outlined in
Chapter 4 of the Wildlife Code, and regulations pertaining to
endangered species are listed in section 3CSR10-4.111. Under the
Wildlife Code, citizens can possess (but not sell or purchase) up to
five individuals of any species without a permit and when not
specifically protected elsewhere in the code (3CSR10-9.110). However,
when a species is listed as endangered, citizens cannot possess any
individuals and cannot import, transport, purchase, or take the species
without a scientific collecting or special use permit. Although the
term ``refuge'' is not defined under the Wildlife Code, there is also a
provision that enables MDC's Director to establish refuges not to
exceed 1 square mile for not more than 60 days to provide essential
protection to endangered species. Furthermore, the Wildlife Code states
that a species' ``home'' is protected. The term ``home'' is not defined
in this statute and may provide limited or no protection for the
cavesnail's habitat. For instance, the creek where the cavesnail
resides and the cave's recharge area would probably not be considered a
home and thus receive no protection under the Wildlife Code (Bob White,
MDC, Protection Division Chief, pers. comm., October 2, 2001).
The Federal Cave Resources Protection Act of 1988 (18 U.S.C. 4301-
4309; 102 Stat. 4546) was passed to ``secure, protect, and preserve
significant caves on Federal lands'' and to ``foster increased
cooperation and exchange of information between governmental
authorities and those who utilize caves located on Federal lands for
scientific, educational, or recreational purposes.'' Although this
statute and a final rule to implement the Federal Cave Resources
Protection Act on Forest Service land (59 FR 31152; June 17, 1994)
provide protection for caves located on property owned by the Forest
Service, they do not provide protection for caves whose recharge areas
are within Forest Service boundaries if the caves themselves are under
private lands, as is the case with Tumbling Creek Cave.
Under Section 578.215 of the Missouri Cave Resources Act (Missouri
Department of Conservation 2002), the following actions are prohibited:
``A person shall not purposely introduce into any cave, cave system,
sinkhole, or subsurface waters of the state any substance that will or
could violate any provision of the Missouri clean water law as set
forth in chapter 204, RSMo (Revised Statutes of Missouri), or any water
quality standard or effluent limitation promulgated pursuant thereto.''
Although this statute is intended to prevent harmful chemicals from
being placed into a cave, it is rarely enforced, and an individual
prosecuted for a violation of this measure can be convicted of no more
than a Class A misdemeanor; therefore, it is largely ineffective at
providing protection for aquatic animals within a cave stream (Bill
Elliott, Cave Biologist, Missouri Department of Conservation, Jefferson
City, MO, pers. comm., March 15, 2002).
The protection afforded Antrobia culveri from the statutes
mentioned above is limited, does not provide adequate protections to
its habitat, and includes no provisions to protect areas within the
delineated recharge area for Tumbling Creek Cave. Therefore, we
conclude the most likely threats to the species cannot be addressed by
existing regulatory mechanisms.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Several other potential factors, including point and non-point
pollution, threats from residential and commercial development, and
recent changes to the hydrological cycle within the 2,349-hectare
(5,804-acre) delineated recharge area supporting Tumbling Creek Cave
may have negative effects on the species. It is possible that the
recent decline in cavesnail numbers is attributable to some yet to be
identified point or non-point source pollution within the cave's
recharge area. Because the Tumbling Creek cavesnail occupies a
permanent, flowing stream, it will likely come in contact with any
deleterious chemical or other material that enters the cave's recharge
system. Silt deposition has been identified as a potential problem,
especially to younger
[[Page 52886]]
cohorts of the cavesnail's population, but additional research is
needed to determine if other contaminants are potentially involved.
(See Factor A above.)
Non-point source pollution may be a problem in a significant
portion of the recharge area that feeds Tumbling Creek Cave. Potential
sources of pollution include the drainage of barnyard and feedlot
wastes and the discharge of treated sewage into sinkholes and losing
streambeds within the cave's recharge area. The water quality of
Tumbling Creek may also be threatened due to accidental spills into
sinkholes or losing stream valleys feeding Tumbling Creek Cave from
State and county highways passing through the recharge area. Such
sources of pollution have been identified as potential problems for
ground water in the Springfield-Salem Plateaus of southern Missouri
(including the watershed that encompasses Tumbling Creek and its
identified recharge zone) (Harvey 1980). The decline in numbers of the
Tumbling Creek cavesnail may be due to one or several sources of
pollution that have resulted in a deterioration of water quality within
the recharge area for Tumbling Creek as outlined in Factor A. In
comparing the quality of groundwater sites within the Ozark Plateaus
(including southwestern Missouri) with other National Water-Quality
Assessment Program (NAWQA) sites, Petersen et al. (1998) documented
that: (1) Nitrate concentrations in parts of the Springfield Plateau
aquifer were higher than in most other NAWQA drinking-water aquifers,
and (2) volatile organic compounds were detected more frequently in
drinking-water aquifers within the Ozark Plateaus than in most other
drinking-water aquifers. Tumbling Creek Cave is within the NAWQA study
boundaries; consequently, the cavesnail could be threatened from these
contaminants. Peck (1998) concluded that all aquatic cave species were
especially vulnerable to karst groundwater pollution. Elliott (2000)
summarized numerous examples of cave systems being contaminated by a
wide range of pollutants that are directly or indirectly dumped into
cave streams and further suggested that reduced biotic diversity
correlated with degraded water quality in three caves in Tennessee.
Although no detailed water analyses have yet been performed on Tumbling
Creek, an instrumentation package to measure water quality parameters
will be installed in Tumbling Creek Cave during the summer of 2002.
Aley (pers. comm., Jan. 19, 2001) postulated that the decline in
cavesnail numbers may actually be because of too much gray bat guano
that could deplete oxygen levels in Tumbling Creek, especially during
periods of reduced flows as occurred during 1999-2001. Vandike (1982)
and Elliott (2000) reported on a massive die-off of the Salem cave
crayfish (Cambarus hubrichti) and the southern cavefish (Typhlichthys
subterraneus) when a large quantity of liquid fertilizer containing
ammonium nitrate and urea accidentally spilled into a losing stream and
significantly lowered dissolved oxygen levels in Meramec Spring, which
is 21 km (13 mi) downstream from the spill. What importance gray bat
guano plays in the life history requirements of the Tumbling Creek
cavesnail is yet to be tested experimentally. The instrumentation
package mentioned above will provide data on dissolved oxygen levels
once it is installed.
Tumbling Creek Cave is approximately 45 km (28 mi) southeast of
Branson, MO, which is one of the most rapidly expanding areas in the
State due to tourism, outdoor recreation, and entertainment
developments. If recent trends continue, it has been projected that the
number of visitors attracted to this area would increase from an
estimated level of 6 million in 1992 to 11 million by the year 2015.
The accompanying growth in entertainment- and recreation-related
activities will place even greater demands on this area of the State
(Mullen and Keith 1992). Tumbling Creek Cave is about 4 km (2.5 mi)
northwest of Bull Shoals Lake which is also undergoing additional real
estate development. Consequently, it is likely that sections of the
recharge zone for Tumbling Creek Cave will be adversely affected by
real estate development and related construction and land management
activities. Elliott (2000) provided multiple examples of how various
land development activities have adversely impacted important karst
resources in the eastern United States.
Another potential threat to the species results from the close
hydrologic association of Tumbling Creek with nearby Bull Shoals Lake.
Occasional high water levels in this CE reservoir are believed to cause
water to backup into the cave stream, threatening roosting bats and the
cavesnail (Aley, pers. comm., July 16, 2000). The CE is considering
raising the conservation pool of the reservoir by 10 feet, which will
likely increase the frequency and duration of the backup events in
Tumbling Creek Cave. Lewis (1994) reported that the habitat of the
subterranean hydrobiid snail Antroselates spiralis in Mammoth Cave, KY,
was reduced significantly due to ponding of the adjacent Green River by
a dam downstream of the cave. The back-flooding created a siltation
problem that fragmented previously occupied areas into disjunct islands
of habitat (J. Lewis in litt., January 27, 2002).
Climatic changes, especially recent periods of drought, may also be
a contributing factor to the decline of the cavesnail. The National
Oceanic and Atmospheric Administration's (NOAA) Palmer Drought Severity
Index provides a widely recognized and accepted standard measurement of
moisture conditions (NOAA 2001). The Index varies roughly from -6.0
(extreme drought) to +6.0 (extremely wet), with -0.49 to 0.49
indicating near normal conditions. Since the 1974 survey by Greenlee,
there have been 4 periods in Southwest Missouri where the Index was
below normal for 6 months or longer and was below an Index value of -
2.0 (moderate drought) for some part of that period. These events
occurred in 2-year cycles: 1980-1981; 1991-1992; 1995-1996; and 1999-
2000. The 1980-1981 drought was the most prolonged and severe, with the
Index reaching -5.0 (extreme drought). We further analyzed a 6-year
period between 1995 and 2000, which is the approximate period that
Ashley conducted his cavesnail monitoring. The Index was below normal
for 6 months or more for 4 of these 6 years. The years, number of
months the Index was below normal, and the averages for the negative
indices are: 1995, 6 months, average Index -1.54; 1996, 7 months,
average Index -1.2; 1999, 6 months, average Index -1.29; 2000, 10
months, average Index -1.65. Preliminary data on NOAA's Web site
indicate that below-normal moisture (negative Palmer Index) occurred in
this region during the early part of 2001, but precipitation levels are
now near normal.
According to these climatic data, in 2 recent periods (1995-1996
and 1999-2000) precipitation within the recharge area for Tumbling
Creek Cave was below normal for an extended period. The direct or
indirect impacts of these droughts on the cavesnail are unknown.
Reduced flows in the cave stream, especially when combined with other
threats, could hamper essential life history requirements (e.g.,
reproduction, food availability, water temperature); decrease the
flushing of silt, guano, and harmful contaminants from the stream; and
create an environment more favorable for competitors (e.g., limpets,
isopods, and amphipods).
[[Page 52887]]
The small population size and endemism (i.e., restricted to a
single site) of Antrobia culveri makes it vulnerable to extinction due
to genetic drift, inbreeding depression, and random or chance changes
to the environment (Smith 1990) that can significantly impact cavesnail
habitat. Inbreeding depression can result in death, decreased
fertility, smaller body size, loss of vigor, reduced fitness, and
various chromosome abnormalities (Smith 1990). Despite any evolutionary
adaptations for rarity, habitat loss and degradation increase a
species' vulnerability to extinction (Noss and Cooperrider 1994).
Numerous authors (e.g., Noss and Cooperrider 1994, Thomas 1994) have
indicated that the probability of extinction increases with decreasing
habitat availability. Although changes in the environment may cause
populations to fluctuate naturally, small and low-density populations
are more likely to fluctuate below a minimum viable population (i.e.,
the minimum or threshold number of individuals needed in a population
to persist in a viable state for a given interval; Gilpin and Soule
1986, Shaffer 1981, Shaffer and Samson 1985). Current threats to the
habitat of the Tumbling Creek cavesnail may exacerbate potential
problems associated with its low population numbers and increase the
chances of this species going extinct.
Conclusion
Tumbling Creek cavesnail is known from a single cave in Taney
County, southwestern Missouri. The distribution of this species has
decreased in Tumbling Creek by 90 percent since 1974. Analysis of
survey data collected at established sampling points between September
9, 1996, and March 23, 2002, indicates that numbers of the species have
decreased significantly, and the cavesnail is vulnerable to extinction.
This decline has continued to the point that cavesnails are no longer
present in portions of Tumbling Creek where they had always been found
prior to 2001 using the same monitoring methodology. The Tumbling Creek
cavesnail is likely threatened by habitat degradation through
diminished water quality from upstream locations within the unprotected
or improperly managed areas within the cave's delineated recharge zone.
The dramatic decrease in the population and area occupied by this
species is probably attributable to degraded water quality from one or
a number of the following sources: siltation from poor land management
practices within the cave's recharge area; contamination from numerous
chemicals associated with point or non-point source pollution; or
imbalances in dissolved oxygen, pH, or cation/anion exchange. The
species may also be threatened with competition from limpets or from
changes in the cave's normal hydrological cycles due to recent
droughts. Because the sudden population decline and high magnitude of
threats demonstrates a significant and imminent risk to the well-being
of the Tumbling Creek cavesnail, we find that listing this species as
endangered is appropriate.
In making this determination, we have carefully assessed the best
scientific and commercial information available regarding the past,
present, and future threats faced by the Tumbling Creek cavesnail. From
the discussion under Factor D of this section, it is clear that
currently applicable Federal, State, and local laws, regulations, and
ordinances, individually and collectively, do not provide adequate
protection for the Tumbling Creek cavesnail or its habitat or assure
that the species will continue to survive.
We believe that the survival of the Tumbling Creek cavesnail now
depends on protecting the delineated recharge area of Tumbling Creek
Cave from further degradation and restoring and rehabilitating areas
within the recharge area to improve the water quality in Tumbling
Creek. The small remaining population is vulnerable to extinction from
ongoing threats, as well as from random natural or human-caused events
unless sufficient habitat is protected, water quality improves, and the
current small population greatly increases in size. The recent rapid
population decline makes it clear that this cavesnail is on the brink
of extinction. By listing the Tumbling Creek cavesnail as an endangered
species, we believe the additional protection, funding, and recognition
that immediately become available to the species will greatly increase
the likelihood that extinction can be prevented and the species
ultimately recovered.
We are making this rule effective immediately in order to ensure
there is no gap in the protection provided by the Act to the Tumbling
Creek cavesnail. The temporary protection that was provided by our
emergency listing of the species on December 27, 2001, ends on August
26, 2002. This final rule results in no change to the temporary
protection and regulatory authority that was provided by the emergency
listing, so there is no overriding need for a delayed effective date in
order to provide adequate time to notify individuals, agencies, and
organizations of new regulations that may affect them.
Critical Habitat
Critical habitat is defined in section 3 of the Act as: (i) The
specific areas within the geographical area occupied by a species, at
the time it is listed in accordance with the Act, on which are found
those physical or biological features (I) essential to the conservation
of the species and (II) that may require special management
considerations or protection; and (ii) specific areas outside the
geographical area occupied by a species at the time it is listed, upon
a determination that such areas are essential for the conservation of
the species. ``Conservation'' means the use of all methods and
procedures needed to bring the species to the point at which listing
under the Act is no longer necessary.
Section 4(a)(3) of the Act, as amended, and implementing
regulations (50 CFR 424.12) require that, to the maximum extent prudent
and determinable, we designate critical habitat at the time the species
is determined to be endangered or threatened. However, our budget for
listing and critical habitat activities is currently insufficient to
allow us to immediately complete all of the listing actions required by
the Act. Listing the Tumbling Creek cavesnail without designation of
critical habitat will allow us to concentrate our limited resources on
other listing actions that must be addressed, while allowing us to
invoke protections needed for the conservation of this species without
further delay. This is consistent with section 4(b)(6)(C)(i) of the
Act, which states that final listing decisions may be issued without
critical habitat designations when it is essential that such
determinations be promptly published. The legislative history of the
1982 Act amendments also emphasized this point: ``The Committee feels
strongly, however, that, where biology relating to the status of the
species is clear, it should not be denied the protection of the Act
because of the inability of the Secretary to complete the work
necessary to designate critical habitat. * * * The committee expects
the agencies to make the strongest attempt possible to determine
critical habitat within the time period designated for listing, but
stresses that the listing of species is not to be delayed in any
instance past the time period allocated for such listing if the
biological data is clear but the habitat designation process is not
complete.'' (H.R. Rep. No. 97-567 at 20 (1982)). If prudent and
determinable, we will prepare a critical habitat proposal in the future
at such time as our
[[Page 52888]]
available resources and other listing priorities under the Act will
allow.
Available Conservation Measures
Conservation measures provided to species listed as endangered or
threatened under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing results in public awareness and
conservation actions by Federal, Tribal, State, and local agencies,
private organizations, and individuals. The Act provides for possible
land acquisition and cooperation with the State and requires that
recovery actions be carried out for all listed species. The protection
required of Federal agencies and the prohibitions against certain
activities involving listed species are discussed, in part, below.
Section 7(a) of the Act, as amended, requires Federal agencies to
evaluate their actions with respect to any species that is proposed or
listed as endangered or threatened, and with respect to its critical
habitat, if any is being designated. Regulations implementing this
interagency cooperation provision of the Act are codified at 50 CFR
part 402. If a species is listed on an emergency basis, or is listed
under a non-emergency listing proposal, section 7(a)(2) requires
Federal agencies to ensure that activities they authorize, fund, or
carry out are not likely to jeopardize the continued existence of such
a species or to destroy or adversely modify its critical habitat. If a
Federal agency action may adversely affect a listed species or
adversely modify its designated critical habitat, the responsible
Federal agency must initiate formal consultation with the Service.
Section 7(a)(4) of the Act requires Federal agencies to confer with us
on any action that is likely to jeopardize the continued existence of a
proposed species or result in destruction or adverse modification of
proposed critical habitat. Federal agency actions that may affect the
Tumbling Creek cavesnail and may require consultation with the Service
include, but are not limited to, those within the jurisdiction of the
U.S. Forest Service, U.S. Army Corps of Engineers, Natural Resources
Conservation Service, Environmental Protection Agency, and Federal
Highway Administration.
The Act and its implementing regulations found at 50 CFR 17.21 set
forth a series of general prohibitions and exceptions that apply to all
endangered wildlife. These prohibitions, in part, make it illegal for
any person subject to the jurisdiction of the United States to take
(including harass, harm, pursue, hunt, shoot, wound, kill, trap,
capture, or collect; or attempt any such conduct), import or export,
ship in interstate or foreign commerce in the course of commercial
activity, or sell or offer for sale in interstate or foreign commerce
any listed species. It also is illegal to possess, sell, deliver,
carry, transport, or ship any such wildlife that has been taken
illegally. Certain exceptions apply to Service agents and those of
State conservation agencies.
Permits may be issued to carry out otherwise prohibited activities
involving endangered wildlife under certain circumstances. Regulations
governing permits are codified at 50 CFR 17.22 and 17.23. For
endangered species, such permits are available for scientific purposes,
to enhance the propagation or survival of the species, and for
incidental take in connection with otherwise lawful activities.
As published in the Federal Register on July 1, 1994 (59 FR 34272),
it is the Service's policy to identify, to the maximum extent
practicable at the time a species is listed, those activities that
would or would not constitute a violation of section 9 of the Act. The
intent of this policy is to increase public awareness of the effect of
the listing on proposed and ongoing activities within a species' range.
We believe that, based on the best available information, the
following actions are not likely to result in a violation of section 9,
provided these actions are carried out in accordance with any existing
regulations and permit requirements:
(1) Possession of a Tumbling Creek cavesnail legally acquired prior
to the effective date of this rule;
(2) Actions that may affect the Tumbling Creek cavesnail that are
authorized, funded, or carried out by a Federal agency, when the action
is conducted in accordance with an incidental take statement issued by
the Service under section 7 of the Act;
(3) Actions that may affect the Tumbling Creek cavesnail that are
not authorized, funded, or carried out by a Federal agency, when the
action is conducted in accordance with an incidental take permit issued
by the Service under section 10(a)(1)(B) of the Act. Applicants design
a Habitat Conservation Plan (HCP) and apply for an incidental take
permit. These HCPs are developed for species listed under section 4 of
the Act and are designed to minimize and mitigate impacts to the
species to the greatest extent practicable; and
(4) Actions that may affect the Tumbling Creek cavesnail that are
conducted in accordance with the conditions of a section 10(a)(1)(A)
permit for scientific research or to enhance the propagation or
survival of the species.
We believe that the following actions could result in a violation
of section 9; however, possible violations are not limited to these
actions alone:
(1) Unauthorized possession, collecting, trapping, capturing,
killing, harassing, sale, delivery, or movement, including interstate
and foreign commerce, or harming, or attempting any of these actions,
of Tumbling Creek cavesnails without a permit (research activities
where cavesnails are collected will require a permit under section
10(a)(1)(A) of the Endangered Species Act);
(2) Illegal discharges or dumping of toxic chemicals, silt, or
other pollutants (point source and non-point source pollution) within
the recharge area of Tumbling Creek Cave that alters or degrades the
water quality of Tumbling Creek to the point that it results in death
or injury to individuals of the species or results in degradation of
cavesnail-occupied habitat;
(3) Intentional release of exotic species (including, but not
limited to, fish and crayfish) into Tumbling Creek that adversely
affect the cavesnail;
(4) Unlawful destruction or alteration of the species' occupied
habitat (e.g., vandalism to Tumbling Creek); and
(5) Violation of any discharge or water withdrawal permit within
Tumbling Creek.
We will review other activities not identified above on a case-by-
case basis to determine whether they are likely to result in a
violation of section 9 of the Act. We do not consider these lists to be
exhaustive and provide them as information to the public.
Questions regarding whether specific activities will constitute a
violation of section 9 should be directed to the Field Supervisor of
the Columbia, Missouri Field Office (see FOR FURTHER INFORMATION
CONTACT).
Requests for copies of the regulations regarding listed species and
inquiries regarding prohibitions and permits may be addressed to the
U.S. Fish and Wildlife Service, Endangered Species Permits, Bishop
Whipple Federal Building, 1 Federal Dr., Fort Snelling, MN 55111-4056
(612/713-5343, facsimile 612/713-5292).
National Environmental Policy Act
The Service has determined that an Environmental Assessment, as
defined under the authority of the National Environmental Policy Act of
1969, need not be prepared in connection with
[[Page 52889]]
regulations adopted pursuant to section 4(a) of the Endangered Species
Act, as amended. The Service published a notice outlining our reasons
for this determination in the Federal Register on October 25, 1983 (48
FR 49244).
Paperwork Reduction Act
This rule does not contain any collections of information that
require additional Office of Management and Budget (OMB) approval under
the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An information
collection related to the rule pertaining to permits for endangered and
threatened species has OMB approval and is assigned control number
1018-0094, which expires on July 31, 2004. This rule does not alter
that information collection requirement. An agency may not conduct or
sponsor, and a person is not required to respond to, a collection of
information unless it displays a currently valid control number. For
additional information concerning permits and associated requirements
for endangered wildlife, see 50 CFR 17.21 and 17.22.
Effective Date
This rule is effective upon publication. The Administrative
Procedures Act provides Federal agencies a means under 5 U.S.C. (d)(3)
for making rules effective less than 30 days following publication in
the Federal Register for ``good cause.'' We believe that we have good
cause for making this rule effective upon publication. The emergency
listing rule for the Tumbling Creek cavesnail was published in the
Federal Register on December 27, 2001 (66 FR 66803). That rule listed
the Tumbling Creek cavesnail as endangered on an emergency basis for
240 days through August 26, 2002. We are now publishing a final rule to
the proposed rule (66 FR 66868) that we published on the same day as
the emergency listing rule. To continue to provide this species the
protections of the Act originally provided under the emergency rule, we
must make this final rule effective upon publication.
References Cited
A complete list of all references cited in this rulemaking is
available upon request from the Field Supervisor, Columbia Field Office
(see ADDRESSES).
Author
The primary author of this proposed rule is Paul M. McKenzie,
Ph.D., U.S. Fish and Wildlife Service, Columbia Field Office (see
ADDRESSES).
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Regulation Promulgation
For the reasons given in the preamble, we amend part 17, subchapter
B of chapter I, title 50 of the Code of Federal Regulations, as set
forth below:
PART 17--[AMENDED]
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; Pub. L. 99-625, 100 Stat. 3500, unless otherwise noted.
2. Amend Sec. 17.11(h) by adding the following, in alphabetical
order under SNAILS, to the List of Endangered and Threatened Wildlife:
Sec. 17.11 Endangered and threatened wildlife.
* * * * *
(h) * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Vertebrate
------------------------------------------------------ population where Critical Special
Historic range endangered or Status When listed habitat rules
Common name Scientific name threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * * * *
SNAILS
* * * * * * *
Cavesnail, Tumbling Creek Antrobia culveri... U.S.A. (MO)........ NA................. E 731 NA NA
* * * * * * *
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Dated: July 26, 2002.
Steve Williams,
Director, Fish and Wildlife Service.
[FR Doc. 02-20339 Filed 8-13-02; 8:45 am]
BILLING CODE 4310-55-P