Endangered and Threatened Wildlife and Plants; 90-day Finding on a Petition To Delist Seven Texas Karst Invertebrates

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; 90-day Finding on

a Petition To Delist Seven Texas Karst Invertebrates

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of petition finding.

-----------------------------------------------------------------------

SUMMARY: The U.S. Fish and Wildlife Service (Service) announces a 90-

day finding on a petition to remove seven species of invertebrates that

occur in karst topography in Travis and Williamson counties, Texas,

from the List of Endangered and Threatened Wildlife and Plants. The

Service determines that the petition does not present substantial

scientific or commercial information indicating that delisting the

Coffin Cave mold beetle (Batrisodes texanus), the Tooth Cave spider

(Neoleptoneta myopica), the Tooth Cave ground beetle (Rhadine

persephone), the Tooth Cave pseudoscorpion (Tartarocreagris texana),

the Kretschmarr Cave mold beetle (Texamaurops reddelli), the Bee Creek

Cave harvestman (Texella reddelli), and the Bone Cave harvestman

(Texella reyesi) may be warranted.

DATES: The finding announced in this notice was made on March 7, 1994.

Comments and information related to this petition finding may be

submitted until further notice.

ADDRESSES: Information, comments, or questions may be submitted to the

State Administrator, U.S. Fish and Wildlife Service, Ecological

Services Field Office, 611 East 6th Street, room 407, Austin, Texas

78701. The petition, finding, supporting data, and comments will be

available for public inspection, by appointment, during normal business

hours at the above address.

FOR FURTHER INFORMATION CONTACT: Ruth Stanford, Ecologist, at the above

address (512/482-5436).

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(A) of the Endangered Species Act of 1973, as

amended (16 U.S.C. 1531 et seq.) (Act), requires that the Service 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. To the maximum

extent practicable, this finding is to be made within 90 days of

receipt of the petition, and the finding is to be published promptly in

the Federal Register. If the finding is positive, the Service is also

required to promptly commence a status review of the species.

Judge John C. Doerfler, representing the Williamson County

Commissioners Court, submitted a petition to the Service to delist six

species of endangered karst invertebrates in Travis and Williamson

counties, Texas. The petition was dated June 7, 1993, and received by

the Service on that date. On June 16, 1993, the Service received a

letter from attorney J.B. Ruhl on behalf of the petitioners, clarifying

the intent of the petition to incorporate recent taxonomic revisions

and the taxonomic reevaluation of five listed karst invertebrate

species as seven species.

The final rule listing the Tooth Cave pseudoscorpion (Microgreagris

texana), the Tooth Cave spider (Leptoneta myopica), the Bee Creek Cave

harvestman (Texella reddelli), the Tooth Cave ground beetle (Rhadine

persephone), and the Kretschmarr Cave mold beetle (Texamaurops

reddelli) as endangered species was published in the Federal Register

on September 16, 1988 (53 FR 36029) (final rule). Subsequent taxonomic

revisions have formalized genus reassignments for M. texana and L.

myopica and established that Texella reddelli and Texamaurops reddelli

each actually comprise two species. Microcreagris texana has been

reassigned to Tartarocreagris texana (Muchmore 1992). Leptoneta myopica

has been formally reassigned to Neoleptoneta myopica following Brignoli

(1977) and Platnick (1986). Texella reddelli has been found to comprise

two species, Texella reddelli (Bee Creek Cave harvestman) and Texella

reyesi (Bone Cave harvestman) (Ubick and Briggs 1992). Texamaurops

reddelli has been found to comprise two species, Texamaurops reddelli

(Kretschmarr Cave mold beetle) and Batrisodes texanus (Coffin Cave mold

beetle) (Chandler 1992). A Federal Register notice announcing the

latter two revisions was published on August 18, 1993 (58 FR 43818).

Several caves in Travis County contain more than one of the

endangered karst invertebrates. These include Tooth Cave, Amber Cave,

Gallifer Cave, Kretschmarr Cave, and Kretschmarr Double Pit. These

caves and others are protected under the stewardship of the Texas

System of Natural Laboratories (TSNL). In addition, some other caves

are in preserves regulated by the Cities of Austin and Georgetown. (For

further discussion, see Factor D, ``The inadequacy of existing

regulatory mechanisms,'' below.) However, many of the caves containing

endangered karst invertebrates currently have no protection other than

that provided by the Act.

The petitioners point out that, since publication of the final

rule, new locations have been discovered for several of the species,

most notably the Tooth Cave ground beetle and the Bone Cave harvestman.

The Tooth Cave ground beetle was known from two caves about 2.5

kilometers (km) (1.5 miles (mi)) apart in Travis County, Texas, at the

time of listing. It is currently known from about 27 locations (24

confirmed, 3 tentative) along a 14-km (9-mi) distance in Travis and

Williamson counties, Texas. Only 10 of these caves are provided any

degree of local protection (James Reddell, Texas Memorial Museum, in

litt., 1993). Seven of these caves are located in the small TSNL

preserves discussed above, one is in a small preserve owned by the City

of Austin, and two are in small preserves acquired as mitigation for a

development project.

The Bone Cave harvestman was not described at the time of the

original listing, but was thought to be the same species as the Bee

Creek Cave harvestman. The Bone Cave harvestman is currently known from

about 69 locations (60 confirmed, 9 tentative) along a 40-km (25-mi)

distance in Travis and Williamson counties, Texas. Of the 69 caves

recorded as locations of the Bone Cave harvestman, only 9 are provided

any local protection. Three are TSNL caves, two are in City of Austin

preserves, two are in City of Georgetown preserves, and two were

acquired as mitigation for a development project. In addition, this

species exhibits considerable geographical variation and loss of a

significant number of locations within a part of its range would result

in a loss of genetic diversity within the species (Reddell, in litt.,

1993). Few caves are provided any protection other than that now

provided by the Act and their distribution is disjunct and at the

extremes of the species' range.

The number of caves in which the other five endangered karst

invertebrates have been found or tentatively identified has increased

slightly for three of the species, remained the same for another

species (although its range has decreased), and decreased for the fifth

species.

The Tooth Cave pseudoscorpion, known at the time of listing from

Tooth and Amber caves, within a 1.3-km (0.8-mi) radius in Travis

County, remains confirmed only from the two original caves. The species

has been tentatively identified from Stovepipe Cave and Kretschmarr

Double Pit, lying within the original range. Stovepipe Cave is located

on private property that the City of Austin has approved for

development. The three remaining caves are located in the small TSNL

preserves discussed above.

The Tooth Cave spider, known at the time of listing only from Tooth

Cave, is now also confirmed at New Comanche Trail Cave and tentatively

identified from Gallifer and Stovepipe caves, all lying along a 4.5-km

(3-mi) distance in northwest Travis County, Texas. Tooth and Gallifer

caves lie within small TSNL preserves, Stovepipe Cave is on private

property approved for development, and New Comanche Trail Cave is not

protected and may be adversely impacted by a planned realignment of New

Comanche Trail Road.

The Coffin Cave mold beetle was not described at the time of

listing, but was thought to belong to the same species as the

Kretschmarr Cave mold beetle. The Coffin Cave mold beetle is currently

confirmed from four caves and tentatively identified from one cave, all

occurring along a 17-km (10-mi) distance in Williamson County, Texas.

Off Campus and Sierra Vista caves are located in a small preserve

surrounded by a subdivision; the adequacy of the preserve for long-term

protection of the species at those sites is uncertain. On Campus Cave

lies on a high school campus. The status of the type locality (Coffin

Cave) is unknown; recent attempts to locate the species in Inner Space

Cavern were unsuccessful (Reddell, in litt., 1993).

The Kretschmarr Cave mold beetle was believed to occur in four

caves in Travis and Williamson counties at the time of listing and is

currently known from four caves in Travis County. A specimen from

Coffin Cave was redescribed as the Coffin Cave mold beetle and a new

location for the Kretschmarr Cave mold beetle was discovered at

Stovepipe Cave. The range of the Kretschmarr Cave mold beetle has

consequently decreased since the original listing from a 45-km (28-mi)

distance in Travis and Williamson counties to a 2-km (1.2-mi) distance

in Travis County. Stovepipe Cave lies within a proposed subdivision and

the other three locations for the species, Tooth, Amber, and

Kretschmarr caves, lie within small TSNL preserves.

The Bee Creek Cave harvestman was believed to occur in five caves

in Travis and Williamson counties at the time of listing. It is

currently confirmed at four caves and tentatively identified from two

caves. The distribution of the Bee Creek Cave harvestman consists of

two disjunct areas, one about 5 km (3 mi) long and the other about 8 km

(5 mi) in length, with a distance of about 28 km (17 mi) between the

northernmost and southernmost localities, all of which lie in Travis

County. Little Bee Creek Cave, Jester Estates Cave, and Kretschmarr

Double Pit (a TSNL cave) are located in small preserve areas. Bandit

Cave is maintained as a small preserve, although attempts to relocate

the Bee Creek Cave harvestman in the cave in 1966, 1988, and 1989 were

unsuccessful (Reddell, in litt., 1993). Cave Y is located in a proposed

development area; the species' status in Bee Creek Cave is unknown

since it has not been possible to obtain permission to inspect the cave

since 1975 (Reddell, in litt., 1993).

None of these invertebrates are known to occur in large numbers

(William Elliott, Texas Memorial Museum, in litt., 1993; Reddell, in

litt. and pers. comm., 1993). The fact that several of the species are

known to occur at several dozen locations should not be interpreted to

mean that those species are abundant. (See Factor A, ``The present or

threatened destruction, modification, or curtailment of its habitat or

range,'' below).

Summary of Factors Affecting the Species

Section 4(a)(1) of the Act and its implementing regulations (50 CFR

part 424) set forth the procedures for adding species to or removing

species from the Federal Lists. 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). These factors and their application to

the seven karst invertebrates are re-evaluated in light of new

information available to the Service and information presented in the

petition and are as follows:

A. The Present or Threatened Destruction, Modification, or Curtailment

of Its Habitat or Range

The Service determined that the primary threat to these species

comes from loss of habitat due to ongoing and proposed development

activities (final rule). The proximity of the caves inhabited by these

species to the City of Austin makes them vulnerable to continuing

expansion of the Austin metropolitan area. Threats to specific caves

occupied by these species were addressed in the final rule (53 FR

36029).

The known ranges of the Tooth Cave pseudoscorpion, the Tooth Cave

spider, the Kretschmarr Cave mold beetle, the Coffin Cave mold beetle,

and the Bee Creek Cave harvestman have not appreciably increased since

the original listing. Although the range and number of known locations

for the Tooth Cave ground beetle and the Bone Cave harvestman have

increased since the original listing, the degree of threat of habitat

destruction or modification remains significant, and may have

increased, throughout the range of each species.

Searches for karst features and karst fauna surveys have become

more frequent since the listing, as developers and landowners have

sought to comply with the Act. Many of the new locations of these karst

invertebrates have been discovered as a result of biological surveys

conducted prior to development or sale of land; consequently, newly

discovered locations are frequently threatened by habitat destruction

and other threats associated with development. The recent

revitalization of the real estate market in the Austin metropolitan

area has maintained and intensified the threat of karst invertebrate

habitat destruction and other associated threats.

The petitioners present a list of caves with endangered species

that have been subject to some degree of disturbance. They cite these

cases as demonstrating that activities such as dumping, vandalism, and

sealing of cave entrances do not actually threaten the karst

invertebrates. Reddell (in litt., 1993) counters that, in most of these

cases, the disturbance to the cave environment is recent in origin,

minor in scale, and/or generally restricted to the immediate entrance

zone. The Service concurs with Reddell and believes that these examples

do not present convincing evidence that dumping, vandalism, and sealing

entrances are harmless to the karst invertebrates. In most cases, not

enough time has elapsed since the disturbance to detect an effect on

the karst invertebrates. The Service agrees with the petitioners that

there is little quantitative data available on the direct effects of

trash dumping, vandalism, sealing, and other disturbances on the karst

invertebrates. However, there is substantial qualitative evidence

indicating that the threats to the karst invertebrates discussed in the

final rule and in this finding are real, significant, and ongoing.

Reddell (in litt., 1993) and Elliott (in litt., 1993) both cite

examples in which trash dumping, vandalism, and over-visitation have

resulted in decreased occurrence of karst invertebrates in affected

areas.

The petitioners cite the work of Crawford (1981) and Veni (1992) as

evidence that the caves where the karst invertebrates occur are not

isolated ``islands'' of special habitat and that the invertebrates

likely occur and move throughout the karst in the interstitial spaces.

In this interpretation, the petitioners misunderstand the Service's use

of the ``island'' analogy in the final rule. The final rule listing the

karst invertebrates stated that the caves containing the karst

invertebrates ``occur in isolated `islands' '' of the Edwards limestone

formation that were separated from one another when stream channels cut

through overlying limestone to lower rock layers'' (53 FR 36029). The

Service applied the island analogy to the distinct, geologically

isolated karst areas (referred to in the Draft Recovery Plan (U.S. Fish

and Wildlife Service 1993) and hereinafter as ``regions'') within which

the caves containing the karst invertebrates have formed, not to the

individual cave systems. Veni's work (1992) delineates these karst

regions and identifies areas ``having a high probability of suitable

habitat for endangered or other endemic invertebrate cave fauna.'' A

letter from Veni in response to the petition clarifies that he did not

intend that his work be interpreted to mean that there are thousands of

acres of habitat suitable for the karst invertebrates (George Veni,

Veni and Associates, in litt., 1993).

While the Service believes that the karst invertebrates are likely

to use interstitial spaces in the karst, particularly in areas with

some surface nutrient input to the karst system, the Service does not

believe that this suitable habitat exists uniformly within the larger

karst regions (as delineated by Veni (1992) and described by the

Service in the final rule as ``islands''). Finally, Crawford (1981)

focuses on aquatic karst species. In the aquatic karst ecosystems upon

which Crawford based his ideas, continuously flowing water through

caves and the interstitium may provide more continuous habitat for

aquatic subterranean species and thus provide more opportunity for

aquatic invertebrates to inhabit interstitial spaces. Given that the

Travis and Williamson County karst invertebrates are exclusively

terrestrial and that habitat for terrestrial species is more patchy and

distributed according to the occurrence of food, cover, and moisture,

Crawford's ideas may not apply to these invertebrates.

The petitioners cite the work of Curl (1966), Juberthei and Delay

(1981), and Culver (1986) as evidence that most caves have no entrance,

that caves are rare even in karst areas, and that caves may be less

favorable environments for karst invertebrates than interstitial

spaces. They cite these papers as evidence that habitat for terrestrial

troglobites (obligate cave-dwelling species) is ubiquitous in karst

areas and that the Texas karst invertebrates exist throughout the karst

even where there are no caves or openings to the surface. Culver (1986)

says that ``the number of caves (defined as cavities large enough for

human access) more or less corresponds to the number of habitable

patches for terrestrial troglobites.'' Reddell (in litt., 1993) and

Peck (1976) believe that cave entrances provide an important avenue of

nutrient input for cave fauna. Reddell (in litt., 1993) also cites

several examples in which sub-surface voids having no natural entrance

were encountered during construction activities and found not to

contain karst invertebrates. Similarly, clay-filled sinkholes with no

openings to the surface rarely contain karst invertebrates, whereas

caves and sinkholes that are sealed to human access by soil or rock

fill or with openings to the surface that allow access by cave crickets

or small mammals (and associated nutrients) more often contain karst

fauna (Reddell, in litt., 1993).

B. Overutilization for Commercial, Recreational, Scientific or

Educational Purposes

No threat from overutilization of these species is known to exist

at this time. Collection for scientific or educational purposes could

become a threat if specific localities become widely known.

C. Disease or Predation

At the time of listing, predation by and competition with non-

native species introduced in association with human habitation was

considered a potential threat to the karst invertebrates. Human

activities facilitate movement of non-native competitors and predators

such as sowbugs, cockroaches, and fire ants into an area. Buildings,

lawns, roadways, and landscaped areas provide habitat from which these

species can disperse. The relative accessibility of the shallow caves

in Travis and Williamson counties makes them especially vulnerable to

invasion by non-native species.

Fire ants are a major threat to the karst invertebrates. The

significance of this threat and the difficulty of controlling fire ants

should not be underestimated. Fire ants are voracious predators and

there is evidence that overall arthropod diversity drops in their

presence (Vinson and Sorensen 1986, Porter and Savignano 1990). Reddell

(in litt., 1993) lists at least nine cave-inhabiting species that he

has observed being preyed upon by fire ants. Elliott (1992) cites other

examples and notes that fire ant activity has increased dramatically in

Central Texas since 1989.

Although the threat posed by fire ants was not recognized at the

time these species were listed, the magnitude of the threat the ants

pose has subsequently become quite apparent. Even in the unlikely event

that fire ants do not prey upon the listed species, their presence in

and around caves could have a drastic detrimental effect on the cave

ecosystem through loss of species, inside the cave and out, that

provide nutrient input and critical links in the food chain.

Controlling fire ants once they have invaded the cave and vicinity

is difficult. Chemical control methods have some effectiveness but the

effect of these agents on non-target species is unclear. Consequently,

using chemicals to control fire ants in and near caves is not

advisable. Currently, the Service recommends only boiling water

treatment for control of fire ant colonies near caves inhabited by

listed invertebrates. This method is labor-intensive and only

moderately effective. Presently, the burden of carrying out such

practices is not a designated or mandated duty of any agency,

individual, or organization. This type of control will likely be needed

indefinitely or until a long-term method of fire ant control is

developed.

D. The Inadequacy of Existing Regulatory Mechanisms

Invertebrates are not included on the Texas Parks and Wildlife

Department's list of threatened and endangered species and are provided

no protection by the State; nor do the Department regulations contain

provisions for protecting habitat of any listed species.

As previously discussed, some of the caves containing endangered

invertebrates are in TSNL and city preserves. A small preserve

surrounds the entrance to each of these caves. However, these preserves

encompass only a fraction of the surface drainage area that provides

input of nutrients and moisture into the caves. The entire surface and

subsurface drainage area is the minimum area believed necessary to

provide adequate long-term protection for cave ecosystems. The

preserves around these caves are not sufficient to counter nutrient

depletion and prevent pollution, should the surrounding areas be

developed.

Some of the TSNL caves are under temporary deed to TSNL and may be

sold at the owner's discretion (U.S. Fish and Wildlife Service 1993).

In addition, City of Austin cave protection laws do not apply in most

cases, since the great majority of these caves lie outside the city

limits.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

The Service is unaware of other threats to these species beyond

those discussed under factors A-D (above). As noted under Factor A, the

Bone Cave harvestman exhibits considerable geographical variation. Loss

of a number of locations within any one part of its range would result

in a loss of genetic diversity for the species (Reddell, in litt.,

1993). The Tooth Cave pseudoscorpion, Tooth Cave spider, Coffin Cave

and Kretschmarr Cave mold beetles, and Bee Creek Cave harvestman are

each known from fewer than 10 locations (4, 4, 5, 4, and 6 locations

respectively, including unconfirmed identifications). Therefore, the

loss of even a single location would represent a significant loss of

genetic diversity for any of those species. Lack of genetic diversity

can accelerate the decline or extinction of rare species.

Conclusion

As discussed in the final rule, these species remain extremely

vulnerable to losses. For the Tooth Cave pseudoscorpion, the Tooth Cave

spider, the Kretschmarr Cave mold beetle, the Coffin Cave mold beetle,

and the Bee Creek Cave harvestman, neither the range nor the number of

confirmed localities within the range has expanded significantly since

the original listing. The Tooth cave ground beetle and the Bone Cave

harvestman occur in more locations and are more widespread than was

originally believed, but the expansion of the overall range is not

significant and the majority of caves in which these species occur are

subject to one or more of the threats discussed above (Reddell, in

litt., 1993).

The Service recently released a Draft Recovery Plan for the karst

invertebrates (U.S. Fish and Wildlife Service 1993). That document

details recovery actions and criteria that, when met, may result in

reclassification or delisting of the endangered karst invertebrates.

Continued efforts to locate new inhabited caves, to implement habitat

conservation measures, and to control the threat of fire ants could

bring the karst invertebrates to the point where protection under the

Act is no longer necessary.

The Service has carefully assessed the information presented in the

petition, as well as the best and most current scientific and

commercial information, in determining that the petition does not

present substantial scientific and commercial information indicating

that delisting of any of the seven karst invertebrates may be

warranted. These species continue to require the protection provided by

the Act because of their extremely small, vulnerable, and limited

habitats located within an area that is experiencing continued

pressures from economic and population growth.

References Cited

Brignoli, P.M. 1977. Spiders from Mexico. III. A new leptonetid from

Oaxaca (Araneae, Leptonetidae). Acad. Naz. Lincei, Probl. Att. Sci.

Cult., 171(3): 213-218.

Chandler, D.S. 1992. The Pselaphidae of Texas caves (Coleoptera).

Pages 241-254 in: Texas Memorial Museum Speleological Monographs 3:

Studies on the cave and endogean fauna of North America II. Edited

by James Reddell. 257 pp.

Crawford, R.L. 1981. A critique of the analogy of caves and islands.

Proc. Eighth Intl. Cong. of Speleol. 1:295-297.

Culver, D.C. 1986. Cave Faunas. Pages 427-443 in: Conservation

Biology: The science of scarcity and diversity. M.F. Soule (ed.).

Sinauer Associates, Sunderland, MA. 584 pp.

Curl, R.L. 1966. Caves as a measure of karst. J. of Geology 74:798-

830.

Elliott, W.R. 1992 (rev. 1993). Fire Ants and Endangered Cave

Invertebrates: A Control and Ecological Study. Section 6 report

prepared for the Texas Parks and Wildlife Department and the U.S.

Fish and Wildlife Service.

Juberthei, C., and B. Delay. 1981. Ecological and biological

implications of the existence of a ``superficial underground

compartment.'' Proc. Eighth Intl. Cong. of Speleol. 1:203-206.

Muchmore, W.B. 1992. Cavernicolous pseudoscorpions from Texas and

New Mexico (Arachnida:Pseudoscorpionida). Pages 127-154 in: Texas

Memorial Museum Speleological Monographs 3: Studies on the cave and

endogean fauna of North America II. Edited by James Reddell. 257 pp.

Peck, S.B. 1976. The effect of cave entrance on the distribution of

cave-inhabiting terrestrial arthropods. Int. J. Speleol. 8:309-321.

Platnick, N.I. 1986. On the tibial and patellar glands,

relationships, and American genera of the spider family Leptonetidae

(Arachnida, Araneae). Amer. Mus. Novit., 2855. 16 pp.

Porter, S.D., and S.A. Savignano. 1990. Invasion of polygyne fire

ants decimates native ants and disrupts arthropod community. Ecology

71(6):2095-2106.

Ubick, D., and T.S. Briggs. 1992. The harvestman family

Phalangodidae. 3. Revision of Texella Goodnight and Goodnight. Pages

155-240 in: Texas Memorial Museum Speleological Monographs 3:

Studies on the cave and endogean fauna of North America II. Edited

by James Reddell. 257 pp.

U.S. Fish and Wildlife Service. 1993. Draft Recovery Plan for

Endangered Karst Invertebrates in Travis and Williamson Counties,

Texas. Albuquerque, New Mexico. 133 pp.

Veni and Associates. 1992. Geologic controls on cave development and

the distribution of cave fauna in the Austin, Texas, region.

Prepared for the U.S. Fish and Wildlife Service. v + 77 pp.

Vinson, S.B., and A.A. Sorensen. 1986. Imported Fire Ants: Life

history and impact. Texas Dept. of Agriculture 1986. 28 pp.

Author

The primary author of this notice is Ruth Stanford (See ADDRESSES

section).

Authority

The authority for this action is the Endangered Species Act of

1973, as amended (16 U.S.C. 1531-1544).

List of Subjects in 50 CFR Part 17

Endangered and threatened species, Exports, Imports, Reporting and

recordkeeping requirements, and Transportation.

Dated: March 7, 1994.

Mollie H. Beattie,

Director, Fish and Wildlife Service.

[FR Doc. 94-5854 Filed 3-11-94; 8:45 am]

BILLING CODE 4310-55-P