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Texas Endangered Invertebrate Species
|
RECOVERY
PLAN FOR ENDANGERED
KARST INVERTEBRATES IN
TRAVIS AND Prepared
by: and Ruth
A. Stanford Edited
by: For: Region
2 LITERATURE
CITATIONS Literature
citations for this document should read as follows: U. S. Fish and Wildlife Service.
1994. Recovery Plan for Endangered Karst Invertebrates in
Travis and Williamson Counties, Additional copies may be
purchased from: Fish and Wildlife Reference
Service (301) 492-6403 or 1-800-582-3421 The fee for the plan varies depending
on the number of pages of the plan. The study of caves and karst in process. Much of the information
presented in this plan was derived from research in
progress. Besides William R. Elliott, who prepared the initial
draft of this plan, contributors include James R.
Reddell, George Veni, Mike Warton, and Bill provided
significant comments to William Elliott in the early
development stages of this plan. EXECUTIVE SUMARY OF THE RECOVERY PLAN OR
ENDANGERED KARST INVERTEBRATES IN TRAVIS AND Current
Species’ Status: All seven species (Texella reddelli, Texella reyesi,
Tartarocreagris texana, Neoleptoneta
myopica, Rhadine persephone,
Texamaurops reddelli, and Batrisodes texanus) are
endangered. They spend their entire lives underground and are endemic to
karst formations (caves, sinkholes, and other subterranean voids) in Travis
and Williamson counties, Habitat
Requirements and Limiting Factors: All tend to
occur in the dark
zone of caves, but occasionally in deep twilight. All prefer
relative humidities near 100%, but some may be less sensitive to
drying than others. Presumably all are predators upon small or
immature arthropods, or, as in the case of the ground beetle,
possibly cave cricket eggs. TABLE OF CONTENTS Disclaimer Literature Citations Table of Contents I. Introduction and
Background A.
Taxonomic and Legal Classification, and Description B.
Distribution C.
Habitat, Ecosystem, and Ecology D.
Reasons for Listing and Current Threats II. Recovery A.
Objective and Criteria B.
Recovery Outline C.
Narrative Outline for Recovery Actions III. Implementation Schedule IV. Appendices A.
Glossary B.
List of Commenters C.
Summary of Comments and USFWS Response Tables Table 1 – 3 Figures Figure 1 - 11 I. INTRODUCTION AND BACKGROUND [Appendix A contains a glossary
of terms used in this recovery plan. Terms defined in
the glossary are indicated by BOLD face type in the text.] This
recovery plan covers seven species of karst invertebrates and their
ecosystems. The seven species are: Texella
reddelli ( Texella reyesi
( Tartarocreagris
texana ( Neoleptoneta
myopica (Tooth Cave spider), Rhadine
persephone ( Texamaurops
reddelli ( Batrisodes
texanus ( Five species (Texella
reddelli, Tartarocreagris texana, Neoleptoneta
myopica, Rhadine persephone, and Texamaurops reddelli) were listed as
endangered on (53 FR 36029).
A refinement of the taxonomy has expanded this group into seven distinct
species (58 FR 43818) Because Texella reyesi and
Batrisodes texanus were considered to be populations of Texella
reddelli and Texamaurops
reddelli, respectively, at the time of listing, they are also considered to be
listed as endangered under the Endangered Species Act (58.FR
43818). Of
the seven listed species, three are insects (one ground beetle and two mold
beetles) and four are arachnids (one pseudoscorpion, one spider,
and two harvestmen) . All are troglobites, which spend their entire lives underground and have small or absent eyes,
elongated appendages, and other adaptations to the
subterranean environment. Although troglobites must complete
their life cycles underground, they are dependent
on moisture and nutrient inputs from the surface.
Troglobites typically inhabit the dark zone of the cave
where temperature and humidity are relatively constant. Most are
usually found under rocks. All seven species appear to be
predators and are found in relatively small numbers. Each
species may have a different preferred microhabitat
and may depend on certain prey species for survival.
Troglobites tend to be rare and limited in distribution and
are of special interest to evolutionary biologists,
ecologists, biogeographers, and educators. Their limited
distributions combined with low reproductive rates, ecological
specialization, and other factors, make troglobites
especially vulnerable to habitat destruction, fire ant
infestations, pollution, and other factors. A. Taxonomic
and Legal Classification, and Description Note on Common
Names and Arthropod Systematics Few
invertebrates have common names. Common names are often used for convenience sake
and may become standardized for well-known or commonly
studied species. The common names for the karst invertebrates
included in this recovery plan are given in this section
(A) However, because there are no official common names for
these invertebrates, because taxonomy is most clearly
understood in terms of scientific names, and because
most biologists working with these species refer to them by
scientific name, we use scientific names throughout this
plan. Scientific
names are sometimes changed by scientists according to the International
Code of Zoological Nomenclature. As taxonomists
study certain groups, they publish descriptions of new or
previously unrecognized species or assign known species
to different groups. For example, the spider Leptoneta
myopica was reassigned to the All
of the listed species are members of the Phylum Arthropoda. With some arthropods,
it is important to obtain mature male specimens for
study. In many cases, as in the mold beetles and
harvestmen, species are identified based on the structure of the
male genitalia. These structures are highly
species-specific and believed to be under genetic control. Often a
first collection from a cave contains only immature and
female specimens. Other species, such as the ground
beetles, pseudoscorpions, and several species of spiders
(including Neoleptoneta myopica), can be
differentiated based on male or female structures (such as the
ovipositor), as long as an adult specimen is obtained. SPECIES 1 — Scientific
name: Neoleptoneta myopica (Gertsch), formerly Leptoneta
myopica Gertsch Common Name: Taxonomic
Classification: Class Arachnida (arachnids), Order Araneae
(spiders), Infraorder Araneomorphae (true spiders), Spiders and other arachnids are
not insects. Unlike insects, arachnids possess four
pairs of legs, pedipalps, and chelicerae,
and lack antennae. Insects have three pairs of legs,
mandibles, and antennae. Leptonetids are minute spiders
with six eyes, commonly found in caves and similar
habitats. Some leptonetid spiders in eyeless, but members of this
family typically have small eyes. Original
Description: Gertsch (1974) Type Specimen: Male holotype,
County, Reddell. Female specimen
described but not designated as paratype. Type
specimens are deposited in the Other
Taxonomic Literature: Brignoli (1972) erected the genus Neoleptoneta for
all spiders and reserved the genus Leptoneta
for other regions. In 1977, Brignoli
formally removed Leptoneta myopica to Neoleptoneta.
The validity of Neoleptoneta was further supported by Platnick
(1986). This recovery plan follows these two
authorities in using the name Neoleptoneta. Selected
characteristics: A small, whitish, longlegged troglobitic spider with six obsolescent
eyes. Eyes medium sized, without dark
pigment; front eye row moderately recurved; eyes subcontiguous and subequal in size; posterior eyes
subcontiguous, set back from anterior lateral eyes. First leg
in both sexes 6.1 times as long as carapace. Body length 1.6 mm, carapace 0.7 mm long and 0.5 mm
wide, abdomen 0.9 mm long and 0.5 mm wide. Tibia of
male palpus with thin retrolateral process set
with curved spine. Intraspecific
Variation: Not known. Distinctiveness: Neoleptoneta
myopica is related to several other troglobites in the
Balcones Fault Zone of County; N. concinna from a
cave and a mine in Travis County; N. devia from one
cave in N. microps from one cave
in Geographically, the Neoleptoneta
species closest to N. myopica is N. devia
from only 2.5 km from Cave, the type locality. Neoleptoneta
devia is dull yellow with a whitish abdomen and
the eyes enclose a dusky field, whereas N.
myopica is whitish and has very reduced eyes that are not
set in a dusky field. Neoleptoneta
devia and
N. concinna, the other two species in Gertsch (1974) did not discuss
evolutionary relationships among the six that he described. Listed: Endangered; Recovery
Priority: 2C. According to the 13. 5. Fish and Wildlife Service’s (USFWS)
criteria (48 FR 51985) this indicates a species with a
high degree of threats, high potential for
recovery, and in conflict with construction or development
projects or other forms of economic activity. SPECIES 2 — Scientific
name: Tartarocreagris texana (Muchmore), formerly Microcreagris
texana Muchmore. Common Name: Taxonomic
Classification: Class Arachnida (arachnids), Order Pseudoscorpiones
(pseudoscorpions), Family Neobisiidae. Pseudoscorpions are
quite distinct from scorpions in lacking a postabdomen (tail), stinger, and book
lungs. Most pseudoscorpions are
no more than a few mm long. Original
Description: Muchmore (1969). Type Specimen: Female
holotype, County, Reddell. Deposited in History. Male known from Other
Taxonomic Literature: Muchmore (1992) reassigned Microcreagris
texana to Tartarocreagris, a genus described by Curcic (1984),
based on the female holotype of M. infernalis from
Inner Space Cavern, collected males of both species,
it became clear that M. texana also belonged
in Tartarocreagris. Curcic (1989) had previously reassigned
N. texana to Australinocreagris
Curcic
(1984), which is based on M. grahami from that classification to be
incorrect based on internal male genitalia. Muchmore (1992)
described a new species of Tartarocreagris, T.
comanche, from New Comanche Trail Cave 1.8 km
southwest of and reassigned N. reddelli, from
County, to Tartarocreagris. In
Muchmore (1992) , all four Tartarocreagris.
The
genus Microcreagris is no longer believed to occur in the of Tartarocreagris are
extremely limited in distribution. Three of the species occur within 4.9 km
of each other in the vicinity of the RM 2222 and RM 620 intersection on the
central Jollyville Plateau in Travis Selected
Characteristics: A large (female body length 4.1 mm), eyeless pseudoscorpion
with attenuated appendages. Carapace, chelicerae,
and palps golden brown, body and legs light tan.
Carapace about 1/3 longer than broad. No eyes or
eyespots present. Chelicera about 2/3 as long as
carapace, 1.95 times as long as broad. Palps relatively
long and slender; femur 1.5 and chela
2.55 times as long as carapace. Intraspecific
Variation: Male very similar to female in most respects — male body
length 3.96 mm. Distinctiveness: Tartarocreagris
texana can be distinguished from its closest
relatives only by microscopic inspection. Tartarocreagris
comanche from New and relatively robust appendages,
whereas the others are eyeless and more slender.
Among the species of Tartarocreagris
there
are many minor differences in tergal
chaetotaxy and in the proportions of the palps. Confirmation of the species may
require dissection and study of the female spermathecae or the male internal genitalia. Listed: Endangered; Recovery
Priority: 2C SPECIES 3 — Scientific
name: Texella reddelli Goodnight and Goodnight Common Name: Taxonomic
Classification: Class Arachnida (arachnids), Order Opiliones (opilionids, or
harvestmen) , Suborder Laniatores, evolutionarily quite distinct
from spiders (Order Araneae) and are not properly referred to as “spiders”.
Phalangodid harvestmen are predaceous. Other North American genera are Banksula
in Original
Description: Goodnight and Goodnight (1967) Type Specimen: Male holotype, Collected by Deposited in the Redescription by Thick and Briggs
(1992) is based on holotype, female paratopotype, and 14 other specimens deposited in the Darrell Thick collection, and
Marie Goodnight collection. Other
Taxonomic Literature: Goodnight and Goodnight (1942), Ubick and Briggs (1992).
The genus Texella was erected by Goodnight and
Goodnight (1942) on the basis of one troglomorphic
individual, described as Texella mulaiki,
from
Selected
Characteristics: Body length 1.90-2.18 mm, scute length 1.21-1.66 mm, leg II
length 4.92-7.59 mm, leg II/scute length 3.81-5.20 mm
(N = 16). Color orange. Body of medium rugosity. Eye mound broadly conical, eyes well developed.
Male (holotype) — Postopercular
process length 0.44; penis: ventral plate prong with two dorsal, 10
lateral, and three ventral setae; apical spine
curved, apically pointed; glans: basal knob slender; middle
lobe present; parastylar lobes
claw-like; stylus spatulate, basal fold present. Female
(paratopotype) — Ovipositor cuticle intricately
folded; one pair of apical teeth present. Intraspecific
Variation: Juveniles are white to yellowish-white (as in most Texella);
adults are orange.
The
tarsal count (number of tarsomeres) and the leg-to-body-length ratio (leg
II/scute length) may vary from the south to north part
of the species’ range, with the least
troglomorphic (cave-adapted) population being in Cave Y (south
of the River) and the
most troglomorphic in Jester Estates Cave (north of the this species is not easily
explainable in that it is distributed on both sides of the is a major barrier to other
terrestrial troglobites. Troglomorphy in this genus
is marked by increased leg/body ratio, greater number of
tarsomeres, depigmentation, reduction of protuberances,
and loss of retinas followed by loss of
corneas. Distinctiveness: Goodnight
and Goodnight (1942) described Texella mulaiki from
Ezell’s Cave), but in 1967 reported
it from Cotterell Cave in and Beck’s and material, they did not note
that the distribution patterns of the two species were
incongruously mixed. Apparently the identifications
were based more on leg length than other characters.
Thick and Briggs (1992) examined more specimens from more
caves and epigean sites and in their revision
distinguished T. reddelli from T. reyesi (below). They described 18 new species and transferred one species from Sitalcina
to Texella. Sixteen of the 21 Texella species
are cavernicoles and five are troglobites. Fifteen of
the species occur along the Balcones Escarpment in T. reddelli can be
distinguished in the field from its closest relative, T. reyesi
by its shorter legs, its well developed eyes
(versus extremely small or no eyes in T. reyesi), and its color,
which is more orange. The species is not
“without eyes” as noted by Goodnight and Goodnight but has
“eye mound broadly conical, eyes well developed” (Thick and Briggs 1992). Such details can be seen with the naked eye or a hand lens in the field. However, confirmation of the species must
be made microscopically by a qualified systematist on a preserved, adult
specimen. In their
redescription of the Texella species, Thick and Briggs (1992) state that Texella reddelli and Texella reyesi “are clearly very closely related and, using the standards of genitalia distinctness applied to other Texella species, may even be considered
conspecific.” However, given that the two groups can be distinguished, and
are considered separate in the taxonomic description, the USFWS follows Thick
and Briggs and considers the two species separately. Listed: Endangered; Recovery Priority: 2C SPECIES 4 — Scientific name: Texella
reyesi Thick and Briggs Common Name: Taxonomic Classification: Class Arachnida (arachnids) Order Opiliones (opilionids, or harvestmen), Suborder Laniatores, Original Description: Ubick and Briggs (1992). This paper describes 18 new species of Texella, with a total of 21 species in three species groups in species diversity (15 species) is along the Balcones Escarpment in Type Specimen: Male holotype, County, Elliott, paratype, Cave. All specimens are deposited at the Other Taxonomic Literature: Goodnight and Goodnight (1942, 1967). The genus Texella was erected by Goodnight and Goodnight (1942). In 1967 they described Texella reddelli, which at that time included some populations of Texella reyesi. Selected Characteristics: A long-legged, blind, pale orange harvestman. Body length 1.41-2.67 mm, scute length 1.26-1.69 mm, leg II length 6.10-11.79 mm, leg II/scute length 4.30-8.68 mm (N = 85). Body finely rugose. Few small tubercles on eye mound; eye mound broadly conical, retina absent, cornea variable (well developed, reduced, or absent). Penis with ventral plate prong round apically; two dorsal, 17 lateral, and four ventral setae; apical spine bent, apically pointed, length 0.05 mm.
Glans with basal knob narrowly conical; middle lobe long; parastylar lobes claw-shaped. Stylus long, curved, ventrally carinate, apically spatulate; basal fold well developed. Intraspecific Variation: Juveniles are white to yellowish-white. Adults are pale orange. Elliott (unpublished data) has observed an adult with a pale green abdomen in County, and an adult with a yellowish abdomen in Distinctiveness: Texella reyesi can be
distinguished from its closest relative T.
reddelli by its longer legs, its lack of retinas (versus well developed eyes in Texella reddelli), and its color, which is pale orange. Such differences can be seen with the naked eye or a hand lens in the field. However, confirmation of the
species must be made microscopically by a qualified systematist on a preserved
adult. Listed: Because Texella reyesi was considered to be Texella reddelli before Ubick and Briggs’ redescription (1992) and five localities (Tooth, McDonald, Weldon, Bone, and Root caves) of T. reyesi were included with T.
reddelli at the time T. reddelli was listed as endangered on 36029), T. reyesi
is considered to be listed as endangered under the Endangered Species Act. The USFWS has reviewed the taxonomic change (Ubick and Briggs 1992) and other available information on this species and determined it should remain listed as endangered (58 FR 43818) Recovery Priority: 2C SPECIES 5 — Scientific name: Rhadine
persephone Barr Common Name: Taxonomic Classification: Class Insecta (insects), Order Coleoptera (beetles), Suborder Adephaga, Carabidae (ground beetles), Tribe Agonini
(agonines). Many troglobitic ground beetles have evolved in and other parts of the world. The genus Rhadine contains more than 60 eyed and eyeless species in the mostly in caves of the Balcones Escarpment of Texas and are members of the subterranea species group, a monophyletic assemblage. The subterranea group is closely related to the perlevis group, which contains eyed, troglophilic members found in caves of the contains a “robust”, or heavy-bodied, subgroup, which is generally found south of the which includes R. persephone north of the river. A “slender” subgroup, including R. subterranea, is widely distributed on both sides of the river. At least three different species pairs coexist in some caves, consisting of a robust species and a slender species in each case. In most situations the robust species is more abundant. These data suggest that the ranges of the various species may overlap broadly, but that minimal niche
overlap occurs between robust and slender species, which allows the two species to coexist in some caves. Original Description: Barr (1974a) Type Specimen: Holotype male, County, Mitchell, T.C. Barr, Jr., and W.M. Andrews. Deposited in Selected Characteristics: A moderately robust and convex beetle, more so than other species of the subterranea group. Reddish-brown, head and pronotum shining. Head half as wide as long, neck about 0.57- 0.59 of greatest head width. Eye rudiment larger than in other species of subterranea group. Pronotum about 0.7 as wide as long, widest in apical three-eighths, slightly wider than head. Antenna about 0.85 total body length, attaining apical third
of elytra when laid back. Aedeagus very
large for subterranea group, 1.24-1.31 mm long, elongate, feebly arcuate, basal bulb slender and set off by slight constriction, keel prominent, apex attenuate and slightly produced; internal sac with proximal
patch of numerous scales. Body length 8.0 mm, head 2.17 mm long by 1.08 mm wide, pronotum 1.80 mm long by 1.18 mm wide, elytra 4.46 mm long by 2.29 mm wide, antenna 6.8 mm long. Fifty paratypes and four specimens from with length 7.2-8.7 mm, mean 7.8. Intraspecific Variation: Not known. Distinctiveness: Rhadine persephone is
distinguished from R. subterranea by its more robust build and its shorter and wider pronotum (the most distinguishing characteristic) . The two species are about the same length. Tenerals (young adult beetles that have recently emerged) of all Rhadine species are pale yellow but soon darken to reddish brown. Other species that
can be confused with R. Persephone include R. austinica (southern
Listed: Endangered; Recovery Priority: 2C SPECIES 6 — Scientific name: Texamaurops
reddelli Barr and Steeves Common Name: Taxonomic Classification: Class Insecta (insects) Order Coleoptera (beetles), Suborder Polyphaga, Pselaphidae (mold beetles), Tribe Batrisini. Pselaphids, or short-winged mold beetles, are a group of small beetles found under stones and logs, in rotting wood, moss, ant and termite nests, and caves. The European and North American cave faunas include many species. The genus Texamaurops was erected for one species, T. reddelli,
from Texamaurops remains a monotypic genus found only in a few Original Description: Barr and Steeves (1963) Type Specimen: Female holotype, James R. Reddell and David McKenzie. Deposited in the Field a rock in the second room of the
cave, about 10 m from the entrance. Other Taxonomic Literature: The first pselaphid described from a schneiderensis Park (1960), based on a single female from (1974b) classified a male pselaphid from Inner Space Cavern as Texamaurops reddelli, but the specimen is now recognized by texanus (below). Selected Characteristics: A small, long-legged beetle with short elytra leaving five
abdominal tergites exposed; metathoracic wings absent.
Body length 2.72- 3.08 mm. Color reddish-brown, shiny; pubescent hairs pale, moderately abundant and partially laid back; general body surface sparsely and weakly dotted with small pits. Ventral surface of head heavily pubescent. Eyes absent, but represented by small knobs with six vestigial eye
facets. Antennae 11- segmented, simple. Intraspecific Variation: the holotype female from from having only two basal
foveae (pits) on each elytron, whereas the others have three equal foveae. All others features appear to be similar. Distinctiveness: Texamaurops reddelli can only be distinguished from other pselaphid beetles by a qualified systematist upon microscopic study. The species is “superficially similar to Batrisodes texanus by the greatly elongated antennae and
legs, as well as body size” ( definitively separated from Batrisodes texanus by its ocular knobs and its lack of
the pencil of setae on the metatibia. the form of the aedeagus and antennal characters Texamaurops is probably best considered a lineage derived from Batrisodes
that has lost the metatibial pencil of setae.” In life Texamaurops reddelli is a tiny, long-legged form that can be confused with other species such as Tachys ferrugineus, which is an eyed, short-legged, shiny, fast-moving
carabid beetle with full-length elytra; and Batrisodes uncicornis, an eyed species occurring in many caves in Other pselaphids, both blind and eyed, occur in caves outside the range of this species ( Listed: Endangered; Recovery Priority: lC. Indicates a monotypic genus with a high degree of threats, high potential for recovery, and in conflict with construction or development projects or other forms of economic activity (48 FR 51985) SPECIES 7 — Scientific name: Batrisodes
texanus Common Name: Taxonomic Classification: Class Insecta (insects), Order Coleoptera (beetles), Suborder Polyphaga, Pselaphidae (mold beetles), Tribe
Batrisini. Mold beetles are generally minute (about
2 or 3
mm long) rounded beetles with short elytra (wing covers), which expose the posterior half of the abdomen. Original Description: Type Specimen: Male holotype from Inner Space Cavern, William H. Natural History, Space Cavern and Off (deposited in Donald S. Chandler
collection) and first collected on Other Taxonomic Literature: Barr (1974b) classified a male pselaphid from Inner Space
Cavern as Texamaurops reddelli, but the specimen is now recognized by Selected Characteristics: A small, long-legged beetle with short elytra leaving five abdominal tergites exposed; metathoracic wings absent. Body length 2.60- 2.88 mm. Male with vague groove across the head anterior to antennal bases. Sides of head smoothly curved and flat with a few granules present where eyes should be. Intraspecific Variation: In females, the transverse impression anterior to
the antennal bases is absent, and the tenth antennal segment is barely wider and longer than the ninth. In males the tenth is twice as wide as the ninth. No geographical variation has been noted. Distinctiveness: Batrisodes texanus can only be distinguished from other pselaphid beetles by a qualified systematist upon microscopic study. The species can be definitively separated from Texamaurops reddelli by its lack of ocular knobs and the
presence of a pencil of setae on the metatibia. In life the beetle is a tiny, long-legged form that can be confused with other species such as Tachys ferrugineus, which is an eyed, short-legged, shiny, fast-moving carabid beetle with full-length elytra; and Batrisodes uncicornis, an eyed species occurring in many caves in both blind and eyed, occur in caves outside the range of this species ( Listed: Because Batrisodes texanus was considered to be Texamaurops reddelli before redescription (1992) and one locality ( B. texanus was included with Texamaurops
reddelli at the time Texamaurops reddelli was listed as endangered on considered to be listed as endangered under the Endangered Species Act. The USFWS has reviewed the species description ( available information on this species and determined it should remain listed as endangered (58 FR 43818). Recovery Priority: 2C B. Distribution Population
estimates: No population estimates are currently available for any of
the species due to their secretive habits, rarity, and
inaccessibility. Generally, no more than one or two
individuals of each species are seen on a visit to a cave and
often none are observed, even in caves where they are
considered relatively abundant. Some of the species, such as the
pseudoscorpion and mold beetles, are so secretive that
finding an individual is a rare event (Elliott, pers.
observation) . Current mark- recapture methods are of little
use with such small populations. Historic range: Since karst
surveys and biospeleological studies in the early 1960’s, there is no
information on the species’ ranges prior to that time.
Further, the status of some of the caves from which listed
species have been collected is unknown. Some of these caves may
have been filled or destroyed due to land
development. For example, attempts to relocate have been unsuccessful ( Museum, pers. communication) Current range: The level of
interest and effort in conducting karst and
biospeleological surveys greatly increased with the listing of the
invertebrate species in 1988. Regional studies were funded
by the USFWS, the Parks and
Wildlife Department (TPWD), the Texas Department of Transportation, the the City of 1989, Reddell 1991, Reddell and Elliott
1991, Veni & Associates 1988a,b). Additional
surveys have been done by developers, financial
institutions, and private landowners. These studies have assisted in
clarifying the range and taxonomy of each species.
Although additional localities for each species may still be
discovered with continuing survey efforts, the species’
ranges are now fairly well- defined, particularly for those
species that are restricted to the Jollyville Plateau (Neoleptoneta
myopica, Tartarocreagris
texana, and Texamaurops reddelli) Some
specimens collected from certain localities have been tentatively identified as
listed species (Tables 1 and 2). Positive
identification of these specimens is contingent upon identification by
a qualified systematist and/or additional collections
including well-preserved, intact adult specimens. The
information in these tables will be revised and updated as
positive identifications are made. Figure
1 shows all the caves in Travis and Williamson counties currently known to
contain one or more of the listed species or from which
tentative identifications have been made. Figure 2 shows the
seven karst fauna regions (corresponding to the karst fauna
areas in Figure 19 of Veni & Associates 1992) that
support one or more of the listed species. The in the figure even though it is
not currently known to have listed species. It is included in
the event that future surveys locate any listed species
in this region. To date, no listed species have been found
in the caves that have been surveyed in the local biospeleologists believe
that portions of the South investigation to determine
whether there are karst features inhabited by listed species,
particularly along the south side of Barton Creek. The species
most likely to occur in this region is Texella
reddelli, which occurs in the adjacent Rollingwood karst fauna region.
Since this species’ current distribution occurs on both sides of the Creek, which separates the Rollingwood and South Travis County karst fauna regions. Two karst fauna
regions from Veni’s 1992 report, the McNeil and Round Rock regions, have been combined for the purposes of this plan (hereafter referred to as the McNeil/Round Rock karst fauna region), since they contain virtually the same species and present no significant geologic barriers to troglobitic migration between them (Veni, in litt., 1993). The
distribution of each species is as follows: SPECIES 1 - Neoleptoneta myopica: Known to occur in two caves and tentatively identified
from two additional caves within a 4.5 km stretch
in the Jollyville Plateau karst fauna region,
Travis County, SPECIES 2 - Tartarocreagris texana: Known to occur in two caves and tentatively
identified from two additional caves within a 1.3 km
radius in the Jollyville Plateau karst fauna
region, SPECIES 3 - Texella reddelli: Occurs in three caves (one positive, two tentative identifications) in the Jollyville
Plateau karst fauna region and four caves (one
positive, three tentative identifications) in the
Rollingwood karst fauna region, Travis County, Texas
(Table 1, Figure 5). Previously reported from
Tooth, McDonald, Weldon, and Root caves, (53 FR 36029), but these populations have been redescribed as Texella reyesi (Ubick
and Briggs 1992) (58 FR 43818). Kretschmarr
Double Pit, of the The other four caves are located in the Rollingwood karst fauna region, south of
the collections do
not include the male specimens necessary to confirm the occurrence of
this species. However, the females are similar
to the females collected from on opposite sides of the different blocks of limestone may be an indication that the populations are
genetically distinct. SPECIES 4 - Texella reyesi: Occurs in 69 caves (60 confirmed, 9
tentative identifications) from northern Travis to northern distance of 40 km (Tables 1 and 2, Figure
6). This species occurs in six karst fauna
regions (Jollyville, McNeil/Round Rock, (1967)
described Texella reddelli they included four populations, three of which are now recognized as Texella reyesi ( (1992) redescription of Texella
mulaiki included four populations, three of which are now recognized as Texella reyesi ( County (58 FR 43818)) SPECIES 5 - Rhadine
persephone:
Occurs
in ten caves (8 positive, 2 tentative
identifications) in the Jollyville Plateau karst fauna
region ( 1 tentative identifications) in the karst fauna
region (Travis and Williamson counties) (Tables 1 and 2, Figure 7),
with a total distance of about 14 km between the northern and southernmost locations.
Sympatric in at least four caves with a slender
species, R. subterranea. SPECIES 6 - Texamaurops reddelli: Known to occur in four caves within a 2 km radius in the Jollyville Plateau karst fauna region,
Travis County, reported from FR 36029), but the been redescribed as Batrisodes texanus
( 1992) (58 FR
43818) SPECIES
7
- Batrisodes texanus: Occurs in two caves in the region (both positive identifications)
and three caves (two positive, one tentative identification) in the region, 9) . All localities occur within a 17 km
stretch. Of the seven listed
species, Rhadine persephone and Texella reyesi are the only two known from more than
seven sites. Rhadine persephone appears to be restricted to sites within the fauna regions (Figure 7). Texella reyesi has both the greatest number of sites and the widest distribution, occurring in six karst fauna regions (Figure 6). Texella reddelli is the only species that occurs both north
and south of the Except for Batrisodes texanus, which
occurs only in ranges include the Jollyville Plateau karst fauna region in myopica, Tartarocreagris texana, and Texamaurops
reddelli) occur entirely within this region. One cave cluster, located in the vicinity of the RM 2222 and RM 620 intersection in a proposed residential subdivision, harbors six of the listed species. This cluster supports one of the most diverse, terrestrial, cave-adapted faunas in the southwestern cave systems, such as more diverse faunas. cluster and contains five of the listed species. Stovepipe Cave, located to the northeast, also contains five of the listed species. Many of the
reconnaissance studies conducted
since 1988 have resulted in the discovery
of new localities for the listed species as well as new endemic species. Because current methods of locating karst features are time intensive and require on-site inspections, many areas within each karst fauna region have not yet been surveyed. As surveying efforts continue, new localities may be discovered in all karst fauna regions. To date, karst fauna regions that have received the least amount of study are the northwestern part of study. A large knowledge gap also exists between Round Rock and to the property is limited. The Society (TSS), a private, non-profit research group, recorded numerous caves in that area in 1963, but none have been investigated recently. Many of those caves may still exist. In addition to
continuing surveys for new endangered species localities, more intensive biospeleological studies of currently known karst features may also provide additional information on species distributions. More than 700 karst features have been located in Travis and Williamson counties (Elliott, pers. communication), of which about 100 are known or believed (through tentative identification of collected specimens) to contain endangered species (tables 1 and 2). Biospeleological surveys of many of the remaining karst features are either nonexistent, outdated (e.g. recent surveys have not been conducted), incomplete, or cursory. Detailed faunal surveys of those features that have not been adequately studied but which could support one or more of the listed species may lead to the discovery of additional endangered species localities. Although these surveys may increase the total number of known locations for the karst invertebrates, most new locations will occur within the currently defined range of each species. The overall range of each species is not expected to increase significantly beyond what is defined in this plan. C. Habitat, Ecosystem, and Ecology Little is known
about the life history, ecology, and habitat requirements of the listed species and other karst fauna in central in emphasis has been on taxonomy, biogeography, and a few behavioral studies (Barr 1974a,b; Barr and Steeves 1963; Bull and Mitchell 1972; Christiansen and Culver 1969; Elliott and Mitchell 1973; Elliott 1976, 1978a,b; Gertsch 1974; Goodnight and Goodnight 1967; Holsinger 1967; Maguire 1960; Mitchell 1968a,b,c, 1970; Mitchell and Reddell 1971; Muchmore 1969; Reddell 1965, 1966, 1967, 1970a-c), and more recently on geologic and hydrologic processes of karst (Veni & Associates 1988a,b, 1992). Elliott (1991a-f, 1992b-e) has begun a long-term, baseline ecology study of three caves as part of the LakeLine Mall Habitat Conservation Plan (see discussion in Section E). Origin of Karst Features: “Karst” is a type of terrain that is formed by the slow dissolution of calcium carbonate from limestone bedrock by mildly acidic groundwater. This process creates numerous subterranean voids (caves, sinkholes, fractures, interconnections, etc.) so that the bedrock somewhat resembles a honeycomb. The formation of these features depends largely on the solubility of the bedrock and the rate and direction of groundwater movement. Water enters the subsurface through cracks, crevices, and other openings, dissolving away soluble beds of rock as it moves through the ground, until it discharges downhill at a spring outlet. Many of the karst
features occupied by the listed species were formed at or below the water table, and thus were once filled with water. As the groundwater table lowered through canyon downcutting and regional uplift, these features dried out and are now air-filled. These features are referred to as “dry” because they tend to have small catchment areas, take very little runoff, and contain little or no perennially flowing water. In some cases, cave and sinkhole entrances were formed as the groundwater table lowered, resulting in ceiling collapse of some cavities. Some karst features may
act as recharge structures to underground stream systems. For example, Buttercup Creek in the overlies an important karst network composed of several caves such as Cave, sinkholes and caves that may contribute to an underground stream ( infeeder to the system. Available information indicates that the stream exits either at a spring in Bull Creek to the south, which contributes to feeds into the northern pool of the Edwards Aquifer. Evolution of Troglobites: Troglobites have been referred to as “relicts” of surface soil and leaf-litter faunas. A widely accepted explanation for the evolution of troglobites is that, during the course of climatic changes in the Pleistocene epoch (two million to ten thousand years ago), certain creatures retreated into the more stable cave environments, while their respective surface relatives either emigrated or became extinct (Barr 1968, Mitchell and Reddell 1971, Elliott and Reddell 1989). The troglobitic species survived and adapted to the cave environment and colonized the caves and other subterranean voids. Through faulting and canyon downcutting, the karst terrain along the Balcones Fault Zone became increasingly dissected, particularly around the Jollyville Plateau, creating “islands” of karst and barriers to dispersal. This led to increasing isolation of troglobitic populations from each other with subsequent speciation. Some groups speciate very readily, while others appear to speciate more slowly. Some species are more mobile than others and can achieve larger ranges. The restricted distribution of troglobitic species makes many of them highly susceptible to extinction (Elliott and Reddell 1989). Habitat Requirements - Moisture and Temperature: Troglobites require high humidities (nearly l00%), and many are very susceptible to drying. Generally, areas within caves that have low humidities are almost entirely devoid of cave fauna (Elliott and Reddell 1989, Barr 1968). Caves that are encased with an inner shell of calcite, which can cut off water and nutrient infiltration, are also nearly biologically sterile (Elliott, pers. observation). Water enters the
karst ecosystem though groundwater and surface drainage. Well-developed pathways, such as cave openings, fractures, and solutionally enlarged bedding planes, rapidly transport water through karst with little or no purification. Caves are susceptible to pollution from contaminated water entering the ground because karst has little capacity for self-purification. The route that has the greatest potential to carry water-borne contaminants into the karst ecosystem is through the surface and subsurface drainage basin that supplies water to the ecosystem. Certain activities within this hydrologically sensitive area, such as application of pesticides and fertilizers, leakage from sewer lines, and urban runoff, could contaminate the karst ecosystem. The potential for contaminants to travel through karst systems may be increased in some areas relative to others due to local geologic features. Most troglobites
require stable temperatures. Cold, dry air entering a cave causes the fauna to retreat to more humid, warmer recesses (Reddell and Elliott 1991). During these times, some troglobites may be found in small ceiling pockets where the conditions are presumably warmer and damper, rather than on the floor where they are normally found (Elliott, pers. observation). During hot, dry periods,
cave fauna may retreat into the cave soil or interstitial spaces where
environmental conditions are more stable (Howarth 1983). Habitat Requirements - Importance of Surface
Communities: Due to the paucity of light and limited capability for photosynthesis, karst ecosystems are almost entirely dependent upon surface plant and animal communities for nutrient and energy input. Karst ecosystems receive nutrients from the surface in the form of leaf litter and other organic debris that have washed or fallen into the caves, from tree and other vascular plant roots, or through the feces, eggs, or dead bodies of troglophiles and trogoxenes (for example,
cave crickets, raccoons). Certain animal
species, such as cave crickets, daddy longlegs, and raccoons appear to use most caves, provided there is sufficient area on the surface with habitat to support these species and the cave entrance is not blocked. A study to determine the foraging range and spatial/temporal
distributions of cave crickets and daddy longlegs is currently underway as
part of the LakeLine Mall Habitat Conservation Plan (see discussion in
Section E). Recent research indicates cave crickets may forage more than 50
meters from cave entrances (W.R. Elliott, pers. comm., 1993). Cave crickets (Ceuthophilus spp.) are an
especially important component of the cave ecosystem, because many invertebrates are known to feed on their eggs, feces, nymphs, and dead body parts. Cave crickets typically roost and lay eggs in caves during the day, then emerge at night to feed. They are general predators and scavengers, but the exact food preferences of Ceuthophilus species in are still unclear. Daddy longlegs
harvestmen (Leiobunum townsendii), which are
abundant in many caves, may similarly introduce nutrients into the cave ecosystem. Raccoons are also ecologically important in many cave communities because their feces provide a rich medium for the growth of fungi and, subsequently, localized population blooms of several species of collembolans. Collembolans are tiny, hopping insects that reproduce rapidly on rich food sources and may become prey for some predatory troglobites. Caves with large bat
colonies usually harbor a community dominated by guano-feeders and related species. Some of the small caves of Travis and Williamson counties once harbored small bat colonies, usually cave bats (Myotis velifer). This species often abandons
caves because of human disturbance or other factors (Elliott, in press). However, most of the caves inhabited by the listed species were not significant bat roosts in the past. The exceptions to this rule follow: 1) small bat colony at one time, but has not contained bats for many years (Reddell, pers. communication); 2) Steam Cave at some Myotis velifer individuals, according to numerous cavers’ reports; 3) On Campus Cave at apparently a major bat cave at one time, was sealed during land development, then reopened in 1992 (Mike Warton, geologist, pers. communication); 4) Beck Bat, Beck Horse, and Beck Ranch caves have had bat colonies at different times (Elliott, pers. observation). These data suggest that although the karst ecosystems containing the listed species may not depend on bats for nutrient input, some of the listed species can tolerate conditions around small bat colonies and may benefit from the increased nutrients. Surface plant
communities around karst features supporting the listed species range from pasture land to mature oak-juniper woodland. In general, exotic plants and animals (particularly fire ants) are believed to be detrimental and may result in competition with or predation upon native species and a decreased overall species diversity. In addition to
providing nutrients to the karst ecosystem, the surface plant community also serves to buffer the karst ecosystem against changes in the temperature and moisture regimes, pollutants entering from the surface (Biological Advisory Team 1990, Veni & Associates 1988a), and other factors such as sedimentation from soil erosion. Protecting native vegetation may also help control certain exotics (such as fire ants) that may compete with and/or prey upon the listed species and other karst fauna. Fire ants are particularly detrimental to karst ecosystems, although the full extent of their impact has not yet been determined. Soil disturbance, introduction of nursery plants and sod containing fire ants, garbage (potential food source), and electrical equipment are some of the factors contributing to fire ant infestations. Habitat Requirements - Use of Interstitial Spaces: The extent to which the species use small humanly inaccessible voids, referred to as “interstitial spaces” (such as fractures, fissures, cracks, etc.), between or around caves is not fully known. Use of interstitial spaces by troglobites has been observed in (Howarth 1983). At the LakeLine Mall site in Williamson County (see Section B), six boreholes (referred to as “coreholes” in certain documents) were drilled to determine the presence of interstitial fauna. The two caves on the site, species (Rhadine
persephone and Texella reyesi). Four to five Rhadine persephone beetles and one Rhadine
subterranea beetle were found in one of the four boreholes that located about 600 feet northwest of five boreholes (Horizon Environmental Services, Inc. 1991a) Howarth (1983)
refers to these interstitial communities as “crack fauna” and asserts that “caves are not isolated but connect with other subterranean habitats to constitute a single functioning system”. He argues that troglobites primarily live in interstitial spaces, where environmental conditions are more stable, but will venture into larger voids and caves when conditions are suitable. Some troglobites have a lower metabolic rate and are able to use energy more efficiently than their surface relatives, and many have exhibited the ability to withstand long periods without consuming food. Thus, a steady food supply for these species may not be as limiting a factor as the need for high moisture levels and stable temperatures. This may explain the seasonal distribution of the cave fauna and the apparent paucity of troglobites during periods of dryness or temperature extremes (Howarth 1983) Troglobites
occupying interstitial spaces may receive nutrients through root systems of surface vegetation and through many small holes and fissures in karst areas where raccoons, cave crickets, and other surface fauna can enter the subsurface. Groundwater flow and surface infiltration are also vehicles for transporting nutrients through interstitial spaces. Certain strata in the Edwards Limestone are more prone to developing karstic solutional openings and thus may be more penetrable by nutrients than other strata. The extent of nutrient infiltration into the interstitium appears to be site-specific and is largely dependent on the nature of the limestone strata and the juxtaposition of subterranean voids. Thus, some strata may receive nutrient input over a large area, while others may receive input only through caves and sinkholes. The distance that
the listed species or other karst fauna retreat from cave openings is unknown but is probably dependent upon the presence of contiguous voids large enough for the fauna to occupy, proximity to nutrient supplies, and the ecological requirements of the species. For example, if the “epikarst” (the surface of the karst) is extremely honeycombed, as in the LakeLine Mall area, then troglobites may be found where there are continuous passages or open bedding planes. Furthermore, more mobile species, such as Rhadine persephone, may range farther
from cave openings, while more sedentary species, such as Neoleptoneta myopica, may be physically restricted to nutrient-rich areas. Habitat Requirements - Management Considerations: The karst features inhabited by these species and the ecosystems on which they depend have evolved slowly over millions of years and cannot be recreated once they have been destroyed. Protection of these ecosystems will require maintaining moist, humid conditions and stable temperatures in the air-filled voids; maintaining an adequate nutrient supply; preventing contamination of the water entering the ecosystem; preventing or controlling invasion of exotic species, such as fire ants; and other actions as deemed necessary. Additional research may help to develop or refine conservation and management practices necessary to achieve these goals. In determining
appropriate management techniques of surface communities, the ecological requirements of other species, such as the federally listed endangered black- capped vireo (Vireo
atricapillus) and golden-cheeked warbler (Dendroica
chrysoparia), whose ranges overlap with those of the listed invertebrates, will also need to be considered. Recovery plans for these species have been prepared (USFWS 1991, 1992) Ecology: Most of the endangered karst invertebrates are believed to be predators of microarthropods,
such as collembolans. Many troglobites also feed on well- decomposed organic matter. Others, such as the ground beetle, may consume cave cricket eggs or dead cave cricket parts. The limited data available suggest that most troglobites are food generalists (Barr 1968), although this does not preclude the development of food specialization in some species. Since several predator species coexist in most caves, one can expect some degree of prey specialization in these species. Elliott and Reddell
(1989) note that “there is no direct information on the life cycle of any of these species. Many surface relatives have a distinct seasonal life cycle, but collections throughout the year indicate that all of these species have lost this seasonality...” The following list summarizes currently available on each species’ biology. Species 1 - Neoleptoneta myopica: This species
preys on microarthropods and has been described as a “sedentary aerial spider that hangs from a small tangle or sheet web on long, thin legs” (Gertsch 1974). Mitchell and Reddell (1971) observed that “in spiders are the most important animals filling the ‘small predator’ niches.” Since a cave can contain several different species of spiders, such as members of the genera Neoleptoneta, Cicurina, Nesticus, and Eidmannella,
slightly different small predator niches apparently have developed in those communities. For example, in County, there are 11 co-existing, troglobitic, small predators (6 spiders, a harvestman, 2 pseudoscorpions, and 2 Rhadine beetles) (Elliott and Reddell 1989). Species 2 - Tartarocreagris texana: Tartarocreagris texana is usually found under rocks. Finding individuals of this species is so rare that little else is known of its habits (Elliott and Reddell 1989). All known pseudoscorpions are predators of microarthropods. Species 3 - Texella
reddelli: This species is usually found under rocks in darkness or in dim twilight. All phalangodids have large, raptorial pedipalps designed to seize and hold prey. Elliott (1978b) observed that Banksula melones and Banksula grahami, members of
the same family from (psocopterans) and collembolans placed in small containers, but preferred the collembolans, which were smaller. Texella and other small harvestmen tend to walk
rather slowly and deliberately, unlike spiders, which tend to move faster. See further remarks on Texella reyesi. Species 4 - Texella reyesi: This species is
especially sensitive to drying and requires very moist, humid conditions (Elliott 1991a-f and unpublished data). Most individuals are found under large rocks, but are occasionally seen walking on moist floors. In the entrance in total darkness, where humidity is high; they seldom occur farther in the cave where there is less water and food. In the hottest part of the summer when many of the small caves warm up and become drier, individuals may retreat into the interstitium or may be found only in the coolest, dampest spots in the caves. This species feeds on microarthropods. One individual in dead raccoon. Species 5 - Rhadine persephone: Rhadine persephone is the largest, most visible, and most active of the species and is sometimes visible in strong light from a distance of 5 to 10 m. Rhadine persephone is usually found under
rocks, although some individuals have been observed walking on damp rocks and silt. The beetle runs rapidly and patrols the floor area in search of prey, as does R. subterranea, a closely related and sympatric species. While feeding
behavior has not been observed in R. persephone, Mitchell (1968a, b) observed R.
subterranea feeding on cave cricket eggs and dead cave cricket parts in Beck’s communication, in Mitchell 1968b) reported one observation of a R. subterranea beetle carrying a collembolan. Rhadine subterranea appears to be restricted to areas of
deep, uncompacted silt, where it digs holes to remove and feed on eggs deposited into the silt by cave crickets. Mitchell also found R. subterranea larvae in the silt, but he
felt the food supply was the limiting factor in the beetle’s distribution. Rhadine subterranea is not believed to
feed on organic material, fungi, raccoon feces, cricket droppings, or live cave cricket nymphs, as are some other invertebrates. Fungi may harbor parasites that result in beetle mortality. Predation on cave cricket eggs has apparently evolved in at least four different genera of troglobitic carabid beetles in 1983). In in 1965, R. persephone are more abundant than R. subterranea. The high population levels of R.
subterranea in the Round Rock and with its rarity at the southern margin of its range (for example, further range extension may be checked by interspecific competition. Competition due to broad niche overlap between R. persephone and R. subterranea may
limit the latter in Tooth and Kretschmarr caves (Barr 1974a) On one occasion
Elliott (1992b) observed Rhadine persephone in This may indicate a residual nocturnal behavior, similar to that seen in fully-eyed species of Rhadine beetles
observed in caves on the observations) Species 6 - Texamaurops reddelli: Texamaurops reddelli is found in total darkness under and among rocks and buried in silt (Barr and Steeves 1963, Reddell 1966). All members
of the family are believed to be predators. Both Texamaurops reddelli and Batrisodes texanus (below)
have well-developed mouth parts and are also believed to be predators (Donald S. Hampshire, in litt., 1993). Pselaphids are found
in soil, moldy wood, moss, under stones and logs, in caves, or in termite nests. The term “mold beetle” refers to an old definition of “mold” as rotting plant material. Species 7 - Batrisodes texanus: Batrisodes texanus is found in total darkness under rocks. In Off it was found on the underside of a rock lightly buried in silty clay in total darkness ( Space Cavern in August 1968, Elliott (unpublished data) collected a female as it ran from under a moldy match box in the Mud Room. It is believed to be a predator (see Texamaurops reddelli, above). D. Reasons for Listing and Current Threats One of the main
threats to the listed species is loss of habitat due to urban development activities (53 FR 36029). The species occur in an area that is undergoing continued urban expansion at a rapid rate and few caves are adequately protected. Most of the species’ localities occur adjacent to or near developed areas (residential subdivisions, schools, golf courses, roads, commercial and industrial facilities, etc.) or in areas that are proposed for development. Unless proper protective measures can be devised, urban development may lead to the filling in or collapse of caves, alteration of drainage patterns, alteration of surface plant and animal communities, as well as increased contamination and human visitation. One cave cluster in
the Jollyville Plateau karst fauna region occurs in an area that presently supports some residential and industrial development and where additional development has been proposed. Another cave to the north of this cave cluster occurs in an area that is undergoing expansion of a residential community. These two areas support six of the listed species and include the entire ranges of Tartarocreagris texana and Texamaurops
reddelli. Filling in and Collapsing of Caves: Some caves
have been filled, collapsed, or otherwise altered during road construction and building site preparation (53 FR 36029). Various construction and development activities over caves or sinkholes may also result in the collapse of cave ceilings. There are limited data available on the number of caves that have been filled to date. Elliott and Reddell (1989) estimate that at least 10% of the caves in will only accelerate with increasing urban expansion. To date, two caves containing Texella reyesi are known to
have been filled (Fossil and Sore-ped caves). filled in 1991 by the owner but was reopened after negotiations with the USFWS. 1980 and has not been reopened. Trap #6 will be destroyed as part of the LakeLine Mall Section 10 (a) (1) (B) permit (see discussion in Section E) Other caves (such as texanus) may already have been filled due to
recent development. Attempts to relocate unsuccessful (53 FR 36029) Ranching activities
may also lead to the filling of cave entrances. The earliest published reference to local ranchers routinely filling cave entrances was by Vinther and Jackson (1948), who stated that entrances were closed in ‘varmints’— predatory animals.” Ranchers sometimes fill entrances or cover cave entrances by placing “cedar” (juniper) limbs across entrances to prevent cattle and goats from falling in (Elliott, pers. observations). Alteration of Drainage Patterns: Because
karst ecosystems depend on air-filled voids with some water infiltration, diverting water away from a cave could lead to drying and subsequent mortality of karst fauna, while increasing water infiltration could lead to flooding and loss of air-breathing
species. Altering the quantity of water inflow could also result in changes in the nutrient regime. Development
activities that result in the alteration of natural drainage patterns include altering the topography, increasing impervious cover, installing water collecting devices, spray-irrigation systems, and other activities. Opening too many or too large entrances into a cave system during cave exploration may also result in drying. The extent to which these activities are impacting the listed species’ localities needs to be determined. Alteration of Surface Plant and Animal Communities: Land development and other human activities (such as agriculture) can lead to the loss of surface plant and animal communities on which karst ecosystems depend for nutrient supplies. With urbanization, native vegetation may be removed and replaced with impervious cover, nursery plants, and/or exotic plants. Subsequent changes in the animal community include the introduction of exotics, such as fire ants; loss or reduction of certain animals due to habitat loss, competition, predation, or other factors; and overall declines in species diversity. Many of these plants and animals (for example, cave crickets and daddy longlegs) may be critical to the nutrient regime of the karst ecosystem, and loss of these species could lead to nutrient reduction or depletion within the karst ecosystem. Removal of the native surface vegetation may lead to increases in temperature fluctuations, changes in the moisture regime, increased potential for contamination, and increases in sedimentation in the caves from soil erosion on the surface. The impacts that
altering surface plant and animal communities have on karst ecosystems are not fully understood and warrant further research. Important contributors to the karst ecosystem’s nutrient regime need to be identified, as well as the surface area and other ecological requirements necessary to sustain these nutrient sources. Some of this information will be gathered as part of the LakeLine Mall Habitat Conservation Plan’s studies (see discussion in Section E) Contamination: Because karst is highly susceptible to groundwater contamination, urbanization (including industrial, residential, road, and commercial development) may result in the contamination of karst ecosystems. Types of contaminants associated with urbanization may include chemical, sewage, and oil pollution. These pollutants are derived from urban runoff; broadcasting, spraying, and fogging pesticides and fertilizers; hazardous materials spills; pipeline and storage tank leaks; power transformer and industrial accidents; leakage from septic systems, landfills, and sewer lines; and other sources. Primary routes of
contaminant entry into karst ecosystems include the surface and subsurface drainage basin of a karst ecosystem; air (for air-borne contaminants); and dumping of household garbage, construction debris, motor oil, alkaline batteries (which contain mercury), pesticides and other materials directly into cave entrances. Many caves are currently subject to disposal of refuse, urban runoff, and contamination from pesticides and fertilizers. Several chemical facilities are located along RM 2222 in the Jollyville Plateau karst fauna region near caves known to support six of the listed species. A cave containing Texella reyesi is directly under an oil pipeline. Provisions for protecting karst ecosystems from contamination need to be developed. Human Visitation, Vandalism, and Dumping: Urban development near cave entrances is likely to increase human visitation to these caves. Possible impacts from human entry into a cave include habitat disturbance or loss due to soil compaction or changes in atmospheric conditions, abandonment of the cave by bats or other trogloxenes, and direct mortality (e.g., from stepping on karst fauna). These impacts may be reduced or avoided, depending on the caving skills and caution of the person(s) entering the cave. Vandalism may also result in the destruction or deterioration of the karst ecosystem. Dumping of toxic trash (such as alkaline batteries) can lead to contamination of the karst ecosystem. Disposal of household and other wastes may also attract fire ants. Cave gates and
fences are often installed to deter unauthorized human visitation and dumping; however, these devices may inadvertently alter the air flow, moisture, and nutrient regimes of the karst ecosystem. Installation of a cave gate may also destroy the aesthetics of the cave opening. Furthermore, the soil disturbance generated during the installation of cave gates and fences may encourage fire ant infestations in these areas. Nonetheless, carefully constructed and monitored cave gates and fences are appropriate in some situations and should be considered as an option at heavily visited or vandalized caves. Caves gates are further discussed in Tasks 4.3 and 7.3. Fire ants: Fire ant activity in central have increased dramatically since 1989 (Elliott 1992a). The fire ant is an aggressive predator, and current evidence shows that it has a devastating and long-lasting impact on native ant populations and other arthropod communities (Vinson and Sorenson 1986; Porter and Savignano 1990). Fire ants have been observed building nests both within and near cave entrances as well as foraging in caves, especially during the summer. The relative
accessibility of the shallow caves inhabited by the listed invertebrates makes them especially vulnerable to invasion by fire ants and other exotic species. Fire ants can enter karst ecosystems through the cave entrance or through small holes from the surface and attack karst fauna in areas that humans cannot observe. Fire ants have been found in more than 50 percent of the caves that contain listed karst invertebrates and have been observed attacking and preying on several troglobitic species, as well as scorpions, cave crickets, and other karst dwellers ( litt., 1993). Karst fauna that are most vulnerable to fire ant predation are the slower-moving adults, nymphs, and eggs. (Reddell, pers. communication). Even in the unlikely event that fire ants do not prey directly upon the listed invertebrates, their presence in and around karst areas could have a drastic detrimental effect on the karst ecosystem through loss of both surface and subsurface species that are critical links in the food chain. Fire ant colonies
occur in two forms: single-queen and multiple-queen colonies. Multiple-queen fire ant colonies occur in very dense concentrations (about 750-5000 mounds per acre) and successfully dominate areas previously occupied by the less dense (100-200 mounds/acre) single- queen form (Porter et al. 1991). The multiple-queen form is three times more abundant in of its range and recent surveys indicate it is spreading. This form invaded the 1980’s (Porter et al. 1991). Fire ant studies
conducted by Porter et al. (1988) in In the first phase, fire ant queens invade an area through long-distance dispersal of winged queens or are introduced through imported products such as nursery stock or soil containing small fire ant colonies. Their invasion is aided by “any disturbance that clears a site of heavy vegetation and disrupts the native ant community.” Several native ants are known to attack and kill founding fire ant queens. These native ants are especially important in eliminating founding fire ant queens and their colonies from non-infested areas. Once the fire ant becomes established, they enter the second phase during which the native ant communities are gradually eliminated and show little resurgence as the fire ant slowly expands and increases in number. This phase takes many years to complete (Porter et al. 1988) . These factors should be considered when determining short and long-term methods of fire ant control. Mining, quarrying, or blasting above/in caves: There are several limestone quarries in the contain suitable habitat for one or more of the listed species. Vinther and Jackson (1948) reported three caves south of and Finch (1963) reported two other caves in this area that were destroyed in 1960 and 1963 by quarry activities and at least 22 other caves and sinks on ranches that are now part of or adjacent to that quarry. Both Batrisodes texanus and Texella reyesi occur in caves to the north of this
quarry. Other quarry properties in the area may still contain caves. E. Conservation Measures This section
summarizes the regional karst and biospeleological surveys, research, and other conservation measures that have been conducted to date. Regional karst and biospeleological surveys: Since the listing of the endangered species, numerous surveys have been conducted to better define the distribution and taxonomy of karst fauna in Travis and Williamson counties. Many of the studies are proprietary reconnaissance studies conducted by environmental consultants, geologists, engineers, cavers, and biospeleologists to locate caves and sinkholes on properties proposed for development. These studies have been funded primarily by private landowners, financial institutions, school districts, and governmental agencies and have resulted in the discovery of new endangered species localities. In early 1989, the
Texas Department of Transportation (formerly known as the Texas Department of Highways and Public Transportation) sponsored a karst feature survey and biospeleological study of karst features along the right-of-way of the proposed Highway 45) from Comanche Trail to That same year, Elliott and Reddell (1989) completed a major study of several caves in Travis and Williamson counties to further define the status and range of the listed species. Elliott and Reddell’s surveys were funded by TPWD and TNC in preparation for a regional endangered species conservation effort involving local and state government and several conservation organizations. The report also discussed cave ecology, scientific and economic values of cave faunas, destruction rates of caves, and threats to cave fauna. Acquisition, scientific, and management recommendations were also given, including long-term ecological studies, stewardship programs, cooperative agreements, and greenbelts. Through an Endangered Species Act Section 6 cooperative agreement with TPWD, USFWS funded continued karst and biospeleological studies by Reddell and his associates (1991). These studies helped further clarify the range of the listed species and determine areas that warranted additional study. From 1990 to 1991,
the City of extensive study of 21 caves and 19 other karst features in Elliott 1991). As a result of the study, Temples of Thor and Red Crevice caves were discovered and later sold to Melvin Simon & Associates,
Inc. to become part of the LakeLine Mall Habitat Conservation Plan. Known cave locations from the Texas Speleological Society files were mapped onto the City of system. Through an
Endangered Species Act Section 6 cooperative agreement with TPWD, the USFWS funded a study (Veni & Associates 1992) of geologic controls on cave development and the distribution of karst fauna in the vicinity of Travis and Williamson counties. This study significantly improved the ability to predict where endangered species’ localities might occur in Travis and Williamson counties. Veni divided Travis, Williamson, Hays, and Burnet counties into 11 areas (referred to as “karst fauna regions” in this recovery plan) based on geologic continuity, hydrology, and the distribution of 38 rare troglobites. By correlating distribution data for the 38 troglobites to the 11 karst fauna regions, Veni observed that the Jollyville Plateau, Ridge regions have more endemic species than McNeil, Round Rock, and McNeil and Round Rock karst fauna regions have been combined, and areas where listed species do not occur have been omitted from Figure 2, with the exception of South Veni and Associates
(1992) mapped four zones in Travis and Williamson Counties indicating areas with different likelihoods of having extensive cave development and listed species. The boundaries are matched to known outcrops of cavernous limestone garnered from numerous geologic maps and studies and to hydrologic boundaries extrapolated from the elevations of cave passages compared to surface water divides. Zone 1 includes areas in the Edwards Group limestones that are known to contain listed species. Zone 2 comprises areas that may contain listed species or other endemic fauna. Zone 3 probably does not contain listed species or their habitat, and Zone 4 consists of noncavernous rock and thus does not contain caves or other karst features. Together, Zones 1 and 2 comprise about 55,000 acres in Fire ant control study: In 1991, USFWS funded, through
a Section 6 cooperative agreement with TPWD, a fire ant control study in and around 12 caves containing listed species in Travis and Williamson counties (Elliott 1992a). Three types of treatments were used including hot (nearly boiling) water, and the chemicals Amdro® and Logic®. Additional research is needed to determine the effectiveness of the treatments against fire ants and effects on the listed species. Both Logic®
and Amdro® are harmful to arthropods. Use of Amdro or Logic may result in the mortality of the endangered species through consumption of the chemical(s) or contaminated prey which have ingested the bait. Adverse impacts to the species may be avoided through strict control of chemical applications. For example, applying chemical baits away from the cave entrance and outside of areas used by cave crickets may prevent introduction of the active ingredients into the food chain. By applying chemicals in the morning under dry, warm conditions, the ants may consume most or all of the chemicals before cave crickets exit the cave at sundown to forage. Despite effective
initial treatments, some areas may be rapidly re-infested with fire ants from surrounding areas, as happened at more than one treatment each year. The level and type of fire ant control necessary for each area will likely be site-specific, depending on adjacent land use and severity of the fire ant infestation. LakeLine Mall Habitat Conservation Plan (HCP): On February 13, 1992, the USFWS issued a Section 10(a) (1) (B) permit under the Endangered Species Act to Melvin Simon and Associates, Inc., to allow the “taking” of some Rhadine persephone and Texella reyesi individuals as
a result of the proposed LakeLine Mall development. The Endangered Species Act authorizes the USFWS to permit the taking of federally listed species if such taking is “incidental to, and not the purpose of, the carrying out of an otherwise lawful activity” (16 U.S.C. Section 1539). Two caves (LakeLine and Underline) and one bore-hole (Well Trap #6) were found to contain listed species. contains T. reyesi, and Well Trap
#6 contains R. persephone, while Both during mall construction. The initial two to three-acre fenced preserve around less than 0.5 acre about two years after completion of the mall, which may result in loss or degradation of the cave ecosystem. As part of
mitigation for the taking as outlined in their Habitat Conservation Plan, Melvin Simon and Associates, Inc., acquired a total of 232 acres of preserve land in three separate areas known to support four caves containing Rhadine persephone (Rolling Rock and Testudo Tube caves) and Texella reyesi (Red Crevice and Thor caves). Three of the caves occur in Williamson County. Rolling Parks and Wildlife Department is the
management authority for the LakeLine HCP. Other mitigation
measures in the LakeLine HCP include a 10-year monitoring program of certain environmental conditions (such as temperature, humidity, air movements, and rainfall) and karst fauna (including species, abundance, activity and location within the cave) for years before and 5 years after mall completion, as well as during construction. The purpose is to determine the impacts of mall development on the cave ecosystem and the listed species. Commensurate five-year studies of environmental conditions and karst fauna will be done in Testudo Tube and Temples of Thor Caves to serve as control sites to the food preferences, foraging range, and distribution of cave crickets and daddy longlegs harvestmen at the above three caves and fire ant control at all five sites. A karst ecosystem exhibit for public education will be displayed within the LakeLine Mall development project (Horizon Environmental Services, Inc., 1991b). Elliott (1991a-f,
1992c-e) initiated the studies in May 1991 and began
investigations of Testudo Tube and Temples of Thor caves in May 1992. Monthly ecological monitoring visits to these caves provide information on temperature, humidity, air movements, nutrient inputs, fire ants, and the distribution of numerous species in the cave, but may not provide much data on life histories and other aspects of the listed species’ biology. The cave cricket/daddy longlegs study is providing data on the foraging behavior and spatial/temporal distributions of these species, which feed above ground at night. The cave cricket study will help determine the surface area around the caves needed to sustain these species. A major goal of this research is to determine whether the karst invertebrate community in the shopping mall and to assist in making preserve recommendations for other caves. In addition to the
mitigation outlined above and prior to the development of the HCP, Melvin Simon and Associates, Inc. funded research designed to help determine the extent to which karst fauna occur in the interstitial spaces at the LakeLine Mall site. Six bore-holes were drilled into the bedrock near a cluster of surface karst features. Five-foot sections of 4-inch PVC pipe were installed in each borehole. To prevent surface material from entering the boreholes, approximately 2 feet of pipe protruded above the surface, and the edges around each pipe were sealed with rocks and dirt. Each pipe was then sealed to prevent moisture loss. Pitfall traps
containing a variety of baits, including moldy blue cheese, banana, peanut butter, and yeast were placed inside each borehole to attract karst fauna. This method was successful in trapping Rhadine persephone in
one borehole. No troglobites were found in the other five. The baits do not attract many species, particularly more sedentary predatory species such as Neoleptoneta myopica and the Texella species. Baits may attract fire ants,
as may the surface disturbance generated during the drilling process. Regional Habitat Conservation Plan (HCP): The City of although specific preserve boundaries for the karst features have not been determined at this time. Individual applications for 10(a) (1) (b) permits and associated HCP’s should contribute to achieving recovery plan goals, particularly in setting aside cave preserves. Security measures: To control access to caves where unauthorized human visitation and vandalism present a serious threat to the karst ecosystems and possible injury to humans, cave gates have been installed at some cave entrances. Caves where gates have been installed to date include Tooth, Gallifer, Kretschmarr, Kretschmarr Salamander, LakeLine, and Sore-ped caves. Most of these cave gates consist of a locked door fashioned from an open steel grid to prevent unauthorized entry. Cave gates should be designed to permit normal air flow, water infiltration, and nutrient input. Since some cave gates have been known to filter out important nutrient sources, particularly larger animals such as raccoons, they should be closely monitored and rectified should such problems occur. One alternative to
gating that may pose less interference with the nutrient regime and other environmental factors (such as air and water movement) is the installation of a high fence around a cave preserve. Chain-link fences have been installed around Kretschmarr Cave and are subject to vandalism, they may require frequent surveillance. The effectiveness of gating and fencing and their effects on the karst ecosystems should be closely monitored. Other alternatives to protecting caves from human visitation and vandalism, such as public education and routine site patrols, should also be explored. Other conservation measures: In late 1988, the USFWS, in conjunction with two groups of developers, sponsored a hydrogeologic study of a
cave cluster located to the northwest of the RM 2222 and RM 620 intersection to aid in determining measures to protect this cluster, which supports six of the listed species. The project, conducted by Veni & Associates (1988a), provided guidelines for protecting the caves based largely on hydrogeologic factors, but did not involve biological investigations. The study was used by a group of experts assembled by USFWS to prepare guidelines for the protection of the cave cluster. The group’s guidelines were used in discussions between USFWS and the developers about protecting the caves and cave fauna. Local caving organizations
have been instrumental in locating and monitoring karst features and maintaining a database of their findings. Several of these organizations have published reports of their findings and made conservation and management recommendations that are useful to the USFWS. Other contributions made by local cavers include the removal of trash from cave openings and the detection of contaminant spills. The entrances to been under the stewardship of the Texas System of Natural Laboratories (TSNL) on behalf of the owners since about 1970. This resulted in the discovery of several more caves containing troglobites. A small area (about 0.6 acres) around Tooth Cave and a total of about six acres encompassing Jollyville Plateau were deeded by the owner to the TSNL in 1990. However, the preserves around these caves are not sufficient to counter nutrient depletion and prevent pollution should the surrounding areas be developed. The entire area is now infested with fire ants. Furthermore, some of these caves are under temporary deed to TSNL and may be sold at the owners’ discretion. F. Recovery Strategy This recovery plan
is designed to outline steps for long-term protection of the listed invertebrate species, including restoration and enhancement of the habitat where necessary. The recovery criteria state that each species will be considered for downlisting from endangered to threatened when three karst fauna areas (if at least three exist) within each karst fauna region in each species’ range are protected in perpetuity (see Section II.A for a more detailed delineation of the criteria). The “karst fauna regions” depicted in Figure 2 of this plan are adapted from the karst fauna areas delineated in Veni & Associates’ 1992 report (see discussion in Section I.B) . These regions are delineated based on geologic continuity, hydrology, and the distribution of 38 rare troglobitic species. Each karst fauna region can be further subdivided into karst fauna areas. For the purposes of this plan, a “karst fauna area” is an area known to support one or more locations of a listed species and is distinct in that it acts as a system that is separated from other karst fauna areas by geologic and hydrologic features and/or processes that create barriers to the movement of water, contaminants, and troglobitic fauna. Karst fauna areas should be far enough apart so that if a catastrophic event (for example, contamination of the water supply, flooding, disease) were to destroy one of the areas and/or the species in it, that event would not likely destroy any other area occupied by that species. As troglobitic
populations become increasingly isolated due to hydrogeologic processes, subsequent speciation among the isolated populations may occur. The recovery criteria are designed to allow these natural evolutionary processes to continue for each species. The recovery criteria aim at protecting populations and preserving genetic diversity across each species’ range. Full implementation
of the recovery criteria should protect against catastrophic loss of the listed species. Because karst ecosystems can never be recreated once they are destroyed, an adequate number of karst fauna areas per karst fauna region should be protected in perpetuity to ensure the continued survival and conservation of each species. Ideally, at least three karst fauna areas per karst fauna region should be protected to provide a margin of safety against extinction if one or more protected areas are lost due to an unanticipated catastrophic event. This is particularly important for karst species since their habitat can not be recreated. If a given species only occurs in two karst fauna areas, that species would still be considered for downlisting provided both areas were adequately protected. Species whose entire range consists of only one karst fauna area (should one area be destroyed) will not be considered for downlisting. If a species occupies several karst fauna regions (such as Texella reyesi), but one or more of those karst fauna
regions contains less than three karst fauna areas, then all karst fauna areas within that region must be protected in order to meet the recovery objective. The first step in
recovering these species is to identify the karst fauna areas targeted for recovery. According to the recovery criteria, all localities inhabited by four of the listed species (Neoleptoneta myopica, Tartarocreagris texana, Texamaurops reddelli, and Batrisodes texanus) should be provided long-term protection prior to consideration for downlisting. Three of the listed species, Texella reddelli, Texella reyesi, and Rhadine persephone, occupy karst fauna regions that contain more than three karst fauna areas. Table 3 identifies the karst fauna regions in which each species occurs, the approximate number of karst fauna areas inhabited by each species, and the number of karst fauna areas that should be protected, based on the recovery criteria for downlisting and current knowledge of the species’ distributions (figures 3-9). Continuing surveys for caves and karst invertebrates may result in an increase in the number of karst fauna areas occupied by some species. In selecting karst
fauna areas to be targeted for recovery, priority should be given to those areas that exhibit high species diversity and contain other rare or listed species. This ecosystem-based approach to choosing karst fauna areas for preservation should consider both the listed species and other endemic species and may prevent the need for listing additional species in the future. Numerous rare species inhabit the same karst terrains in Travis and Williamson counties. For example, contains at least 32 rare karst species,
25 of which are not federally-listed and some of which are undescribed (Elliott 1992a). Many of those rare species were taxonomically described in 1992 and some may become candidates for the endangered species list, especially those found in urbanizing areas. Therefore, judicious selection of karst areas for preservation will aid in the recovery of the listed species, help protect other important elements of the karst ecosystem in Travis and Williamson counties, and possibly prevent the need to list other species in the future. Within each karst
fauna region, karst fauna areas that are targeted for recovery should be located as far apart as possible, to protect against catastrophic loss and to preserve genetic diversity within each species. Other factors to consider when selecting karst fauna areas include ability to ensure long-term protection, current level of habitat disturbance, past and present land use, presence of other rare or candidate species, ease of protection (landowner cooperation), and, where applicable, importance to the regional groundwater system. Where the listed
species’ ranges overlap, particularly on the Jollyville Plateau, more than one of the species may occur in a given karst fauna area. For example, six of the seven species occur in the Jollyville Plateau karst fauna region, and three of the species’ entire ranges are in the vicinity of the RM 2222/RM 620 intersection. Two areas within the
Jollyville Plateau karst fauna region that are already known to be very important to the survival and recovery of several of the listed species represent two distinct karst fauna areas and should be targeted for protection. One of these areas, the Tooth Cave karst fauna area, harbors six of the seven listed species and one of the most diverse cave biotas in the southwestern Cave karst fauna area, contains five of the listed species. Preservation of these two karst fauna areas would protect 100% of the range of two of the listed invertebrates (Texamaurops reddelli and Tartarocreagris texana) and
67% of the range of Neoleptoneta myopica. A suggested karst fauna area for the Figure 11. The second major
step in recovery is to determine the appropriate size and configuration of each of the karst fauna areas targeted for recovery. To be considered “protected”, a karst fauna area should contain a large enough expanse of contiguous karst and surface area to maintain the integrity of the karst ecosystem on which each species depends. The size and configuration of each karst fauna area should be adequate to maintain moist, humid conditions, air flow, and stable temperatures in the air- filled voids; maintain an adequate nutrient supply; prevent contamination of surface and groundwater entering the ecosystem; prevent or control the invasion of exotic species, such as fire ants; and allow for movement of the karst fauna and nutrients through the interstitium between karst features. Several factors
should be considered in determining the size and configuration of karst fauna areas, including the pattern and direction of groundwater movement, direction and area of surface and subsurface drainage, preservation of the surface community above and surrounding the cave, and the presence of other caves or karst features. In general, land bounded by the contour interval at the cave floor is the area within which contaminants moving over the surface or through the karst could move toward the cave. Outside this contour, contaminants would move away from the cave. A hydrogeologic investigation may be useful in determining the surface and subsurface drainage basin of the karst ecosystem, local recharge areas, and direction of groundwater movement. This information would be used to determine the area necessary to protect the karst fauna area’s water supply. The amount of surface area necessary to maintain the ecological processes of the karst ecosystem should also be considered and may be larger than the surface drainage area of the cave. Other nearby karst features, which may affect the moisture, air flow, temperature, and nutrient regimes and allow movement of karst fauna through the interstitium, should be included in each karst fauna area. Major sources of nutrient input and areas necessary to sustain these sources should be considered. Recent research as part of the LakeLine Mall HCP may provide some information on the importance of the surface area surrounding karst features in providing nutrients to the cave ecosystem. Wherever possible, karst fauna areas should connect to larger undeveloped lands that are not slated for future development, in order to ensure adequate nutrient flow into the karst ecosystem and to help combat the fire ant threat. Setting aside large
preserves may help to control fire ants. Porter et al. (1991) state that control of fire ants in large areas (>5 hectares) (12 acres) may be more effective than in smaller areas since multiple queen fire ant colonies reproduce primarily by “budding” (whereby queens and workers branch off from the main colony and form new sister colonies) . Budding is a relatively slow process, and fire ants may not as quickly reinvade areas where they have, been eliminated with this method. Native ant communities may also require large, undisturbed areas to help them combat the fire ant threat. Research in some
areas, including the fire ant’s native range, indicates that fire ants are associated with open habitats disturbed as a result of human activity (such as old fields, lawns, roadsides, ponds, and other open, sunny habitats) but are absent or rare in late succession or climax communities such as mature forest (Tschinkel 1986) . Although this association is not apparent in all areas, especially in central 1991), maintaining native vegetation communities may help sustain native ant populations and further deter fire ant infestations. Chemical control methods have some effectiveness in controlling fire ants, but the effect of these agents on non-target species (including the listed invertebrates) is unclear and, if used indiscriminately, may also eliminate native ant populations. Ideally, intensive fire ant control should be implemented along disturbed areas on the periphery of large preserves. This type of fire ant control, combined with safer but more labor intensive methods (such as hot water applied mound- by-mound) in the vicinity of cave entrances, should help sustain the native ant fauna and reduce the need to implement intensive control within the preserve. Due to the
multiplicity of factors to consider when determining the size and configuration of the karst fauna areas, the design of each karst fauna area will be site- specific. Although many factors (such as the species’ ecological requirements, distribution in the interstitium, and the amount of surface area necessary to sustain nutrient flow) are unknown, the amount of time and financial expense to acquire this knowledge would preclude achieving the recovery objective if karst fauna area protection were delayed pending additional research in these areas. To compensate for this lack of knowledge, delineation of the karst fauna areas should be based on protecting the integrity of the karst terrain supporting the listed species and a conservative interpretation of the available biological and hydrogeological information. Another step needed to
accomplish recovery is to provide long-term protection for the targeted karst fauna areas. Methods could include land acquisition, conservation easements, and cooperative agreements with private landowners and public entities. Implementation of
appropriate conservation and management measures for each targeted karst fauna area is also needed for recovery. This may include control of fire ants and other threats; management of surface plant and animal communities; maintaining surface and groundwater quality and quantity; preventing vandalism, dumping, and unauthorized human visitation; and other actions deemed necessary. Additional studies will be necessary to monitor the effects of each management program, refine management techniques as appropriate, and determine any other steps necessary to fully recover the species. Regardless of
whether a listed species occurs in a karst ecosystem that is in or outside of a karst fauna area targeted for protection, the listed species are still protected under the Endangered Species Act (Act) unless authorization for incidental “take” has been obtained under Section 7 or Section 10 of the Act. II. RECOVERY A.
OBJECTIVE AND CRITERIA <snip> B. RECOVERY OUTLINE <snip> C. NARRATIVE OUTLINE FOR RECOVERY ACTIONS <snip> D.D. REFERENCES CITED Barr,
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of Agriculture and III. RECOVERY
PLAN IMPLEMENTATION SCHEDULE <snip> Appendix A. Glossary Aedeagus - In male insects, the mating
organ which is everted from the posterior. Apical - At the tip of a
structure (see proximal). Apophysis - In arthropods, a chitinous ingrowth of the exoskeleton for muscle insertion. Attenuated — Elongated,
especially appendages, antennae, etc. Biospeleology
— The study of cave
life and its relations to the surface and subsurface environment. Book lungs — Primitive breathing
organs found in lower arachnids such as scorpions and some
spiders. Borehole - In this work, a
vertical hole drilled in bedrock for sampling karst fauna. Referred to
as “corehole” in certain documents. Carabid - Ground beetle,
including Rhadine Persephone. Carapace — The upper
exoskeleton of the thorax of an arachnid. Carinate — Having a carina, or
keel, running lengthwise along an appendage. Cavernicole — A species occurring
only in caves, not necessarily eyeless and depigmented. Chelae — The pincerlike claw
of a scorpion’s or pseudoscorpion’ s pedipalp. Chelicerae — The first pair of
appendages in an arachnid in front of the mouth, adapted for
grasping and cutting up food; usually claw-like. Collembolans
(springtails)
- Minute insects that
have a forked structure on the abdomen that
enables them to jump. Usually common and abundant. Feed on
plant material, fungi, bacteria, arthropod feces, pollen,
algae, and/or other food sources. Dark zone — The permanently dark
zone of the deep cave environment where no light penetrates,
as opposed to twilight zone. DNA (Deoxyribonucleic
acid) - the substance that
carries the cell’s genetic code in the nucleus. Elytra — In beetles, the
hardened front wings which serve as covers to protect the delicate hind
wings when the insect is not flying. Endemism, endemic — Indigenous or native to a restricted area. Epigean — Living on the
surface, as opposed to living below the surface (hypogean). Eye mound — In harvestmen, the conical projection on the dorsum (upper side) of the body bearing
the two eyes. Facet — An individual visual
organ in the compound eye of an insect. Feebly
arcuate - slightly arched. Femur — The third joint of
an arachnid appendage. Foveae - Small pits on the surface of the arthropod
body. Genital
operculum - In harvestmen, a
flap covering the genital opening. Holotype — The primary type
specimen selected as representative of a species by a
taxonomist who describes the species. A holotype must be housed
in a scientific collection that is available for study
by qualified scientists. Hydrogeology
— The study of water
dynamics in relation to geology, especially groundwater. Infragroup - A collection of species within a subgroup (see below) that share similar physical
and/or genetic traits. The smallest division in a hierarchical
system of grouping species based on degrees of
relatedness. Karst — A terrain
characterized by landforms and subsurface features, such as sinkholes and caves,
that are produced by solution of bedrock (usually limestone
or gypsum) .
Karst areas commonly have few surface
streams; most water moves through cavernous openings underground. Metathoracic
wings —
The
hind wings of an insect. Metatibial
pencil of setae — A
small brush of setae (hairs) found on the tibia of the third leg. Microarthropod
— A tiny arthropod,
such as a springtail, mite, etc. Monophyletic
assemblage — A
group of species that has descended from a common ancestor. Niche - The role a species
plays within its community or ecosystem. Obsolescent
eyes —
Eyes
that are nearly absent; only a small remnant may remain. Ocular knobs
- Eye remnants (bumps)
that would normally bear a compound eye. Ovipositor
cuticle — The surface of the
female ovipositor (an organ for laying eggs in the soil). Palpal — Pertaining to the
pedipalps. Parastylar - On either side of the stylus, part of the harvestman’s penis. Paratopotype
— A type specimen
selected by a taxonomist as a representative example of a species
and which comes from the original type locality which he/she
designates. Paratype — A secondary type
specimen selected by a taxonomist to represent a species being
described; not necessarily of the same sex as the
holotype or from the type locality. Pedipalps — The second pair of
appendages in arachnids, the bases of which provide a jaw-like
function; the pedipalps provide a grasping or pinching function
for handling food. Phalangodid - Daddy longlegs harvestman, including Texella reddelli and Texella reyesi. Polymorphic — Exhibiting much
physical variation among individuals. Postopercular
process — In
some harvestmen, a projection posterior to the genital operculum. Pronotum — In insects, the
dorsal (upper) side of the anterior (front) part of the thorax. In
Rhadine
beetles, the pronotum is elongated like a neck. Protuberance
- A knob or
prominence. Proximal — At the base of a
structure (see apical) Pselaphid - Short winged mold
beetle, including Texamaurops reddelli and Batrisodes texanus Psocid - Small, soft-bodied insect, usually less than 6
mm long. Punctulate - Pitted. Retrolateral
— On the backside of
an appendage. Robust - Relatively
thick-bodied, compared to others in the same
group (opposite of slender, below) Rugosity — A rough or scaly
quality to the exoskeleton. Scute — An exoskeletal plate
on the dorsal (upper) side of a harvestman’s body. Setae - Hairs. Slender - Relatively thin-bodied, compared to others in
the same group (opposite of robust, above) Spatulate — Flattened like a
spatula. Species
group -
A
collection of species that share similar physical and/or genetic traits. The
highest division in a hierarchical system of grouping species
based on degrees of relatedness. Spermathecae
— Sacs used for the
storage of sperm in female pseudoscorpions and other invertebrates. Stylus — The long, thin part of a harvestman’s penis. Subcontiguous
— Not quite touching. Subgroup - A collection of
species within a species group (see above) that share similar physical
and/or genetic traits. An intermediate division in a
hierarchical system of grouping species based on degrees of
relatedness. Speleology— The scientific study
and exploration of caves. Sympatric — Two species within the same genus occurring in the same place. Tarsomeres - The segments at the
end of an arthropod leg. Taxonomy — The classification
and nomenclature of living things, also referred to as
“systematics”. A taxonomist publishes species descriptions and/or
revisions in scientific journals, based on studies
of the anatomy, biology, or genetics of a certain taxon
(group). Tergal
chaetotaxy — The
pattern of setae (hair-like structures) on the dorsal (upper)
plates of an arthropod. Tergite — The dorsal (upper) plate of an arthropod’s abdominal segment. Tibia — The fourth joint of
an arthropod leg. Transverse
impression - A crease that runs
from side to side. Trochanter - In arthropods, the second joint of the leg. Troglobite — An animal that completes its lifecycle and spends its entire life in openings
underground (such as caves) usually with small or absent
eyes, attenuated appendages, and other adaptations to
the subsurface environment. Troglomorphy,
troglomorphism, troglomophic — The physical characteristics of a troglobite,
typified by eyelessness, attenuated appendages, depigmentation,
delicate integument or exoskeleton, and greater development
of some sensory organs. Troglophile — An animal that
spends most of its life in openings underground, but may also be
found above ground; not usually eyeless or depigmented. Trogloxene — A cave-dwelling animal that leaves the cave on a regular basis to feed, such as bats
and cave crickets. Tubercle - A small, rounded nodule or mound. Twilight
zone — The cave zone in
which light from the entrance is still visible. Vestigial — Having only a
vestige, or a remnant, of a structure left. Appendix B. Individuals
and Agencies Providing Comments on the Draft
Recovery Plan for Endangered Karst Invertebrates in Travis and Appendix C.
Simmary of Comments Received on the Draft Recovery Plan
for Endangered Karst Invertebrates in Travis and
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27 Jan 2007 Mike Quinn / Texas Entomology