Principles and Practice for Design of Cave Preserve Management and Monitoring Plans for Invertebrate Species of Concern, San Antonio, Texas

Kemble White SWCA, Inc. Environmental Consultants. 1712 Rio Grande Austin, Texas 78701-1124 (512) 476-0891 email: [email protected] Kenneth J. Kingsley SWCA, Inc. Environmental Consultants. 343 South Scott Ave. Tucson, Arizona 85701 (520) 325-9194 email: [email protected]

Abstract

Karst areas around San Antonio, Texas contain over 300 known caves, some of which contain invertebrate species that are unique to the area. The U.S. Fish and Wildlife Service have proposed nine invertebrate species as Endangered Species. Concerned landowners and local agencies, hoping to obviate listing (which would be economically costly and an impediment to use of private property), have formed a coalition to protect, preserve, and manage caves known to have the species. Preserve Manage- ment and Monitoring Plans have been prepared for several caves based on guidelines promulgated by Fish and Wildlife Service and evaluation of conditions at each site. Important factors include protection of surface and sub-surface drainage areas, preservation of adequate foraging areas for trogloxenes, reduction of disruptive human access, control of non-native fire ants, and periodic monitoring to evaluate conditions and populations of species of concern. This paper will discuss the principles for design of Monitoring Plans and their practical application at one specific site.

Introduction the petition; and infernalis, another , with two described subspecies: R. infer- In 1991, nine species of invertebrates known nalis infernalis, known from two caves, and R. only from caves in Bexar County, Texas, were infernalis ewersi, known only from one cave, petitioned for listing as Endangered Species and specimens that could not be identified to under the Federal Endangered Species Act. The subspecies, described as “hybrids,” known taxa include: four apparently different species from at least seven other caves. of blind baronia, Cicurina The U.S. Fish and Wildlife Service published madla, Cicurina venii, and Cicurina vespera, a proposed rule to list the species as Endan- each known from only one cave at the time the gered on December 30, 1998. Threats consid- petition to list the species was submitted; ered to be potentially endangering these Neoleptoneta microps, a spider known from species are listed in the Proposed Rule as: one cave; , a harvestman destruction and/or deterioration of habitat by known from one cave for certain and tenta- commercial, residential, and road construc- tively from another; venyivi, a bee- tion; filling of caves; loss of permeable cover; tle known only from one cave, Rhadine exilis, potential contamination from such things as a beetle, known from four sites at the time of septic effluent, sewer leaks, runoff, and pesti-

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cides; predation by and competition with non- important, and has laid down the requirement native fire ants; and vandalism. that they be considered in determining the Subsequent to the petition, additional re- adequacy of protection of the species. For pur- search has found that some of the species are poses of determining adequacy of protection, much more widely distributed and abundant the Fish and Wildlife Service requires that for than had been known previously. No new lo- all species that are known from at least three cations were found for Cicurina baronia, caves in one or more karst regions, protection Cicurina venii, or Texella cokendolpheri. of at least three Invertebrate Conservation Ar- Cicurina vespera has been found in one new eas within each region is necessary. The Fish location, as have Neoleptoneta microps, and and Wildlife Service has not determined the Batrisodes venyivi. Texella cokendolpheri has appropriate course of action for those species not been positively identified in its previously known from fewer than three caves, except to known habitat and may be extinct. No docu- require thorough surveys for additional loca- mented records of this species are known since tions. 1985. Cicurina madla has been found in four An Invertebrate Conservation Area is de- new locations. Both of the Rhadine species fined by the Fish and Wildlife Service as: “an were found to be more widespread than pre- area known to support one or more locations viously thought, with many newly discovered of a species and is distinct in that it acts as a sites for each species. The number of caves system that is separated from other karst from which each species is currently known is: fauna areas by geologic and hydrologic fea- Rhadine exilis: 31 caves; Rhadine infernalis: tures and/or processes that create barriers to 22 caves, with three putative subspecies; Ba- the movement of water, contaminants, and trisodes venyivi: two caves; Cicurina madla: troglobitic fauna.” five caves; Cicurina baronia: one cave; This includes one or more caves and the Cicurina venii: one cave; Cicurina vespera: surrounding areas that may provide surface two caves, and Neoleptoneta microps: two and subsurface drainage, as well as surface caves. The species are currently known from a foraging areas for trogloxenes. combined total of at least 56 caves. To protect an Invertebrate Conservation Most of the land in the area is privately Area, Fish and Wildlife Service specifies cer- owned, and many landowners have plans for tain general considerations that must be development of their properties. Coopera- taken into account. The first step is to define tion of the landowners is essential for the the area to be protected so that it provides for protection of the species and the cave and maintenance of adequate levels of all ecosys- karst environments in which they are found. tem components necessary for survival of the In a series of meetings with landowners and species of concern, and for adequate protec- local agencies, Fish and Wildlife Service tion against definable threats. This is neces- agreed that if the long-term conservation of sarily unique for each cave, and must be the nine species could be assured, then the evaluated by examination of conditions listing proposal would be withdrawn. Spe- above and below ground. cific criteria were issued by Fish and Wildlife Service for protection of caves and Inverte- Important Factors brate Conservation Areas. These were based on the Recovery Plan for Endangered Karst Fish and Wildlife Service defined the follow- Invertebrates in Travis and Williamson Coun- ing as important factors for creating preserves: ties, Texas. This paper describes the criteria “To be considered ‘protected,’ a karst fauna and suggests specific ways that they can be area should contain a large enough expanse of implemented to create Preserve Management contiguous karst and surface area to maintain and Monitoring Plans. the integrity of the karst ecosystem on which each species depends. The size and configura- Fish and Wildlife Service Criteria tion of each karst fauna area should be ade- quate to maintain moist, humid conditions, air The karst areas of Bexar County have been flow, and stable temperatures in the air-filled divided into six regions, based on geology. At voids; maintain an adequate nutrient supply; one time it was thought that these regions prevent contamination of surface and ground- might be related to the distribution of the spe- water entering the ecosystem; prevent or con- cies, but this has not been consistently sup- trol the invasion of exotic species, such as fire ported by new records of distribution. ants; and allow for movement of the karst fauna However, the Fish and Wildlife Service consid- and nutrients through the interstitium be- ers these regions to be valid and biologically tween karst features.”

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For each preserve designed, and for which a having a hydrogeologist examine the cave and Management Plan is to be created, all of these surrounding area and make his or her best factors must be examined, and provisions approximation on the parameters of the sur- made for them. face and subsurface drainage. Factors relevant to this determination may include but are not Protection of Surface and limited to regional dip, influences of fractures Subsurface Drainage Areas and faulting, and proximity to potentially re- lated karst features. Often, some portion of The first principle of cave preserve design is these may extend beyond the property owned to protect the entrance and the surface area by or available to the conservation entity creat- above the maximum footprint of the cave from ing the preserve. In practice, with local land all forms of disturbance and potential contami- values exceeding seven dollars per square foot, nation by human-generated chemical or bio- economy calls for making the preserve size as logical contaminants. Under conditions small as possible, while still maintaining a func- designed to eliminate all conceivable threats to tioning ecosystem and reducing the potential the petitioned species, no matter how remote for contaminants entering the cave. This may in probability of occurrence and regardless of call for acquiring additional property, develop- cost or impact on human land use decisions, ing cooperative agreements with neighbors, or preserves would be large areas of undisturbed limiting the area draining into the cave by cre- wilderness. With that level of protection as its ating berms around a suitable surface drainage implicit objective, the U.S. Fish and Wildlife area. In the San Antonio area, strict local regu- Service has issued a guideline on karst species lations prohibit contamination of the aquifer, preserve size for the Travis and Williamson and greatly reduce the likelihood that any cave County species: habitats would be contaminated. “In general, land bounded by the contour interval at the cave floor is the area within Preservation of Trogloxene which contaminants moving over the surface Foraging Areas or through the karst could move toward the cave. Outside this contour, contaminants The proposed endangered species are very would move away from the cave.” poorly understood by science. Very little is Applying that principle to the example of a known about their trophic levels and depend- cave that is 100 feet deep with its surface at encies, although it is presumed that they are 1,000 feet above sea level and its floor at 900 predators and/or scavengers that feed either feet above sea level, ideally the preserve area directly or indirectly on the eggs, bodies, or should include all land surrounding the cave wastes of trogloxenes. Maintenance of a com- outward to the 900-foot elevation level. Al- munity of trogloxenes is deemed necessary to though the Fish and Wildlife Service guideline support populations of the dependent caverni- may be practicable for caves that are shallow or coles. For most caves in the area, the primary in rugged topography, it becomes essentially source of nutrient inflow appears to be crickets unworkable and unnecessary for deep caves (Ceuthophilus spp.) and daddy-long-legs located in flatter landscapes. For example, ap- (Leiobunum townsendii Weed). Secondary, plying the U.S. Fish and Wildlife Service guide- and probably much less important, is input line to one cave known to contain Rhadine from leaves and water falling or draining into exilis and to be approximately 115 feet deep, the cave entrance or penetrating through seep- would result in a preserve area of over 125 age. In some caves, droppings of mammals square miles—that is, most of northwest Bexar such as bats and raccoons may be important County, including a large portion of the devel- sources of nutrient input, but this is not true of oped City of San Antonio. Clearly, the threat of many of the caves from which the species of contamination from areas miles away from the concern are known. cave, even if higher in elevation, is remote. So, Specific management actions that can be certain aspects of the ideal may be impractical included in preserve plans to protect and pro- and, perhaps, truly irrelevant to the effective vide for continuing nutrient inflow to the caves protection of the species of concern. are based on protecting sufficient foraging re- For the karst invertebrates, by far the most sources and access to provide for a population important preserve objective will be protection of trogloxenes typical of the cave. If possible, of the surface above the entire cave footprint the preserve design should include an area of and the immediate surface and evident subsur- undisturbed native vegetation greater than face drainage areas directly affecting the cave would be necessary for trogloxene foraging, of concern. This may be best determined by based on current understanding of foraging

1999 National Cave and Karst Management Symposium 205 White & Kingsley range. Unfortunately, there are no data to sup- Control of Invasive Exotic Species port any notion of the size of trogloxene popu- lation necessary to support a viable population Several species of exotic have in- of any of the proposed endangered species or vaded Texas caves. Effective Integrated Pest the abundance of foraging resources necessary Management programs have not yet been de- to provide for healthy populations of tro- veloped and tested for species likely to occur gloxenes. A radius of 30 meter (100 feet) from in this situation. Of greatest current concern is each cave entrance may be considered as the the introduced fire ant (Solenopsis invicta), maximum likely foraging distance for crickets, which is thought to be a predator on at least based on data from Elliott. This is the furthest some of the species of concern. Although direct that Elliott found crickets wandering from the predation on any of the petitioned species has cave entrance. Alternatively, it may be possible not been described, fire ants are known to prey to enhance the resources available to tro- on and also to forage inside caves. Fire gloxenes, thereby enabling smaller areas to ant control is considered necessary for the provide for the same (or larger) populations. protection of karst ecosystems. Methods that For example, planting persimmons (Diospyros have no impact on desirable species are texana), an important producer of food for not known to be especially effective for fire ant crickets, may increase the resources for these control. Current research is examining alterna- trogloxenes, and indirectly benefit troglobites. tive ways of controlling fire ants, and may find Where bats or other mammals contribute to the more effective methods than those that are cave ecosystem, every effort should be made to currently available. Any preserve plan should maintain accessibility of the cave to these ani- include recommendations currently being mals. Appropriate gates can be designed and made by the Fish and Wildlife Service for fire installed to permit easy access by trogloxenes ant control near caves known to have endan- while excluding unwanted human access. gered species. All portions of the preserves should be accessible for fire ant control using Reduction of Disruptive Human Access the most appropriate approved technique. The current approved method calls for application Although there has been no evidence that of boiling water to active fire ant mounds human intruders, other than speleobiologists, within 35 feet of the cave entrances. Access to actually threaten any of the species of concern, apply boiling water must be possible to all the general concept that human intrusion is points within the preserve. Beyond the 35-foot bad for the species is strongly held by advocates radius, toxic baits can be placed in the morning of preservation. For property owners, reduc- and picked up before sunset, when the tro- tion of exposure to liability for injury is an gloxenes emerge. Fire ant control should be important consideration. Limiting human ac- done quarterly, as part of the Preserve Manage- cess to the cave preserve is the appropriate ment and Monitoring Plan. Preserve managers answer, either by gates, fences, or both. The should be aware of exotic invasive species in best method to do this has not yet been devel- the preserves, and should keep abreast of cur- oped—all gates can be breached, and fences rent techniques available for least toxic Inte- can be climbed or cut. Some proponents argue grated Pest Management in sensitive situations. that the least obtrusive type of fence, such as barbed wire, is less likely to invite vandalism Periodic Monitoring and Maintenance than more conspicuous fencing material. How- ever, the Fish and Wildlife Service does not Because the primary reason for establishing believe that barbed wire fencing is sufficient for and maintaining the cave preserves is protec- cave preserves. It is not currently known what tion of biota, some form of biological monitor- type of fencing would be acceptable to the Fish ing is necessary to evaluate the success of the and Wildlife Service, reasonable in cost, resis- preserves. Funding for the monitoring pro- tant to trespassers, esthetically harmonious gram could come from the landowner, land with the surroundings, and transparent to tro- trust, or other management agency, or from a gloxenes. As with any other cave gate, a gate for public agency such as the Fish and Wildlife a preserve must be custom designed and built Service that was concerned about the welfare for that particular cave. It must be resistant to of the species. Appropriate biological monitor- trespass but not disrupt access by trogloxenes, ing would, ideally, provide sufficient data to and be accessible to personnel carrying out the effectively evaluate conditions, estimate popu- monitoring program. Also, provision should be lation parameters of species of concern, and made for access by rescue teams, in the event detect incipient problems before they become of an emergency. detrimental to the ecosystem.

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Biological monitoring over time should lead • Count all visible cave fauna in the cave, to accumulation of a body of useful data and using minimally disruptive techniques, information contributing to scientific under- map the locations of all species observed, standing of the species and their ecosystems. using a standard cave map prepared for Unfortunately, normal, healthy population pa- that purpose. rameters for any of the species known to occur • Examine the ground surface within and ad- in Texas caves are completely unknown. The jacent to the preserve for fire ant mounds handful of speleobiologists who have worked and institute control measures as necessary. in the area have, at best, accumulated lists of • Measure temperature and humidity in at species they found on only one or a few expe- least three consistent locations within the ditions to any particular cave. There is no pub- cave. Use of HOBO data loggers perma- lished knowledge of population size nently installed and downloaded at each fluctuations in relation to any normal cycles or monitoring session would give more data, perturbations for any species of troglobite, tro- and may be useful. gloxene, or any cave in the area. Even anecdotal • Examine all gates and fences and repair or accounts are minimal. Therefore, systematic apply preventive maintenance as needed. monitoring of populations of karst inverte- • Evaluate for other threats that may be im- brates over time and related to changing con- pacting the karst ecosystem and the effects ditions would be breaking new scientific of management techniques employed to ground. control or eliminate these threats. Crucial to the success of such an endeavor would be minimal disruption of the system by Who Pays and Who is in Charge? the monitoring process. Until very recently, the best speleobiology was based on the The most important unanswered question scorched earth policy of collecting at least confronting the process of creating and man- one of everything in sight, and turning over aging preserves is that of responsibility for the rocks and debris in the quest for a complete costs and continued upkeep of the program. list of species present. This “bugs in a bottle” Initially, anticipating a cooperative relationship science is not appropriate for protection of with the Fish and Wildlife Service, a coalition species of concern in a carefully managed of land owners formed a non-profit organiza- preserve. Monitoring must be performed in tion for the protection and management of the least disruptive manner consistent with caves in the area, called the Bexar County Cave acquiring useful data, and the impact of the Protection Alliance. The Texas Parks and Wild- monitoring process itself must be included as life Department was an active participant in the among the factors studied. process. Unfortunately, the relationship be- The team responsible for the monitoring tween the coalition and the Fish and Wildlife process would ideally be the same year after Service has not been as cooperative as the year. It would include competent observers coalition had hoped, and the future of the familiar with the species of concern and com- organization is in some doubt. The Fish and fortable in the cave environment. The moni- Wildlife Service asserts that only an organiza- toring team should understand the objectives tion with a history and track record of success of the preserve and the long-term manage- in cave invertebrate conservation would be ment goals, and be capable of performing all acceptable as a managing agency, and yet there of the necessary tasks of monitoring and is no such organization active in the area. Reso- maintenance. Because of the interest of the lution of this dilemma is imperative for the Fish and Wildlife Service, the monitoring successful development of a program of cave team should provide copies of their monitor- protection. ing reports to the Fish and Wildlife Service, Many of the caves known to contain species and should welcome Fish and Wildlife Service of concern are on land owned by the Texas biologists’ participation in the monitoring Parks and Wildlife Department and by Camp process. Because the greatest value of moni- Bullis Military Reservation. These agencies may toring data would come only after a period of develop their own programs for creating and at least several years of study, a central reposi- maintaining cave preserves. The remaining tory of data with continuity of personnel caves known to have the species are privately would be ideal. owned. Any expenses incurred in protecting To establish a baseline, monitoring should and managing cave preserves accrues to the be performed quarterly for several years at landowner. Many of the landowners are willing least. At each monitoring session, the following to assume these expenses, and incorporate activities should be performed: cave preserves into open space plans for devel-

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opment on their property. However, it is likely • Contamination by drainage of chemicals that more landowners would be cooperative into the cave is prevented. and proactive if there were reasonable expec- • A program of fire ant control is included. tation of an agreement from the Fish and Wild- • Vandalism is prevented. life Service that would ensure against exposure • A monitoring program is established. to prosecution under the ESA in the event that the species are listed as endangered. The major current impediment to the estab- lishment of a network of preserves is the ab- Conclusions sence of acceptance by the Fish and Wildlife Service of a responsible management agency or If these principles are put into practice, the organization that is also acceptable to the land- threats defined by the Fish and Wildlife Service owners in the area and agreement on the de- as likely to harm karst invertebrates will be tails of Preserve Management and Monitoring removed or reduced to insignificance in this Plans for each cave of concern. If these obsta- area. These principles assure that: cles can be overcome, and Preserve Manage- ment and Monitoring Plans put in place for at • The cave is protected from destruction or least some of the caves known to be inhabited deterioration. by the species of concern, the long-term wel- • Permeable cover and natural vegetation fare of the species can be increased, and scien- within the cave drainage area is preserved. tific understanding can progress from • Sufficient drainage and forage area is pro- speleobiology toward speleoecology. tected to support a community of cave ani- mals.

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