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 animal 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 Rhadine infernalis, another beetle, 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 spider Cicurina 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; Texella cokendolpheri, 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; Batrisodes 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- 1999 National Cave and Karst Management Symposium 203 White & Kingsley 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.” 204 1999 National Cave and Karst Management Symposium White & Kingsley 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.