The Karst Fauna Region Concept and Implications for Endangered Karst Invertebrate Recovery in Bexar County, Texas

Nine Species of karst invertebrates known only from caves in Bexar County, Texas, are currently listed as endangered by the U.S. Fish and Wildlife Service. Although a recovery strategy has not been developed for the Bexar County species, accurately delineating the distribution and range of each species is a vital first step. A study contracted by the U.S. Fish and Wildlife Service indicated that the distribution of these rare species has been influenced largely by geologic controls on their habitat imposed primarily by faulting and the down-cutting of streams. Preliminary data based on local geology and the distribution of endemic fauna known at the time suggested that up to six areas, referred to here as karst fauna regions, might exist in Bexar County. They include the Culebra Anticline, Alamo Heights, Government Canyon, Helotes, University of Texas at San Antonio, and Stone Oak karst fauna regions. However, recently collected species distribution data indicate that the number of karst fauna regions in Bexar County may only be four or even as few as three. This presentation will explore the karst fauna region concept and the implications of new data for a Bexar County endangered karst invertebrate recovery strategy.