home to at least 14 endemic freshwater fishes, including two subterranean species of catfish and 13 fish species considered to be spring-associated. Mechanisms for spring association of fishes is not fully understood, but thought to mediated by water temperature. The large numbers of reptiles and birds also include breeding populations of the Texan endemic golden-cheeked warbler (Setophaga chrysoparia). Nearly all the natural habitat of the plateau has been converted to ranchland, farmland, or urban areas, such as Austin and San Antonio, with only about 2% remaining in scattered fragments, especially to the east of the plateau. Further alteration to the savanna has incurred though the encroachment of shrubs now that grassland fires are carefully controlled. Small areas of intact habitat remain, particularly around Austin, where areas are protected, such as the Balcones Canyonlands National Wildlife Refuge. Another important area for wildlife is Fort Hood military base. Human history Earliest human settlement of this area was by Native Americans. First it was used and wandered about by Jumano and Coahuiltecan groups, then the Apacheria extended into the Southern Plains by the forerunners of the Lipan and Mescalero Apaches. After the expulsion of the Apachean groups from the Plains by the Comanche, this area was dominated by the Penateka band of the Southern Comanche. Counties in the Edwards Plateau According to the Texas Parks and Wildlife Department, all or portions of these 41 counties comprise the Edwards Plateau geographic region: The Texas Water Development Board, a state government agency, includes additional counties all or partly in the Edwards Plateau area: A map showing the counties is provided by Texas Parks and Wildlife Department for the Edwards Plateau Ecoregion. The ecoregion is somewhat larger than the geographic region, as the map from Texas Parks And Wildlife includes additional counties that are listed by the Texas Water Development Board, notably the isolated area of Edwards Plateau in Taylor, Runnels, and Nolan Counties that is separated from the main region. Edwards Plateau gallery See also Balcones Canyonlands National Wildlife Refuge Colorado River (Texas) Mount Bonnell List of ecoregions in the United States (EPA) List of ecoregions in the United States (WWF) References External links Texas counties map showing the ecoregion Landforms of Texas Plateaus of the United States Regions of Texas Tropical and subtropical grasslands, savannas, and shrublands of the United States Ecoregions of the United States Geography of Texas Grasslands of Texas Texas Hill