Edwards Plateau - wikipedia Edwards Plateau Edwards Plateau A photograph taken by NASA of the Edwards Plateau and Balcones Escarpment Ecology Biome Temperate grasslands, savannas, and shrublands Bird species 191 Mammal species 64 Geography Country United States State Texas Conservation Habitat loss 5.35 % Protected 2.26 % Edwards Plateau terrain as seen from U.S. Route 277 between Del Rio and Sonora. The Edwards Plateau is a region of west - central Texas which is bounded by the Balcones Fault to the south and east, the Llano Uplift and the Llano Estacado to the north, and the Pecos River and Chihuahuan Desert to the west. San Angelo, Austin, San Antonio and Del Rio roughly outline the area. The eastern portion of the plateau is known as the Texas Hill Country. Contents 1 Counties in the Edwards Plateau 2 Natural history 3 Human history 4 See also 5 Footnotes 6 External links Counties in the Edwards Plateau According to the Texas Parks and Wildlife Department, the following 41 counties comprise the Edwards Plateau : Bosque Bandera Bell Blanco Burnet Coke Comal Comanche Concho Coryell Crockett Edwards Erath Gillespie Hamilton Hays Hood Irion Kendall Kerr Kimble Lampasas Llano Mason McCulloch McLennan Menard Mills Palo Pinto Reagan Real San Saba Schleicher Somervell Sterling Sutton Tom Green Travis Upton Val Verde Williamson Natural History The bedrock consists primarily of limestone, with elevations ranging between 100 and 3000 ft. Caves are numerous. The landscape of the plateau is mostly savanna scattered with trees. It mostly lacks deep soil suitable for farming, though the soil is fertile mollisols and some cotton, grain sorghum and oats are grown. For the most part, though, the thin soil and rough terrain areas are primarily grazing regions, with cattle, sheep and Angora goats predominant. Several rivers cross the region, which generally flow to the south and east through the Texas Hill Country toward the Gulf of Mexico ; springs occur ( in wet years ), but permanent surface water supplies are sparse throughout the area, except for man - made reservoirs. The area is well drained ; rainwater flows into the Edwards Aquifer recharge zone at the south of the plateau to feed rivers to the south. Rainfall varies from 15 to 33 inches per year, on average, from northwest to southeast, and the area has a moderate temperature and a reasonably long growing season. Flora Trees of the savanna include a juniper - oak mix and a mesquite - acacia mix scattered over fairly short grasses, which traditionally were affected by droughts and regular fires. Some pecan trees are found near the springs and rivers. The Balcones Fault is associated with the Edwards Plateau formation. This fault line is an ecological demarcation for the range definition of a number of species. For example, the California fan palm, Washingtonia filifera, is known to occur only west of the Edwards Plateau or Balcones Fault, and Buddleja racemosa is known only from the southern edge of the plateau. Fauna Caves of the Edwards Plateau are important habitats for a great deal of wildlife. The area is home to some of the largest colonies of bats in the world, including millions of Mexican free - tailed bats. The largest colony of these inhabits Bracken Cave near San Antonio, while the Congress Avenue Bridge in Austin is the summer home for over half a million ( they winter in Mexico ) and is the largest bat colony anywhere in an urban area. The Edwards Plateau is home to at least 14 endemic freshwater fishes, including 2 subterranean species of catfish and 13 fish species considered to be spring - associated. There are also large numbers of reptiles and birds, including breeding populations of the Texan endemic golden - cheeked warbler ( Dendroica 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. See also Texas Hill Country Balcones Canyonlands National Wildlife Refuge Colorado River ( Texas ) Mount Bonnell List of ecoregions in the United States ( EPA ) Footnotes ^ Jump up to : Hoekstra, J.M. ; Molnar, J.L. ; Jennings, M. ; Revenga, C. ; Spalding, M.D. ; Boucher, T.M. ; Robertson, J.C. ; Heibel, T.J. ; Ellison, K. ( 2010 ). Molnar, J.L., ed. The Atlas of Global Conservation : Changes, Challenges, and Opportunities to Make a Difference. University of California Press. ISBN 978 - 0 - 520 - 26256 - 0. Jump up ^ Demarest, D. `` Edwards Plateau ''. Partners in Flight. Retrieved September 2, 2014. Jump up ^ Texas Parks and Wildlife http://www.tpwd.state.tx.us/huntwild/wild/birding/pif/assist/pif_regions/region_7.phtml Jump up ^ Johnson, E.H. `` Edwards Plateau ''. Handbook of Texas Online. Retrieved March 12, 2009. Jump up ^ Hill, Robert T. ( 1891 ). `` A brief description of the Cretaceous rocks of Texas and their economic uses ''. In E.T. Dumble. First Annual Report of the Geological Survey of Texas, 1889. Austin : State Printing Office. p. 134. Jump up ^ Bowles, David E. ; Arsuffi, Thomas L. ( 1993 - 12 - 01 ). `` Karst aquatic ecosystems of the Edwards Plateau region of central Texas, USA : A consideration of their importance, threats to their existence, and efforts for their conservation ''. Aquatic Conservation : Marine and Freshwater Ecosystems. 3 ( 4 ) : 317 -- 329. ISSN 1099 - 0755. doi : 10.1002 / aqc. 3270030406. Jump up ^ Craig, Cody A. ; Kollaus, Kristy A. ; Behen, Kenneth P.K. ; Bonner, Timothy H. ( 2016 - 02 - 01 ). `` Relationships among spring flow, habitats, and fishes within evolutionary refugia of the Edwards Plateau ''. Ecosphere. 7 ( 2 ) : n / a -- n / a. ISSN 2150 - 8925. doi : 10.1002 / ecs2. 1205. Jump up ^ `` Edwards Plateau ''. Terrestrial Ecoregions. World Wildlife Fund. Jump up ^ Maria de Fátima Wade. 2003. The Native Americans of the Texas Edwards Plateau, 1582 - 1799, University of Texas Press, 293 pages ISBN 0 - 292 - 79156 - 9, ISBN 978 - 0 - 292 - 79156 - 5 External links Johnson, E.H. `` Edwards Plateau ''. TSHA Handbook of Texas Online. Texas State Historical Association. `` Plateaus and Canyonlands ''. Texas Beyond History. University of Texas at Austin. Texas counties map showing the ecoregion State of Texas Austin ( capital ) Topics Architecture Climate Cuisine Geography Government Healthcare History Languages Law Literature Media Newspapers Radio TV National Historic Landmarks Recorded Texas Historic Landmarks National Register of Historic Places Sites Sports Symbols Texans Tourist attractions Transportation Seal of Texas Society Culture Crime Demographics Economy Education Gambling Politics Regions Ark ‐ La ‐ Tex Big Bend Blackland Prairies Brazos Valley Central Texas Coastal Bend Concho Valley Cross Timbers Deep East Texas East Texas Edwards Plateau Golden Triangle Hill Country Llano Estacado Northeast Texas North Texas Osage Plains Panhandle Permian Basin Piney Woods Rio Grande Valley Southeast Texas South Plains South Texas Texoma Trans - Pecos West Texas Metropolitan areas Abilene Amarillo Austin -- Round Rock Beaumont -- Port Arthur Brownsville -- Harlingen College Station -- Bryan Corpus Christi Dallas -- Fort Worth -- Arlington El Paso Houston -- The Woodlands -- Sugar Land Killeen -- Temple Laredo Longview Lubbock McAllen -- Edinburg -- Mission Midland Odessa San Angelo San Antonio -- New Braunfels Sherman -- Denison Texarkana Tyler Victoria Waco Wichita Falls Counties See : List of counties in Texas Coordinates : 30 ° 18 ′ N 99 ° 36 ′ W ﻿ / ﻿ 30.3 ° N 99.6 ° W ﻿ / 30.3 ; - 99.6 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Edwards_Plateau&oldid=806419876 '' Categories : 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 the United States Texas Hill Country Physiographic sections Hidden categories : Use mdy dates from November 2016 Coordinates on Wikidata Talk Contents About Wikipedia Languages Беларуская Čeština Deutsch Français Italiano Latviešu Norsk Português Русский Svenska Edit links This page was last edited on 21 October 2017, at 22 : 36. 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Question: how have the physical features of the edwards plateau limited human activities in the region
Answer: affected by droughts and regular fires