1. ECOREGIONS OF TEXAS

2. What is an ecoregion? An ecoregion is a large area of land that has a distinct group of plants and animals. Each of these plants and animals in the region have adapted to live in the conditions of that region.

3. Factors Affecting Our Ecoregions Weathering – chemical and physical break down of rocks into sediment Erosion – the movement of sediment from one place to another Deposition – the placement of sediment after being carried from place of origin

4. Ecoregions of Texas Piney Woods Gulf Coastal Prairies and Marshes Edwards Plateau/ Llano Basin High Plains Trans-Pecos South Texas Plains Oak Woods and Prairies and Blackland Prairie Crosstimbers

5. PINEY WOODS Conroe Huntsville Jefferson Longview Nacogdoches Texarkana Tyler It is the wettest region of the state. This allows for a high rate of plant decay to occur resulting in healthy, nutrient-rich soils. The topography is gently rolling to near flat throughout the region. Soils are somewhat poorly drained and streams are slow-moving. the amount of trees and plants can prevent erosion If there are no plants and the soil is exposed to water and wind, it is easily eroded Weathering, erosion, deposition

6. GULF COAST PLAINS Aransas Pass Beaumont Corpus Christi Galveston Houston Refugio Rockport South Padre Island Victoria Along the Gulf Coast, waves can erode beaches in one area and redeposit the sand in a different location along the coast. The sand may also redeposit to form sandbars. Strong storms and hurricanes in this area can increase beach erosion. This erosion can destroy habitats for animals such as turtles, seagulls, and pelicans. Weathering, erosion, deposition

7. Small wave deltas form between the barrier islands Sand dunes are a result of wind deposition Catastrophic events such as tropical storms can increase wave erosion and deposition.

8. Edwards Plateau / Llano Basin Austin San Antonio Weathering, erosion, deposition Erosion by streams and rivers above ground has left most of the region with very shallow soils (less than 10 inches )

9. The shape of the hills in this region is rounded due to increased precipitation and chemical weathering. Central Texas' Flash Flood Alley is one of the most flood-prone areas nationwide. When rocks and soil can absorb no more rainfall, it gets carried off into a stream or at the bottom of a lake

10. Erosion below ground caused by water seeping through the porous limestone. It contribute to the recharge of the Edwards Aquifer The Llano Basin gets its name from the granitic rock that is uncovered at the surface. There are several large thin sheets of rock that slough off. This is a form of mass movement (erosion)called exfoliation.

11. HIGH PLAINS/GREAT PLAINS Amarillo Lubbock Palo Duro Canyon Because this area is so flat, it experiences some of the highest winds in the United States. It is a very dry ecoregion, prone to drought, and on average receives only 15 to 22 inches of rain annually. Weathering, erosion, deposition

12. Poor land management, drought, and high wind speeds contributed to the Dust Bowl in the 1930’s

13. Palo Duro Canyon was formed by water erosion The water widens and deepens the canyon by moving sediment downstream The canyon can have land slides

14. Deposition after the weathering and erosion of the Guadalupe and Davis Mountains has formed the soil in this ecoregion. In the Chihuahuan Desert, wind acts as the main erosion agent, creating sand dunes. When this ecoregion does receive rain, it can lead to flashfloods, which can weather and erode the rocks and sediment TRANS PECOS El Paso Presidio Big Bend National Park Weathering, erosion, deposition

15. The weathered bedrock in this area has high amounts of calcium As a result of erosion and deposition in the area, the soil has high amounts of calcium called caliche. It is the hottest and most arid (driest) region of the state. Hot days, cool nights contribute to physical weathering of rock.

16. This region also has salt flats, dunes and windblown sand Alluvial fans of rubble, sand, and gravel build at the base of the mountains

17. SOUTH TEXAS PLAINS Weathering, erosion, deposition The area is know as “brush Country” due to the shorter trees and many shrubs. Over grazing of the lands has allowed nutrient rich top soil to erode away by wind and water erosion. Rocky, dry soil can not support grasses, trees can survive because of their deeper root system. The Rio Grande is a very long river. Where it flows through South Texas is called the lower Rio Grande valley McAllen San Antonio

18. Blackland Prairies and Oakwood’s Weathering, erosion, deposition Large herd of bison graze on grasses a one time. Blacklands are mostly composed of clays and are eroded primarily by water Secondary causes are wind and burrowing animals (biological weathering) Oakwood’s have nutrient rich soil and receive a good amount of rainfall each year If the land is clear of any vegetation then the land can be easily eroded by wind and water Plowing farmland in order to plant crops also increases soil erosion. Because of its rich soil, most of the Blackland Prairie has been converted to farmland. Dallas Mineral wells

19. Crosstimbers The Crosstimbers ecoregion has limestone uplands. It has rolling hills and dark clay soils that are well drained. Well draining soils allow rainfall to quickly infiltrate the soil and become groundwater, rather than to become runoff, which can lead to erosion. The limestone in this region is vulnerable to chemical weathering, so limestone land features are constantly changing. Fort Worth Weathering, erosion, deposition