Texas Ecoregions

1. Texas Ecoregions Effects of Weathering, Erosion and Deposition

2. What is an Ecoregion? • an area defined by its environmental conditions, esp. climate, landforms, and soil characteristics.

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. Piney Woods • It is the wettest region of the state. • This allows for a high rate of decompositionto occur resulting in healthy, nutrient-rich soils. • The topography is gently rolling to near flat through out the region. • Pine trees, woody vines, and hardwood trees dominate the vegetation. • Unless an area has been clear-cut of vegetation for construction, the amount of trees and plants can prevent erosion. • Very little erosion takes place in these areas. http://www.youtube.com/watch?v=9o8lKGhJ5KI&list=PL6353227E5419A80D

5. Oak Wood Prairies • These areas have nutrient-rich soils and receive good amounts of rainfall through the year. • If the land is clear-cut of natural vegetation for construction nutrients can easily be eroded by wind and water.

6. Blackland Prairies • Large herds of bison grazed on the grasses at one time. • Blackland prairies in Texas, which are mostly composed of clays, are eroded primarily by water. Secondary causes include wind, and the action of burrowing animals (bio erosion). http://www.youtube.com/watch?v=lBl-FruPos0&list=PL6353227E5419A80D

7. Gulf Coast Prairies and Marshes • A narrow band about 60 miles wide along the Texas coast from the Louisiana border to Brownsville roughly outlines the Gulf Coast Prairies and Marshes • Near the gulf waters you can see marshes, barrier islands, estuaries (where salty sea water and fresh river water meet), and bays. • Catastrophic events such as hurricanes can increase wave erosion. http://www.youtube.com/watch?v=mZdsyKaIAYE&list=PL6353227E5419A80D

8. Llano Uplift • A basin; in some places, it is 1000 feet below the level of the surrounding limestone escarpment. • It gets its name from the granitic mass that is exposed in the basin, granite that has been dated at one billion years old. • Upland soils are shallow, reddish brown, stony, sandy loams over granite, gneiss, and schist with deeper sandy loams in the valleys.

9. South Texas Brush Country • The area is known as “Brush Country” due to the shorter trees and many shrubs. • Overgrazing of the land has allowed nutrient-rich topsoil to erode way by wind and water. • Rocky, dry soil cannot support grasses, trees can thrive because of their deeper root system. http://www.youtube.com/watch?v=XyluCiAOdso&list=PL6353227E5419A80D

10. Coastal Sand Plains • Soil in the region is primarily sand-based. • If there isn’t enough vegetation to keep the soil in place, rainfall received can cause severe erosion. • Catastrophic events such as hurricanes can increase wave erosion.

11. Edwards Plateau • This region is located between dry western plains and moist prairies and woods. • Unfortunately, water erosion has left most of the region with very shallow soils (less than 10 inches) lined with limestone rock layers. • High amounts of rain in a short amount of time can. cause flash flooding http://www.youtube.com/watch?v=DY7ueukM1QQ&list=PL6353227E5419A80D

12. Rolling Plains • This region is part of the Great Plains of the central United States. • Soils in this area are most fertile and sought after for crop production. • Periods of drought and then sudden increase in rainfall causes large amounts of erosion and deplete the soil of nutrients. http://www.youtube.com/watch?v=0UlDeYfJ1XU&list=PL6353227E5419A80D

13. High Plains • “Texas Panhandle” • Largest and most completely flat areas of it size in the world! • The High Plains ecoregion is one of the windiest regions in the United States. • The climate is generally dry, and areas without vegetation experience wind erosion. • The Palo Duro Canyon was formed by water erosion by a fork of the Red River. The canyon continues to become deeper as the water moves sediment downstream. Wind and water erosion gradually widen the canyon.

14. Trans-Pecos • “Desert portion” of Texas. • The weathered bedrock in this area has high amounts of calcium. • The Guadalupe Mountains and the Davis Mountains are located in this ecoregion, making it the most mountainous area of Texas. • * In general, soil in this region is eroded due to the decline of grasslands. • Flash-flooding and rapid runoff are causes of erosion in the park. • Erosion of the limestone cliffs takes place because of acid rain. • http://www.youtube.com/watch?v=b1FErNrxVZo&list=PL6353227E5419A80D

15. Marine Environment • This ecoregion has seagrasses, oyster reefs, barrier islands, muddy estaurine bottoms, reefs and open water. • These areas provide plants and animals with their basic needs and support hundreds of species. • Global warming has one of the most negative impacts in marine ecosystems.