4B_Changes in Texas Ecoregions

What is an ecoregion? An ecoregion is an ecosystem that covers a large area. Texas is grouped into six TYPES: Coastal prairies and marshes Plains Prairies Woodlands Plateau Desert/montane woodlands

How can natural processes change ecoregions? Natural processes, such as weathering, erosion, and deposition, are constantly changing the environment within ecoregions. Weathering- breaks downs rocks Erosion- moves material from one place to another Deposition- laying down, or depositing the eroded material

How can humans change ecoregions? Humans change ecoregions by activities such as agriculture, construction, harvesting natural resources, and urbanization. The larger the population, the greater its effect on an ecoregion.

Gulf Coast Prairies and Marshes Characteristics- Coastline of Texas Along the coast are wetlands like marshes and estuaries, inland are prairies (large, treeless areas with fertile soil) Also includes low islands, bluffs, sand dunes, and mud and sand flats

Gulf Coast Prairies and Marshes Processes that change this region- Wind and waves are a strong continuous force of erosion and deposition A tropical storm can cause severe coastal erosion in a very short period of time

Gulf Coast Prairies and Marshes Natural Processes- Always being reshaped by high winds and waves of tropical storms. Slowly the shoreline is being eroded and moving inland. Barrier islands are slowly moving toward the shore as well.

Gulf Coast Prairies and Marshes Human Activities- Much is now used for agriculture, urban development, and industry. Dams in rivers reduce the deposition of sand from inland.

Plains Ecoregions- High Plains, Rolling Plains, South Texas Plains Characteristics- Panhandle and southern TX near Mexican border Plain is an area of land that has gentle slopes and small differences in elevation High Plains - has the large, flat Llano Estacado, dotted with sand dunes and playas (which can fill with rain and form a lake)

Plains Ecoregions- High Plains, Rolling Plains, South Texas Plains Processes that change this region- All contained significant grasslands in the past. Reduction of grassland has increased erosion and deposition Winds are a huge factor because of its very dry, windy climate.

Plains Ecoregions- High Plains, Rolling Plains, South Texas Plains Natural Processes- Wildfires used to maintain grasses and remove trees Dry and windy Periods of drought, worsens wind erosion

Plains Ecoregions- High Plains, Rolling Plains, South Texas Plains Human Activities- Lots of farming (agriculture) so wind erosion and deposition is problem. Farmers try to reduce effects by soil conservation methods like conservation tillage, plowing along curvature of land, and efficient irrigation systems

The Prairie Ecoregions- Blackland Prairie, Cross Timbers and Prairies Characteristics- Our areas Widespread farming in Blackland Prairie Cross Timbers and Prairies are a mosaic of prairie and oak woodlands, used for rangeland, and pastureland.

The Prairie Ecoregions- Blackland Prairie, Cross Timbers and Prairies Processes that change this region- Agriculture – been farmed since the 1800s Used to be uncultivated, tallgrass prairies now only 1% remains

The Prairie Ecoregions- Blackland Prairie, Cross Timbers and Prairies Natural Processes- Blackland- deep, dark, fertile soils Periodic fires and grazing bison used to shape the prairies Fires reduced the woody plant and favored grasses

The Prairie Ecoregions- Blackland Prairie, Cross Timbers and Prairies Human Activities- Blackland changed to cropland, loss of native plants and farming cause wind and water erosion Urban development (building homes and roads) and removal of natural resources (oil wells) has increased erosion as well.

Woodland Ecoregions- East Texas Pineywoods, Post Oak Savannah Characteristics- Woodland is an ecosystem where trees are the main form of plant life. Pine trees grow in the sandy soil, cypress and oak trees in hardwood wetlands, and oak and cedar hardwood trees in Post Oak Savannah

Woodland Ecoregions- East Texas Pineywoods, Post Oak Savannah Processes that change this region- Fire is natural in woodlands but has been suppressed for many years Logging also causes erosion.

Woodland Ecoregions- East Texas Pineywoods, Post Oak Savannah Natural Processes- When woodlands remain undisturbed, little erosion occurs Wetlands increase water quality and hold floodwaters, and reduce pollutants

Woodland Ecoregions- East Texas Pineywoods, Post Oak Savannah Human Activities- Hardwoods are cut for paper Forestry services try to reduce runoff and erosion Dams and reservoirs affect sediments that help build up river banks and deltas

Plateau Region- Edwards Plateau – Central Texas Characteristics- Plateau is a large, flat area that is higher than the surrounding land Edwards Plateau is a limestone plateau with many streams and springs. A karst region, meaning it contains caves and flowing groundwater causing sinkholes Within the Edwards Plateau, a series of granite hills are exposed in the Llano Uplift.

Plateau Region- Edwards Plateau – Central Texas Processes that affect the region- Water weathers and erodes limestone (caves) Chemical weathering rounds the limestone hills In the granite hills, a physical weathering process called exfoliation peels the rock off in sheets, producing dome shapes Overgrazing replaced grasses with brush increasing soil erosion

Desert/Montane Woodland Ecoregion- Trans-Pecos Characteristics- Westernmost part of Texas Montane- describes a mountainous area in which evergreens are the main plant life Guadalupe Mountains and Chihuahuan Desert make up a large part of this region Woodlands in higher elevation, desert in lower Large areas of sand dunes and salt flats, water is very scarce

Desert/Montane Ecoregion- Trans-Pecos Processes that affect this region- Overgrazing of the Guadalupe Mountains caused it to be replaced by desert Loss of grassland increases erosion by wind and by water Little water, so wind is important force of weathering, erosion, and deposition Flash floods result in erosion when they occur