1. 4B_Changes in Texas Ecoregions

2. 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

4. 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

5. 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.

6. 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

7. 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

8. 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.

9. 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.

10. 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)

11. 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.

12. 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

13. 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

14. 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.

15. 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

16. 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

17. 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.

18. 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

19. 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.

20. 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

21. 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

22. 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.

23. 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

24. 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

25. 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