Texas Ecoregions
Effects of Weathering, Erosion
and Deposition
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
i. Piney Woods
1. This ecoregion is found in Southeast
Texas.
2. It is the wettest region of the state. This
allows for a high rate of decomposition to
occur resulting in healthy, nutrient-rich
soils.
3. The topography is gently rolling to near flat
through out the region.
4. Pine trees, woody vines, and hardwood
trees dominate the vegetation.
1. It is a fire climax system. Fire is necessary
in order for pines to maintain dominance in
the area.
1. Unless an area has been clear-cut of
vegetation for construction, the amount of
trees and plants can prevent erosion.
ii. Gulf Coastal Plain
1. Coastal region; soil in
the region is primarily
sand-based.
2. If there is not enough
vegetation to keep the
soil in place, rainfall
received can cause
severe erosion.
3. Catastrophic events
such as hurricanes can
increase wave erosion
and deposition.
iii. Blackland Prairie
• Precipitation
35 to 45 inches
• Topography
Ranges from gently rolling hills to level land.
• Soils
Upper Cretaceous marine chalks, limestone, and shale
give rise to the development of the characteristic black,
heavy clay soils.
• Vegetation Description
Perennial and annual grasses. Live oaks are the trees
that dominate a large part of this eco-region.
• Impacts of Fire
For the most part fires in this eco-region no longer
greatly impact vegetation.
iv. Edwards Plateau
1. This region is located
between dry western
plains and moist prairies
and woods.
2. Unfortunately, erosion
has left most of the very
shallow soils (leregion
with ss than 10 inches)
lined with limestone rock
layers.
3. High amounts of rain in a
short amount of time can
cause flash flooding.
v. Rolling Plains
1. This region is part of the
Great Plains of the
central United States.
2. Soils in this area are
most fertile and sought
after for crop
production.
3. Periods of drought and
then sudden increase in
rainfall causes large
amounts of erosion and
deplete the soil of
nutrients.
vi. Crosstimbers and Prairies
1. This is a small, thin
region running North to
South on either side of
the prairies and plains.
2. The soil is not as prone
to flooding because it
allows water to infiltrate
very easily.
3. The region is described
as rough, hilly terrain.
vii. High Plains
1. “Texas Panhandle”
2. Largest and most
completely flat areas of it
size in the world!
3. The region extends to the
Palo Duro Canyon-the
nation’s 2nd largest
canyon.
4. Palo Duro Canyon was
formed by water erosion
from the Prairie Dog
Town Fork of the Red
River.
5. The water deepens the
canyon by moving
sediment downstream.
6. Wind and water erosion
gradually widen the
canyon.
vii. South Texas
Plains
1. The area is known as
“Brush Country” due
to the shorter trees
and many shrubs.
2. Overgrazing of the
land has allowed
nutrient-rich topsoil to
erode way.
3. Rocky, dry soil
cannot support
grasses, trees can
thrive because of
their deeper root
system.
ix. Post Oak Savannah
• Precipitation
35 to 45 inches
• Topography
Forested areas in the western region of the Post
Oak Savannah are generally restricted to
bottomland areas associated with water.
• Soils
Soils range from a clay to sandy soil.
• Vegetation Description
Dominated by native bunch grasses and scattered post
oaks.
• Impacts of Fire
Fire has been completely removed from the management
of this eco-region to support the raising of cattle.
x. Mountain and Basins
1. Home of the tallest
mountain in Texas,
Guadalupe Peak. Elevation
is 8,749 feet.
2. Pines and Oaks dominate
the tree species.
3. Soils are shallow and rocky.
Weathering continues to
play a role in developing
soil and will for thousands
of years to come.
4. Soils in the canyon bottoms
and valleys are deeper as a
result of deposition.