Transcript tx_ecoregions2013_weatheringerosion_and_deposition

Texas Ecoregions
Effects of Weathering, Erosion
and Deposition
What is an Ecoregion?
• an area defined by its environmental
conditions, esp. climate, landforms, and
soil characteristics.
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
Piney Woods
• It is the wettest region of the state.
• This allows for a high rate of decomposition to
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=9o8lKGh
J5KI&list=PL6353227E5419A80D
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.
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=lBlFruPos0&list=PL6353227E5419A80D
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=mZdsy
KaIAYE&list=PL6353227E5419A80D
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.
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=XyluCiA
Odso&list=PL6353227E5419A80D
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.
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=DY7ueu
kM1QQ&list=PL6353227E5419A80D
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=0UlDeYfJ
1XU&list=PL6353227E5419A80D
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.
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=PL6353227E5
419A80D
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.