Transcript Texas eco regions 2016x

ECOREGIONS
OF
TEXAS
What is an ecoregion?
• An ecoregion is
a large area of
land that has a
distinct group
of plants and
animals.
• Each of these
plants and
animals in the
region have
adapted to live
in the
conditions of
that region.
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
Ecoregions of Texas
• Piney Woods
• Gulf Coastal Prairies and Marshes
• Edwards Plateau/ Llano Basin
• High Plains
• Trans-Pecos
• South Texas Plains
• Oak Woods and Prairies and Blackland Prairie
• Crosstimbers
PINEY WOODS
Weathering, erosion,
deposition
Conroe
Huntsville
Jefferson
Longview
Nacogdoches
Texarkana
Tyler
• It is the wettest region of the state.
This allows for a high rate of plant
decay to occur resulting in healthy,
nutrient-rich soils.
• The topography is gently rolling to
near flat throughout the region. Soils
are somewhat poorly drained and
streams are slow-moving.
• the amount of trees and plants can
prevent erosion
• If there are no plants and the soil is
exposed to water and wind, it is easily
eroded
GULF COAST PLAINS
Weathering, erosion, deposition
• Along the Gulf Coast, waves can erode
beaches in one area and redeposit the
sand in a different location along the
coast.
Aransas Pass
Beaumont
Corpus Christi
Galveston
Houston
Refugio
Rockport
South Padre
Island
Victoria
• The sand may also redeposit to form
sandbars. Strong storms and
hurricanes in this area can increase
beach erosion. This erosion can
destroy habitats for animals such as
turtles, seagulls, and pelicans.
Small wave deltas form
Sand dunes are a result of wind
between the barrier islands
deposition
Catastrophic events such
as tropical storms can
increase wave erosion
and deposition.
Edwards Plateau / Llano
Weathering, erosion, deposition
Basin
Austin
San Antonio
Erosion by streams and rivers above
ground has left most of the region with
very shallow soils (less than 10 inches)
The shape of the hills
in this region is
rounded due to
increased precipitation
and chemical
weathering.
Central Texas' Flash Flood
Alley is one of the most
flood-prone areas
nationwide. When rocks
and soil can absorb no
more rainfall, it gets
carried off into a stream or
at the bottom of a lake
The Llano Basin gets its name
from the granitic rock that is
uncovered at the surface. There
are several large thin sheets of
rock that slough off. This is a form
of mass movement (erosion)called
exfoliation.
Erosion below ground
caused by water seeping
through the porous
limestone. It contribute
to the recharge of the
Edwards Aquifer
HIGH PLAINS/GREAT
PLAINS
Weathering, erosion, deposition
• Because this area is so flat, it
experiences some of the
highest winds in the United
States.
Amarillo
Lubbock
Palo Duro Canyon
• It is a very dry ecoregion, prone
to drought, and on average
receives only 15 to 22 inches of
rain annually.
Poor land
management, drought,
and high wind speeds
contributed to the
Dust Bowl in the
1930’s
• Palo Duro Canyon was formed by water erosion
• The water widens and deepens the canyon by moving
sediment downstream
• The canyon can have land slides
TRANS PECOS
Weathering, erosion, deposition
• Deposition after the weathering
and erosion of the Guadalupe
and Davis Mountains has formed
the soil in this ecoregion.
El Paso
Presidio
Big Bend National
Park
• In the Chihuahuan Desert, wind
acts as the main erosion agent,
creating sand dunes. When this
ecoregion does receive rain, it
can lead to flashfloods, which
can weather and erode the
rocks and sediment
• The weathered
bedrock in this area
has high amounts of
calcium
• As a result of
erosion and
deposition in the
area, the soil has
high amounts of
calcium called
caliche.
• It is the hottest
and most arid
(driest) region of
the state.
• Hot days, cool
nights contribute
to physical
weathering of
rock.
Alluvial fans of
rubble, sand, and
gravel build at the
base of the
mountains
This region
also has salt
flats, dunes
and windblown
sand
SOUTH TEXAS PLAINS
Weathering, erosion, deposition
• The area is know as “brush Country” due to the
shorter trees and many shrubs.
• Over grazing of the lands has allowed nutrient
rich top soil to erode away by wind and water
erosion.
• Rocky, dry soil can not support grasses, trees can
survive because of their deeper root system.
• The Rio Grande is a very long river. Where it flows
through South Texas is called the lower Rio
Grande valley
McAllen
San Antonio
Blackland Prairies and Oakwood’s
Weathering, erosion, deposition
Dallas
Mineral wells
• Large herd of bison graze on grasses a
one time.
• Blacklands are mostly composed of
clays and are eroded primarily by water
• Secondary causes are wind and
burrowing animals (biological
weathering)
• Oakwood’s have nutrient rich soil and
receive a good amount of rainfall each
year
• If the land is clear of any vegetation
then the land can be easily eroded by
wind and water
• Plowing farmland in order to plant crop
also increases soil erosion. Because of
its rich soil, most of the Blackland
Prairie has been converted to farmland.
Crosstimbers
Fort Worth
Weathering, erosion, deposition
• The Crosstimbers ecoregion
has limestone uplands. It has
rolling hills and dark clay
soils that are well drained.
• Well draining soils allow
rainfall to quickly infiltrate
the soil and become
groundwater, rather than to
become runoff, which can
lead to erosion.
• The limestone in this region
is vulnerable to chemical
weathering, so limestone land
features are constantly
changing.