RIO
GRANDE VALLEY
[Please see region's
landscape video]
The South Texas Plains consist of roughly 20 million
acres of grassland,
oak
savanna, and brush country that receive between 20 and 30 inches of rain.
The dominant brush country includes
drought-tolerant, thorny legumes, such as mesquite, huisache, Texas
ebony,
and cenizo, interspersed among Texas prickly pear, buffalograss, and
various
forbs. The extreme southern portion of the Plains includes rare
examples of
Texas palmetto forest within the floodplain of the Rio Grande (once
known as
the Rio de las Palmas by early Spanish settlers). Eastern sections of
the
Plains include some saline grasslands and wetland brush areas.
Industry in the South Texas Plains has traditionally been oriented
towards
ranching and petroleum, but has evolved to support hunting, birding,
tourism, and diversified assembly and trade (especially among the
maquiladoras of the border zone). The principal cities of the South
Texas
Plains include Alice, Brownsville, Corpus Christi, Harlingen, Kingsville,
McAllen, and Sinton.
Major protected areas within the South Texas Plains include Chaparral
State
Wildlife Management Area (15,200 acres), Laguna Atascosa National
Wildlife
Refuge (65,137 acres), Las Palomas State Wildlife Management Area (4262
acres), Lower Rio Grande Valley National Wildlife Refuge (76,257 acres),
Sabal Palm Grove Sanctuary (525 acres), Santa Ana National Wildlife
Refuge
(2087 acres)
The principal threats to the South Texas Plains include exotic plant
invasion (for instance, by buffelgrass and King Ranch bluestem),
agricultural land clearing for grazing and cultivation, and habitat
fragmentation and residential development associated with the area's
rapid
population growth. The residential development of colonias, typically
without adequate road, potable water, and wastewater infrastructure,
has
raised public health concerns. Uranium mining and subsequent leachate
and
hazardous waste disposal in the Kingsville and Panna Maria areas have
caused
soil and groundwater pollution. Development of maquiladoras in the
border
zone and discharges of polluted wastewater from these facilities have
also
been troubling. And in this dry area, over-allocation of the Rio Grande's
water, construction of dams for the Amistad and Falcon reservoirs, and
erection of levees along the lower Rio Grande's course have severely
interfered with the river's historic patterns of flow and flood.
Rio Grande
Valley communities are represented in the archive by:
For more information about conservation in the South Texas Plains,
please
refer to:
Caesar Kleberg Wildlife Research Institute
Coastal Bend Bays Foundation
Coastal Bend Sierra Club
Rio Grande International Study Center
Rio Grande Rio Bravo Basin Coalition
Sabal Palm Audubon Center and Sanctuary
Valley Land Fund
Welder Wildlife Foundation
World Birding Center
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