Amistad Resevoir along Rio Grande, Texas, USA Photograph by Laura Pierce-Rio Grande/Rio Bravo Basin Coalition   Southern North America: Southern United States into northeastern Mexico Deserts and Xeric Shrublands   About 54,600 square miles (141,500 square kilometers) -- about the size of Illinois Critical/Endangered

· Abundant Desert
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
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Abundant Desert

The Tamaulipan Mezquital ecoregion of southern Texas and northeast Mexico has unique plant and animal communities containing tree and brush covered dunes, wind tidal flats, and dense native brushland. Within these habitats you can find ocelots, jaguarundis, Texas indigo snakes, and more than 400 species of birds. The most important of the plants here include mesquite, various species of acacia, desert hackberry, javelina bush, cenizo, common bee-brush or white brush, Texas prickly pear, and tasajillo, or desert Christmas cactus.

Special Features

The animal and plant diversity of this ecoregion ranks among the very highest in the United States. It's not quite as diverse as the Chihuahuan desert to the southwest, but it does support more than 600 species of plants and animals. It is particularly rich in tree species and birds. This shrubland/desert is unique in numbers of endemic cactus and other plant species.

	The Mexican prairie dog is endemic to this ecoregion and is the only endangered prairie dog species.

Wild Side

Mammals, snakes, and birds are abundant in this ecoregion. Small mammals such as eastern American moles, kangaroo rats, and pocket gophers are common throughout the region, while black bears and cougars can be seen in Sierra Pichachos. Birds such as the Tamaulipas crow, crimson-collared grosbeak and screen owl can be seen here, too. Like so many habitats throughout the world, the vegetation here has changed over the years because of natural or human-induced causes. Plants that used to be abundant in this ecoregion were curly mesquite grass and shrubs such as chaparro and jazmincillo. Montezuma bald cypress was once common along the lower Rio Grande.

Cause for Concern

Only about two percent of this ecoregion remains intact. Most of the Rio Grande floodplain, the flat area next to the river that is subject to flooding, has been cleared for agriculture, grazing of livestock, and development. Both banks of the river are crowded with homes, businesses, and farms, and clearing for development and agriculture throughout the ecoregion continues to pose a significant threat. Other threats include erosion, pollution from chemicals used for farming, and invasion of exotic species. The area's woody plants are being cleared for grazing and are being cut for fuelwood and lumber.

For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.