Desert Scrub and Long-Billed Thrashers
This arid ecoregion lies in the lower elevations of the eastern Sierra Madre Oriental Mountains in northeastern Mexico in the states of Nuevo León and Tamaulipas. The landscape undulates with mountains, hills, valleys, and vast plateaus. Where rainfall levels are below 40 inches (100 cm) per year, dominant plant species include anacahuite, mesquites, leatherstem, prickly pear cactus, Don Quixotés lace, and the wait-a-minute bush. In the lower elevation of the Sierra Madre Oriental Mountains the soil is shallow and supports piedmont scrubs. Montane chaparral occurs at elevations over 5,600 feet (1,700 m). The long-billed thrasher is one of many birds that builds its home in the dry thickets and brush.
The Tamaulipan Matorral is rich in plant and animal biodiversity. A high number of endemic cacti, such as Agave victoria-reginae, make it a priority area for the conservation of succulents. The ecoregion contains at least four endemic genera of woody plants (Clappia, Nephropetalum, Pterocaulo, and Runyonia) and is a center of diversity for the Lamiaceae plant family. The vegetation represents a transition from the desert scrub of the drier mezquital in the lowlands to the woodlands of the Sierras. The matorral of this zone is full of shrubs and small trees that can survive here with the benefit of more moisture from mountain storms.
The highly endangered Mexican prairie dog and the rare Worthen's sparrow have remnant populations in this xeric scrub ecoregion. Carmen mountain shrew, Saussure's shrew, Allen's squirrel, and the black-eared mouse are among the resident rodents. The hooded oriole, eastern meadowlark, yellow-crowned yellowthroat, blue bunting and olive sparrow can all be found here, many concentrated around thick vegetation near streams. The threatened burrowing owl also nests in abandoned burrows in the matorral. Green jays, golden fronted woodpeckers, and Tamaulipan crows can be found in riparian areas.
Cause for Concern
Despite significant human populations in the Tamaulipas Matorral, the ecoregion is in a good state of conservation. The desert shrublands are primarily threatened by agriculture, goat, sheep, and cattle farming, and the expansion of urban areas. Fires also destroy habitat when used as a means to convert the matorral to farms. Illegal extraction and trade of cacti have helped make several species endangered. The Mexican prairie dog has become one of the most endangered mammals in the country due to intentional poisoning. Adequate protected areas need to be established, particularly ones that provide intact linkages to montane habitats and include riparian habitats along streams.
For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.All text by World Wildlife Fund © 2001