Sierra Corona Rodrigo1, Ed L. Fredrickson2, Gerardo Ceballos Gonz�lez2, Alfredo L. Gonz�lez2, Andrea S. Laliberte2, Ana D. Davidson2, Rurik List S�nchez2, Gerardo Bezanilla3, and Eduardo Ponce Gevara2. (1) Universidad Nacional Aut�noma de M�xico, (2) USDA-ARS, (3) Universidad Autonoma de Chihuahua
Chihuahuan Desert grasslands are undergoing a rapid transition to desert scrub conditions. In an effort to remove prairie dogs that are believed to compete with cattle, pastoralists have created a cascade of events promoting shrub expansion and severely reducing the viability of pastoralism within many Chihuahuan Desert ecosystems. The resulting desertification leads to depauperate socio-ecological conditions, with attempts to remediate desertified landscapes often being tenuous and seldom cost effective. The goal of this and other studies are to develop a better understanding of ecosystem drivers, and their interactions, within the Janos-Nuevo Casas Grandes prairie dog (Cynomys ludovicianus) complex in northwest Chihuahua. Beef cattle (Bos taurus) habitat selection was measured on a desert grassland-prairie dog ecosystem using GPS, GIS, and remote sensing technologies inside 4 x 4 km pasture. To classify vegetation we used multispectral Quickbird imagery with 60 cm resolution and eCognition software. We grouped the vegetation in 6 different types: Aristida spp. (50%), Pleuraphis mutica (8%), Panicum obtusum (8%), Bouteloa gracilis (15%), Amaranthus palmeri (4%) and prairie dog colonies (15%). Analyses of cattle movements during the dormant season show a direct preference for the prairie dog colonies, with minimal use of other vegetation types. In smaller scale studies beef cattle showed a preference for forages near the margins of the prairie dog colonies. From these observations we further hypothesize that cattle may help maintain black-tailed prairie dog colonies via mutualistic interactions that may promote the formation and maintenance of Chihuahuan Desert grasslands in this region.
Keywords: Cynomys ludovicianus, Desertification, Grassland remediation
