Tuesday, August 7, 2007
Exhibit Halls 1 and 2, San Jose McEnery Convention Center
Sierra Corona Rodrigo1, Ed L. Fredrickson2, Gerardo Ceballos González3, Alfredo L. González3, Andrea S. Laliberte4, Ana D. Davidson5, Rurik List Sánchez3, Gerardo Bezanilla6 and Eduardo Ponce Gevara3, (1)Instituto de Ecología, Universidad Nacional Autónoma de México, México, Mexico, (2)USDA-ARS, Jornada Experimental Range, Las Cruces, NM, (3)Jornada Experimental Range, USDA-ARS, Las Cruces, NM, (4)Universidad Autónoma de Chihuahua, Chihuahua, (5)Universidad Nacional Autónoma de México, Mexico, Mexico, (6)Facultad de Zootecnia, Universidad Autonoma de Chihuahua, Chihuahua, Mexico
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
