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ARS Home » Plains Area » Las Cruces, New Mexico » Range Management Research » Research » Publications at this Location » Publication #242979
Title: Rapid response of a grassland ecosystem to an experimental manipulation of a keystone rodent and domestic livestock

Author
item DAVIDSON, ANA - Institute De Ecologia - Mexico
item PONCE, EDUARDO - Institute De Ecologia - Mexico
item LIGHTFOOT, DAVID - University Of New Mexico
item Frederickson, Eddie
item BROWN, JAMES - University Of New Mexico
item CRUZADO, JUAN - Institute De Ecologia - Mexico
item Toledo, David
item BRANTLEY, SANDRA - University Of New Mexico
item SIERRA, RODRIGO - Institute De Ecologia - Mexico
item LISK, RURIK - Institute De Ecologia - Mexico
item CEBALLOS, GERARDO - Institute De Ecologia - Mexico

Submitted to: Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2010
Publication Date: 11/9/2010
Citation: Davidson, A.D., Ponce, E., Lightfoot, D.C., Fredrickson, E.L., Brown, J.H., Cruzado, J., Toledo, D.N., Brantley, S.L., Sierra, R., Lisk, R., Ceballos, G. 2010. Rapid response of a grassland ecosystem to an experimental manipulation of a keystone rodent and domestic livestock. Ecology. 91(11):3189-3200.

Interpretive Summary: Large mammalian herbivores and small burrowing rodents often co-exist and play important functional roles in grassland ecosystems worldwide. The interactive effects of these large and small herbivores in shaping the structure and function of grassland ecosystems are poorly understood. In North America’s central grasslands, domestic cattle (Bos taurus) have supplanted bison (Bison bison), and now co-exist with prairie dogs (Cynomys spp.), a burrowing-herbivorous keystone rodent. Understanding the ecological relationships between cattle and prairie dogs and their independent and interactive effects is essential to address important conservation issues affecting North American grassland ecosystems. To address these needs, we established a long-term manipulative experiment that separates the independent and interactive effects of prairie dogs and cattle. Our study is located in the Janos-Casas Grandes region of northwestern Chihuahua, Mexico, which supports one of the largest remaining complexes of black-tailed prairie dogs (C. ludovicianus). Two years of post-treatment data show large increases in prairie dog abundance on plots grazed by cattle when compared to plots without cattle, relative to pre-treatment conditions. We also measured dramatic changes in vegetation on the plots where both animals co-occurred when compared to the absence of either or both species. Vegetation changes significantly affected abundance and composition of other grassland animal species, including grasshoppers and banner-tailed kangaroo rats (Dipodomys spectabilis). Our results indicate that cattle and prairie dogs had important, synergistic effects on the grassland that differed from their individual effects, and that the ecological relationships and interactive impacts of species that belong to different functional groups are fundamentally important in shaping the structure and function of ecosystems.

Technical Abstract: Megaherbivores and small burrowing mammals commonly co-exist and play important functional roles in grassland ecosystems worldwide. The interactive effects of these two functional groups of herbivores in shaping the structure and function of grassland ecosystems are poorly understood. In North America’s central grasslands, domestic cattle (Bos taurus) have supplanted bison (Bison bison), and now co-exist with prairie dogs (Cynomys spp.), a keystone burrowing rodent. Understanding the ecological relationships between cattle and prairie dogs and their independent and interactive effects is essential to understanding the ecology and important conservation issues affecting North American grassland ecosystems. To address these needs, we established a long-term manipulative experiment that separates the independent and interactive effects of prairie dogs and cattle using a 2 x 2 factorial design. Our study is located in the Janos-Casas Grandes region of northwestern Chihuahua, Mexico, which supports one of the largest remaining complexes of black-tailed prairie dogs (C. ludovicianus). Two years of post-treatment data show nearly 2-fold increases in prairie dog abundance on plots grazed by cattle compared to plots without cattle. This positive effect of cattle on prairie dogs resulted in synergistic impacts when they occurred together. Vegetation height was significantly lower on the plots where both species co-occurred compared to where either or both species was absent. The treatments also significantly affected abundance and composition of other grassland animal species, including grasshoppers and banner-tailed kangaroo rats. Our results demonstrate that two different functional groups of herbivorous mammals, burrowing mammals and domestic cattle, have distinctive and synergistic impacts in shaping the structure and function of grassland ecosystems.