Monday, April 05, 2010, 12:00PM - 1:00PM
Department of Integrative Biology, University of Colorado Denver
Full title: "Effects of disease and global change factors on role of prairie dogs (Cynomys ludovicianus) as ecosystem engineers in Colorado."
Prairie dogs are an iconic species in the American west. Through their burrowing and grazing, they alter plant community composition, nutrient cycling rates, and provide habitat for other grassland animal species. Introduced plague caused by Yersinia pestis, exotic plant species, urbanization, nitrogen deposition, and warmer and longer growing seasons could influence the role of prairie dogs as keystone species and ecosystem engineers in Colorado. The first part of this talk will present research results suggesting that introduced plague is altering the spatial characteristics of prairie dog colonies on the shortgrass steppe such that colonies no longer persist on the landscape for decades as they did prior to introduction of plague. On the Pawnee National Grassland, approximately 98% of colonies experience a plague epizootic within 15 years of continuous activity, nearly half remain inactive for at least 5 years following an epizootic, and less than half attain their pre-plague area within 10 years of an epizootic. The second part of this talk will focus on research results showing that plague epizootics mediate the role of prairie dogs in shaping plant communities and nutrient cycling. The effects of prairie dogs on vegetation and nutrient cycling increase with colony age, but few colonies persist more than 15 years because of plague. The effects of prairie dogs on vegetation and nutrient cycling also decrease quickly after a colony is extirpated by plague. The final part of this talk will focus on recent pilot data and proposed research related to the role of prairie dogs in shaping urban plant communities. In urban areas, high densities of prairie dogs, legacy effects from agriculture and other soil disturbances, propagule pressure from non-native plant species, and climate-mediated changes to potential vegetation may all interact with prairie dog grazing and burrowing to produce novel plant communities.