Influence of a Highly Interactive Species Upon Bird Diversity Within a Gradient of Urbanization (Paperback)

Urbanization and subsequent habitat fragmentation have significantly reduced the range of the black-tailed prairie dog (Cynomys ludovicianus ). Studies suggest that prairie dogs are highly interactive species that can influence bird species diversity, abundance, and richness. Past research was conducted on native prairie and few studies investigated whether this relationship exists in an urban/suburban setting. The landscape changes that reduced the prairie dog's range also impact bird species directly, resulting in habitat loss and isolation. I performed bird counts on 20 habitat fragments stratified along an urban gradient in the Denver metropolitan area to examine the influence of fragment area, isolation, and distance from city center on bird diversity measures. I used 12 fragments (six colonized by prairie dogs, six uncolonized by prairie dogs) in a paired study to determine whether the presence of prairie dogs influences bird diversity measures in an urban setting. Diversity measures were generally higher on colonized fragments for every season except winter; however, these trends were not statistically significant. Diversity measures for the paired study increased significantly with increasing area and increasing isolation. When I analyzed all 20 habitat fragments, I found that larger fragment area and fragments further from the city center exhibited significantly higher diversity measures in univariate models. I found that diversity measures were significantly higher on fragments that were older, larger, and had higher forb cover in multivariate models. Future biodiversity studies along the urban gradient in Denver should include an analysis of the matrix adjacent to habitat fragments and should employ better indices for estimating urbanization. Future studies of the role of prairie dogs as highly interactive species in urban systems should also include an analysis of other taxa.