Prairie dog towns increase grassland bird diversity at the landscape scale

Prairie dogs (Cynomys sp.) are recognized as keystone species because their colonies provide habitat heterogeneity and are inhabited by specialized plant and animal communities. While many studies have demonstrated the unique ecological properties of prairie dog colonies and their effects on local grassland bird communities, few have examined how their presence influences bird diversity at a landscape scale. We collected species diversity data across 192 points within 64 80-ha sampling cells. With 11 of those 64 cells containing an active prairie dog town, we tested if the presence of black-tailed prairie dog (Cynomys ludovicianus) colonies would result in higher landscape-scale avian biodiversity in a mixed-grass prairie and sagebrush steppe ecosystem in north-central Montana. Utilizing permutational multivariate analysis of variance, we observed significant dissimilarities between avian communities with and without prairie dog colonies, and colony presence explained a moderate proportion of variance in avian diversity. Indicator species analysis found 5 species significantly associated with colony cells: Horned Lark (Eremophila alpestris), Marbled Godwit (Limosa fedoa), Brewer's Blackbird (Euphagus cyanocephalus), Killdeer (Charadrius vociferus), and Burrowing Owl (Athene cunicularia). These findings suggest prairie dogs play an important role in maintaining high avian biodiversity at a landscape scale within grassland ecosystems. Further, our results emphasize the importance of incorporating prairie dogs into conservation efforts for grassland birds.