This research will employ cross-site and within-site comparisons using three LTER sites to extend and enrich our knowledge of biodiversity and its dynamics at these sites and establish a baseline for understanding the long-term dynamics of a critical and sensitive component of these ecosystems. To answer this question they will document how species and communities of ground-dwelling ants respond to local and regional gradients in vegetation and land-use between the Central Plains site (Colorado shortgrass steppe), the Sevilleta site (transitional between grassland and Chihuahuan Desert), and the Jornada site (Chihuahuan Desert). The work focuses on ground-dwelling ants because they are easily sampled and observed, are abundant and diverse, are characterized by strong behavioral and competitive interactions, are sensitive to both small-scale and large-scale environmental variations, and may play a major role in the movement of materials in arid and semiarid ecosystems. The sites represent a gradient in temperature, precipitation, vegetation, and biogeography. Within each site, ant communities and functional roles will be compared in grass-dominated and shrub- dominated vegetation and in locations differing in grazing intensity. Observations at nest sites of foraging individuals and of removal of seeds and mealworms from food stations will be used to document how the relative magnitude of material flow generated by ants of different functional groups differs among habitats within a site and how these differences are affected by factors operating at the regional scale.
