The influence of arroyo edges on Pogonomyrmex rugosus nest distribution in the Chihuahuan Desert, New Mexico

The dissection of ephemeral drainage channels into alluvial fan deposits create distinct geomorphic edges. This study describes the spatial distribution of Pogonomyrmex rugosus harvester ant colonies in relation to arroyo channel edges in the Chihuahuan Desert. Statistical tests were conducted including the calculation of a distance index of dispersion (Johnson & Zimmer, 1985. Ecology, 66: 1669–1675). A sample of 74 nests revealed aggregated arroyo edge-to-nest distances nearest the arroyo margin with decreased densities away from the edge. Nest densities nearest the edge were significantly greater than those typically observed in this desert environment