Scavenging ant foraging behavior and variation in the scale of nutrient redistribution among semi-arid grasslands

The scavenging of arthropod carrion by ants can be an important mechanism of nutrient redistribution in grasslands. By removing materials to nests over different sized areas, scavenging ants may contribute to differences in ecosystem patchiness. We asked how variation in overall ant foraging activity among three desert/grassland Long-Term Ecological Research sites creates differences in the distances that scavenged material is laterally redistributed. Generally, species with large-bodied workers and thermophilic species removed baits the farthest. Overall, this resulted in a positive relationship between removal distance and vapor pressure deficit. Mean removal distance across all ants increased from the shortgrass steppe to the Chihuahuan desert grassland, creating a seven-fold variation in the spatial scale of nutrient concentration by ants. The dominant species creating this pattern are inconspicuous and little-known when compared to the harvester ants that have been emphasized in ecosystem studies. (C) 2002 Elsevier Science Ltd.