Effects of a common harvester ant (Messor andrei) on richness and abundance of soil biota

Soil biota and chemistry were compared between harvester ant (Messor andrei) nests and adjacent, non-ant soil from a semi-arid, serpentine grassland. The major soil groups (bacteria, fungi, nematodes, miscellaneous eukaryotes, and microarthropods) were quantified. All soil groups examined were more abundant and diverse in ant nests than in non-ant soil, and all soil nutrients were similarly enriched inside nests. A principal component analysis indicated that the enrichment of bacteria and fungi inside ant nests explained the majority of variation in the other response variables. Thus, it appears that M. andrei performs some activity and/or enriches one or more nutrients (e.g. phosphorous), which heavily impacts the base of the soil foodweb (bacteria and fungi). This suggests that these ant nests exert significant effects on the resident soil biota via bottom-up processes. (C) 2003 Elsevier Science B.V. All rights reserved.