CO(2) efflux from subterranean nests of ant communities in a seasonal tropical forest, Thailand

Many ant species construct subterranean nests. The presence of their nests may explain soil respiration “hot spots”, an important factor in the high CO(2) efflux from tropical forests. However, no studies have directly measured CO(2) efflux from ant nests. We established 61 experimental plots containing 13 subterranean ant species to evaluate the CO(2) efflux from subterranean ant nests in a tropical seasonal forest, Thailand. We examined differences in nest CO(2) efflux among ant species. We determined the effects of environmental factors on nest CO(2) efflux and calculated an index of nest structure. The mean CO(2) efflux from nests was significantly higher than those from the surrounding soil in the wet and dry seasons. The CO(2) efflux was species-specific, showing significant differences among the 13 ant species. The soil moisture content significantly affected nest CO(2) efflux, but there was no clear relationship between nest CO(2) efflux and nest soil temperature. The diameter of the nest entrance hole affected CO(2) efflux. However, there was no significant difference in CO(2) efflux rates between single-hole and multiple-hole nests. Our results suggest that in a tropical forest ecosystem the increase in CO(2) efflux from subterranean ant nests is caused by species-specific activity of ants, the nest soil environment, and nest structure.