Collaborative Research: RUI: The influence of ants on regional-scale soil carbon dynamics

Soil organic carbon is an important property of ecosystems that impacts soil fertility and the global carbon cycle. Animals have been shown to affect carbon in soils, but it is poorly understood how different types of animals ultimately affect processes that determine the amount of carbon in soils. Ants are highly abundant animals that nest in soils all over the world. Their nests impact bacteria and fungi living in the soil which, in turn, affect soil conditions including carbon content. Ants may therefore be an important animal group affecting the processes that determine carbon content in soils. This research advances our understanding of how highly abundant insect animals that live in the soil alter and improve conditions for bacteria and fungi that live in or near ant nests. Over many ant nests across large areas, these impacts on soil conditions and microbes may be very large and important for determining, for example, how much carbon is present in soils. The research includes (1) a controlled field experiment to test how ants influence soil physical, chemical, and biological conditions, hypothetically creating microbial hotspots that affect carbon content in soils; and (2) field surveys across a 1,550-km regional transect to quantify ant nest impacts on soil conditions in forests and grasslands in southeastern North America. The approach allows testing of causation to discern the directionality of ant effects on carbon dynamics and microbial communities. The observational surveys facilitate estimates of the magnitude of ant effects on carbon. This combined approach provides the basis for scaling ant effects to their potential ecosystem, landscape, and regional significance. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.