Submitted to: Soil Biology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2016
Publication Date: 9/3/2016
Citation: Mueller, K.E., Blumenthal, D.M., Pendall, E., Eisenhauer, N., Carrillo, Y., Hines, J., Cesarz, S., Ciobanu, M., Wall, D., De Tomasel, C.M. 2016. Elevated CO2 and warming shift the functional composition of soil nematode communities in a semiarid grassland. Soil Biology and Biochemistry. 103:46-51.

Interpretive Summary: Nematodes are abundant in grassland soils and influence the functioning of grasslands by feeding on plant roots and other soil organisms, including bacteria and fungi. Thus, interactions among plants, nematodes, and other environmental factors could influence ecosystem services in grasslands. This study evaluated how nematode communities in a mixed-grass prairie respond to futuristic climatic conditions, including elevated carbon dioxide and warmer temperatures. It was observed that both elevated carbon dioxide and warming altered the functional composition of the nematode community. More specifically, the nematode community under futuristic climatic conditions was comprised of fewer predators and omnivores, fewer nematodes that feed on plant roots, and more nematodes that are either small or have short life-cycles. The decline in plant-feeding nematodes could be part of a suite of responses to elevated carbon dioxide and warming that enable greater plant production in the mixed-grass prairie. Collectively, the shifts in functional composition of the nematode community suggest that other ecological processes, such as decomposition and respiration, in the mixed-grass prairie could be altered by on-going climate change.

Technical Abstract: Climate change can alter soil communities and functions, but the impacts are uncertain for most ecosystems. We assessed the impacts of climate change on soil nematodes in a semiarid grassland using a 7-year, factorial manipulation of temperature and [CO2]. Elevated CO2 and warming decreased the abundance of plant-feeding nematodes and nematodes with intermediate to high values on the colonizer-persister scale (cp3-5), including predators and omnivores. Thus, under futuristic climate conditions, nematode communities were more dominated by r-strategists (cp1-2) that feed on bacteria and fungi. These results indicate that climate change could alter soil functioning in semiarid grasslands. For example, the lower abundance of plant-feeding nematodes could facilitate positive effects of elevated CO2 and warming on plant productivity. The effects of elevated CO2 and warming on nematode functional composition were typically less than additive, highlighting the need for multi-factor studies.