Assistant Professor of Soil Health Michigan State University, Michigan, United States
Abstract: Free-living nematodes have the potential to indicate how soil food webs respond to drought and can also serve as indicators of ecosystem resilience. This study aimed to 1) assess how nematode communities shift under induced drought in two contrasting terrestrial ecosystems and 2) determine if the nematode community is able to recover after variable and long-term drought. The study was conducted at the KBS-LTER comparing a no-till row-cropped system and an early successional community under deployed rain exclusion shelters. Free-living nematode communities were assessed under three precipitation regimes: natural rainfall (reflecting a 30-year average), a three-week intermittent drought, and a six-week drought. Nematode community samples are taken at peak-drought (the sixth week of the induced drought), and post-drought (one week after re-wetting). Nematodes were extracted and identified by microscope at 40-100x magnification. Principal coordinate ordination analyses (PCOA) indicate that system and precipitation significantly altered nematode community structure at peak drought, whereas system had a significant effect on nematode community structure at recovery (p< 0.05). Surprisingly, drought was shown to increase the structure and enrichment of the soil food web when compared to the irrigated systems. In addition, the structure and enrichment of the soil food web under drought shifted to resemble the irrigated system during recovery. These results indicate that soil food webs can recover from drought effects one week after re-wetting. Moreover, this study indicates that nematode communities are highly responsive to induced effects of drought, thus making them desirable indicators of soil food web responses to climatic disturbances.
