Climatic warming shifts the soil nematode community in a desert steppe

Climatic warming is known to impact terrestrial ecosystem structure and functioning. The response of belowground fauna such as soil nematodes to climatic warming has received little attention, yet the fauna plays crucial roles in the nutrient decomposition and cycling processes. An in situ factorial experiment was conducted to examine the effects of warming on the soil nematode community in a desert steppe. Both moderate-long and severe-short warming treatments were established using a thermal infrared heating facility, along with an unheated control, from 2011 to 2015. The main results were as follows: (i) climatic warming significantly decreased the abundances of total nematodes, plant parasites, fungal-feeding nematodes, and nematodes with high values on the colonizer-persister scale, such as predators and omnivores; (ii) warming significantly decreased the generic richness, maturity index, plant-parasite index, modified maturity index, and structural index, while increased the basal index of the nematode community; (iii) the soil nutrition status was significantly associated with the changes in the composition of the nematode community; and (iv) the responses of the soil nematode community to climatic warming and the consequent drought depended on soil layers and growing seasons. These results indicate a promotion of a more acquisitive resource-use strategy, one in which soil nematodes and soil microbes together impose an adaptive coordination to accelerate soil nutrient cycling by influencing carbon and nitrogen decomposition under climatic change in the desert grassland. The findings suggest that climatic warming could alter ecosystem functioning by altering the soil nematode community in arid areas.