Changes in diversity and functional groups of soil mite communities are associated with properties of food resources along a subalpine secondary succession

It is hypothesized that soil animal diversity is supported by environmental and food diversity. Mites are the most abundant microarthropods in soil communities that occupy several trophic levels in soil food webs and play important role in litter decomposition and nutrient cycling. However, it is not clear if diversity of mite communities is associated with diversity and quality in corresponding food resources across trophic levels. Here, we studied the influences of resource diversity (plants, fungi, and nematodes) and abiotic factors (litter and soil attributes) on taxonomic richness of detritivorous, fungivorous, and predatory mites (75 mite genera in total) in a subalpine succession (grassland, shrubland, secondary forest, primary forest) in southwestern China. Supporting our main hypothesis, diversity of the bulk mite community and individual functional groups was associated with the diversity and quality of resources across trophic levels. The total taxonomic richness was highest in the shrubland successional stage, where plant diversity was the highest, and decreased in late-successional stages despite a similar abundance. Diversity of predatory and fungivorous mites was positively associated with the diversity of nematode and fungal communities and reached maximum at the shrubland and grassland stages, respectively. Diversity of detritivorous mites was similar across different successional stages, being associated with litter quality. These findings provide empirical evidence that supports general ecological theory on the mechanisms that support multitrophic biodiversity in soils.