Ecological intensification alters the trait-based responses of soil microarthropods to extreme precipitation in agroecosystem

Soil biodiversity is of key importance to many essential ecosystem functions, but currently it is severely threatened by both intensive agriculture and climate changes. Ecological intensification, including organic amendments and less disturbance, is expected to buffer the degradation of biodiversity and ecosystem functioning induced by intensive agriculture, but its effects in the context of climate changes are poorly understood. In the present work, we studied the responses of agricultural soil biodiversity to ecological intensification under different natural rainfall intensities in a subtropical field. We focused on a numerically dominant group of soil microarthropods, the Collembola, and three conservation managements, i.e., straw, manure, and no-tillage. The experimental site was established with a full-factorial design of different managements. Soil physiochemical parameters and the density, taxonomic diversity, and morpho-functional traits of the collembolan community were measured over three consecutive years. Results showed that rainfall intensification markedly reduced collembolan density and had severe impact on large euedaphic species. Straw amendment buffered the detrimental effect of dense rainfall on collembolan density, but aggravated the body size reduction caused by the rainfall. Manure input and no-tillage mainly affected the community functional composition, in which manure favours more active and mobile species characterised by a well-developed furca, whereas no-tillage favoured surface-dwelling species. These results support the hypothesis that external resource enrichment and reduced disturbance would shape the functional traits of soil fauna, and further modified their response to climate change events. Our findings call for more attention on the functional consequences of ecological intensification and the interactions among soil biodiversity, agricultural managements and climate changes.