Species richness enhances natural enemy biomass stability by decreasing their temporal turnover in agricultural landscapes

While the temporal stability of communities of natural enemies in agroecosystems is crucial to sustain pest control services over time, little is known about what drives this stability. Using a 6-year dataset composed of carabid collections, together with local and landscape-level management descriptors from 57 arable fields in France, we examined the abiotic and biotic drivers of mean carabid biomass and its inter-annual variation in each field. We show that mean α-richness increases the mean and stability of carabid biomass by decreasing the temporal turnover of the community. Surprisingly, carabid asynchrony and evenness had no influence on either stability or mean carabid biomass. At the landscape level, diversifying crop phenology appears to be the most efficient way to support carabid biomass stability. The stability of agrosystem functioning requires further analysis because the mechanisms operating in such habitats may be totally different from those operating in natural or experimental grasslands.