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Intensification of agriculture reduces heterogeneity at local and landscape levels and thereby impact biodiversity and ecosystem processes. We studied a host-antagonist system of cavity-nesting bees, wasps and their antagonists and hypothesised that hosts and antagonists show different responses to local land-use intensity, the diversity of landscape in terms of composition and the spatial structure of landscape in terms of configuration. In a highly replicated study, we established nesting resources on 95 grasslands in three geographic regions across Germany and measured species richness and abundance of hosts (bees and wasps) and their antagonists, and rates of parasitism. For each site, we quantified local land-use intensity as well as landscape heterogeneity in terms of composition and configuration at spatial scales ranging from 250 m to 2000 m. Increasing landscape heterogeneity enhanced species richness, abundance and parasitism rate, whereas local land-use intensity only marginally negatively affected total abundance. Bee and wasp abundance as well as wasp species richness were enhanced by landscape composition at 250 m, whereas their antagonists were enhanced by landscape configuration at 1500 m. In conclusion, landscape composition and configuration affect trophic levels differently and are more relevant than local land-use intensity. Solitary bees and wasps, which offer important pollination and pest control services, could be supported by enhancing landscape diversity, while their antagonists could benefit from measures that promote landscape connectivity. Hence, scale-dependent and trophic group specific conservation management schemes are required, that address different components of landscape heterogeneity to enhance functional diversity and trophic interactions in agricultural landscapes.

Although temporal heterogeneity is a well-accepted driver of biodiversity, effects of interannual variation in land-use intensity (LUI) have not been addressed yet. Additionally, responses to land use can differ greatly among different organisms; therefore, overall effects of land-use on total local biodiversity are hardly known. To test for effects of LUI (quantified as the combined intensity of fertilization, grazing, and mowing) and interannual variation in LUI (SD in LUI across time), we introduce a unique measure of whole-ecosystem biodiversity, multidiversity. This synthesizes individual diversity measures across up to 49 taxonomic groups of plants, animals, fungi, and bacteria from 150 grasslands. Multidiversity declined with increasing LUI among grasslands, particularly for rarer species and aboveground organisms, whereas common species and belowground groups were less sensitive. However, a high level of interannual variation in LUI increased overall multidiversity at low LUI and was even more beneficial for rarer species because it slowed the rate at which the multidiversity of rare species declined with increasing LUI. In more intensively managed grasslands, the diversity of rarer species was, on average, 18% of the maximum diversity across all grasslands when LUI was static over time but increased to 31% of the maximum when LUI changed maximally over time. In addition to decreasing overall LUI, we suggest varying LUI across years as a complementary strategy to promote biodiversity conservation.