Grassland management intensification weakens the associations among the diversities of multiple plant and animal taxa

Land-use intensification is a key driver of biodiversity change. However, little is knownabouthowitaltersrelationshipsbetweenthediversitiesofdifferenttaxonomicgroups,which are often correlated due to shared environmental drivers and trophic interactions.Usingdata from 150 grassland sites, we examined how land-use intensification (increased fertilization, higher livestock densities, and increased mowing frequency) altered correlations between the species richness of 15 plant, invertebrate, and vertebrate taxa.We found that 54% of pairwise correlations between taxonomic groups were significant and positive among all grasslands, while only one was negative.Higher land-use intensitysubstantiallyweakenedthesecorrelations(35%decrease inrand 43% fewer significantpairwisecorrelationsathigh intensity), apatternwhichmayemergeasaresult of biodiversity declines and the breakdown of specialized relationships in these conditions. Nevertheless, some groups (Coleoptera, Heteroptera, Hymenoptera and Orthoptera) were consistently correlated with multidiversity, an aggregate measure of total biodiversity comprised of the standardizeddiversities ofmultiple taxa, at bothhighand low land-use intensity.The formof intensificationwasalsoimportant;increasedfertilizationandmowingfrequencytypicallyweakened plant–plantandplant–primaryconsumercorrelations,whereasgrazing intensificationdidnot.This may reflect decreased habitat heterogeneity under mowing and fertilization and increased habitat heterogeneity under grazing.While these results urge caution in using certain taxonomic groups to monitor impactsofagriculturalmanagementonbiodiversity, theyalsosuggestthat thediversitiesof some groups are reasonably robust indicators of total biodiversity across a range of conditions.