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Abstract

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.Using data 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 in rand 43%fewer significantpairwise correlations athighintensity),apatternwhichmayemerge as a result 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 both high and lowland-use intensity.The formof intensificationwasalsoimportant; increasedfertilizationandmowingfrequencytypicallyweakened plant–plantandplant–primaryconsumer correlations,whereasgrazingintensificationdidnot.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 impacts ofagriculturalmanagementonbiodiversity, theyalsosuggestthat thediversitiesof some groups are reasonably robust indicators of total biodiversity across a range of conditions.