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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.
