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

Manning P, Gossner M, Bossdorf O, Allan E, Prati D, Blüthgen N, Boch S, Böhm S, Börschig C, Hölzel N, Jung K, Klaus VH, Klein A, Kleinebecker T, Krauss J, Lange M, Müller J, Pašalić E, Socher S, Tschapka M, Türke M, Weiner C, Werner M, Gockel S, Hemp A, Renner S, Wells K, Buscot F, Kalko E, Linsenmair KE, Weisser WW, Fischer M

Abstract

Land-use intensification is a key driver of biodiversity change. However, little isknownabouthowitaltersrelationshipsbetweenthediversitiesofdifferenttaxonomicgroups,whichare often correlated due to shared environmental drivers and trophic interactions.Using data from150 grassland sites, we examined how land-use intensification (increased fertilization, higherlivestock densities, and increased mowing frequency) altered correlations between the speciesrichness of 15 plant, invertebrate, and vertebrate taxa.We found that 54%of pairwise correlationsbetween taxonomic groups were significant and positive among all grasslands, while only one wasnegative.Higher land-use intensitysubstantiallyweakenedthesecorrelations(35%decrease in rand43%fewer significantpairwise correlations athighintensity),apatternwhichmayemerge as a resultof biodiversity declines and the breakdown of specialized relationships in these conditions.Nevertheless, some groups (Coleoptera, Heteroptera, Hymenoptera and Orthoptera) wereconsistently correlated with multidiversity, an aggregate measure of total biodiversity comprisedof the standardizeddiversities ofmultiple taxa, at both high and lowland-use intensity.The formofintensificationwasalsoimportant; increasedfertilizationandmowingfrequencytypicallyweakenedplant-plantandplant-primaryconsumer correlations,whereasgrazingintensificationdidnot.Thismay reflect decreased habitat heterogeneity under mowing and fertilization and increased habitatheterogeneity under grazing.While these results urge caution in using certain taxonomic groups tomonitor impacts ofagriculturalmanagementonbiodiversity, theyalsosuggestthat thediversitiesofsome groups are reasonably robust indicators of total biodiversity across a range of conditions.

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