From diverse to simple: butterfly communities erode from extensive grasslands to intensively used farmland and urban areas

Abstract

The severe biodiversity decline in European agricultural landscapes demands a specific evaluation of the various land-use practices. Many butterflies in Europe, as an important ecological indicator and pollinator taxon, require human interventions to sustain their populations in cultivated landscapes. However, land-use changes and management intensification are currently responsible for their decline. In this study, we compare butterfly communities occurring on 93 sites in seven widely distributed land-use types, viz. extensive meadows and pastures, semi-intensive meadows, vineyards, arable land, settlements and apple orchards. We recorded a high butterfly diversity in supposedly high nature-conservation value (HNV) grasslands (extensive meadows and pastures). All other land-use types showed significantly lower diversity, with decreasing diversity from semi-intensive meadows to apple orchards. Moreover, functional traits uncovered a general trend: extensive grasslands supported communities of more specialized and sedentary species whilst all other non-HNV land-use types showed communities characterized by mobile generalists. Community composition was driven by the land-use type and explained by plant-based indicator values for nutrients and light and temperature variables. Important life-history traits further correlated with site variables confirming the shift from specialists to generalists along increasing land-use intensity gradients and the effect of the thermal environment on phenological traits. We found supporting evidence for the effectiveness of regional Agri-Environmental Measures for butterfly conservation in European cultural landscapes and for the European conservation schemes to focus at least partly on the preservation of HNV grasslands with extensive management. Furthermore, we clearly show the poor ecological state of butterfly communities in more disturbed land-use types (including urban areas) and propose adopting measures to improve butterflies’ conservation in these environments.