Landscape homogenization correlates with decreasing butterfly diversity

Abstract

Abstract Agricultural intensification leads to a strong homogenization of landscapes. Plots have become larger, boundaries of fields straight, and land plots have been cultivated more intensively. Field copses, ruderal areas and hedgerows were removed. As a result, most of these small-scale habitats located at the edges of fields have disappeared. Thus, many potential habitats of plant and animal species have been destroyed, and the permeability of the landscape decreased during the past decades. Landscape homogenization consequently impacts biodiversity and reduces species richness and abundance of many taxa. In this study, we surveyed changes of land cover and landscape configuration on a field-by-field basis, based on historical (1953) and recent (2018) aerial and satellite images. We further compiled data of butterfly diversity for the same time periods and region. Our data show significant decrease of field copses over the past decades. The landscape structure changed towards rather homogenous fields with straight boundaries among single land plots. The expected number of species per sample unit of an assumed species decreased significantly. Particularly butterflies relying on oligotrophic and xerothermic grasslands decreased, as well as sedentary specialist species. In contrast, the proportion of ubiquitous and mobile generalist species increased. This underlines the general trend of faunal homogenization and the loss of specialized and sedentary species, in the wake of landscape homogenization.