Carabid beetles in solar parks: assemblages under solar panels are severely impoverished compared to gaps between panel rows and edge areas

Abstract

Renewable energies are a major tool to reduce greenhouse gas emissions and combat climate change. Among renewables, solar parks are a key technology and their expansion will strongly increase in the future. Hence, there is a great need for research regarding their impact on biodiversity. In this study, we investigated the importance of three solar parks in northern Germany as habitat for carabid beetles. More specifically, we determined how habitat characteristics (temperature, vegetation structure), species richness, activity densities and carabid beetle assemblages vary between different locations within solar parks: areas under solar panels “UNDR”, gaps between panel rows “BTW” and areas at the edge of solar parks “EDGE”. We found that UNDR strongly differed from BTW/EDGE in terms of habitat conditions, species richness and activity densities of carabid beetles. UNDR mainly provided habitat for a species- and individual-poor subset of species already present in BTW/EDGE and made only a small contribution to the total species richness of the investigated solar parks. BTW and EDGE, on the other hand, differed only slightly. Thus, the narrow gaps between the panel rows were of similar importance as a habitat for carabid beetles as the edge areas. Overall, the investigated solar parks—and thus also the more species-rich areas EDGE and BTW—almost exclusively provided habitat for widespread and common non-threatened generalists, while species of conservation concern were extremely rare.Implications for insect conservationThe low importance of UNDR for carabid beetles should be considered when assessing the biodiversity value of solar parks, since a large proportion of these facilities is covered with solar panels. Between panel rows and at the edge of solar parks, larger areas should be kept free from construction with solar panels in order to provide habitats for carabid beetles and other species groups. More research should be conducted on how to further improve solar parks for carabid beetles and overall biodiversity.