Spruce dieback as chance for biodiversity: standing deadwood promotes beetle diversity in post-disturbance stands in western Germany

Abstract

Anthropogenic climate change poses a major threat to ecosystems and their biodiversity. Forests, for example, are suffering from climate-amplified disturbances like droughts or pest outbreaks. Throughout Europe, such disturbances resulted in large-scale diebacks of managed spruce stands in recent years. While such stands are often salvage-logged to reduce economic losses, it is still rather unclear how post-disturbance management affects forest biodiversity in anthropogenic spruce stands. By comparing epigeal beetle communities among salvage-logged sites, standing deadwood patches, and succession areas, we show that spruce dieback can be a chance for biodiversity conservation. Even though individual beetle families responded partly differently to post-disturbance management, standing deadwood enhanced the overall diversity of ground-dwelling beetles compared to salvage logging, while succession sites were intermediate. We also show that community composition and functional guilds vary strongly between management categories. Implications for insect conservation: We suggest to set-aside areas of standing deadwood for natural succession to enhance beetle taxonomic and functional diversity, especially of deadwood-dependent species. As different types of management support different species assemblages, well-planned post-disturbance management, including a partial abandonment of salvage logging and a consideration of natural succession, may counter biodiversity losses in forests.