Soil biodiversity and agroforestry

Tree lines in agroforestry systems increase habitat heterogeneity and connectivity, modulating community assembly processes with potential benefits for biodiversity and associated ecosystem services. These biodiversity effects have to be considered at different spatial scales including macro- and microorganisms in above- and belowground communities in the context of a multidiversity framework. Multidiversity, including species composition, biotic interactions and ecosystem functions across multiple taxonomic groups, ultimately determines the potential of agroforestry to optimize Nature’s Contribution to People (NCP). To gain a mechanistic understanding of biodiversity responses in agroforestry systems, we quantify gradients in above and belowground biodiversity across different scales, from soil invertebrates and soil microorganisms including Bacteria, Archaea and fungi (belowground) through epigaeic arthropods (aboveground herbivores, predators) to pollinators). We employ well-established as well as novel research methods to investigate two agroforestry systems (organic and conventional) characterized by contrasting site conditions and the surrounding landscape mosaic by emphasizing complementarity in data collection. We provide an in-depth knowledge of the effects of biodiversity on the NCPs characteristic of agroforestry systems by focusing on the spatial configuration (distance to the tree rows as well as depth gradients along the transects). Cooperation with four complementary subprojects of the FORMULA Research Unit allows for relating below- and aboveground biodiversity functions and the spatial dynamics of biodiversity patterns with respect to biogeochemical cycles (especially carbon and nitrogen), habitat heterogeneity and management.