Biodiversity-ecosystem functioning relationships in forests: Do the same processes drive biodiversity-ecosystem functioning relationships above- and belowground in forests?

Abstract

Climate change and deforestation are presenting huge threats to forest biodiversity. This decline poses a risk to the ecosystem functioning of forests. The processes determining how biodiversity impacts ecosystem services in forests can differ between above- and belowground communities. This literature review provides an overview of the different processes driving the above- and belowground biodiversity-ecosystem functioning relationships in forests. Evidence for both the complementarity effect hypothesis and the selection effect hypothesis was evaluated. Among the complementarity causes (i.e. spatial partitioning, temporal partitioning, partitioning across the chemical form of nitrogen, resource enrichment, physical stress buffering, negative and positive biotic feedback) that enhance ecosystem functioning, spatial partitioning is predominant above- and belowground in forests. In addition, temporal partitioning and physical stress buffering were also widely found to drive the aboveground positive biodiversity-ecosystem functioning relationship. Whereas partitioning across the chemical form of nitrogen together with the overlap between resource enrichment and positive biotic feedback, via nitrogen fixing species and mycorrhizae, enhances belowground ecosystem functioning. Furthermore, the selection effect hypothesis can also act as a driver of the biodiversity-ecosystem functioning relationship above- and belowground in forests. Compared to aboveground studies, belowground processes are poorly studied. Therefore, future research should focus on providing a more detailed picture of the belowground processes driving biodiversity and their effect on ecosystem functioning. Which could increase the efficiency of management and conservation of ecosystem functioning in forest.