Resilience and diversity in aquatic metacommunities: Effects of dispersal and the spatial scale of disturbance

• Applicant: Professor Dr. Helmut Hillebrand
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2009 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 108975007

Recent years have seen stringent advances in the analysis of spatial ecological dynamics embedded in the concept of metacommunities, in which species coexistence is mediated by local interactions and regional dispersal. However, we lack information on how metacommunity dynamics alter responses of diversity and resilience to disturbance and environmental fluctuations, especially if these disturbances differ in their spatial extent. To test this idea, we will establish experimental metacommunities consisting of connected microcosms inhabited by phytoplankton (and their consumers). The metacommunities differ in their dispersal rates (which affect regional and local diversity) and their coexistence mechanism (patch dynamics versus source-sink dynamics). In these communities, we will alter mortality by removing biomass in local or regional extent and measure the recovery of community composition and important ecosystem functions (primary production, nutrient retention) after this disturbance. We except resilience to be a function of dispersal rate, local richness and regional richness, but we expect different relative importance of these factors at different spatial scales of mortality. In a second set of experiments, we will address the importance of spatial coexistence for the stability of ecosystem processes over time under undisturbed but fluctuating environmental conditions. The results from this project will allow addressing the importance of spatial insurance mechanisms in fragmented landscapes in cases of habitat destruction, which are considered to be major causes of biodiversity loss in future environments.

• DFG Programme: Research Grants