The diversity – stability debate is a long-standing issue in ecology, asking whether more diverse communities show higher stability over time and more rapid recovery from disturbance. Recent studies showed that disentangling the mechanisms for local and regional diversity requires the analysis of spatial and temporal ecological dynamics as embedded in the metacommunity framework. However, we lack on information how these differences in diversity constrain the response of species communities to spatial disturbance and environmental fluctuations, especially if these disturbances vary in their frequency and spatial scale. We use an experimental metacommunity design to test the link between dispersal, disturbance, and stability using marine phytoplankton as a model system. A metacommunity consisted of three connected microcosms (local patches), which were connected by tubes allowing for different dispersal rates by different opening times of the tubes. Each patch contained the same species pool of fifteen marine phytoplankton species, which were isolated from the same habitat. The four different disturbance treatments comprise an undisturbed control and three disturbed treatments, where we either removed 75% of the algal biomass in one randomly chosen local patch or 25% or 75% of the algal biomass in each local patch.
Results/Conclusions
Across a total of 80 metacommunities, we tested whether resilience is a function of dispersal rate and local or regional diversity. We defined resilience as the rate of recovery i.e. how fast the disturbed treatments approach the state of the control treatment after disturbance. We found that both dispersal and diversity affected standing biomass and recovery of the assemblages, with strong interactions to the scaling of disturbance. Therewith, we can contribute to the diversity- stability debate by addressing local and regional stability in response to species richness, disturbance regimes, and dispersal rates.
