Dispersal mitigates biologically induced disturbances in heterogeneous metacommunities

Abstract

AbstractThe global increase in anthropogenic disturbances has introduced patterns of heterogeneity across many landscapes. Local disturbances are often studied from the perspective of the local habitat patch, where their direct effects on local community composition are more evident. However, local disturbances can have regional implications when connected to other patches within a metacommunity. Invasive species provide a unique opportunity for studying the influence of biologically induced disturbances on metacommunity dynamics, because invasive species are influential in structuring local communities and have a propensity for dispersing across landscapes, producing gradients in disturbance intensity. The invasive zebra mussel, Dreissena polymorpha, is widespread throughout the eastern USA and is having negative impacts on native communities. Using zebra mussels to induce disturbances in mesocosm zooplankton communities, we tested how the relative abundance of disturbed and undisturbed habitat patches within a metacommunity influenced community and metacommunity biodiversity and composition. The zebra mussels negatively affected pelagic zooplankton species richness, while facilitating the population growth of littoral species. Undisturbed communities mitigated disturbance‐induced local and regional pelagic species loss in heterogeneous metacommunities, while the fully disturbed metacommunity experienced significant losses of pelagic zooplankton at local and regional scales. Disturbed communities influenced undisturbed communities in heterogeneous metacommunities by increasing the densities of littoral zooplankton species. Overall, these results highlight the important effects that undisturbed habitat patches can have on mitigating species loss in locally disturbed patches and maintaining regional biodiversity in heterogeneous metacommunities.