Abstract

Here we propose two metrics to assess the ecological resilience of communities based on how changes in the overall abundance of individuals affect the number of species. The community sensitivity expresses the rate of change in the log expected number of species with respect to the log expected total number of individuals, whereas the community resistance is the proportional reduction in community size that will reduce the expected number of species by one. Estimates of these metrics in four bird communities in European deciduous forests using a stochastic model for the community dynamics revealed large differences in the resilience to permanent changes of the environment. In particular, stochastic influences from environmental fluctuations strongly affected the sensitivity and the resistance caused by area loss or increased environmental stochasticity. This shows that ecological resilience is closely related to which processes that most strongly affect the temporal dynamics of communities.