Using an innovative experimental approach, this Project aims to explore the causes and consequences of largely unchanging species numbers over time in local ecological communities, but unprecedented changes in species composition, recently documented across the globe. The implications of these compensatory dynamics for the resilience of ecological communities, and how they will affect ecosystem functioning, remain largely unknown. These are pressing questions in community ecology, with much conservation significance. The Project aims to show how compensatory dynamics proceed in response to environmental change. In doing so it has the potential to deliver unprecedented insights into the functional consequences of temporal community change.