In the face of biodiversity loss, we rely upon measures of diversity to
describe the health of ecosystems and to direct policymakers and conservation
efforts. However, there are many complexities in natural systems that can
easily confound biodiversity measures, giving misleading interpretations of the
system status and, as a result, there is yet to be a consistent framework by
which to measure this biodiversity loss. Ecosystems are governed by dynamic
processes, such as reproduction, dispersal and competition for resources, that
both shape their biodiversity and how the system responds to change. Here, we
incorporate these processes into simulations of habitat and environmental
change, in order to understand how well we can identify signals of biodiversity
loss against the background inherent variability these processes introduce. We
developed a tool for Ecosystem Simulation through Integrated Species
Trait-Environment Modelling (EcoSISTEM), which models on the species-level for
several sizes of ecosystem, from small islands and patches through to entire
regions, and several different types of habitat. We tested a suite of
traditionally-used and new biodiversity measures on simulated ecosystems
against a range of different scenarios of population decline, invasion and
habitat loss. We found that the response of biodiversity measures was generally
stronger in larger, more heterogeneous habitats than in smaller or homogeneous
habitats. We were also able to detect signals of increasing homogenisation in
climate change scenarios, which contradicted the signal of increased
heterogeneity and distinctiveness through habitat loss