Smaller habitats mean even less diversity than scientists thought

By Dana Kobilinsky

Islands of scrub habitat are surrounded by an agricultural matrix in Israel. Researchers found the quality of the matrix — the area between islands — is important in determining ecosystem decay. Credit: Yaron Ziv

Researchers recently found that biodiversity on small patches of landscape is even smaller than they expected. While biodiversity forecasts of certain areas are used to inform conservation and management policies, the researchers said those assumptions are based on theoretical models that may underestimate how many species are going locally extinct.

The team looked at 123 studies of island habitats around the world. These included tropical forest islands, islands in lakes created during the construction of dams and isolated nature reserves. They found an overall effect of ecosystem decay, but they also found that the quality of areas between islands — or what they call the matrix — influenced how strong the effects of ecosystem decay were.

Many biodiversity forecasts are too optimistic, they concluded. “What we found is that it is possible to make more realistic projections for how biodiversity will be lost as habitats are lost,” said Jonathan Chase, head of the Biodiversity Synthesis research group at the German Center for Integrative Biodiversity Research (iDiv) and lead author of the study. “This will allow us to make more informed policies regarding habitat protection and provides added incentives for restoring habitats to restore the biodiversity within.”