Beyond species loss: extinction of interactions in a changing world.

Abstract

[eng] 1.The effects of the present biodiversity crisis have been largely focused on the loss of species.However, a missed component of biodiversity loss that often accompanies or even precedesspecies disappearance is the extinction of ecological interactions. 2.Here, we propose a novel model that (i) relates the diversity of both species and interactionsalong a gradient of environmental deterioration and (ii) explores how the rate of loss of eco-logical functions, and consequently of ecosystem services, can be accelerated or restraineddepending on how the rate of species loss covaries with the rate of interactions loss. 3.We find that the loss of species and interactions are decoupled, such that ecological interac-tions are often lost at a higher rate. This implies that the loss of ecological interactions mayoccur well before species disappearance, affecting species functionality and ecosystems servicesat a faster rate than species extinctions. We provide a number of empirical case studies illus-trating these points. 4.Our approach emphasizes the importance of focusing on species interactions as the majorbiodiversity component from which the 'health' of ecosystems depends.