Biodiversity as spatial insurance in heterogeneous landscapes

TLDR

Biodiversity loss impacts ecosystem functioning locally, yet its effects on larger spatial scales remain poorly understood, highlighting the need to consider spatial processes across heterogeneous landscapes. We propose that biodiversity provides spatial insurance for ecosystem functioning by virtue of spatial exchanges among local systems in heterogeneous landscapes. We explore this hypothesis using a simple theoretical metacommunity model with explicit local consumer–resource dynamics and dispersal among systems. The model shows that dispersal rate nonmonotonically alters productivity mean and variability through spatial averaging by intermediate species and functional compensations, with maximal spatial insurance at intermediate rates, underscoring important conservation implications.

Abstract

The potential consequences of biodiversity loss for ecosystem functioning and services at local scales have received considerable attention during the last decade, but little is known about how biodiversity affects ecosystem processes and stability at larger spatial scales. We propose that biodiversity provides spatial insurance for ecosystem functioning by virtue of spatial exchanges among local systems in heterogeneous landscapes. We explore this hypothesis by using a simple theoretical metacommunity model with explicit local consumer–resource dynamics and dispersal among systems. Our model shows that variation in dispersal rate affects the temporal mean and variability of ecosystem productivity strongly and nonmonotonically through two mechanisms: spatial averaging by the intermediate-type species that tends to dominate the landscape at high dispersal rates, and functional compensations between species that are made possible by the maintenance of species diversity. The spatial insurance effects of species diversity are highest at the intermediate dispersal rates that maximize local diversity. These results have profound implications for conservation and management. Knowledge of spatial processes across ecosystems is critical to predict the effects of landscape changes on both biodiversity and ecosystem functioning and services.