Loreau Michel, Mouquet Nicolas, Gonzalez Andrew
Laboratoire d'Ecologie, Unité Mixte de Recherche 7625, Ecole Normale Supérieure, 46 Rue d'Ulm, F-75230 Paris Cedex 05, France.
Proc Natl Acad Sci U S A. 2003 Oct 28;100(22):12765-70. doi: 10.1073/pnas.2235465100. Epub 2003 Oct 20.
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.
在过去十年中，生物多样性丧失对局部尺度生态系统功能和服务的潜在影响受到了广泛关注，但对于生物多样性如何在更大空间尺度上影响生态系统过程和稳定性却知之甚少。我们提出，生物多样性凭借异质景观中局部系统之间的空间交换为生态系统功能提供空间保障。我们通过使用一个简单的理论集合群落模型来探索这一假设，该模型具有明确的局部消费者 - 资源动态以及系统间的扩散。我们的模型表明，扩散率的变化通过两种机制强烈且非单调地影响生态系统生产力的时间平均值和变异性：一是在高扩散率下倾向于在景观中占主导地位的中间类型物种的空间平均作用，二是通过维持物种多样性实现的物种间功能补偿。物种多样性的空间保障效应在使局部多样性最大化的中间扩散率时最为显著。这些结果对保护和管理具有深远意义。了解跨生态系统的空间过程对于预测景观变化对生物多样性以及生态系统功能和服务的影响至关重要。
