Goudard Alexandra, Loreau Michel
Biogéochimie et Ecologie des Milieux Continentaux, Unité Mixte de Recherche 7618, Ecole Normale Supérieure, 46 rue d'Ulm, F-75230 Paris cedex 05, France.
Am Nat. 2008 Jan;171(1):91-106. doi: 10.1086/523945.
Research into the relationship between biodiversity and ecosystem functioning has mainly focused on the effects of species diversity on ecosystem properties in plant communities and, more recently, in food webs. Although there is growing recognition of the significance of nontrophic interactions in ecology, these interactions are still poorly studied theoretically, and their impact on biodiversity and ecosystem functioning is largely unknown. Existing models of mutualism usually consider only one type of species interaction and do not satisfy mass balance constraints. Here, we present a model of an interaction web that includes both trophic and nontrophic interactions and that respects the principle of mass conservation. Nontrophic interactions are represented in the form of interaction modifications. We use this model to study the relationship between biodiversity and ecosystem properties that emerges from the assembly of entire interaction webs. We show that ecosystem properties such as biomass and production depend not only on species diversity but also on species interactions, in particular on the connectance and magnitude of nontrophic interactions, and that the nature, prevalence, and strength of species interactions in turn depend on species diversity. Nontrophic interactions alter the shape of the relationship between biodiversity and biomass and can profoundly influence ecosystem processes.
对生物多样性与生态系统功能之间关系的研究主要集中在物种多样性对植物群落以及最近对食物网中生态系统属性的影响上。尽管人们越来越认识到非营养相互作用在生态学中的重要性，但这些相互作用在理论上仍研究不足，其对生物多样性和生态系统功能的影响在很大程度上尚不清楚。现有的互利共生模型通常只考虑一种类型的物种相互作用，并不满足质量平衡约束。在此，我们提出一个相互作用网络模型，该模型既包括营养相互作用也包括非营养相互作用，并且遵循质量守恒原则。非营养相互作用以相互作用修饰的形式表示。我们使用这个模型来研究整个相互作用网络的组装所产生的生物多样性与生态系统属性之间的关系。我们表明，诸如生物量和生产力等生态系统属性不仅取决于物种多样性，还取决于物种相互作用，特别是非营养相互作用的连通性和强度，而且物种相互作用的性质、普遍性和强度反过来又取决于物种多样性。非营养相互作用改变了生物多样性与生物量之间关系的形状，并能深刻影响生态系统过程。
