Illinois Natural History Survey and Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA.
Oecologia. 2011 Sep;167(1):189-98. doi: 10.1007/s00442-011-1967-3. Epub 2011 Mar 26.
Understanding the ability of biodiversity to govern ecosystem function is essential with current pressures on natural communities from species invasions and extirpations. Changes in fish communities can be a major determinant of food web dynamics, and even small shifts in species composition or richness can translate into large effects on ecosystems. In addition, there is a large information gap in extrapolating results of small-scale biodiversity-ecosystem function experiments to natural systems with realistic environmental complexity. Thus, we tested the key mechanisms (resource complementarity and selection effect) for biodiversity to influence fish production in mesocosms and ponds. Fish diversity treatments were created by replicating species richness and species composition within each richness level. In mesocosms, increasing richness had a positive effect on fish biomass with an overyielding pattern indicating species mixtures were more productive than any individual species. Additive partitioning confirmed a positive net effect of biodiversity driven by a complementarity effect. Productivity was less affected by species diversity when species were more similar. Thus, the primary mechanism driving fish production in the mesocosms was resource complementarity. In the ponds, the mechanism driving fish production changed through time. The key mechanism was initially resource complementarity until production was influenced by the selection effect. Varying strength of intraspecific interactions resulting from differences in resource levels and heterogeneity likely caused differences in mechanisms between the mesocosm and pond experiments, as well as changes through time in the ponds. Understanding the mechanisms by which fish diversity governs ecosystem function and how environmental complexity and resource levels alter these relationships can be used to improve predictions for natural systems.
理解生物多样性管理生态系统功能的能力对于当前自然群落面临的物种入侵和灭绝的压力至关重要。鱼类群落的变化可能是食物网动态的主要决定因素，即使物种组成或丰富度发生微小变化，也可能对生态系统产生重大影响。此外，将小规模生物多样性-生态系统功能实验的结果推断到具有现实环境复杂性的自然系统中存在很大的信息差距。因此，我们在中观和池塘中测试了生物多样性影响鱼类生产力的关键机制（资源互补和选择效应）。通过在每个丰富度水平内复制物种丰富度和物种组成来创建鱼类多样性处理。在中观系统中，丰富度的增加对鱼类生物量有积极影响，表现出过度生长模式，表明物种混合物比任何单个物种更具生产力。加性分区证实了由互补效应驱动的生物多样性的净正效应。当物种更相似时，物种多样性对生产力的影响较小。因此，中观系统中驱动鱼类生产的主要机制是资源互补。在池塘中，驱动鱼类生产的机制随着时间的推移而变化。关键机制最初是资源互补，直到生产受到选择效应的影响。由于资源水平和异质性的差异导致的种内相互作用强度的变化可能导致中观和池塘实验之间的机制存在差异，以及池塘中时间的变化。了解鱼类多样性管理生态系统功能的机制，以及环境复杂性和资源水平如何改变这些关系，可以用于提高对自然系统的预测。
