Relative effects of species composition and richness on ecosystem properties in ponds
Relative effects of species composition and richness on ecosystem properties in ponds
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DOI：
10.1890/03-0239
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发表时间：
2005-03-01
期刊：
影响因子：
4.8
通讯作者：
Downing, AL
中科院分区：
文献类型：
--
作者：
Downing, AL
生物多样性很复杂，可以通过多种方式描述和量化。探索生物多样性对生态系统功能的影响的研究通常集中在生物多样性的四个组成部分的影响上：物种丰富度和组成，以及功能群丰富度和组成。迄今为止，大多数研究都集中在单一营养级内的生物多样性影响。本研究的目的是通过水生中生态系统实验来比较整个池塘食物网生物多样性的这四个组成部分的相对影响，其中所有四种群落属性都是独立操纵的。功能类群根据营养类群进行定义，包括水生大型植物、附生食草动物和无脊椎动物捕食者。物种组成和物种丰富度在功能组内进行控制。生态系统响应变量包括受操纵的类群（大型植物、食草动物和捕食者）的最终生物量、生态系统速率（生产力和分解）和营养结构（浮游植物和附生生物生物量）。结果揭示了物种组成对生态系统响应变量的很大一部分的强烈影响。相比之下，物种丰富度、功能群丰富度和功能群组成改变了受操纵类群的生物量，但对其他生态系统变量没有额外影响。结果表明，当在食物网背景下考虑时，物种在生态系统中的作用通常是直接和间接影响的结果，而这些影响很难根据物种与特定功能组的关联来预测。如果生物多样性研究的目标是预测生态系统对生物多样性丧失的反应，那么整个食物网的组成和物种丧失的影响必须充分纳入生物多样性-生态系统功能研究。
Biological diversity is complex and can be described and quantified in various ways. Research exploring the consequences of biodiversity for ecosystem functioning has generally focused on the effects of four components of biodiversity: species richness and composition, and functional group richness and composition. Most of the research to date has focused on biodiversity effects within single trophic levels. The aim of this study was to compare the relative effects of these four components of biological diversity across pond food webs using aquatic mesocosm experiments in which all four community properties were manipulated independently. Functional groups were defined in terms of trophic groups, and consisted of aquatic macrophytes, periphyton grazers, and invertebrate predators. Species composition and species richness were manipulated within functional groups. Ecosystem response variables included the final biomass of the manipulated taxa (macrophytes, grazers, and predators), ecosystem rates (productivity and decomposition), and trophic structure (phytoplankton and periphyton biomass). Results reveal strong effects of species composition on a significant proportion of ecosystem response variables. In contrast, species richness, functional group richness, and functional group composition altered the biomass of the manipulated taxa, but had no additional effects on other ecosystem variables. Results suggest that the roles of species in ecosystems, when considered in a food web context, are often the result of both direct and indirect effects that are difficult to predict based on the association of a species to a particular functional group. If a goal of biodiversity research is to predict the response of ecosystems to biodiversity loss, effects of composition and species losses across food webs must be fully integrated into biodiversity-ecosystem functioning research.