Gravel Dominique, Albouy Camille, Thuiller Wilfried
Département de biologie, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Quebec, Canada J1K 2R1 Québec Centre for Biodiversity Science, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland
Landscape Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland Swiss Federal Research Institute WSL, Birmensdorf 8903, Switzerland.
Philos Trans R Soc Lond B Biol Sci. 2016 May 19;371(1694). doi: 10.1098/rstb.2015.0268.
There is a growing interest in using trait-based approaches to characterize the functional structure of animal communities. Quantitative methods have been derived mostly for plant ecology, but it is now common to characterize the functional composition of various systems such as soils, coral reefs, pelagic food webs or terrestrial vertebrate communities. With the ever-increasing availability of distribution and trait data, a quantitative method to represent the different roles of animals in a community promise to find generalities that will facilitate cross-system comparisons. There is, however, currently no theory relating the functional composition of food webs to their dynamics and properties. The intuitive interpretation that more functional diversity leads to higher resource exploitation and better ecosystem functioning was brought from plant ecology and does not apply readily to food webs. Here we appraise whether there are interpretable metrics to describe the functional composition of food webs that could foster a better understanding of their structure and functioning. We first distinguish the various roles that traits have on food web topology, resource extraction (bottom-up effects), trophic regulation (top-down effects), and the ability to keep energy and materials within the community. We then discuss positive effects of functional trait diversity on food webs, such as niche construction and bottom-up effects. We follow with a discussion on the negative effects of functional diversity, such as enhanced competition (both exploitation and apparent) and top-down control. Our review reveals that most of our current understanding of the impact of functional trait diversity on food web properties and functioning comes from an over-simplistic representation of network structure with well-defined levels. We, therefore, conclude with propositions for new research avenues for both theoreticians and empiricists.
使用基于性状的方法来描述动物群落的功能结构正受到越来越多的关注。定量方法大多源自植物生态学，但现在用其描述各种系统的功能组成已很常见，如土壤、珊瑚礁、远洋食物网或陆地脊椎动物群落。随着分布和性状数据的不断增加，一种用于表示动物在群落中不同作用的定量方法有望找到能促进跨系统比较的一般性规律。然而，目前尚无将食物网的功能组成与其动态和特性相关联的理论。植物生态学中关于功能多样性越高导致资源利用效率越高和生态系统功能越好的直观解释，并不容易适用于食物网。在此，我们评估是否存在可解释的指标来描述食物网的功能组成，从而能更好地理解其结构和功能。我们首先区分性状在食物网拓扑结构、资源获取（自下而上的效应）、营养调节（自上而下的效应）以及在群落中保持能量和物质的能力等方面所起的各种作用。然后我们讨论功能性状多样性对食物网的积极影响，如生态位构建和自下而上的效应。接着我们讨论功能多样性的负面影响，如增强的竞争（包括利用性竞争和似然竞争）以及自上而下的控制。我们的综述表明，目前我们对功能性状多样性对食物网特性和功能影响的大多数理解，都来自对具有明确层级的网络结构的过度简化表述。因此，我们最后为理论家和实证研究人员提出了新的研究途径建议。
