食物链长度理论研究进展

Food chain length theory: a review

食物链长度(Food chain length,FCL)是生态系统中最重要的特点之一,它通过改变生物间的营养关系,影响着生物多样性,群落的结构以及稳定性;它是反映食物网物质转换与能量传递的综合指数,食物链及其动态特征是生态学许多重要理论的基础,食物链长度理论的研究进展,推动了人们对水域生态系统中生物和非生物相互作用的理解。回顾了食物链长度的3种度量方法及其详细的计算方法,在此基础上简述了各方法的特点。综述了食物链长度的决定因素的4种假说(资源可利用性假说、生产力空间假说、生态系统大小假说、动态稳定性假说)及其交互作用,重点总结了湖泊食物链长度的空间格局与决定因素的研究进展。最后,食物链长度研究展望,包括食物链长度决定因子研究存在的问题及发展方向的总结,以及在在水域生态学中的应用的研究进展,例如食物链长度在指示污染物的生物富集中的研究进展、食物链食物链长度在指导生物操作、以及在食物链长度在对气候变化响应方面的研究进展等等。

Food-chain length （FCL）is a significant ecosystem index. It can influence the biodiversity, pattern and stability of the biological community by altering trophic interactions within it. Food chains are caricatures of communities that trace linear either energy or the effect strength pathways from primary producers to apex predators embedded within more complex food webs. And Food chains are also the basis for many important concepts in ecology. In the last few years, innovative process-level studies have been expanding rapidly. Food chain length theory to ecological research is becoming increasing common and to significant new levels of understanding of ecological processes and elemental fluxes through biological and abiotic systems. Food webs represent a road map of feeding relationships in ecological community and can be defined in at least three different ways. we defined three commonly used operational definitions of FCL and reviewed the method measuring of the three kind of food chain length including the characteristics. Conventional wisdom holds that either resource availability or disturbance limit food-chain length; however, new researches and new techniques challenge the conventional wisdom and broaden the discourse on food-chain length. We reviewed four hypotheses on the determinant of FCL including resource availability hypothesis, productivity space hypothesis, ecosystem size hypothesis and dynamic stability hypothesis and the relation among these hypotheses. In this article, we discussed the evidence for controls on FCL in freshwater ecosystems. Recent results suggest that resource availability limits food-chain length only in system that the resource availability is very low. Different defines of ecosystem size can cause different result about the ecosystem size hypothesis. And ecosystem size controls food chain length only at local region, while at the global pattern the relationship between ecosystem size and food chain length is very weak. The independence and interaction between four hypotheses indicate the complexity and diversity of food chain length controls in ecosystems. Food-web structure is closely relevant to the functioning of ecosystems. We further synthesized the spatial pattern and determinants of FCL in lake ecosytems as a empirical complementation to the theoretical study. So the factors that control or alter food webs are more and more considered in managing, conserving, and restoring aquatic ecosystems. At the last part of this study, we reviewed the problems in the recent research on this issue and looked into the meaningful research in the future including movement of contaminants, biomanipulation, and climate change, several important areas of use of basic food-web research in applied issues.