Community and Conservation Ecology Group, Centre for Ecological and Evolutionary Studies (CEES), University of Groningen, P.O. Box 11103, 9700CC, Groningen, The Netherlands.
Ecology. 2012 Nov;93(11):2353-64. doi: 10.1890/11-1102.1.
Current theories about vegetation succession and food web assembly are poorly compatible, as food webs are generally viewed to be static, and succession is usually analyzed without the inclusion of higher trophic levels. In this study we present results from a detailed analysis of ecosystem assembly rules over a chronosequence of 100 years of salt marsh succession. First, using 13 yearlong observations on vegetation and soil parameters in different successional stages, we show that the space-for-time substitution is valid for this chronosequence. We then quantify biomass changes for all dominant invertebrate and vertebrate species across all main trophic groups of plants and animals. All invertebrate and vertebrate species were assigned to a trophic group according to feeding preference, and changes in trophic group abundance were quantified for seven different successional stages of the ecosystem. We found changes from a marine-fueled, decomposer-based (brown) food web in early stages to a more terrestrial, plant-based, herbivore-driven (green) food web in intermediate succession stages, and finally to a decomposer-based, terrestrial-driven food web in the latest stages. These changes were accompanied not only by an increase in live plant biomass and a leveling toward late succession but also by a constant increase in the amount of dead plant biomass over succession. Our results show that the structure and dynamics of salt marsh food webs cannot be understood except in light of vegetation succession, and vice versa.
当前关于植被演替和食物网组装的理论不太兼容，因为食物网通常被认为是静态的，而演替通常是在不包括更高营养层次的情况下进行分析的。在这项研究中，我们展示了对盐沼演替 100 年时间序列进行详细分析的结果。首先，通过对不同演替阶段的植被和土壤参数进行 13 年的长期观测，我们表明时间替代空间的替代是有效的。然后，我们量化了所有主要动植物营养组中所有优势无脊椎动物和脊椎动物物种的生物量变化。根据摄食偏好，所有无脊椎动物和脊椎动物物种都被分配到一个营养组中，并且对生态系统的七个不同演替阶段的七个不同营养组的丰度变化进行了量化。我们发现，从早期的以海洋为燃料、以分解者为基础的（棕色）食物网，到中间演替阶段更具陆地性、以植物为基础、以食草动物为驱动的（绿色）食物网，最后到以分解者为基础、以陆地为驱动的食物网。这些变化不仅伴随着活体植物生物量的增加和演替后期的水平化，而且伴随着死体植物生物量在演替过程中的持续增加。我们的结果表明，除非考虑到植被演替，否则无法理解盐沼食物网的结构和动态，反之亦然。
