Limiting similarity and functional diversity along environmental gradients
Limiting similarity and functional diversity along environmental gradients
复制标题
DOI：
10.1111/j.1461-0248.2004.00720.x
复制
发表时间：
2005-03
期刊：
影响因子：
8.8
通讯作者：
D. Schwilk;D. Ackerly
中科院分区：
文献类型：
--
作者：
D. Schwilk;D. Ackerly
群落模型的最新发展强调了将随机过程（例如生态漂移）纳入生态位结构群落组装模型的重要性。我们构建了一个有限的、空间明确的彩票模型来模拟具有环境条件梯度的一维景观中的物种分布。我们的框架将生态漂移的潜力与异质环境中环境介导的空间竞争结合起来。我们研究了生态位宽度、扩散距离、群落规模（个体总数）和环境梯度宽度对物种水平和功能性状多样性（即生态位最佳值的差异）的影响。该模型得出了三个新颖的结果：（1）由于竞争效应和有限种群规模的相互作用，较小群落中相邻物种之间的生态位差异（例如限制相似性）增加； （2）来自区域物种库的移民、随机性和生态位组装产生异质环境下物种停留时间（短暂和常驻）的双峰分布； (3) 环境异质性的大小对多样性具有 U 形效应，因为常驻物种与暂住物种的物种丰富度发生了变化。这些预测说明了随机（尽管不一定是中性）过程在社区组装中的潜在重要性。
Recent developments in community models emphasize the importance of incorporating stochastic processes (e.g. ecological drift) in models of niche-structured community assembly. We constructed a finite, spatially explicit, lottery model to simulate the distribution of species in a one-dimensional landscape with an underlying gradient in environmental conditions. Our framework combines the potential for ecological drift with environmentally-mediated competition for space in a heterogeneous environment. We examined the influence of niche breadth, dispersal distances, community size (total number of individuals) and the breadth of the environmental gradient on levels of species and functional trait diversity (i.e. differences in niche optima). Three novel results emerge from this model: (1) niche differences between adjacent species (e.g. limiting similarity) increase in smaller communities, because of the interaction of competitive effects and finite population sizes; (2) immigration from a regional species pool, stochasticity and niche-assembly generate a bimodal distribution of species residence times (transient and resident) under a heterogeneous environment; and (3) the magnitude of environmental heterogeneity has a U-shaped effect on diversity, because of shifts in species richness of resident vs. transient species. These predictions illustrate the potential importance of stochastic (although not necessarily neutral) processes in community assembly.