Data_Sheet_1_Effects of abiotic heterogeneity on species densities and interaction strengths lead to different spatial biodiversity patterns.pdf

During community assembly, abiotic factors can influence species at multiple stages during their life history, for example by affecting early settlement or establishment probabilities and thus initial densities (route 1: abiotic effects on density), or later by affecting the strength of biotic interactions during subsequent life stages (route 2: abiotic effects on interaction strengths). Since real abiotic landscapes are multivariate and complex, how these two distinct routes of abiotic influence affect community patterns has not been quantified. Using an individual-based spatially explicit simulation model, we compared scenarios where abiotic conditions shaped initial densities, interaction strengths, or both, of plant species with unique abiotic niches. We then partitioned the effect of the abiotic landscape on community patterns into components arising from variable density, variable interaction strengths, and their interaction. Even when plants responded to identical landscapes, variable density and variable interaction strengths led to different community patterns, and their combined effects were non-additive. Variable density promoted more spatial structure, while variable interaction strengths promoted higher local species richness. We highlight important implications these findings have in applied plant community ecology.

在群落构建过程中，非生物因素能够在物种生命史的多个阶段对其产生影响，例如通过影响早期定居或建立概率，从而影响初始密度（途径1：非生物因素对密度的影响），或者后来通过影响后续生命阶段中生物相互作用的强度（途径2：非生物因素对相互作用强度的影响）。鉴于真实非生物景观的多维性和复杂性，这两种不同的非生物影响途径如何影响群落模式尚未得到量化。利用基于个体的空间显式模拟模型，我们比较了非生物条件塑造植物物种独特非生物生态位初始密度、相互作用强度或两者兼有的情景。随后，我们将非生物景观对群落模式的影响分解为源于密度变化、相互作用强度变化及其相互作用的组成部分。即使植物对相同的景观做出响应，密度变化和相互作用强度的变化也会导致不同的群落模式，其综合效应并非简单相加。密度变化促进了更多的空间结构，而相互作用强度的变化则促进了更高的局部物种丰富度。我们强调了这些发现对应用植物群落生态学的重要启示。