Data from: Context dependent colonization dynamics: regional reward contagion drives local compression in aquatic beetles

1. Habitat selection by colonizing organisms is an important factor in determining species abundance and community dynamics at multiple spatial scales. Many organisms select habitat patches based on intrinsic patch quality, but patches exist in complex landscapes linked by dispersal and colonization, forming metapopulations and metacommunities. Perceived patch quality can be influenced by neighboring patches through spatial contagion, wherein perceived quality of one patch can extend beyond its borders and either increase or decrease the colonization of neighboring patches and localities. These spatially-explicit colonization dynamics can result in habitat compression, wherein more colonists occupy a patch or locality than in the absence of spatial context dependence.
2. Previous work on contagion/compression focused primarily on the role of predators in driving colonization patterns. Our goal was to determine whether resource abundance can drive multiscale colonization dynamics of aquatic beetles through the processes of contagion and compression in naturally-colonized experimental pools.
3. We established two levels (high/low quality) of within-patch resource abundances (leaf litter) using an experimental landscape of mesocosms, and assayed colonization by 35 species of aquatic beetles. Patches were arranged in localities (sets of two patches), which consisted of a combination of two patch-level resource levels in a 2 × 2 factorial design, allowing us to assay colonization at both locality and patch levels.
4. We demonstrate that patterns of species abundance and richness of colonizing aquatic beetles are determined by patch quality and context-dependent processes at multiple spatial scales. Localities that consisted of at least one high quality patch were colonized at equivalent rates that were higher than localities containing only low quality patches, displaying regional reward contagion. In localities that consisted of one high and one low quality patch, reward contagion produced by higher leaf litter levels resulted in greater abundance of beetles in such localities, which then compressed into the highest quality patches.
5. Our results provide further support for the critical roles of habitat selection and spatial context, particularly the quality of neighboring habitat patches, in generating patterns of species abundances and community structure across landscapes.

1. 定居生物的生境选择是决定多空间尺度下物种丰度与群落动态的核心调控因子。诸多生物会依据生境斑块的固有质量选择栖息斑块，但斑块存在于由扩散与定居过程相互连接的复杂景观中，进而形成集合种群（metapopulation）与集合群落（metacommunity）。斑块的感知质量可通过空间传染（spatial contagion）受邻域斑块的影响：某一斑块的感知质量可超越其边界，提升或降低邻域斑块与样区的定居率。这类具有空间显式性的定居动态可引发生境压缩效应，即相较于无空间背景依赖的情况，更多定居个体占据单个斑块或样区。
2. 过往关于传染/压缩效应的研究主要聚焦于捕食者对定居模式的驱动作用。本研究旨在探明，在自然定居的实验水池中，资源丰度是否可通过传染与压缩过程调控水生甲虫的多尺度定居动态。
3. 我们利用中宇宙（mesocosm）实验景观设置了斑块内资源丰度（落叶凋落物）的两个梯度（高质量/低质量），并对35种水生甲虫的定居情况进行了检测。斑块以样区（每组包含两个斑块）为单位排布，采用2×2析因设计组合两种斑块级资源水平，从而可同时在样区与斑块两个尺度上检测定居过程。
4. 本研究证实，定居水生甲虫的物种丰度与丰富度格局由斑块质量与多空间尺度下的背景依赖过程共同决定。至少包含一个高质量斑块的样区，其定居率显著高于仅含低质量斑块的样区，呈现出区域资源奖励传染效应。在由一个高质量斑块与一个低质量斑块组成的样区中，高凋落物水平引发的资源奖励传染效应使得该样区内甲虫丰度更高，随后这些甲虫会向最高质量的斑块发生生境压缩。
5. 本研究结果进一步证实，生境选择与空间背景——尤其是邻域生境斑块的质量——在塑造跨景观的物种丰度与群落结构格局中发挥着关键作用。