Dispersal rates affect species composition in metacommunities of Sarracenia purpurea inquilines
Dispersal rates affect species composition in metacommunities of Sarracenia purpurea inquilines
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DOI：
10.1086/376585
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发表时间：
2003-08-01
影响因子：
2.9
通讯作者：
Miller, TE
中科院分区：
文献类型：
--
作者：
Kneitel, JM;Miller, TE
在局域群落之间的扩散对本地和区域尺度上的物种组成和多样性具有多种影响。局域条件（例如，资源和捕食者密度）可以产生独立影响，并且与扩散相互作用，从而改变这些模式。基于集合群落模型，我们预测局域多样性与扩散频率呈单峰关系。我们对紫瓶子草（Sarracenia purpurea）充满水的叶片中的群落之间的扩散频率、资源水平以及捕食者（蚊子幼虫）的存在进行了操控。测量了中营养级物种（原生动物和轮虫）的多样性和丰度。扩散频率的增加显著提高了区域物种丰富度和原生动物的丰度，同时降低了局域群落之间的差异。在局域群落尺度上，扩散频率与捕食作用相互影响，产生了与模型一致的多样性模式。当没有捕食者时，我们发现扩散频率和多样性之间呈单峰关系，而当有捕食者时，则呈现出一种平缓的关系。中等扩散频率通过抵消灭绝率，使一些物种在寄生物群落中得以维持。局域群落组成以及群落之间的连通程度对于理解本地和区域尺度上的物种多样性模式都很重要。
Dispersal among local communities can have a variety of effects on species composition and diversity at local and regional scales. Local conditions (e. g., resource and predator densities) can have independent effects, as well as interact with dispersal, to alter these patterns. Based on metacommunity models, we predicted that local diversity would show a unimodal relationship with dispersal frequency. We manipulated dispersal frequencies, resource levels, and the presence of predators (mosquito larvae) among communities found in the water-filled leaves of the pitcher plant Sarracenia purpurea. Diversity and abundance of species of the middle trophic level, protozoa and rotifers, were measured. Increased dispersal frequencies significantly increased regional species richness and protozoan abundance while decreasing the variance among local communities. Dispersal frequency interacted with predation at the local community scale to produce patterns of diversity consistent with the model. When predators were absent, we found a unimodal relationship between dispersal frequency and diversity, and when predators were present, there was a flat relationship. Intermediate dispersal frequencies maintained some species in the inquiline communities by offsetting extinction rates. Local community composition and the degree of connectivity between communities are both important for understanding species diversity patterns at local and regional scales.