Habitat age influences metacommunity assembly and species richness in successional pond ecosystems
Habitat age influences metacommunity assembly and species richness in successional pond ecosystems
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DOI：
10.1002/ecs2.1871
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发表时间：
2017-06
期刊：
影响因子：
2.7
通讯作者：
Christopher O. Sferra;J. Hart;Jennifer G. Howeth
中科院分区：
文献类型：
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作者：
Christopher O. Sferra;J. Hart;Jennifer G. Howeth
元群落理论表明，物种多样性可能取决于群落聚集开始后的时间，即生境年龄，因为区域和局部结构过程对演替的相对影响发生变化。然而，很少有研究评估生境年龄在构建元群落次生演替的大的、精细分辨率的年龄梯度上的物种丰富度(多样性-年龄)的作用。为了验证群落多样性-年龄关系的理论预测，对河狸池塘浮游动物物种丰富度和组成进行了评估。池塘的年龄是用树状年代学和历史摄影确定的，年龄从23岁到69岁不等。在演替生态系统中，浮游动物物种丰富度与生境年龄呈单峰关系。这种驼峰形状与群落聚集时间的关系与集合群落物种丰富度的理论预测是一致的，并可以用局部相对于区域的结构过程相对于演替轨迹日益重要的方式来解释。观察到的多样性和组成模式响应了年龄对当地池塘环境的影响；较老的池塘更深，具有较低的有色溶解有机碳，并且是永久性的。此外，对该地区的群落组成有微弱但显著的分散作用。演替阶段缺乏一致的群落组成反映了池塘养分可获得性和物种扩散的差异。结果表明，区域和地方年龄相关的结构机制在每个演替阶段作用于不同的地方殖民者群体和环境，产生的群落在其丰富度反应中反映了演替。因此，次生演替应该被认为是元群落中物种多样性在时间和空间尺度上的一个有影响力的驱动因素。
Metacommunity theory suggests that species diversity can depend upon the time since initiation of community assembly, or habitat age, as the relative influence of regional and local structuring processes changes over succession. There are, however, few studies that evaluate the role of habitat age in structuring species richness (diversity–age) over large, fine-resolution age gradients of secondary succession in metacommunities. To test theoretical predictions of diversity–age relationships in metacommunities, zooplankton species richness and composition along a successional chronosequence in beaver (Castor canadensis) ponds were evaluated. The age of ponds was determined using dendrochronology and historical photography, and ranged from 23 to 69 yr of age. A unimodal relationship between zooplankton species richness and habitat age was observed among the successional ecosystems. This hump-shaped relationship with community assembly time is congruent with theoretical predictions of species richness in metacommunities and can be explained by the increasing importance of local, relative to regional, structuring processes over successional trajectories. Observed patterns of diversity and composition responded to age-mediated effects on the local pond environment; older ponds were deeper, had lower colored dissolved organic carbon, and were permanent. Additionally, there were weak but significant dispersal effects on community composition across the region. The lack of consistent community composition by successional stage reflected variation from differences in pond nutrient availability and species dispersal. The results indicate that regional and local age-dependent structuring mechanisms operate at each successional stage on different local colonist pools and environments yielding communities that reflect succession in their richness response. Consequently, secondary succession should be considered an influential driver of species diversity across temporal and spatial scales in metacommunities.