Temporal variability in the spatial and environmental determinants of functional metacommunity organization - stream fish in a human-modified landscape
Temporal variability in the spatial and environmental determinants of functional metacommunity organization - stream fish in a human-modified landscape
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DOI：
10.1111/j.1365-2427.2012.02842.x
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发表时间：
2012-09-01
影响因子：
2.7
通讯作者：
Biro, P.
中科院分区：
文献类型：
--
作者：
Eros, T.;Saly, P.;Biro, P.
1. 在元群落生态学的背景下，量化环境过滤与区域空间结构的相对重要性已成为一个深入研究的领域。然而，大多数研究使用单快照调查的分类数据集来评估环境和空间过程的作用。2. 在这里，我们研究了人类改造景观中河流鱼类功能元群落组织模式的时间变化和可能的过程。具体地说，我们(i)研究了匈牙利Balaton湖集水区40个可水溪流地点在3年研究期间鱼类组合功能组成的一般变化，（ii）量化了空间和环境因素作为元群落结构决定因素的相对重要性，（iii）研究了空间和环境过程对该元群落的相对作用的时间变异性。3. 部分三元分析表明，从以机会主义生活史策略为主导的无脊椎消耗物种到具有多种功能属性的组合，可以沿着功能梯度有效地排序。分析还表明，在采样期间，功能鱼类组合结构在不同的地点之间是中等稳定的。4. 尽管有一定的稳定性，但使用冗余分析（RDA）的方差划分显示，环境和空间因素对这一格局的贡献具有相当大的时间变异性。分析还表明，总体而言，环境变量比空间变量对群落元结构的影响更大。其中，自然环境变量（如海拔高度、流速）被证明比与人类有关的影响（如池塘面积、场地以上居住面积百分比、营养物富集程度）更有影响力，即使在海拔高度和河流大小变化相对较小的景观中也是如此。5. 池塘面积是最重要的人类压力变量，与具有不同功能属性的外来物种丰度呈正相关。环境和空间因素相对重要性的时间变化可能是由洪水事件期间鱼塘向河流系统释放的非本地鱼类形成的。6. 综上所述，空间过程和环境控制共同塑造了人类改造景观中河流鱼类群落的功能元群落组织，但其重要性在时间上存在差异。因此，我们认为，元群落研究应更好地考虑决定景观级群落组织动态的生态机制（如扩散限制、物种分选）的时间变异性。
1. Quantifying the relative importance of environmental filtering versus regional spatial structuring has become an intensively studied area in the context of metacommunity ecology. However, most studies have evaluated the role of environmental and spatial processes using taxonomic data sets of single snapshot surveys. 2. Here, we examined temporal changes in patterns and possible processes behind the functional metacommunity organization of stream fishes in a human-modified landscape. Specifically, we (i) studied general changes in the functional composition of fish assemblages among 40 wadeable stream sites during a 3-year study period in the catchment area of Lake Balaton, Hungary, (ii) quantified the relative importance of spatial and environmental factors as determinants of metacommunity structure and (iii) examined temporal variability in the relative role of spatial and environmental processes for this metacommunity. 3. Partial triadic analysis showed that assemblages could be effectively ordered along a functional gradient from invertebrate consuming species dominated by the opportunistic life-history strategy, to assemblages with a diverse array of functional attributes. The analysis also revealed that functional fish assemblage structure was moderately stable among the sites between the sampling periods. 4. Despite moderate stability, variance partitioning using redundancy analyses (RDA) showed considerable temporal variability in the contribution of environmental and spatial factors to this pattern. The analyses also showed that environmental variables were, in general, more important than spatial ones in determining metacommunity structure. Of these, natural environmental variables (e.g. altitude, velocity) proved to be more influential than human-related effects (e.g. pond area, % inhabited area above the site, nutrient enrichment), even in this landscape with relatively low variation in altitude and stream size. 5. Pond area was, however, the most important human stressor variable that was positively associated with the abundance of non-native species with diverse functional attributes. The temporal variability in the relative importance of environmental and spatial factors was probably shaped by the release of non-native fish from fish ponds to the stream system during flood events. 6. To conclude, both spatial processes and environmental control shape the functional metacommunity organization of stream fish assemblages in human-modified landscapes, but their importance can vary in time. We argue, therefore, that metacommunity studies should better consider temporal variability in the ecological mechanisms (e.g. dispersal limitation, species sorting) that determine the dynamics of landscape-level community organization.