《Wetlands》杂志刊登“河漫滩湿地河流连通性对沉水植物及浮水植物的影响”

作者：Rebecca C. Rooney, Chris Carli, Suzanne E. Bayley

刊物：《Wetlands》,2013年8月

关键词：孤立；洪水响应；群落结构；结构方程模型；哥伦比亚河

摘要：到目前为止，对哥伦比亚河上游河漫滩湿地的沉水植物和浮水植物群落的研究较少。为探索洪水对植物的影响机制，我们调查了植物种群对洪水的响应，调查对象在44个洪泛平原和河流间沿着不同的连通梯度分。我们还调查了连通性对水和泥沙的影响以及连通性对植被的影响。我们用群聚和指示种分析来刻画集合体的特征，采用了非度量测度法并且测试了一个模型，这个模型定义了组成成分、沉积物、水质和河流连通性之间的关系。我们发现了四种组合，每一种都和不同的水和泥沙状况相关，并处于不同的连通程度。该模型很好的拟合了数据。据此我们得出结论：在具有高度连通性的河漫滩湿地中，洪水的直接影响取代了水和沉积物质量对植被组合结构的影响。然而在洪水不很强烈的地方，这些环境变量恢复了其重要作用。

River Connectivity Affects Submerged and Floating Aquatic Vegetation in Floodplain Wetlands

Authors: Ming-Chih Chiu,Chao-Hsien Yeh,Mei-Hwa Kuo

Journal:Wetland, August 2013

Key words:Isolation;Flood response guilds;Community structure;Structural equation modeling;Columbia river

Abstract: The submerged and floating plant communities in floodplain wetlands of the Upper Columbia River have never been described. To explore mechanisms behind the influence of the annual flood pulse on vegetation, we investigated how species group into flood response guilds whose distributions vary along a connectivity gradient between 44 floodplain wetlands and the river, how connectivity influences water and sediment, and to what degree the effect of connectivity on vegetation is mediated by its effects on these environmental variables. We characterised assemblages with cluster and indicator species analysis, as well as non-metric scaling ordination and tested a structural equation model, which defined the relationship between assemblage composition, sediment and water quality, and connectivity to the river. We found four assemblages, each associated with different water and sediment conditions, and positioned at differing degrees of connectivity. The model provided a good fit to the data. We conclude that in highly connected floodplain wetlands the direct effect of flooding supersedes the influence of water and sediment quality in structuring vegetation assemblages. Yet where flooding is less intense, these environmental variables resume their structuring role.

原文链接：http://link.springer.com/article/10.1007/s13157-013-0471-4