Invertebrate Metacommunity Structure and Dynamics in an Andean Glacial Stream Network Facing Climate Change.
Invertebrate Metacommunity Structure and Dynamics in an Andean Glacial Stream Network Facing Climate Change.
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DOI：
10.1371/journal.pone.0136793
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Dangles O
中科院分区：
文献类型：
--
作者：
Cauvy-Fraunié S;Espinosa R;Andino P;Jacobsen D;Dangles O
在气候持续变化的背景下，了解冰川水系网络中水生物种空间分布的结构机制，对预测冰川融化时水生生物多样性的响应具有重要意义。在这项研究中，我们建议使用元群落理论作为一个概念框架，以更好地理解河网结构如何影响冰川流域水生群落的空间组织。在安第斯冰川流域（厄瓜多尔）的51个河流站点，我们对底栖大型无脊椎动物进行了采样，测量了物理化学和食物资源条件，并计算了所有站点之间的地理、海拔和冰川距离。利用部分冗余分析，我们划分了群落变化，以评估环境条件（如冰川、食物资源）与空间过程（如陆地、水道和下游定向扩散）在组织水生元群落中的相对强度。结果表明，环境变量和空间变量都能解释不同立地间的群落差异。在所有环境变量中，冰川影响分量最能解释群落的变化。基于地理距离和海拔距离的陆地空间变量对群落变化有显著影响。基于冰川距离的水道空间变量对群落变化具有独特的显著影响。在高山流域，冰川融水以多种方式影响大型无脊椎动物群落结构。事实上，以冰川影响为特征的恶劣环境条件不仅构成了主要的环境过滤器，而且限制了水生大型无脊椎动物的扩散。因此，冰川径流起到了水生传播屏障的作用，隔离了源头溪流中的物种，并阻止了不适应的物种在整个河流网络中定居。在冰川径流减少的情况下，我们预计环境过滤和扩散限制都会减少，导致冰川集水区水生动物的分类同质化，以及水源地下水和冰川补给河流中特定物种的灭绝，从而导致区域多样性的不可逆转的减少。
Under the ongoing climate change, understanding the mechanisms structuring the spatial distribution of aquatic species in glacial stream networks is of critical importance to predict the response of aquatic biodiversity in the face of glacier melting. In this study, we propose to use metacommunity theory as a conceptual framework to better understand how river network structure influences the spatial organization of aquatic communities in glacierized catchments. At 51 stream sites in an Andean glacierized catchment (Ecuador), we sampled benthic macroinvertebrates, measured physico-chemical and food resource conditions, and calculated geographical, altitudinal and glaciality distances among all sites. Using partial redundancy analysis, we partitioned community variation to evaluate the relative strength of environmental conditions (e.g., glaciality, food resource) vs. spatial processes (e.g., overland, watercourse, and downstream directional dispersal) in organizing the aquatic metacommunity. Results revealed that both environmental and spatial variables significantly explained community variation among sites. Among all environmental variables, the glacial influence component best explained community variation. Overland spatial variables based on geographical and altitudinal distances significantly affected community variation. Watercourse spatial variables based on glaciality distances had a unique significant effect on community variation. Within alpine catchment, glacial meltwater affects macroinvertebrate metacommunity structure in many ways. Indeed, the harsh environmental conditions characterizing glacial influence not only constitute the primary environmental filter but also, limit water-borne macroinvertebrate dispersal. Therefore, glacier runoff acts as an aquatic dispersal barrier, isolating species in headwater streams, and preventing non-adapted species to colonize throughout the entire stream network. Under a scenario of glacier runoff decrease, we expect a reduction in both environmental filtering and dispersal limitation, inducing a taxonomic homogenization of the aquatic fauna in glacierized catchments as well as the extinction of specialized species in headwater groundwater and glacier-fed streams, and consequently an irreversible reduction in regional diversity.