Biodiversity under threat in glacier-fed river systems
Biodiversity under threat in glacier-fed river systems
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DOI：
10.1038/nclimate1435
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发表时间：
2012-05-01
影响因子：
30.7
通讯作者：
Dangles, Olivier
中科院分区：
文献类型：
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作者：
Jacobsen, Dean;Milner, Alexander M.;Dangles, Olivier
淡水生物多样性正在全球范围内受到威胁(1)，气候变化是一个重要因素(2，3)。气候变化的一个影响是冰川迅速萎缩(4)，导致许多冰川集水区的冰川融水对河流流量的贡献减少(5，6)。这些变化可能会影响专门的冰川补给河流群落的生物多样性(7)。也许令人惊讶的是，尽管淡水生物多样性是一项主要的保护优先事项(3)，但迄今为止，冰川萎缩和消失对河流生物多样性的影响还没有得到很好的量化。在这里，我们将重点放在大型无脊椎动物(主要是昆虫幼虫)上，并证明局部(阿尔法)和区域(伽马)多样性以及河段之间的周转(贝塔多样性)将随着冰川的缩小而持续减少。我们表明，在一个流域的冰川完全消失后，预计将失去11-38%的区域物种池，包括特有物种，稳定的萎缩可能会减少冰川河系的分类群周转，并减少下游河段的当地丰富度，那里的集水区冰川覆盖率低于5-30%。我们的分析不仅证明了当地生物多样性热点的脆弱性，而且还表明，灭绝可能会远远超过冰川补给的河流中为数不多的已知特有物种。
Freshwater biodiversity is under threat across the globe(1), with climate change being a significant contributor(2,3). One impact of climate change is the rapid shrinking of glaciers(4), resulting in a reduction in glacial meltwater contribution to river flow in many glacierized catchments(5,6). These changes potentially affect the biodiversity of specialized glacier-fed river communities(7). Perhaps surprisingly then, although freshwater biodiversity is a major conservation priority(3), the effects of shrinkage and disappearance of glaciers on river biodiversity have hitherto been poorly quantified. Here we focus on macroinvertebrates (mainly insect larvae) and demonstrate that local (alpha) and regional (gamma) diversity, as well as turnover among reaches (beta-diversity), will be consistently reduced by the shrinkage of glaciers. We show that 11-38% of the regional species pools, including endemics, can be expected to be lost following complete disappearance of glaciers in a catchment, and steady shrinkage is likely to reduce taxon turnover in proglacial river systems and local richness at downstream reaches where glacial cover in the catchment is less than 5-30%. Our analysis demonstrates not only the vulnerability of local biodiversity hotspots but also that extinction will probably greatly exceed the few known endemic species in glacier-fed rivers.