Climate change poised to threaten hydrologic connectivity and endemic fishes in dryland streams
Climate change poised to threaten hydrologic connectivity and endemic fishes in dryland streams
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DOI：
10.1073/pnas.1320890111
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发表时间：
2014-09-23
影响因子：
11.1
通讯作者：
Pelland, Noel A.
中科院分区：
文献类型：
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作者：
Jaeger, Kristin L.;Olden, Julian D.;Pelland, Noel A.
保护淡水生态系统的水文连通性对于确保物种的持久性、生态系统的完整性和人类福祉至关重要。与气候变化相关的更频繁和更严重的干旱将显著改变美国西南部旱地河流的水流阻力模式和水文连通性，对高度濒危鱼类产生有害影响。通过将局部尺度水文模型与景观生态学中的新兴方法相结合，我们量化了美国Verde河流域预测气候变化下栖息地大小，间距和连通性的精细分辨率，流域尺度变化。模型模拟预测，到本世纪中叶，年度零流量日频率将增加27%，对连续性（离散位置的时间连续性）和连通性（网络内的空间连续性）产生不同的季节性影响。预计整个网络中蒸汽干燥事件的频率将增加17%，这些事件的持续时间也会相应增加。河流网络的流动部分将在春季和初夏减少8%至20%，并因更频繁和更长的干燥河道片段而变得越来越孤立，从而限制了本地鱼类进入产卵栖息地和季节性避难所的机会。模型预测表明，世纪中期和世纪晚期的气候将减少6-9%，在一年的过程中，高达12-18%，在春季产卵月份的本地鱼类的网络水文连通性。我们的工作量化了气候引起的河流干燥和大型河流网络连通性的变化，并展示了它们对全球特有鱼类动物群持续存在的影响。
Protecting hydrologic connectivity of freshwater ecosystems is fundamental to ensuring species persistence, ecosystem integrity, and human well-being. More frequent and severe droughts associated with climate change are poised to significantly alter flow intermittence patterns and hydrologic connectivity in dryland streams of the American Southwest, with deleterious effects on highly endangered fishes. By integrating local-scale hydrologic modeling with emerging approaches in landscape ecology, we quantify fine-resolution, watershed-scale changes in habitat size, spacing, and connectance under forecasted climate change in the Verde River Basin, United States. Model simulations project annual zero-flow day frequency to increase by 27% by midcentury, with differential seasonal consequences on continuity (temporal continuity at discrete locations) and connectivity (spatial continuity within the network). A 17% increase in the frequency of stream drying events is expected throughout the network with associated increases in the duration of these events. Flowing portions of the river network will diminish between 8% and 20% in spring and early summer and become increasingly isolated by more frequent and longer stretches of dry channel fragments, thus limiting the opportunity for native fishes to access spawning habitats and seasonally available refuges. Model predictions suggest that midcentury and late century climate will reduce network-wide hydrologic connectivity for native fishes by 6-9% over the course of a year and up to 12-18% during spring spawning months. Our work quantifies climate-induced shifts in stream drying and connectivity across a large river network and demonstrates their implications for the persistence of a globally endemic fish fauna.