Current distributions and future climate‐driven changes in diatoms, insects and fish in U.S. streams
Current distributions and future climate‐driven changes in diatoms, insects and fish in U.S. streams
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DOI：
10.1111/geb.13193
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发表时间：
2020
影响因子：
6.4
通讯作者：
Katrina L. Pound;Chad A. Larson;S. Passy
中科院分区：
文献类型：
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作者：
Katrina L. Pound;Chad A. Larson;S. Passy
地球上的生物多样性受到气候变化的威胁。尽管淡水生境易受人类影响，但大多数气候变化预测都侧重于陆地系统。在这里，我们研究了目前的分布和生物多样性的流类群可能会改变缓解，稳定和增加温室气体emissions. LocationConteminous USA.Time periodPresent day to 2070.Major taxa studiedStream硅藻，昆虫和fish.MethodsWe开发了336个淡水类群从1,227个不同的流地方使用水化学，流域和气候变量的物种分布模型。仅基于气候的模型被用来预测在代表性浓度途径（RCP）范围从2.6到8.5 W/m2.ResultsIn所有三个生物群的分布和生物多样性的变化，冷水与温水类群，气候成为最强的预测物种分布，提供可比的解释力水化学和流域变量相结合。基于RCP的预测表明，暖水类群的广泛扩张，超过了冷水类群的下降。因此，总体物种丰富度将增加，但随着气候变化的严重性，β多样性将急剧下降。对单个分类群和功能团的仔细研究表明，脆弱的冷水分类群包括：（a）形成生物膜基础和主体的硅藻团;（B）环境敏感的昆虫，未受影响的溪流的特征;以及（c）生态和娱乐重要的鲑鱼，预计在来源栖息地急剧减少。暖水鱼类预计将增加其分布，包括诱饵桶释放小鱼和占主导地位的predator.Main conclusionsOur结果表明，气候变化对河流生态系统的潜在破坏性影响，硅藻，昆虫和鱼类群落的重组，功能重要类群的分布减少和暖水类群的广泛扩张，引起生物同质化。鉴于这些生物变化的幅度取决于气候变化的严重程度，因此必须作出适当的现行政策决定，以保护淡水生态系统。
AimBiodiversity on Earth is threatened by climate change. Despite the vulnerability of freshwater habitats to human impacts, most climate change projections have focused on terrestrial systems. Here, we examined how the current distributions and biodiversity of stream taxa might change under mitigated, stabilizing and increasing greenhouse gas emissions.LocationConterminous USA.Time periodPresent day to 2070.Major taxa studiedStream diatoms, insects and fish.MethodsWe developed species distribution models for 336 freshwater taxa from 1,227 distinct stream localities using water chemistry, watershed and climatic variables. Models based only on climate were used to project changes in the distributions and biodiversity of cold‐ versus warm‐water taxa under representative concentration pathways (RCPs) ranging from 2.6 to 8.5 W/m2.ResultsIn all three organismal groups, climate emerged as the strongest predictor of species distributions, providing comparable explanatory power to water chemistry and watershed variables combined. The RCP‐based projections suggested a widespread expansion of warm‐water taxa, outpacing the decline of cold‐water taxa. Consequently, overall species richness would increase, but beta diversity would decrease drastically with the severity of climate change. A closer look at individual taxa and functional guilds revealed that vulnerable cold‐water taxa included: (a) diatom guilds forming the base and bulk of the biofilm; (b) environmentally sensitive insects, characteristic of unimpacted streams; and (c) ecologically and recreationally important salmonids, which were forecast to diminish dramatically in source habitats. Warm‐water fish projected to increase their distributions include bait bucket release minnows and dominant predators.Main conclusionsOur results suggest potentially devastating impacts of climate change on stream ecosystems, with the restructuring of diatom, insect and fish communities, diminished distributions of functionally important taxa and widespread expansion of warm‐water taxa, giving rise to biotic homogenization. Given that the magnitude of these biotic shifts depends on the severity of climate change, appropriate current policy decisions are necessary to preserve freshwater ecosystems.