Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd. E., Seattle, WA, 98112, U.S.A.; Current address: U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Dept. 3166, 1000 East University Avenue, University of Wyoming, Laramie, WY, 82071, U.S.A.
Conserv Biol. 2013 Dec;27(6):1179-89. doi: 10.1111/cobi.12170.
The combined effects of water diversion and climate change are a major conservation challenge for freshwater ecosystems. In the Lemhi Basin, Idaho (U.S.A.), water diversion causes changes in streamflow, and climate change will further affect streamflow and temperature. Shifts in streamflow and temperature regimes can affect juvenile salmon growth, movement, and survival. We examined the potential effects of water diversion and climate change on juvenile Chinook salmon (Oncorhynchus tshawytscha), a species listed as threatened under the U.S. Endangered Species Act (ESA). To examine the effects for juvenile survival, we created a model relating 19 years of juvenile survival data to streamflow and temperature and found spring streamflow and summer temperature were good predictors of juvenile survival. We used these models to project juvenile survival for 15 diversion and climate-change scenarios. Projected survival was 42-58% lower when streamflows were diverted than when streamflows were undiverted. For diverted streamflows, 2040 climate-change scenarios (ECHO-G and CGCM3.1 T47) resulted in an additional 11-39% decrease in survival. We also created models relating habitat carrying capacity to streamflow and made projections for diversion and climate-change scenarios. Habitat carrying capacity estimated for diverted streamflows was 17-58% lower than for undiverted streamflows. Climate-change scenarios resulted in additional decreases in carrying capacity for the dry (ECHO-G) climate model. Our results indicate climate change will likely pose an additional stressor that should be considered when evaluating the effects of anthropogenic actions on salmon population status. Thus, this type of analysis will be especially important for evaluating effects of specific actions on a particular species. Efectos Interactivos de la Desviación del Agua y el Cambio Climático en Individuos Juveniles de Salmón Chinook en la Cuenca del Río Lemhi (E.U.A.).
调水和气候变化的综合影响是淡水生态系统保护的主要挑战。在美国爱达荷州的莱姆希流域，调水会导致径流量发生变化，而气候变化将进一步影响径流量和水温。径流量和水温的变化会影响幼鲑的生长、洄游和生存。我们研究了调水和气候变化对幼年奇努克鲑（Oncorhynchus tshawytscha）的潜在影响，该物种在美国濒危物种法案（ESA）下被列为受威胁物种。为了研究幼鲑生存的影响，我们建立了一个模型，将 19 年的幼鲑生存数据与径流量和温度相关联，发现春季径流量和夏季温度是幼鲑生存的良好预测指标。我们使用这些模型来预测 15 种调水和气候变化情景下的幼鲑生存。与未调水的情况相比，当径流量被调水时，幼鲑的存活率降低了 42-58%。对于调水的情况，2040 年气候变化情景（ECHO-G 和 CGCM3.1 T47）导致存活率进一步降低了 11-39%。我们还建立了与径流量相关的栖息地承载能力模型，并对调水和气候变化情景进行了预测。与未调水的情况相比，调水情况下的栖息地承载能力估计降低了 17-58%。气候变化情景导致干燥气候模型（ECHO-G）的承载能力进一步下降。我们的研究结果表明，气候变化可能会带来额外的压力，在评估人为活动对鲑鱼种群状况的影响时应考虑到这一因素。因此，这种类型的分析对于评估特定行动对特定物种的影响将尤为重要。
