Mountain systems throughout the globe are conspicuously sensitive to on-going climate alterations. This condition is much more detrimental in the Himalaya, where the rate of warming and thus the glacier meltdown is much higher than elsewhere. The Himalayan coldwater species are concerningly most vulnerable to these changes because of their limited thermal range. Whilst climate studies strongly prognosticate the altered distribution of plants and mammals in this region, the impact on coldwater fishes still remains unknown. We used snow trout (Schizothorax richardsonii), a Himalayan coldwater specialist as a model organism to predict the current suitability and climate-driven potential range shift in an ensemble-based modeling framework. We collated occurrence data from a long term, extensive field-based sampling with additional records derived from an in-depth literature survey. A comprehensive input data set including topographic, hydrogeomorphic and climatic variables were used to build correlative species distribution models for the current and future time-periods (2050 and 2070) under three-carbon emission scenarios (Representative Concentration Pathways) by integrating five General Circulation Models. Furthermore, we predicted the elevation-specific range shifts of the snow trout in response to climate change. We predict that a wide-ranging mid-elevation river network is currently suitable for the snow trout in Himalaya, however a significant part of its current distributional range would be lost over time. Our results highlight that snow trout would expand their range upwards into the high-altitude streams with a concurrent predominant range contraction in most of their lagging edges, ultimately creating a high-altitude squeeze. The net habitat loss under three RCP scenarios (RCPs 2.6, 4.5 and 8.5) was estimated to range from 7.41% to 16.29% for the year 2050 which would further increase in the year 2070 ranging from 9.46% to 26.56%. These results provide a strategic information on prioritizing climate-adaptive actions to target the currently suitable habitats and future refugia identified. Our modeling framework also provides a foremost basis to conserve not only the snow trout but also to evaluate the climate impact on several other coldwater species, which are equally vulnerable and ecologically important in the Himalaya.

全球的山区系统对持续的气候变化非常敏感。这种情况在喜马拉雅山的危害更大，那里的升温速度以及冰川融化的速度都比其他地方高得多。喜马拉雅冷水物种由于其有限的热范围而最容易受到这些变化的影响。尽管气候研究强烈预测该地区植物和哺乳动物分布的变化，但对冷水鱼类的影响仍然未知。我们用了鳟鱼（Schizothorax richardsonii），喜马拉雅冷水专家作为模型有机体，可以在基于整体的建模框架中预测当前的适用性和气候驱动的潜在范围变化。我们将长期，广泛的基于现场的采样中的发生数据与来自深入文献调查的其他记录进行了整理。通过整合五个通用循环模型，使用包括地形，水文地貌和气候变量在内的综合输入数据集，为三碳排放情景（代表性浓度路径）下的当前和未来时间段（2050年和2070年）建立了相关的物种分布模型。 。此外，我们预测了响应气候变化的雪鳟的海拔特定范围变化。我们预测，目前喜马拉雅地区的雪鳟适合使用范围广泛的中海拔河网，但是随着时间的流逝，其当前分布范围的很大一部分将消失。我们的结果表明，雪鳟将把它们的范围向上扩展到高海拔溪流中，同时在大多数滞后边缘同时出现主要的范围收缩，最终造成高海拔挤压。在三种RCP情景（RCP 2.6、4.5和8.5）下，到2050年的净栖息地丧失估计在7.41％至16.29％的范围内，到2070年将进一步从9.46％升高至26.56％。这些结果提供了有关优先考虑气候适应性行动的战略信息，以针对目前合适的栖息地和确定的未来避难所。