怒江中上游不同营养生态位鱼类生长对近期气候变化的响应研究

Freshwater ecosystems are the material basis for human survival. Meanwhile, they are the most affected ecosystems by global climate change. However, due to the scarcity of environmental history records and proxies, climate change research on freshwater ecosystems is relatively behind other ecosystems. Fish are at the top of the food chain in freshwater ecosystems, and their growth characteristics can reflect the combined effects of internal and external factors such as genetics, water temperature, and food resources. Studying growth responses of fish occupying different trophic niches to climate change is an important way to reveal the response pattern of aquatic ecosystems. In this proposal, the upper and middle Nujiang River, where have been profoundly affected by climate change, was selected as our study area, and three Schizothoracid fish species occupying different trophic niches were selected as study species. Fish growth index chronologies will be developed based on otolith increment width measurements and with applying dendrochronological methods. The relationships between fish growth and climate variables will be investigated. Then we will clarify the growth response patterns of fish occupying different trophic niches to climate change, and identify reasons for differences among these patterns. The outcomes of this project will provide a scientific basis for conservation and management for riverine fish and ecosystems in response to climate change on the Qinghai-Tibet Plateau. It will also promote the application and development of dendrochronological methods in aquatic ecosystems.

淡水生态系统是人类赖以生存的物质基础，同时也是受气候变化影响最为严重的生态系统。但是，由于水环境历史数据和气候代用指标匮乏，导致了淡水生态系统气候变化研究相对滞后。在淡水生态系统中，鱼类处于食物链的最顶端，其生长特征反映了遗传、水温和饵料等内外因子的综合影响。研究不同营养生态位鱼类生长对气候变化响应及差异，是揭示水生生态系统响应气候变化模式的重要途径。本研究以气候变化敏感区怒江中上游为研究区域，以不同营养生态位的裂腹鱼类为研究对象，应用树轮年代学理论方法构建鱼类生长指数年表，结合历史气候环境数据，分析不同营养生态位鱼类生长与环境因子之间的关系，揭示不同营养级鱼类生长对气候变化的响应模式及差异。研究成果，不仅为高原河流鱼类及水生生态系统的气候变化应对和保护策略制定提供科学依据，也将促进树轮年代学理论方法在水生生态系统中的应用和发展。

淡水生态系统是人类赖以生存的物质基础，也是受气候变化影响最为严重的生态系统。但是，由于水环境历史数据和气候代用指标匮乏，导致了淡水生态系统气候变化研究相对滞后。在淡水生态系统中，鱼类处于食物链的最顶端，其生长特征反映了遗传、水温和饵料等内外因子的综合影响。研究不同营养生态位鱼类生长对气候变化响应及差异，是揭示水生生态系统响应气候变化模式的重要途径。本研究以气候变化敏感区怒江中上游为研究区域，以不同营养生态位的裂腹鱼类为研究对象，应用树轮年代学理论方法构建鱼类生长指数年表，结合历史气候环境数据，分析不同营养生态位鱼类生长与环境因子之间的关系，揭示不同营养级鱼类生长对气候变化的响应模式及差异。研究结果表明，基于生长指数年表和生长指数年表特征的研究，发现高营养级鱼类比低营养级鱼类生长更快。线性混合效应模型分析发现，不同营养级鱼类生长均与气温呈正相关，与降雨呈负相关关系，表现出不同营养级鱼类对局域气候变化响应的一致性。不过，高营养级鱼类对降雨变化更为敏感，而低营养级鱼类对气温变化更为敏感。同时，分析了全球性气候因子（北极圈涛动、北大西洋涛动、南方涛动指数、厄尔尼诺南方涛动指数、海洋表面温度）与鱼类生长的关系，发现高营养级鱼类与南方涛动指数呈不显著正相关关系，而低营养级鱼类与海洋表面温度呈不显著正相关关系。该研究探索和发展了树轮年代学理论方法在水生生态系统（鱼类）响应气候变化研究中的应用，为客观评价青藏高原乃至全球河流鱼类群落及其生态系统的气候变化响应提供了方法学和理论基础，对于气候变化下鱼类资源管理和保护具有较好的参考意义。