Collaborative Research: Shifting seasonality of Arctic river hydrology alters key biotic linkages among aquatic systems

摘要本奖项由2009年美国复苏与再投资法案（公法111-5）资助。这项研究将确定北极河流水文的季节性变化如何改变流域湖泊和溪流组成部分内部和之间的关键生物联系，并可能改变北极系统的功能。北极灰鲑（Thymallus arcticus）是一种典型的环极北极物种，它为理解季节性变化对北极生态系统功能的影响提供了一个模型系统，因为维持其种群生存需要一个相互联系和多样化的景观（大冻土带河流、小溪流和湖泊）。破坏其迁移的环境条件变化将影响水生生态系统的系统级功能。灰鲑是其他生物群的食物，包括湖鳟鱼、鸟类和人类，并且在溪流生态系统中作为自上而下的控制，这表明它们的数量变化将对整个耦合的河湖系统产生影响。目前影响冻土带湖泊和溪流的变化的规模和速度使我们迫切需要了解它们是如何联系在一起的，以及它们如何作为一个系统发挥作用。这项工作将解决4个问题：1)气候变化如何影响灰鲑迁徙的季节性、速度和距离？2)河流昆虫种群的生命周期、生活史和属性的季节性是否随气候变化而变化？3)河流流量的季节性变化与昆虫产量的相互作用如何影响河流生产的有效性和向灰鱼的转移？4)气候驱动的迁徙环节中断对冬季难民结构和功能的影响是什么？研究人员将通过以下方式研究气候变化对关键生物联系的影响：1)对河流流量和温度、昆虫和鱼类生产力和迁徙的长期数据库进行回顾性研究；2)对迁徙季节性、河流生产力和营养转移的控制进行新研究；3)对冬季避难所开放水域季节变化和食物网之间的反馈进行新研究。这将集成到系统级模型中，使用grayling作为“货币”。，以评估系统组件之间改变的联系对系统级功能的影响。该项目更广泛的智力价值在于整合了不同领域（水文学、动物生理学、种群生物学和数学建模）的工作，以了解物种在生态系统中的作用。通过生物联系提高对湖泊和溪流生产力相互依存关系的理解，将促进我们对景观生态学、动物在生态系统动力学、生活史进化和渔业生态系统管理中的作用的一般理解。

AbstractThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This research will determine how the shifting seasonality of arctic river hydrology alters key biotic linkages within and among lake and stream components of watersheds and may alter the function of the arctic system. Arctic grayling (Thymallus arcticus) is a quintessential, circumpolar arctic species that provides a model system for understanding the impacts of changing seasonality on arctic ecosystem function because an interconnected and varied landscape (large tundra rivers, small streams and lakes) is required to maintain their population viability. Changes to environmental conditions that disrupt their migration will affect the system-level function of aquatic ecosystems. Grayling serve as food for other biota, including lake trout, birds and humans, and as top-down controls in stream ecosystems suggesting that changes to their populations will have effects that reverberate throughout the coupled river-lake system. The scale and pace of the changes now impacting tundra lakes and streams imparts an urgency to understand how they are linked and how they function as a system.This work will address 4 questions: 1) How are seasonality, rate and distance of grayling migration affected by climate change? 2) Are the seasonality of life-cycles, life-history and attributes of stream insect populations changing in response to climate change? 3) How does changing seasonality of river discharge interact with insect production to affect availability and transfer of stream production to grayling? 4) What is the effect of climate driven disruption of the migratory link on the structure and function of winter refugia?Reseachers will examine the implications of changing climate on key biotic linkages by: 1) retrospective studies of long-term databases of stream flow and temperature and insect and fish productivity and migration, 2) new work on controls on seasonality of migration, stream productivity and trophic transfer and 3) new work on the feedbacks between changing open water season and food webs in winter refugia. This will be integrated into a systems-level model, using grayling as the ?currency?, to evaluate the effects of altered linkages among system components on system level functioning.The broader intellectual merit of this project lies in the integration of work from diverse fields (hydrology, animal physiology, population biology and mathematical modeling) to understand the roles of species in ecosystems. Improved understanding of the interdependence of lake and stream productivity through biotic linkages will advance our general understanding of landscape ecology, the role of animals in ecosystem dynamics, life-history evolution and ecosystem management of fisheries.