LTREB: Climatic and Density-dependent Effects on the Ecology of Sockeye Salmon and their Freshwater Ecosystems

尽管气候对生态动态的影响得到了普遍的评价，但大多数生物学研究都太简短，无法测试气候和生物过程之间的相互作用。或者，许多长期研究没有跨越足够多的生物组织水平，无法对生态对环境变化的反应的复杂性提供有意义的见解。在上个世纪，太平洋鲑鱼的种群动态受到区域气候的大范围变化、固有的密度依赖性调节和渔业活动之间的相互作用的影响。我们建议利用持续40-50年的独特的、高度详细的生物和物理时间序列来测试阿拉斯加西南部红鲑鱼用作苗圃栖息地的淡水生态系统中气候和生物过程之间的相互作用。Sockeye不仅是该地区商业和生存社区的重要渔业资源，也是驱动淡水和河岸生态系统许多组成部分的关键物种。我们建立了一系列可行的假设，以研究气候变量(如水文、冰期)和生物变量(如熊捕食、幼体竞争)之间的相互作用，这些变量相互作用控制淡水生态系统中Sockeye的生活史进化和生态。我们的主要研究主题是探索：1)栖息地特征、气候驱动的水文学变化、熊被捕食和鲑鱼密度之间的相互作用，这些因素控制着成体红鱼的生活史格局和生产力；2)作为育苗栖息地的湖泊，红鱼种群动态和气候控制着湖水条件；3)生物和气候因素控制着红鱼幼鱼的生长速度和向海迁移的年龄。Sockeye是此类研究的理想物种，因为它们在离散的生活史阶段占据溪流、湖泊和开阔海洋的栖息地，对浮游动物群落施加自上而下的控制，在它们死亡和分解时为淡水生态系统提供重要的海洋衍生营养物质，并出现在大量经过充分研究的种群中。这项LTREB研究将：1)维持采样计划，以40多年前在阿拉斯加西南部布里斯托尔湾的两个湖泊系统建立的现有数据集为基础；2)继续开发最先进的数据归档系统，以确保长期的数据安全，以及3)启动新的回溯性研究，以检验几个对理解气候与红眼生态及其生态系统之间的相互作用至关重要的假说。一个主要目标是开发一个活生生的数据库，供淡水生态学和渔业生物学的所有领域的研究人员使用。这些数据集包括成年红鱼的丰度、大小和年龄结构、区域气候、苗圃湖泊的湖水条件以及幼鱼和其他湖泊鱼类的丰度和生长。更具体地说，我们将评估气候变化对对其生态系统的结构和功能以及该地区人民的当地经济和文化起着极其重要作用的鱼类的生活史演变和种群动态的影响。

0128902QuinnDespite the general appreciation for climatic effects on ecological dynamics, most biologicalstudies are too brief to test for interactions between climatic and biological processes. Alternatively,many long-term studies do not span enough levels of biological organization to provide meaningfulinsights into the complexity of ecological responses to environmental change. In the last century,population dynamics of anadromous Pacific salmon have been influenced by interactions among large-scale shifts in regional climate, inherent density-dependent regulation, and fisheries activities. We propose to take advantage of unique, highly detailed biological and physical time series that extend for 40-50 years to test for interactions between climatic and biological processes in the freshwater ecosystems used as nursery habitats by sockeye salmon in southwestern Alaska. Sockeye are not only an important fishery resource to commercial and subsistence communities in this region, but are also keystone species, driving many components of freshwater and riparian ecosystems.We have established a series of working hypotheses to investigate interactions among climaticvariables (e.g., hydrology, ice-out date) and biological variables (e.g., bear predation, juvenilecompetition) that interact to control life history evolution and the ecology of sockeye in freshwaterecosystems. Our main research themes are to explore: 1) interactions among habitat features, climate-driven variation in hydrology, bear predation and salmon density controlling the life history patterns and productivity of adult sockeye, 2) sockeye population dynamics and climate as controllers of limnological conditions in lakes used as nursery habitats, and 3) biological and climatic factors controlling growth rates and age at seaward migration in juvenile sockeye salmon. Sockeye are an ideal species for such studies because they occupy stream, lake and open ocean habitats at discrete life history stages, exert top-down control on zooplankton communities, provide important marine-derived nutrients to freshwater ecosystems when they die and decompose, and occur in large, well-studied populations.This LTREB research will: 1) maintain sampling programs to build on existing data sets established over fourdecades ago in two lake systems of Bristol Bay, Southwest Alaska, 2) continue to develop a state-of-the-art data archive system to ensure long-term data security, and 3) initiate new and retrospective studies to test several hypotheses central to understanding the interactions between climate and the ecology of sockeye and their ecosystems. A major objective is to develop a living database available to investigators from all avenues of freshwater ecology and fisheries biology. These data sets include the abundance, size- and age-structure of adult sockeye salmon, regional climate, limnological conditions in nursery lakes, and abundance and growth of juvenile sockeye salmon and other lacustrine fishes. More specifically, we will evaluate the consequences of climate change for life history evolution and population dynamics of a fish species that plays an exceptionally important role in the structure and function of its ecosystems, and the local economy and culture of people in the region.