Effects of Environmental Change on Arctic-Breeding Shorebirds

北极环境受到全球气候变化的深刻影响，冻原生境的变化，包括积雪状况、气候变异性和生境类型的变化，预计将对北极生物群的生物多样性和分布产生重大影响。气候变化的一个可能影响是不同营养水平的生物体之间的生物相互作用脱钩，导致植物，昆虫，鸟类和更高级别的捕食者的生活史事件的季节性时间的“物候不匹配”。北极繁殖的滨鸟有望成为全球气候变化影响的“综合哨兵”，因为高能量需求、长距离迁徙和季节性活动的同步时间增加了它们对环境变化的脆弱性。本项目将研究北极环境条件对两种迁徙滨鸟生态和营养关系的影响：半掌状鹬（Calidris pusilla）和西部鹬（C. mauri）。评估气候变化的生态后果的一个挑战是缺乏大多数生物的基线数据。该项目的一个独特之处是，研究人员在阿拉斯加诺姆附近一个未受干扰的4平方公里沿海苔原研究地点收集了4年（1993-1996年）内鹬的季节性时间、人口统计和运动的详细数据。在这个为期3年的实地项目（2011-2013）中，研究小组将监测滨鸟种群和四个关键环境因素：气候条件、节肢动物出现、小型哺乳动物和捕食者的丰度。他们还将部署地理定位标签，以确定研究种群的迁移路线和非繁殖地点。在收集原始数据的首席调查员的指导下，将在同一地点使用标准化的实地协议收集滨鸟生态数据，并将跨越15-20年的环境变化间隔。我们研究的更广泛的背景将是对迁徙鹬年周期的全面了解，这是在“西部鹬研究网络”16年研究计划下开发的。这是第一个实地研究之一，以测试北极繁殖滨鸟的“物候不匹配”假设的预测，并检查食物资源，迁徙鹬，和它们的捕食者如果缺乏长期的变化，这一假设将被拒绝，但标准化的采样将为未来的生态恢复力研究提供一个框架。如果变暖的气候条件改变了昆虫出现的时间，而没有改变滨鸟筑巢的物候，可能导致筑巢鸟类密度下降，这一假设将得到支持。北极条件的影响可以作出强有力的推论，因为研究物种同域繁殖，但有不同的迁移路线和非繁殖区。该项目将为保护在北极高纬度地区繁殖的候鸟提供见解。北极鸟类调查的传统方法是基于对鸟巢的监测，本项目将评估更密集的人口统计方法在多大程度上是一种有用的替代方法。该项目将为一名博士生和最多六名本科生提供培训机会。在阿拉斯加州诺姆社区的外联活动将包括与当地利益相关者举行年度会议，采访记者，以及为诺姆游客中心准备公共展示媒体。

Arctic environments have been profoundly affected by global climate change, and changes in tundra habitats, including changes in snow conditions, climatic variability and habitat types are predicted to have major impacts on the biodiversity and distribution of arctic biota. One likely impact of climatic change will be a decoupling of biological interactions among organisms at different trophic levels, leading to a 'phenological mismatch' in the seasonal timing of life-history events for plants, insects, birds and higher-level predators. Arctic breeding shorebirds are expected to be 'integrative sentinels' for the effects of global climate change because high energetic requirements, long-distance migratory movements, and synchronized timing of seasonal activities increase their vulnerability to changing environments.This project will examine the effects of environmental conditions in the Arctic on the ecology and trophic relationships of two species of migratory shorebirds: Semipalmated Sandpipers (Calidris pusilla) and Western Sandpipers (C. mauri). One challenge for assessing the ecological consequences of climate change is a lack of baseline data for most organisms. A unique feature of this project is that the researcher collected detailed data on the seasonal timing, demography and movements of sandpipers in a 4-year period (1993-1996) at an undisturbed 4 square km coastal tundra study site near Nome, Alaska. In this 3-year field project (2011-2013) the research team will monitor shorebird populations and four key environmental factors: climatic conditions, arthropod emergence, abundance of small mammals and predators. They will also deploy geolocator tags to determine migration routes and nonbreeding sites for the study populations. Data on shorebird ecology will be collected using standardized field protocols at the same site, under the direction of the lead investigator who collected the original data, and will span a 15-20 year interval of environmental change. The broader context of our research will be the comprehensive knowledge of the annual cycle of migratory sandpipers that has been developed under the 16-year research program of the 'Western Sandpiper Research Network'.This is one of the first field studies to test predictions of the 'phenological mismatch' hypothesis for arctic-breeding shorebirds and to examine long-term changes in trophic interactions among food resources, migratory sandpipers, and their predators. The hypothesis will be rejected if long-term changes are lacking but standardized sampling will provide a framework for future studies of ecological resilience. The hypothesis will be supported if warming climatic conditions have changed the timing of insect emergence without changes in phenology of shorebird nesting, potentially leading to declines in densities of nesting birds. Strong inferences about the effects of arctic conditions can be made because the study species breed sympatrically but have different migration routes and nonbreeding areas. This project will provide insights for conservation of migratory birds that breed at high latitudes in the Arctic. Traditional methods for surveying arctic birds are based on nest monitoring and this project will evaluate the extent to which more intensive demographic approaches are a useful alternative. The project will offer training opportunities for one PhD student and up to six undergraduate students. Outreach in the community of Nome, Alaska will include annual meetings with native stakeholders, interviews with journalists, and preparation of public display media for the Nome visitor center.