Ecosystem Consequences of Trophic Exchange From A River to Its Watershed

9645175电力这些调查人员将研究河流补贴昆虫生产的影响，在不同的流域消费者的能力，以跟踪和转移这种资源。按照增加移动性的顺序，这些消费者是薄膜圆顶蜘蛛，tetragnathid蜘蛛，curorial狼蜘蛛，西部围栏和山艾树蜥蜴，以及三种常见的蝙蝠。这项研究将检验水生昆虫补贴对这些消费者的生态系统影响将取决于其活动规模的预测。例如，蝙蝠可能是最重要的公会在转运营养物质从河流到高地部分的分水岭，而蜥蜴可能有本地加强对他们的陆地猎物的影响，由于河流补贴。将使用羽化诱捕器、粘性诱捕器和定量分泌物收集来监测昆虫羽化和随后扩散的空间和时间变化。对消费者密度和活动的协调监测将用于评估其在空间和时间上的资源跟踪。昆虫的出现和补贴也将分别在与蜘蛛和蜥蜴有关的空间尺度上进行实验操作。在这些实验中，我们将测试特定消费者跟踪其资源变化的能力，并测试跟踪能力和本地资源变化对消费者人均性能的影响之间的预期权衡。在这项研究的三年中，研究人员预计，水文状况的逐年变化将强烈影响昆虫生产的时间和规模，因为我们已经研究了这个河流食物网的十年。研究这种变化及其对流域食虫动物的影响将有助于预测河流水文状况，包括土地利用或气候变化所改变的水文状况，将如何影响邻近的陆地群落。

9645175 Power These investigators will study the effects of river subsidized insect production on a range of watershed consumers that differ in their abilities to track and translocate this resource. In order of increasing mobility, these consumers are filmy dome spiders, tetragnathid spiders, cursorial wolf spiders, western fence and sagebrush lizards, and three common species of bats. This research will test the prediction that ecosystem-level effects of aquatic insect subsidies on these consumers will depend on the scale of their activities. For example, bats may be the most important guild in translocating nutrients from the river to upland portions of the watershed, while lizards may have locally intensified impacts on their terrestrial prey, due to the river subsidies. Emergence traps, sticky traps, and quantitative exuviae collections will be used to monitor spatial and temporal variation in insect emergence and subsequent dispersal. Coordinated monitoring of consumer densities and activities will be used to assess their resource tracking in space and time. Insect emergence and subsidies will also be manipulated experimentally on spatial scales relevant to spiders and lizards, respectively. In these experiments, we will test the ability of particular consumers to track variation in their resources, and test an anticipated tradeoff between tracking ability and the impact of local resource variation on per capita performance of consumers. During the three years of this study, the investigators anticipate that year-to-year variation in hydrologic regimes will strongly affect the timing and magnitude of insect production, as it has over the ten previous years that we have studied this river food web. Studying this variation and its effects on watershed insectivores will help to forecast how river hydrologic regimes, including those altered by land use or climate change, will influence adjacent terrestrial communities.