Effects of an Introduced Predator on Ecosystem Subsidy and Amphibian Decline

摘要/摘要：引进捕食者对生态系统补贴和两栖动物衰退的影响。这个项目的目的是测试放养的鳟鱼是否会减少作为陆地野生动物猎物的新兴水生物种的数量，并评估减少的两栖动物是否会对鳟鱼的移除做出反应。这一点很重要，因为人们对引进的鳟鱼对陆地物种的间接影响知之甚少，而且鳟鱼与两栖动物数量的减少有关。本研究还讨论了“生态系统补贴”这一更广泛的主题，即当地生态系统受到来自其他地区的营养物质和生物流动的影响。目前，尚不清楚生态系统内的物种相互作用如何影响对邻近生物群落的补贴。我们将量化四种渔业管理方案下盆地水生和陆生群落的差异：活跃放养、停止放养、鱼类移除和历史上未放养。我们将测试鳟鱼对水生物种的影响，将两栖动物和水生昆虫的丰度与蝙蝠、鸟类和蛇的种群规模联系起来，并测量昆虫在高地的分布。我们还将量化数量减少的喀斯喀特蛙的种群规模和栖息地利用情况。我们的主要智力贡献将是在大范围内衡量生态系统补贴的重要性，并评估引入物种在改变补贴方面的作用。更广泛的影响包括为来自代表性不足群体的学生提供研究培训，促进机构间伙伴关系，以及提供对管理山区荒野至关重要的信息。

Summary/Abstract: Effects of an introduced predator on ecosystem subsidy and amphibian decline. S. P. Lawler, P.I.The purposes of this project are to test whether stocked trout decrease the amount of emerging aquatic species that serve as prey for terrestrial wildlife, and to assess whether a declining amphibian responds to trout removal. This is important because the indirect effects of introduced trout on terrestrial species are poorly understood, and because trout have been implicated in amphibian declines. This study also addresses the broader topic of 'ecosystem subsidy', wherein local ecosystems are influenced by flows of nutrients and organisms from other areas. Currently, it is unknown how species interactions within ecosystems affects subsidies to adjacent biological communities. We will quantify differences in aquatic and terrestrial communities in basins under four fisheries management schemes: active stocking, discontinued stocking, fish removals, and historically unstocked. We will test impacts of trout on aquatic species, relate abundances of amphibians and aquatic insects to population sizes of bats, birds and snakes, and measure the distribution of insects in uplands. We will also quantify population sizes and habitat use of the declining Cascades frog. Our main intellectual contribution will be to measure the importance of ecosystem subsidy on a large scale, and to assess the role of introduced species in altering subsidies. Broader impacts include providing research training for students from under-represented groups, promoting inter-agency partnerships, and providing information vital to managing mountain wildernesses.