CRB: Food Web Analysis of Biodiversity: Application to Algal-based River Systems

研究人员提出了一个基于食物网的程序， 分析生物多样性问题。 为了验证这个理论的正确性 方法，他们将把它应用到一个地点的河流食物网， 位于北方加州的古老针叶林中。 在 目前，这个网站是相对原始的，但外来入侵 食肉动物和食草动物（虾蛄和牛蛙） 在几年内。 在入侵前的社区， 研究人员将调查占主导地位的大型藻类 初级生产者组合在河流中，调解捕食者-猎物 优势脊椎动物和无脊椎动物的相互作用 食草动物。 大型藻类对生境选择、摄食、 率，生长，存活和出现1）青蛙蝌蚪（雨蛙 regilla和Rana boylei）在存在和不存在掠夺性的情况下 水生束带蛇（Thamnophis couchi）; 2）食藻 摇蚊幼虫（Pseudochironomus richardsoni）在存在和 没有捕食性鱼类（蟑螂，Hesperoleucas peculicus， 和青少年钢头，虹鳟（Oncorhynchus mykiss）将在 操纵现场实验。 这些研究的结果将 使研究人员能够评估以下方面的相对重要性 大型藻类在提供食物，避难所，或热有利 这些主要脊椎动物和无脊椎动物的微生境 食草动物或它们的捕食者。 预测未来几年 入侵后的藻类或捕食者组合将改变 将建立关键的食物网联系， 在类似的河流中， 已经到了。 这些预测也将在 主要研究者的主要研究中心， 侵略者的建立。

The investigators propose a foodweb-based procedure for analysis of biodiversity problems. To test the validity of this approach, they will apply it to a river food web at a site within an old-growth conifer forest in northern California. At present, this site is relatively pristine, but invasion by exotic predators and herbivores (squawfish and bullfrogs) is anticipated within a few years. In the pre-invasion community, the researchers will investigate how macroalgae, which dominate primary producer assemblages in the river, mediate predator-prey interactions involving the dominant vertebrate and invertebrate grazers. The effects of macroalgae on habitat selection, feeding rates, growth, survival, and emergence of 1) frog tadpoles (Hyla regilla and Rana boylei) in the presence and absence of predatory aquatic garter snakes (Thamnophis couchi); and 2) algivorous midge larvae (Pseudochironomus richardsoni) in the presence and absence of predatory fishes (roach, Hesperoleucas symmetricus, and juvenile steelhead, Oncorhynchus mykiss) will be analyzed in manipulative field experiments. Results from these studies will allow the investigators to evaluate the relative importance of macroalgae in providing food, refuges, or thermally favorable microhabitats to these dominant vertebrate and invertebrate grazers, or to their predators. Predictions of how changes in algal or predator assemblages following invasions will alter critical food web linkages will be developed, then tested in similar river reaches where predatory squawfish and/or bullfrogs have already arrived. These predictions will also be tested at the primary study site of the principle investigators following the establishment of invaders.