Dissertation Research: Population Dynamics of Aquatic Insects in Beaver Ponds: Influence of Dispersal, Behavior, and Predators

9800897 Peckarsky淡水无脊椎动物的丰度和群落结构在有和没有鱼类捕食者的栖息地中往往是不同的。拟议研究的目标是：1）测试鱼类捕食者或其他一些物理化学性质是否决定了落基山海狸池塘中两种昆虫类群的栖息地适宜性，2）检查栖息地质量的差异是否产生了源-汇动态，或者，如果在“无鱼”斑块中增加的无脊椎动物密度是选择性补充的结果，以及3）确定不同的生境是否可以在很大程度上被认为是孤立的，就像集合种群的情况一样，或者在生境之间是否有实质性的移动。拟议方法将采用：1）全池塘鱼类密度的操作结合池塘的理化特性，以确定影响斑块质量的因素，2）围隔和田间实验，以确定每个栖息地类型中的扩散行为和适合度，3）两种栖息地类型中昆虫和鱼类密度和产卵率的田间调查，以测试发生源-库动态，（4）稳定同位素添加实验，确定扩散模式。主要贡献包括源-汇模型的实证检验和研究扩散如何与斑块中的过程相互作用，以确定区域尺度上的种群动态。

9800897 Peckarsky The abundance and community structure of freshwater invertebrates is often different in habitats with and without fish predators. Objectives of the proposed research are: 1) to test whether fish predators or some other physio-chemical property determines habitat suitability for two insect taxa in Rocky Mountain beaver ponds, 2) to examine if differences in habitat quality produce a source-sink dynamic, or, alternatively, if increased invertebrate densities in "fishless" patches are the results of selective recruitment, and 3) to determine if different habitats can largely be considered as isolated as in a situation for a metapopulation or if there is substantial movement among habitats. Proposed methodology will employ: 1) whole-pond manipulations of fish densities combined with physio-chemical characterization of ponds to determine the factor(s) that influence patch quality, 2) mesocosm and field experiments to determine dispersal behavior and fitness in each habitat type, 3) field surveys of insect and fish densities and oviposition rates in the two habitat types to test for the occurrence source-sink dynamics, and 4) a stable-isotope addition experiment to determine patterns of dispersal. Key contributions include an empirical test of source-sink models and examination of how dispersal interacts with processes in a patch to determine the dynamics of a population at a regional scale.