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

9800897佩卡斯基淡水无脊椎动物的丰度和群落结构在有和没有捕食者的生境中往往是不同的。拟议研究的目标是：1)测试鱼类捕食者或某些其他生理化学性质是否决定落基山脉河狸池塘中两个昆虫分类群的栖息地适宜性；2)检查栖息地质量的差异是否产生源-汇动态，或者，替代地，“无鱼”地块中无脊椎动物密度的增加是否是选择性补充的结果；以及3)确定不同的栖息地是否可以被认为在很大程度上与集合种群的情况一样孤立，或者栖息地之间是否有大量的移动。拟议的方法将采用：1)全池塘鱼类密度控制结合池塘的物理化学特征来确定影响斑块质量的因素(S)，2)中观和野外实验来确定每种生境类型中的扩散行为和适宜性，3)实地调查两种生境中的昆虫和鱼的密度以及产卵率，以测试源-汇的发生动态，以及4)稳定同位素相加实验来确定扩散模式。主要贡献包括对源-汇模型的经验测试，以及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.