REU: An Experimental Analysis of Neighborhood Interactions Among Zooplankton

水生群落最显著的特征之一是浮游动物丰度的时空异质性。斑块性的一个主要后果是个体在密度和遇到的物种上不同，因此可能会经历不同的竞争压力和捕食风险。本研究的目的是确定在现实条件下，浮游动物群落的斑块性是否会影响共同发生的物种之间相互作用的结果。这项研究结合了实地测量和实验实验室操作。野外测量表征了每个物种在生长季节的2个日期所经历的邻域（浮游动物和浮游植物的数量和组成）。将测试采样量（1,14和50升）和日运动对空间格局（斑块、每个个体经历的其他动物数量、物种特定的聚集趋势）估计的影响。实验操作测量了两种相互作用的结果，这两种相互作用更可能受到近邻的影响，而不是平均种群密度的影响：邻居的过滤和捕食率抑制。测量这两种相互作用的适当邻域体积将被实验量化，并在可能的情况下与相同尺度的空间格局的现场测量结果进行比较。这种方法将浮游动物丰度的斑块性与实际野外条件下物种相互作用的对照研究联系起来。如果我们要扩大对浮游动物相互作用的研究，以包括在自然界中观察到的引人注目的空间和时间分布模式，那么测量浮游动物之间依赖密度的相互作用是必要的。

One of the most striking characteristics of aquatic communities is the extreme spatial and temporal heterogeneity in zooplankton abundance. A major consequence of patchiness is that individuals differ in the densities and species they encounter, and therefore are likely to experience different competitive pressures and predation risks. The goal of this research is to determine whether patchiness in zooplankton communities affects the outcome of interactions among commonly co-occurring species under realistic conditions. The research combines field measurements and experimental laboratory manipulations. The field measurements characterize the neighborhoods (the number and composition of the zooplankton and phytoplankton in close proximity) experienced by each species in 2 dates during the growing season. The effect of sampling volume (1, 14 and 50 liters) and diurnal movements on estimates of spatial pattern (patchiness, number of other animals experienced by each individual, species specific tendencies to aggregate) will be tested. The experimental manipulations measure the outcome of 2 types of interactions that are more likely to be affected by close neighbors than by mean population densities: filtering and predation rate inhibition by neighbors. The appropriate neighborhood volume for measuring these 2 types of interactions will be experimentally quantified and compared to the field measurements of spatial pattern at the same scales when possible. This approach links patchiness in zooplankton abundance to the controlled study of species interactions under realistic field conditions. Measuring density dependent interactions among zooplankton is necessary if we are to expand the study of zooplankton interactions to include the striking spatial and temporal distribution patterns observed in nature.