Two-Stage Life Histories and Species Interactions: Models and Tests with Sunfishes

本研究采用一个简化的两个生命阶段模型来检验 两种相互竞争的翻车鱼物种之间的相互作用 猎物资源 该模型可用于预测 物种丰度、大小、特定生长率和资源 密度在以下一般条件下：1）物种 发现在同域和异地分布，和2）物种共存， 资源生产力的梯度。 初步现场数据 表明模型和观察到的反应 与基于传统而非结构化的期望相反 模型 对北方威斯康星州的六个湖泊（其中 南瓜子太阳鱼被发现在同域和异地与 蓝鳃金龟）将被用来测试一个物种的预测反应， 竞争对手的存在/不存在。 比较调查 在密歇根州南部的八个湖泊中， 两个竞争物种及其资源对 资源生产力的变化。 一系列实验 密歇根湖的研究将阐明驱动 观察到的物种丰度和个体 应答 在个体水平上观察到的反应（例如， 饮食变化和生长模式）将与 人口的反应（密度的变化）， 对模型进行了严格的测试。

In this study a simplified two.life.stage model to examine the interaction between two competing sunfish species and their prey resources. The model can be used to predict patterns of species abundances, size.specific growth rates, and resource densities under the following general conditions: 1) species found in sympatry and allopatry, and 2) species coexisting across gradients in resource productivities. Preliminary field data suggest that the model, and that the observed responses run counter to expectations based on traditional, not.structured models. Comparative surveys among six northern Wisconsin lakes (where the pumpkinseed sunfish is found in sympatry and allopatry with the bluegill) will be used to test a species' predicted response to the presence/absence of its competitor. Comparative surveys among eight southern Michigan lakes will test the predicted responses of two competing species and their resources to variation in resource productivity . A series of experimental studies in Michigan lakes will elucidate the mechanisms driving the observed patterns of species abundance and individual responses. The responses observed at the individual level (e.g. diet shifts and growth patterns) will be integrated with the responses of populations (changes in densities), to provide rigorous tests of the model.