Krivan Vlastimil, Sirot Etienne
Department of Theoretical Biology, Institute of Entomology, Academy of Sciences of the Czech Republic and Faculty of Biological Sciences, Branisovská 31, 370 05 Ceské Budejovice, Czech Republic.
Am Nat. 2002 Aug;160(2):214-34. doi: 10.1086/341016.
We present a theoretical study of habitat selection strategies for two species that compete in an environment consisting of two different habitats. Our fitness functions are derived from the Lotka-Volterra competition equations, and we assume that individuals settle in the habitat in which their fitness is maximized. We derive an ideal free distribution across the habitats for both species. Our model provides analytical and graphical descriptions of individual habitat selection behavior, isolegs (the boundary lines separating regions where qualitatively different habitat preferences are predicted), and spatial population distributions. Our analysis reveals complex isolegs, several novel patterns of habitat distribution, and even situations where spatial strategies, as well as the relative abundances of coexisting species, exhibit only local stability. Hence, distributions of competing species may be determined not solely by their respective densities but also by the order of colonization. This happens, however, only for extreme levels of interspecific competition. In the situation where one competitor species is dominant over the other, our model predicts isolegs that qualitatively agree with observed behavioral patterns. However, our model predicts a greater variety of possible situations than has been previously described. Finally, we analyze the influence of habitat selection behavior on species isoclines and verify that increasing interspecific competition leads to habitat segregation.
我们对在由两种不同栖息地组成的环境中竞争的两个物种的栖息地选择策略进行了理论研究。我们的适合度函数源自洛特卡 - 沃尔泰拉竞争方程，并且我们假设个体在其适合度最大化的栖息地中定居。我们推导出了两个物种在各栖息地间的理想自由分布。我们的模型提供了个体栖息地选择行为、等适合度线（预测不同定性栖息地偏好区域的分界线）以及空间种群分布的分析和图形描述。我们的分析揭示了复杂的等适合度线、几种新颖的栖息地分布模式，甚至存在空间策略以及共存物种的相对丰度仅表现出局部稳定性的情况。因此，竞争物种的分布可能不仅由它们各自的密度决定，还由定殖顺序决定。然而，这种情况仅在种间竞争达到极端水平时才会发生。在一种竞争物种比另一种占优势的情况下，我们的模型预测的等适合度线在性质上与观察到的行为模式相符。然而，我们的模型预测的可能情况比之前描述的要多得多。最后，我们分析了栖息地选择行为对物种等斜线的影响，并验证了种间竞争加剧会导致栖息地隔离。
