Cuddington K, Wilson W G, Hastings A
Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
Am Nat. 2009 Apr;173(4):488-98. doi: 10.1086/597216.
All organisms alter their abiotic environment, but ecosystem engineers are species with abiotic effects that may have to be explicitly accounted for when making predictions about population and community dynamics. The goal of this analysis is to identify those conditions in which engineering leads to population dynamics that are qualitatively different than one would predict using models that incorporate only biotic interactions. We present a simple model coupling an ecosystem engineer and the abiotic environment. We assume that the engineer alters environmental conditions at a rate dependent on engineer density and that the environment decays back to original conditions at an exponential rate. We determine when the feedback to population dynamics through environmental state can lead to altered equilibrium densities, bistability, or runaway growth of the engineer population. The conditions leading to changes in dynamics, such as susceptibility of a system to engineering or alteration of density-dependent and density-independent controls, define cases in which the engineering concept is essential for ecological understanding.
所有生物都会改变其非生物环境，但生态系统工程师是具有非生物效应的物种，在预测种群和群落动态时可能必须明确考虑这些效应。本分析的目的是确定那些情况下，工程活动导致的种群动态在性质上不同于仅使用包含生物相互作用的模型所预测的动态。我们提出了一个耦合生态系统工程师和非生物环境的简单模型。我们假设工程师以取决于其密度的速率改变环境条件，并且环境以指数速率恢复到原始条件。我们确定何时通过环境状态对种群动态的反馈会导致平衡密度改变、双稳态或工程师种群的失控增长。导致动态变化的条件，例如系统对工程活动的敏感性或密度依赖和密度独立控制的改变，定义了工程概念对生态理解至关重要的情况。
