The colonization model formulates competition among propagules for habitable sites to colonize, which serves as a mechanism enabling coexistence of multiple species. This model traditionally assumes that encounters between propagules and sites occur as mass action events, under which species distribution can eventually reach an equilibrium state with multiple species in a constant environment. To investigate the effects of encounter mode on species diversity, we analyzed community dynamics in the colonization model by varying encounter processes. The analysis indicated that equilibrium is approximately neutrally-stable under perfect ratio-dependent encounter, resulting in temporally continuous variation of species’ frequencies with irregular trajectories even under a constant environment. Although the trajectories significantly depend on initial conditions, they are considered to be “strange nonchaotic attractors” (SNAs) rather than chaos from the asymptotic growth rates of displacement. In addition, trajectories with different initial conditions remain different through time, indicating that the system involves an infinite number of SNAs. This analysis presents a novel mechanism for transient dynamics under competition.

定植模型制定了繁殖体之间为可居住地点进行定植的竞争，这是一种使多种物种共存的机制。该模型传统上假设繁殖体和地点之间的相遇是作为群体作用事件发生的，在这种情况下，物种分布最终可以在恒定环境中达到多个物种的平衡状态。为了研究相遇模式对物种多样性的影响，我们通过不同的相遇过程分析了殖民模型中的群落动态。分析表明，在完全依赖比率的相遇下，平衡近似中性稳定，导致即使在恒定环境下，物种频率也会随时间连续变化，轨迹不规则。尽管轨迹在很大程度上取决于初始条件，但它们被认为是“奇怪的非混沌吸引子”（SNA），而不是位移渐近增长率造成的混沌。此外，具有不同初始条件的轨迹随时间保持不同，表明系统涉及无限数量的 SNA。该分析提出了一种新的竞争瞬态动力学机制。