Data from: Hybridization, species collapse, and species reemergence after disturbance to premating mechanisms of reproductive isolation

There are now a number of well-studied cases in which hybridization between closely related sympatric species has increased, sometimes resulting in the replacement of species pairs by hybrid swarms. Many of these cases have been linked to anthropogenic environmental change, but the mechanisms leading from environmental change to species collapse, and the long-term effects of hybridization on species pairs, remain poorly understood. We used an individual-based stochastic simulation model to explore the conditions under which disturbances that weaken premating barriers to reproduction between sympatric species might lead to increased hybridization and to species collapse. Disturbances often resulted in bouts of hybridization, but in many cases strong reproductive isolation spontaneously reemerged. This was sometimes true even after hybrid swarms had replaced parental species. The reemergence of species pairs was most likely when disturbances were of short duration. Counterintuitively, incipient species pairs were more likely to reemerge after strong but temporary disturbances than after weaker disturbances of the same duration. Even temporary bouts of hybridization often led to substantial homogenization of species pairs. This suggests that ecosystem managers may be able to refill ecological niches, but in general will not be able to resurrect lost species after species collapse.

目前已有多项被充分研究的案例证实，亲缘关系相近的同域物种（sympatric species）之间的杂交频率有所上升，部分案例中甚至出现杂交种群（hybrid swarms）取代原生物种种对的情况。其中多数关联于人为环境变化（anthropogenic environmental change），但从环境变化演变为物种种群崩溃的具体机制，以及杂交对物种种对产生的长期影响，目前仍知之甚少。
本研究采用基于个体的随机模拟模型（individual-based stochastic simulation model），探究了削弱同域物种种间交配前生殖障碍（premating barriers to reproduction）的干扰因素，在何种条件下会引发杂交事件增多并最终导致物种种群崩溃。
干扰因素往往会引发多轮杂交事件，但在多数情形下，强烈的生殖隔离会自发重建。即便在杂交种群取代亲本物种之后，这种情况也时有发生。
当干扰持续时长较短时，物种种对重建的可能性最高。与直觉相悖的是，相较于持续时长相同但强度较弱的干扰，高强度且短暂的干扰更易促成初期物种种对（incipient species pairs）的重建。
即便只是短暂的杂交事件，也往往会导致物种种对发生显著的同质化（homogenization）。这一结果提示，生态系统管理者或许能够填补生态位（ecological niches）缺口，但总体而言，在物种种群崩溃后，无法实现已消失物种的复活。