Ecological traps for large-scale invasive species control: predicting settling rules by recolonising American mink post-culling

1. Management programs worldwide seeking to reduce the density of invasive species must overcome compensatory processes, such as recolonisation by dispersers from non- or partially-controlled areas. However, the scale and drivers of dispersal in such context are poorly known. 2. We investigated the dispersal patterns of American mink reinvading 20,000 km2 of their non-native range following a culling programme led by citizen conservationists. Using multinomial models, we estimated the contributions of density dependence, proxies for patch quality and distance from the natal patch on mink settlement. 3. Seventy seven percent of mink dispersed and settled in non-natal patches. Dispersal distances were large with settlement probabilities only reduced by half at ~60 km, and 20% of mink dispersing > 80 km. 4. Females were more attracted to patches of high quality mostly found at low altitudes. Males favoured patches with intermediate current densities and consistently high quality. ...1. 全球范围内旨在降低入侵物种种群密度的管理方案，均需克服补偿过程（compensatory processes）——例如来自未管控或部分管控区域的扩散个体（dispersers）所引发的重新定殖（recolonisation）。但目前学界对该情境下扩散（dispersal）的规模与驱动因素仍知之甚少。 2. 本研究针对经市民保育人士（citizen conservationists）主导灭杀项目后，重新入侵20000平方千米非原生分布区的美洲水鼬（American mink），分析其扩散模式。我们采用多项模型（multinomial models），量化了密度依赖（density dependence）、生境斑块（habitat patch）质量代理指标，以及与出生斑块（natal patch）的距离对水鼬定居（settlement）的贡献程度。 3. 77%的水鼬发生扩散并在非出生斑块定居。其扩散距离极远：在约60千米处，定居概率仅下降一半，且有20%的水鼬扩散距离超过80千米。 4. 雌性水鼬更倾向于选择高质量生境斑块，这类斑块多分布于低海拔区域；雄性则偏好当前种群密度适中且质量始终较高的生境斑块。