Invasive mammal eradications are increasingly attempted across large, complex landscapes. Sequentially controlled management zones can be at risk of reinvasion from adjacent uncontrolled areas, and managers must weigh the relative benefits of ensuring complete elimination from a zone or minimizing reinvasion risk. This is complicated in urban areas, where habitat heterogeneity and a lack of baseline ecological knowledge increase uncertainty. We applied a spatial agent-based model to predict the reinvasion of a well-studied species, the brushtail possum (Trichosurus vulpecula), across an urban area onto a peninsula that is the site of an elimination campaign in Aotearoa New Zealand. We represented fine-scale urban habitat heterogeneity in a land cover layer and tested management scenarios that varied four factors: the density of possums remaining following an elimination attempt, the maintenance trap density on the peninsula, and effort expended toward preventing reinvasion by means of a high-density trap buffer at the peninsula isthmus or control of the source population adjacent to the peninsula. We found that achieving complete elimination on the peninsula was crucial to avoid rapid repopulation. The urban isthmus was predicted to act as a landscape barrier and restrict immigration onto the peninsula, but reliance on this barrier alone would fail to prevent repopulation. In combination, complete elimination, buffer zone, and source population control could reduce the probability of possum repopulation to near zero. Our findings support urban landscape barriers as one tool for sequential invasive mammal elimination but reaffirm that novel methods to expose residual individuals to control will be necessary to secure elimination in management zones. Work to characterize the urban ecology of many invasive mammals is still needed.

中文翻译：

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根除入侵哺乳动物需要局部消除并减少城市源种群的再次入侵


人们越来越多地尝试在大型、复杂的地区消灭入侵哺乳动物。顺序控制的管理区域可能面临邻近不受控制区域重新入侵的风险，管理人员必须权衡确保完全消除区域或尽量减少重新入侵风险的相对收益。这在城市地区很复杂，因为栖息地的异质性和基线生态知识的缺乏增加了不确定性。我们应用基于空间代理的模型来预测经过充分研究的物种刷尾负鼠 ( Trichosurus vulpecula ) 穿过市区重新入侵新西兰新西兰消灭动物运动地点的半岛。我们在土地覆盖层中代表了精细尺度的城市栖息地异质性，并测试了改变四个因素的管理方案：消灭尝试后剩余负鼠的密度、半岛上的维护陷阱密度以及通过防止负鼠再次入侵所付出的努力。高密度陷阱缓冲区位于半岛地峡或控制邻近半岛的源种群。我们发现，在半岛上实现彻底消除对于避免人口迅速重新增加至关重要。预计城市地峡将充当景观屏障并限制移民进入半岛，但仅依靠这一屏障无法防止人口重​​新增加。综合起来，彻底消灭、设立缓冲区和源头控制可以将负鼠重新繁殖的可能性降低到接近于零。我们的研究结果支持城市景观屏障作为连续消除入侵哺乳动物的一种工具，但重申需要采用新的方法将残留个体置于控制之下，以确保在管理区消除。 仍然需要研究许多入侵哺乳动物的城市生态特征。