Dataset and code for "Unexpected effect of geographic origin on post-translocation survival in a long-lived reptile"

Data include release and mortality information for 2,822 gopher tortoises (<i>Gopherus polyphemus</i>) translocated to Nokuse, a private reserve in the panhandle of Florida. Mitigation translocations move wildlife from specific areas due to conflict with humans over land use at the site. A critical decision when carrying out mitigation translocation is the acceptable distance across which animals can be moved. This decision trades off logistical expediency of unrestricted translocation with the risk of reducing translocation success due to environmental mismatch between origin and translocation site conditions. In this study, we used a large dataset of 502 individually identifiable carcasses to examine the role of geographic origin and translocation distance in the relative survival of 2,822 translocated subadult and adult gopher tortoise<i>s (Gopherus polyphemus</i>), a species experiencing large-scale mitigation translocation, at a recipient site in the Florida panhandle, USA. We hypothesized that if climate or habitat differences between the origin and translocation site influenced survival, tortoises translocated from within the Florida panhandle would have the highest survival. To the contrary, we found that survival slightly increased with increasing climatic difference between origin and recipient site, driven by higher survival of tortoises coming from central Florida sites compared to those from the panhandle and north Florida. This suggests that environmental mismatch due to long-distance translocation is not a main driver of mortality. These models also indicated an effect of season, with a survival advantage to tortoises translocated in the spring and late fall, relative to summer translocations, and a negative effect of initial density on survival. Finally, we also estimated the upper bound on annual survival in three well-monitored groups to be quite low (92-95%) for several years following release, suggesting caution when considering large translocated populations to be viable without first assessing adult survival. Our unexpected results highlight the importance of investigating species-specific sensitivities to translocation distances and indicate the limitations of assumed linear effects of translocation distance on outcomes.<br>

本数据集涵盖2822只哥法地鼠龟（Gopherus polyphemus）的放归与死亡相关信息，这些个体被迁地至美国佛罗里达狭长地带的私人保护区诺库塞（Nokuse）。
缓解性迁地（mitigation translocation）指因原区域土地利用与人类活动产生冲突，将特定区域的野生动物迁移至其他区域的保护操作。开展此类迁地项目时，一项核心决策是允许的动物迁移距离阈值。该决策需要权衡无限制迁地的后勤便捷性，以及因原生境与接收地环境不匹配导致迁地成功率下降的风险。
本研究依托包含502只可个体识别的死亡个体的大型数据集，针对美国佛罗里达狭长地带某接收地的2822只被迁地的亚成体与成体哥法地鼠龟展开分析，探究地理起源与迁地距离对其相对存活率的影响——该物种正面临大规模的缓解性迁地保护操作。
我们提出研究假设：若原生境与接收地的气候或生境差异对个体存活存在影响，那么从佛罗里达狭长地带内部迁出的个体存活率应最高。
但与之相反，研究结果显示，个体存活率随原生境与接收地的气候差异增大而略有提升，这一趋势源于来自佛罗里达中部种群的个体存活率高于来自狭长地带与北佛罗里达的个体。这表明长距离迁地带来的环境不匹配并非导致个体死亡的主要驱动因素。
模型分析还揭示了季节效应：相较于夏季放归的个体，春季与晚秋放归的哥法地鼠龟存活率更高；而初始种群密度对存活率存在负面影响。
最后，我们对3个监测完备的种群组估算得到放归后数年内的年存活率上限较低（92%~95%），这提示在未先评估成体存活率的情况下，贸然认定大规模迁地种群可实现长期存活需谨慎。
本研究的意外结果凸显了探究物种对迁地距离特异性敏感性的重要性，同时也表明“迁地距离对保护结果存在线性影响”这一预设假设的局限性。