Population manipulations such as translocation and head‐starting are increasingly used as recovery tools for chelonians. But evaluating success of individual projects can require decades of monitoring to detect population trends in these long‐lived species. Furthermore, there are often few benchmarks from stable, unmanipulated populations against which to compare demographic rates, particularly for the immature stages. We used 8 years of mark‐recapture data to estimate apparent survival of immature gopher tortoises (Gopherus polyphemus) recruited into an introduced population of gopher tortoises first established on St. Catherines Island, Georgia, USA, in 1987. During 2006–2013, we conducted targeted trapping of immature gopher tortoises and compared survival of the hatchling, juvenile and subadult stages among treatments: individuals released shortly after hatching from eggs obtained from gravid female founders (direct releases), individuals reared in captivity for 6–9 months following hatching (head‐starts), and individuals first encountered as free‐ranging, wild‐recruited offspring (wild recruits). Among the candidate models we examined, the best fit model included additive effects of tortoise stage and treatment; however, overlapping 95% credible intervals among treatments (CrI) suggested that survival did not vary significantly among treatments. Annual apparent survival increased over the immature period, highlighting the importance of calculating separate estimates for the different immature stages. Across all treatments, the additive model estimated annual apparent survival probability to be 0.37 (CrI = 0.25–0.48) for hatchlings, 0.71 (CrI = 0.61–0.81) for juveniles, and 0.83 (CrI = 0.74–0.94) for subadults. Our study, in combination with previous monitoring efforts at St. Catherines Island, provides strong evidence that the translocation and subsequent population augmentation efforts have been successful in establishing a robust population of gopher tortoises. Additionally, our results provide estimates of demographic rates for life stages that are poorly understood but critical to understanding population dynamics of this imperiled species. © 2020 The Wildlife Society.

中文翻译：

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招募到未成年人口中的未成熟地鼠龟的生存

人口操纵，例如易位和先发制人，越来越多地被用作克隆人的恢复工具。但是评估单个项目的成功可能需要数十年的监测，才能发现这些长寿物种的种群趋势。此外，来自稳定，未受操纵的人群的基准通常很少，可以用来比较人口统计学的比率，特别是对于未成熟阶段的人口。我们使用了8年的标记回收数据来估计未成熟的地鼠龟（Gopherus polyphemus）的表观存活率）于1987年被招募到最初在美国乔治亚州圣凯瑟琳岛上建立的地鼠龟群。在2006–2013年期间，我们针对性地诱捕了未成熟的地鼠龟，并比较了各处理之间的孵化，幼年和亚成年阶段的存活率：在孵化后不久从个体雌性创建者获得的卵中释放的个体（直接释放），在孵化后被人工饲养的个体饲养6–9个月（开始），以及首次遇到自由放养的野生后代的个体（野生）新兵）。在我们研究的候选模型中，最合适的模型包括乌龟阶段和治疗的相加作用；但是，治疗之间可信区间的95％重叠（CrI）表明，治疗之间的生存期无显着差异。在不成熟时期，年表观存活率增加了，这突出了为不同的不成熟阶段计算单独的估计值的重要性。在所有处理中，加性模型估计的年平均成年存活率分别为：幼鱼0.37（CrI = 0.25–0.48），少年0.71（CrI = 0.61–0.81）和亚成体0.83（CrI = 0.74–0.94）。我们的研究与圣凯瑟琳岛先前的监测工作相结合，提供了有力的证据表明，易位和随后的人口增加工作已成功建立了强大的地鼠龟种群。此外，我们的研究结果提供了人们对生命阶段人口统计率的估计，虽然人们对其了解甚少，但对于了解这一受威胁物种的种群动态至关重要。©2020野生动物协会。