Wildlife repatriation is an important tool to decrease extinction risk for imperiled species, but successful repatriations require significant time, resources and planning. Because repatriations can be long and expensive processes, clear release strategies and monitoring programs are essential to efficiently use resources and evaluate success. However, monitoring can be challenging and surrounded by significant uncertainty, particularly for secretive species with extremely low detection probability. Here, we simulated how alternative repatriation strategies influence repatriation success for the eastern indigo snake Drymarchon couperi, a federally‐Threatened species that is currently being repatriated in Alabama and Florida. Critically, we demonstrate how observed population growth can differ from true population growth when detection probabilities are low and mark‐recapture analyses are not an option. Specifically, we built a stochastic stage‐based population model to predict population growth and extinction risk under different release strategies and use information from ongoing repatriations to predict success and guide future releases. Because D. couperi is difficult to monitor, we modeled how detection probability influenced perceptions of abundance and population growth by monitoring programs. Simulated repatriation strategies releasing older, head‐started snakes in greater abundance and frequency created wild populations with decreased extinction risk relative to scenarios releasing fewer and younger snakes less frequently. Ongoing repatriations currently have a 0.23 (Alabama) and 0.61 (Florida) probability of quasi‐extinction, but extinction risk decreased to 0.07 and 0.10 at sites upon achieving the targeted number of releases. Abundances observed under realistic detection thresholds for D. couperi did not always predict true population growth; specifically, we demonstrate that monitoring programs during repatriations of secretive species may indicate that efforts have been unsuccessful when populations are actually growing. Overall, our modeling framework informs release strategies to maximize repatriation success while demonstrating the need to consider how detection processes influence assessment of success during conservation interventions.

中文翻译：

---

在难以捉摸和濒危物种的遣返过程中建模策略和评估成功

野生动物遣返是降低濒危物种灭绝风险的重要工具，但成功的遣返需要大量时间、资源和计划。由于遣返可能是漫长而昂贵的过程，因此明确的释放策略和监控计划对于有效利用资源和评估成功至关重要。然而，监测可能具有挑战性并被重大不确定性所包围，特别是对于检测概率极低的秘密物种。在这里，我们模拟了替代遣返策略如何影响东部靛蓝蛇 Drymarchon couperi 的遣返成功，这是一种目前正在阿拉巴马州和佛罗里达州遣返的联邦受威胁物种。关键的是，我们展示了当检测概率较低且标记重捕获分析不是一种选择时，观察到的人口增长与真实的人口增长有何不同。具体来说，我们建立了一个基于随机阶段的种群模型来预测不同释放策略下的种群增长和灭绝风险，并使用来自正在进行的遣返的信息来预测成功并指导未来的释放。由于 D. couperi 难以监测，我们通过监测程序模拟了检测概率如何影响对丰度和人口增长的看法。与释放更少和更年轻的蛇的情况相比，模拟遣返策略以更高的数量和频率释放更老的、先发制人的蛇，创造了灭绝风险降低的野生种群。正在进行的遣返目前为 0。23（阿拉巴马州）和 0.61（佛罗里达州）准灭绝的概率，但在达到目标释放数量后，灭绝风险降低到 0.07 和 0.10。在实际检测阈值下观察到的 D. couperi 丰度并不总是能预测真实的种群增长。具体来说，我们证明了在秘密物种遣返期间的监测计划可能表明，当种群实际增长时，努力并不成功。总体而言，我们的建模框架为释放策略提供信息，以最大限度地提高遣返成功率，同时证明需要考虑检测过程如何影响保护干预期间的成功评估。在实际检测阈值下观察到的 D. couperi 丰度并不总是能预测真实的种群增长。具体来说，我们证明了在秘密物种遣返期间的监测计划可能表明，当种群实际增长时，努力并不成功。总体而言，我们的建模框架为释放策略提供信息，以最大限度地提高遣返成功率，同时证明需要考虑检测过程如何影响保护干预期间的成功评估。在实际检测阈值下观察到的 D. couperi 丰度并不总是能预测真实的种群增长。具体来说，我们证明了在秘密物种遣返期间的监测计划可能表明，当种群实际增长时，努力并不成功。总体而言，我们的建模框架为释放策略提供信息，以最大限度地提高遣返成功率，同时证明需要考虑检测过程如何影响保护干预期间的成功评估。