The importance of including survival release costs when assessing viability in reptile translocations
The importance of including survival release costs when assessing viability in reptile translocations
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DOI：
10.1016/j.biocon.2017.11.023
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发表时间：
2018-01-01
影响因子：
5.9
通讯作者：
Oro, Daniel
中科院分区：
文献类型：
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作者：
Bertolero, Albert;Pretus, Joan Ll.;Oro, Daniel
恢复濒危物种种群的易位是一个重要的保护工具，但需要一个可靠的诊断来评估它们的成功。我们使用捕获-再捕获模型分析了西班牙两个迁移项目中14年和29年监测的释放和居住陆龟的成年表观存活率。我们测试了放生个体和常驻个体之间的长期存活率是否不同，在建立阶段（即放生成本）存活率是否较低，适应持续多长时间，以及放生导致的密度增加是否会影响存活率。我们发现，在建立阶段（1至3年），当居民已经存在时，释放的龟存活率较低。建立后，存活率非常高，不受密度依赖的影响。重新捕获的陆龟和死亡/失踪的陆龟在释放前的身体状况相似，并且不能预测生存。随机种群生存力分析表明，少量放生的成功与否很大程度上取决于成虫的长期存活。不管放生的时间如何，第二批放生的陆龟对数量的增长并不敏感。我们的研究结果强调了长期生存在长寿命物种的易位项目中是至关重要的，当生存释放成本与长期生存不匹配时，短期（第一年）生存评估无效。在建模预测之前，应该在模型估计中包含不同持续时间的发布成本。在大多数情况下，不建议在已经建立的种群中释放陆龟（为了圈养的个体的福利或减轻人类的负面影响）。适应成本紧随其后的是接近野生同类的生存成本。如果没有达到这个里程碑，则需要仔细评估项目以采用其他管理选择，或者应该完全停止。
Translocations to restore populations of endangered species are an important conservation tool, but a reliable diagnosis is needed to assess their success. We used capture-recapture modeling to analyze the adult apparent survival of released and resident tortoises in two translocation projects in Spain monitored for 14 and 29 years. We tested if long-term survival rates differ between released and resident individuals, if survival was lower during the phase of establishment (i.e. release cost), how long acclimation lasts and if increased density due to releases affects survival. We found lower survival of released tortoises during the phase of establishment (1 to 3 years) when residents were already present. After establishment, survival was very high and unaffected by density-dependence. Body condition before release was similar between recaptured and dead/missing tortoises, and did not predict establishment survival. Stochastic population viability analysis showed that success when releasing small numbers of individuals strongly depends upon adult long-term survival. Release of small second batches of tortoises was not sensitive to a growing population, regardless of its release timing. Our results highlight long-term survival as crucial in translocation projects of long-lived species, invalidating short-term (first year) survival assessment, when survival release cost does not match long-term survival. A release cost of different duration should be included in model estimation before modeling predictions. Releasing tortoises (for welfare of captive individuals or for mitigating human negative impacts) in an already established population is not recommended under most circumstances. Acclimation cost is followed by survival approaching wild counterparts. If this milestone is not achieved, the project needs to be carefully assessed to adopt other management options or should be stopped altogether.