Release methods can influence the outcome of reintroductions. We tested the effect of delayed, immediate and supplementary food/shelter release treatments on the reintroduction of brushtail possums Trichosurus vulpecula to an environment in which introduced predators, particularly foxes, were subject to control. Monitoring of 48 radio-collared possums over 3 months revealed that immediate release possums settled into a stable range significantly faster than other groups, but there were no differences in survival, dispersal distance, reproduction or body condition. Ten days after release possums from all treatment groups had lost body mass, but by day 60 most were heavier than at the time of translocation. After release, possums sometimes used shelter sites easily accessible to predators, but within 3 weeks they regularly selected safer shelter. Risky shelter selection and loss of condition immediately after release suggests that supplementary food and shelter could be beneficial, but supportive measures were rarely used or did not have the desired effect. In an environment with higher predator densities, risky shelter selection could lead to high post-release predation, and mass loss could encourage animals to forage in riskier ways, further increasing vulnerability. In these environments effective uptake of supplementary food and shelter could reduce predation risk, but supplementary measures would need to be presented in a way that maximises uptake. In contrast, if post-release predation risk is low then supportive measures may not be required. Innovative methods for providing post-release support should continue to be developed for reintroductions to areas where supportive measures are needed.

中文翻译：

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当功效和摄取低时，支持性释放技术不会提供重新引入的益处

释放方法会影响重新引入的结果。我们测试了延迟、立即和补充食物/庇护所释放处理对重新引入刷尾负鼠的影响毛毛虫引入的捕食者，特别是狐狸，受到控制的环境。在 3 个月内对 48 只带无线电项圈的负鼠进行的监测显示，立即释放的负鼠比其他组明显更快地进入稳定范围，但在生存、散布距离、繁殖或身体状况方面没有差异。从所有治疗组释放负鼠十天后，体重都下降了，但到了第 60 天，大多数负鼠比易位时更重。释放后，负鼠有时会使用捕食者容易到达的庇护所，但在 3 周内，它们会定期选择更安全的庇护所。危险的避难所选择和释放后立即失去条件表明补充食物和避难所可能是有益的，但很少使用支持性措施或没有达到预期的效果。在捕食者密度较高的环境中，危险的避难所选择可能导致放归后的高捕食率，而质量损失可能会鼓励动物以更危险的方式觅食，从而进一步增加脆弱性。在这些环境中，有效摄取补充食物和住所可以降低捕食风险，但需要以最大化摄取的方式提出补充措施。相反，如果释放后捕食风险较低，则可能不需要支持措施。应继续开发提供释放后支持的创新方法，以便重新引入需要支持措施的地区。进一步增加脆弱性。在这些环境中，有效摄取补充食物和住所可以降低捕食风险，但需要以最大化摄取的方式提出补充措施。相反，如果释放后捕食风险较低，则可能不需要支持措施。应继续开发提供释放后支持的创新方法，以便重新引入需要支持措施的地区。进一步增加脆弱性。在这些环境中，有效摄取补充食物和住所可以降低捕食风险，但需要以最大化摄取的方式提出补充措施。相反，如果释放后捕食风险较低，则可能不需要支持措施。应继续开发提供释放后支持的创新方法，以便重新引入需要支持措施的地区。