Post-release survival of translocated Eleutherodactylus coqui in Puerto Rico

Translocating individuals of Eleutherodactylus frogs to alternative, suitable habitat is an adaptation strategy designed to minimize the impact of projected warming and drying in Puerto Rico. The action increases species persistence by increasing spatial redundancy, but it could also be used to supplement extant populations. We released 34 Eleutherodactylus coqui to determine initial, post-release survival under two treatments ? non-translocated (N = 14), and translocated (N=20) to a different location 0.8 km away, but sharing similar habitat and environmental conditions. We defined ?initial? as the first 17 days post-release, a period where we hypothesized that translocated individuals would have lower survival rates because they transition from known-familiar habitat to novel-unfamiliar habitat. Daily survival rates (DSR) were better explained by a model with constant survival and no treatment effect (DSR = 0.999 � 0.001). The best supported model (AICc ? 2) indicated that temperature where frogs perched when captured (in-situ), negatively influenced daily survival, but the effect was weak (95%CIs overlapped 0). All but one of the frogs recaptured gained weight after 17 days post-release (average gain = 0.28 � 0.13 g), suggesting that transmitter/harness setup did not affect foraging behavior. The average daily distance travelled per individual was 0.76 � 0.22 m, being significantly higher for translocated individuals (1.19 � 0.35 m). Findings suggested that managed translocations have the potential to become a useful conservation tool, but challenges remain before it can be considered an integral part of post-translocation monitoring, particularly those Eleutherodactylus species with lower body mass.

将卵齿蟾属（Eleutherodactylus）蛙类个体迁移至替代适宜栖息地，是旨在缓解波多黎各地区预估的气候变暖和干旱化影响的适应性保育策略。该策略通过提升空间冗余度以增强物种种群存续能力，同时也可用于补充现存种群规模。本研究共释放34只科奎树蛙（Eleutherodactylus coqui），以探究两种处理方式下的放归初期存活率：一是非迁移组（样本量N=14），二是迁移组（样本量N=20），后者被转移至0.8公里外、生境与环境条件相似的另一区域。我们将“初始阶段”定义为放归后的前17天，此阶段我们假设迁移个体因从熟悉的原生境转入陌生新环境，存活率将低于非迁移个体。每日存活率（DSR, Daily Survival Rate）可通过恒定存活率且无处理效应的模型得到最优拟合（DSR=0.999±0.001）。最优支持模型（校正赤池信息准则ΔAICc ≤ 2）显示，捕获时蛙类停留位点的原位环境温度对每日存活率存在负向影响，但效应较弱（95%置信区间覆盖0）。在放归17天后被重新捕获的个体中，除1只外其余个体均出现体重增长，平均增重为0.28±0.13克，这表明无线电发射器及背负固定装置的安装并未对蛙类的觅食行为产生影响。每只蛙的日均移动距离为0.76±0.22米，其中迁移个体的日均移动距离显著更高（1.19±0.35米）。研究结果表明，人为调控的蛙类迁移有望成为一项有效的保育手段，但在将其纳入放归后监测的核心环节前仍存在诸多挑战，尤其是针对体型较小的卵齿蟾属（Eleutherodactylus）物种。