Spatiotemporal effects of Hurricane Ivan on an endemic epiphytic orchid: 10 years of follow-up

<b>Background</b>: Hurricanes have a strong influence on the ecological dynamics and structure of tropical forests. Orchid populations are especially vulnerable to these perturbations due to their canopy exposure and lack of underground storage organs and seed banks. <b>Aims</b>: We evaluated the effects of Hurricane Ivan on the population of the endemic epiphytic orchid <i>Encyclia bocourtii</i> to propose a management strategy. <b>Methods</b>: Using a pre- and post-hurricane dataset (2003–2013), we assessed the population asymptotic and transient dynamics. We also identified the individual size-stages that maximise population inertia and <i>E. bocourtii</i>’s spatial arrangement relative to phorophytes and other epiphytes. <b>Results</b>: Hurricane Ivan severely affected the survival and growth of individuals of <i>E. bocourtii</i>, and caused an immediate decline of the population growth rate from λ = 1.05 to λ = 0.32, which was buffered by a population reactivity of ρ₁ = 1.42. Our stochastic model predicted an annual population decrease of 14%. We found an aggregated spatial pattern between <i>E. bocourtii</i> and its host trees, and a random pattern relative to other epiphytes. <b>Conclusion</b>: Our findings suggest that <i>E. bocourtii</i> is not safe from local extinction. We propose the propagation and reintroduction of reproductive specimens, the relocation of surviving individuals, and the establishment of new plantations of phorophytes.

**研究背景**：飓风对热带森林的生态动态与群落结构具有显著影响。兰科植物种群由于其冠层暴露的生长特性，且缺乏地下贮藏器官与种子库，对这类扰动尤为敏感。**研究目的**：本研究评估伊万飓风对特有附生兰<i>Encyclia bocourtii</i>种群的影响，旨在提出针对性的管理策略。**研究方法**：本研究利用飓风前后（2003–2013年）的数据集，评估了该种群的渐近动态（asymptotic dynamics）与瞬时动态（transient dynamics）；同时明确了使种群惯性（population inertia）达到最大的个体大小级，以及<i>E. bocourtii</i>相对于附生宿主（phorophyte）与其他附生植物的空间分布格局。**研究结果**：伊万飓风严重影响了<i>E. bocourtii</i>个体的存活与生长，使其种群增长率λ从1.05骤降至0.32，而种群反应性（population reactivity）ρ₁=1.42缓解了这一下降幅度。本研究的随机模型预测，该种群将以每年14%的速率下降。研究发现，<i>E. bocourtii</i>与其宿主树之间呈聚集分布格局，而与其他附生植物之间则呈随机分布格局。**研究结论**：本研究结果表明，<i>E. bocourtii</i>仍面临局域灭绝的风险。据此，我们提出以下管理策略：繁殖并再引入具备繁殖能力的个体，对存活个体进行重新安置，以及种植更多的附生宿主树。