Data from: Projecting the recovery of a long-lived deep-sea octocoral species after the Deepwater Horizon oil spill using structured population models

1. Deep-water coral communities are hotspots of diversity and biomass in the deep sea. Most deep-sea coral species are long-lived and slow-growing, and are thus expected to recover slowly after disturbance. A better understanding of the recovery potential of these organisms is necessary to make appropriate management decisions. 2. We used data from high resolution monitoring of individual coral colonies that were impacted by the Deepwater Horizon oil spill (April 2010) to parameterise and validate an annual, impact-dependent, state-structured matrix model to estimate the time to recovery for each coral colony. We projected the dynamics of three branch states: visibly healthy, unhealthy and hydroid-colonized. Although we implicitly included branch loss in the model, we focused on the short-term return of extant, damaged, branches to a visibly healthy state and did not consider the far longer-term re-growth of lost branches. 3. Our model estimates that, depending on the initial level of impact, corals impacted by the spill will take up to three decades to recover to a state where all remaining branches appear healthy, though the majority of corals are projected to reach that state within a decade. By that time, some of these colonies will have lost a significant number of branches, leading to approximately 10% reduction in total biomass at all impacted sites. 4. Overall, our model overestimates recovery, but branch loss estimates were reliable. Thus, the available growth rate data suggest that hundreds of years may be necessary for impacted communities to grow back to their initial biomass. 5. Policy implications. Our study quantifies the very slow recovery rate of deep-sea corals and demonstrates the imperative of prioritizing a precautionary approach for these deep-sea ecosystems over restoration after the fact. As anthropogenic pressure on the deep sea is likely to increase, we suggest the establishment of coral-monitoring sites implemented as part of Marine Protected Areas to limit and detect impact to deep-sea corals. Furthermore, estimates from our model may be used to plan short- and longer-term monitoring programmes after impact and to provide a timeline for policy.09-Feb-20181. 深海珊瑚群落（deep-water coral communities）是深海中生物多样性与生物量的热点区域。多数深海珊瑚物种寿命长且生长缓慢，因此受干扰后恢复速度极慢。为制定合理的管理决策，亟需深入了解这类生物的恢复潜力。 2. 我们利用2010年4月深水地平线漏油事件（Deepwater Horizon oil spill）影响的单个珊瑚群体的高分辨率监测数据，对年度、依赖干扰的状态结构化矩阵模型进行参数化与验证，以估算每个珊瑚群体的恢复时长。我们针对三种分枝状态进行动态预测：外观健康、不健康以及被水螅虫定植的。尽管模型中隐含纳入了分枝损失，但本研究聚焦于现存受损分枝短期恢复至外观健康状态的过程，未考虑受损分枝丢失后的长期再生过程。 3. 模型估算结果显示，根据初始干扰程度的不同，受漏油事件影响的珊瑚群体最长需长达三十年，才能恢复至所有剩余分枝均外观健康的状态；不过多数珊瑚群体预计可在十年内达成该状态。到恢复完成时，部分珊瑚群体已丢失大量分枝，导致所有受影响站点的总生物量约降低10%。 4. 总体而言，本模型高估了恢复速率，但分枝损失的估算结果可靠。因此，现有生长速率数据表明，受干扰的珊瑚群落可能需要数百年才能恢复至初始生物量水平。 5. 政策启示。本研究量化了深海珊瑚极慢的恢复速率，证明相较于事后修复，优先为这类深海生态系统采取预防性措施的紧迫性。随着深海面临的人为压力持续增加，我们建议将珊瑚监测站点纳入海洋保护区（Marine Protected Areas）建设，以限制并及时探测对深海珊瑚的干扰。此外，本模型的估算结果可用于规划受干扰后的短期与长期监测计划，并为政策制定提供时间框架。2018年2月9日