Biodiversity influences the effects of oil disturbance on coastal ecosystems

Biodiversity can enhance the response of ecosystems to disturbance. However, whether diversity can reduce the ecological effect of human-induced novel and extreme disturbances is unclear. In April 2010, the Deepwater Horizon (DwH) platform exploded, allowing an uncontrolled release of crude oil into the northern Gulf of Mexico. Initial surveys following the spill found that ecological impacts on coastal ecosystems varied greatly across habitat-type and trophic group; however, to date, few studies have tested the influence of local biodiversity on these responses. We used a meta-analytic approach to synthesize the results of 5 mesocosm studies that included 10 independent oil experiments and 5 independent oil + dispersant experiments. We tested whether biodiversity increased the resistance and/or resilience of coastal ecosystems to oil disturbance, and whether a biodiversity effect depended on the type of diversity present (taxonomic or genetic) and/or the response type measured (population, community or ecosystem-level). We found that diversity can influence the effects of oiling, but the direction and magnitude of this diversity effect varied. Diversity reduced the negative impact of oiling for within-trophic-level responses, and tended to be stronger for taxonomic than genetic diversity. Further, diversity effects were largely driven by the presence of highly resistant or quick to recover taxa and genotypes, consistent with the insurance hypothesis. However, we found no effect of diversity on the response to the combination of oil and dispersant exposure. We conclude that areas of low biodiversity may be particularly vulnerable to future oil disturbances and provide insight into the benefit of incorporating multiple measures of diversity in restoration projects and management decisions.

生物多样性可增强生态系统对干扰的响应能力。然而，生物多样性是否能够减轻人类活动引发的新型极端干扰所带来的生态影响，目前尚不明确。2010年4月，深水地平线（Deepwater Horizon, DwH）钻井平台发生爆炸，导致大量原油未经控制地泄漏至墨西哥湾北部海域。溢油事故后的初步调查显示，沿海生态系统所受的生态影响因生境类型与营养类群的不同差异显著；但截至目前，鲜有研究探讨本地生物多样性对上述响应的调控作用。本研究采用元分析方法，整合了5项中型实验生态系统（mesocosm）研究的数据，这些研究包含10项独立的石油暴露实验与5项独立的石油+分散剂联合暴露实验。本研究旨在验证两个科学问题：其一，生物多样性是否能够提升沿海生态系统应对石油干扰的抵抗能力与/或恢复能力；其二，生物多样性的效应是否取决于所考量的多样性类型（分类多样性或遗传多样性）以及/或所测定的响应层级（种群、群落或生态系统层级）。研究结果表明，生物多样性可影响石油暴露的生态效应，但该效应的方向与强度存在差异。针对营养级内的响应指标，生物多样性可缓解石油暴露带来的负面影响，且分类多样性的缓解效应通常强于遗传多样性。此外，生物多样性的效应主要由高抵抗性或快速恢复的类群与基因型所驱动，这与保险假说（insurance hypothesis）的预测相符。但本研究未发现生物多样性对石油与分散剂联合暴露的响应存在显著影响。本研究得出结论：生物多样性较低的区域可能更易受到未来石油干扰的影响；同时，本研究也为修复项目与管理决策中纳入多维度多样性指标的益处提供了理论依据。