Flynn Rebecca L, Forrester Graham E
Department of Natural Resources Science, University of Rhode Island, Kingston, RI, United States of America.
PeerJ. 2019 May 23;7:e7010. doi: 10.7717/peerj.7010. eCollection 2019.
Community decline is often linked to anthropogenic activities. Coral reef declines, for example, have been linked to overfishing and climate change, but impacts of coastal development, pollution, and tourism have received increasing attention. Here, we isolated the impact of one little-studied aspect of recreational activity on coral reefs-damage from boat anchoring-by performing a survey of 24 sites in the British Virgin Islands (BVI) subject to varying levels of anchoring activity. The percent cover of hard corals and sea fans was reduced by a factor of ∼1.7 and ∼2.6 respectively at highly anchored sites. Hard coral colonies were 40% smaller in surface area and ∼60% less dense at sites experiencing high anchoring frequency. In addition, highly anchored sites supported only ∼60% of the species richness of little anchored sites. Frequently anchored sites were ∼60% as structurally complex and supported less than half as many fish as those rarely anchored, with 5 of 7 fish functional groups affected. Roughly 24% of BVI coral reef by area appears suitable for anchoring, suggesting that impacts associated with boat anchoring may be both locally severe and more pervasive than previously appreciated.
群落衰退通常与人类活动有关。例如，珊瑚礁衰退与过度捕捞和气候变化有关，但沿海开发、污染和旅游业的影响也日益受到关注。在这里，我们通过对英属维尔京群岛（BVI）24个受不同程度锚定活动影响的地点进行调查，分离出娱乐活动中一个较少研究的方面对珊瑚礁的影响——船只抛锚造成的损害。在锚定频繁的地点，硬珊瑚和海扇的覆盖百分比分别降低了约1.7倍和约2.6倍。在锚定频率高的地点，硬珊瑚群落的表面积小40%，密度低约60%。此外，锚定频繁的地点的物种丰富度仅为锚定较少地点的约60%。频繁抛锚的地点的结构复杂性约为很少抛锚地点的60%，所支持的鱼类数量不到很少抛锚地点的一半，7个鱼类功能组中有5个受到影响。英属维尔京群岛约24%的珊瑚礁区域似乎适合抛锚作业，这表明与船只抛锚相关的影响可能在局部地区很严重，且比之前认为的更为普遍。
