Data_Sheet_1_Managing Recovery Resilience in Coral Reefs Against Climate-Induced Bleaching and Hurricanes: A 15 Year Case Study From Bonaire, Dutch Caribbean.docx

Coral reefs are among the world’s most endangered ecosystems. Coral mortality can result from ocean warming or other climate-related events such as coral bleaching and intense hurricanes. While resilient coral reefs can recover from these impacts as has been documented in coral reefs throughout the tropical Indo-Pacific, no similar reef-wide recovery has ever been reported for the Caribbean. Climate change-related coral mortality is unavoidable, but local management actions can improve conditions for regrowth and for the establishment of juvenile corals thereby enhancing the recovery resilience of these ecosystems. Previous research has determined that coral reefs with sufficient herbivory limit macroalgae and improve conditions for coral recruitment and regrowth. Management that reduces algal abundance increases the recovery potential for both juvenile and adult corals on reefs. Every other year on the island of Bonaire, Dutch Caribbean, we quantified patterns of distribution and abundance of reef fish, coral, algae, and juvenile corals along replicate fixed transects at 10 m depth at multiple sites from 2003 to 2017. Beginning with our first exploratory study in 2002 until 2007 coral was abundant (45% cover) and macroalgae were rare (6% cover). Consecutive disturbances, beginning with Hurricane Omar in October 2008 and a coral bleaching event in October 2010, resulted in a 22% decline in coral cover and a sharp threefold increase in macroalgal cover to 18%. Juvenile coral densities declined to about half of their previous abundance. Herbivorous parrotfishes had been declining in abundance but stabilized around 2010, the year fish traps were phased out and fishing for parrotfish was banned. The average parrotfish biomass from 2010 to 2017 was more than twice that reported for coral reefs of the Eastern Caribbean. During this same period, macroalgae declined and both juvenile coral density and total adult coral cover returned to pre-hurricane and bleaching levels. To our knowledge, this is the first example of a resilient Caribbean coral reef ecosystem that fully recovered from severe climate-related mortality events.

珊瑚礁是全球最濒危的生态系统之一。珊瑚死亡可由海洋变暖或其他气候相关事件引发，例如珊瑚白化与强飓风。尽管具有恢复力的珊瑚礁可从这些扰动中复苏，这一现象在热带印度-太平洋海域的珊瑚礁中已有大量记录，但加勒比海地区从未有过类似的全礁尺度恢复案例被报道。气候变化引发的珊瑚死亡虽无法避免，但本地管理措施可改善珊瑚复育以及幼珊瑚定植的环境，从而提升这些生态系统的恢复韧性。既往研究表明，拥有充足植食性生物的珊瑚礁可抑制大型藻类生长，改善珊瑚幼体招募与复育的环境条件。通过管理手段降低藻类丰度，可提升礁体上幼珊瑚与成体珊瑚的恢复潜力。2003年至2017年间，我们在荷属加勒比海的博奈尔岛，每隔一年于多个站点的10米水深处，沿重复固定样带量化了礁区鱼类、珊瑚、藻类以及幼珊瑚的分布与丰度格局。自2002年首次探索性研究至2007年，珊瑚盖度高达45%，大型藻类盖度仅为6%，处于较低水平。2008年10月的飓风奥马尔与2010年10月的珊瑚白化事件接连发生，引发珊瑚盖度下降22%，大型藻类盖度则骤增3倍至18%，幼珊瑚密度降至此前丰度的约一半。植食性鹦嘴鱼的丰度曾持续下降，但在2010年前后趋于稳定——该年当地逐步淘汰了渔笼并禁止捕捞鹦嘴鱼。2010年至2017年间，鹦嘴鱼的平均生物量是东加勒比海珊瑚礁所记录的平均生物量的两倍以上。同期，大型藻类盖度逐渐下降，幼珊瑚密度与成体珊瑚总盖度均恢复至飓风与白化事件前的水平。据我们所知，这是加勒比海地区首个经记录的、可从严重气候相关珊瑚死亡事件中完全恢复的具有恢复韧性的珊瑚礁生态系统案例。