Mumby Peter J, Harborne Alastair R, Williams Jodene, Kappel Carrie V, Brumbaugh Daniel R, Micheli Fiorenza, Holmes Katherine E, Dahlgren Craig P, Paris Claire B, Blackwell Paul G
Marine Spatial Ecology Lab, School of BioSciences, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, United Kingdom.
Proc Natl Acad Sci U S A. 2007 May 15;104(20):8362-7. doi: 10.1073/pnas.0702602104. Epub 2007 May 8.
Reduced fishing pressure and weak predator-prey interactions within marine reserves can create trophic cascades that increase the number of grazing fishes and reduce the coverage of macroalgae on coral reefs. Here, we show that the impacts of reserves extend beyond trophic cascades and enhance the process of coral recruitment. Increased fish grazing, primarily driven by reduced fishing, was strongly negatively correlated with macroalgal cover and resulted in a 2-fold increase in the density of coral recruits within a Bahamian reef system. Our conclusions are robust because four alternative hypotheses that may generate a spurious correlation between grazing and coral recruitment were tested and rejected. Grazing appears to influence the density and community structure of coral recruits, but no detectable influence was found on the overall size-frequency distribution, community structure, or cover of corals. We interpret this absence of pattern in the adult coral community as symptomatic of the impact of a recent disturbance event that masks the recovery trajectories of individual reefs. Marine reserves are not a panacea for conservation but can facilitate the recovery of corals from disturbance and may help sustain the biodiversity of organisms that depend on a complex three-dimensional coral habitat.
海洋保护区内捕捞压力的降低以及捕食者与猎物之间相互作用的减弱,会引发营养级联效应,增加食草鱼类的数量,并减少珊瑚礁上大型藻类的覆盖面积。在此,我们表明保护区的影响不仅限于营养级联效应,还能促进珊瑚的补充过程。主要由捕捞减少驱动的鱼类啃食增加,与大型藻类覆盖面积呈强烈负相关,并导致巴哈马珊瑚礁系统内珊瑚幼体密度增加了两倍。我们的结论很可靠,因为对可能导致啃食与珊瑚补充之间产生虚假关联的四个替代假设进行了检验并予以否定。啃食似乎会影响珊瑚幼体的密度和群落结构,但未发现对珊瑚的总体大小频率分布、群落结构或覆盖面积有可检测到的影响。我们将成年珊瑚群落中这种缺乏规律的现象解释为近期干扰事件影响的症状,该事件掩盖了各个珊瑚礁的恢复轨迹。海洋保护区并非保护的万灵药,但可以促进珊瑚从干扰中恢复,并可能有助于维持依赖复杂三维珊瑚栖息地的生物多样性。