Edmunds P J, Carpenter R C
Department of Biology, California State University, Northridge, CA 91330-8303, USA.
Proc Natl Acad Sci U S A. 2001 Apr 24;98(9):5067-71. doi: 10.1073/pnas.071524598. Epub 2001 Mar 27.
The transition of many Caribbean reefs from coral to macroalgal dominance has been a prominent issue in coral reef ecology for more than 20 years. Alternative stable state theory predicts that these changes are reversible but, to date, there is little indication of this having occurred. Here we present evidence of the initiation of such a reversal in Jamaica, where shallow reefs at five sites along 8 km of coastline now are characterized by a sea urchin-grazed zone with a mean width of 60 m. In comparison to the seaward algal zone, macroalgae are rare in the urchin zone, where the density of Diadema antillarum is 10 times higher and the density of juvenile corals is up to 11 times higher. These densities are close to those recorded in the late 1970s and early 1980s and are in striking contrast to the decade-long recruitment failure for both Diadema and scleractinians. If these trends continue and expand spatially, reefs throughout the Caribbean may again become dominated by corals and algal turf.
20多年来，许多加勒比珊瑚礁从以珊瑚为主导转变为以大型藻类为主导，一直是珊瑚礁生态学中的一个突出问题。替代稳定状态理论预测这些变化是可逆的，但迄今为止，几乎没有迹象表明这种逆转已经发生。在此，我们展示了牙买加出现这种逆转的证据，在该国8公里长海岸线上的五个地点，浅海珊瑚礁现在的特征是有一个平均宽度为60米的海胆啃食区。与向海藻类区相比，大型藻类在海胆区很罕见，在海胆区，刺冠海胆的密度高10倍，幼体珊瑚的密度高达11倍。这些密度接近20世纪70年代末和80年代初记录的密度，与刺冠海胆和石珊瑚长达十年的补充失败形成鲜明对比。如果这些趋势继续并在空间上扩展，整个加勒比地区的珊瑚礁可能会再次由珊瑚和藻草主导。
