Small herbivores suppress algal accumulation on Agatti atoll, Indian Ocean
Small herbivores suppress algal accumulation on Agatti atoll, Indian Ocean
复制标题
DOI：
10.1007/s00338-015-1331-x
复制
发表时间：
2015-12-01
期刊：
影响因子：
3.5
通讯作者：
Horsak, Michal
中科院分区：
文献类型：
--
作者：
Cernohorsky, Nicole H.;McClanahan, Timothy R.;Horsak, Michal
尽管大型草食性鱼类被普遍认为是防止珊瑚礁上藻类积累的主要群体，但很少有研究通过实验检验草食性鱼类的大小对藻类群落的相对重要性。本研究使用两种不同网格尺寸（1 x 1 cm 和 6 x 6 cm）的排除网箱来研究不同尺寸的食草动物对拉克沙群岛阿加蒂环礁浅层（< 2 m）后礁藻类积累率的影响。细网网箱排除了所有可见的食草动物，这对底栖群落产生了快速而持久的影响，并且在部署127天后，藻类（主要是大型藻类）明显增加，藻类数量是邻近开放区域的13倍。粗网网箱排除较大的鱼类（> 8 厘米体深），同时允许较小的鱼类进入区域。与大多数先前研究的结论相反，排除大型食草动物对底栖藻类的积累没有显着影响，并且在整个实验期间，粗网网箱内存在的藻类数量相对稳定（覆盖率约为 50%，高度为 1-2 毫米）。细网和粗网网箱之间藻类积累的差异似乎与能够通过粗网进入的12种草食性鱼类（0.17 ind. m(-2)和7.7 g m(-2)）的小个体的活动有关。尽管仅限于单一栖息地，但这些结果表明，当存在足够的密度和多样性时，小型草食性鱼类可以防止珊瑚礁上藻类生物量的积累。
Despite large herbivorous fish being generally accepted as the main group responsible for preventing algal accumulation on coral reefs, few studies have experimentally examined the relative importance of herbivore size on algal communities. This study used exclusion cages with two different mesh sizes (1 x 1 cm and 6 x 6 cm) to investigate the impact of different-sized herbivores on algal accumulation rates on the shallow (< 2 m) back-reef of Agatti atoll, Lakshadweep. The fine-mesh cages excluded all visible herbivores, which had rapid and lasting effects on the benthic communities, and, after 127 d of deployment, there was a visible and significant increase in algae (mainly macroalgae) with algal volume being 13 times greater than in adjacent open areas. The coarse-mesh cages excluded larger fishes (> 8 cm body depth) while allowing smaller fishes to access the plots. In contrast to the conclusions of most previous studies, the exclusion of large herbivores had no significant effect on the accumulation of benthic algae and the amount of algae present within the coarse-mesh cages was relatively consistent throughout the experimental period (around 50 % coverage and 1-2 mm height). The difference in algal accumulation between the fine-mesh and coarse-mesh cages appears to be related to the actions of small individuals from 12 herbivorous fish species (0.17 ind. m(-2) and 7.7 g m(-2)) that were able to enter through the coarse mesh. Although restricted to a single habitat, these results suggest that when present in sufficient densities and diversity, small herbivorous fishes can prevent the accumulation of algal biomass on coral reefs.