Australian Research Council Centre of Excellence for Coral Reef Studies, and School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia.
Biol Lett. 2012 Dec 23;8(6):1016-8. doi: 10.1098/rsbl.2012.0770. Epub 2012 Oct 24.
Sediments are a ubiquitous feature of all coral reefs, yet our understanding of how they affect complex ecological processes on coral reefs is limited. Sediment in algal turfs has been shown to suppress herbivory by coral reef fishes on high-sediment, low-herbivory reef flats. Here, we investigate the role of sediment in suppressing herbivory across a depth gradient (reef base, crest and flat) by observing fish feeding following benthic sediment reductions. We found that sediment suppresses herbivory across all reef zones. Even slight reductions on the reef crest, which has 35 times less sediment than the reef flat, resulted in over 1800 more herbivore bites (h(-1) m(-2)). The Acanthuridae (surgeonfishes) were responsible for over 80 per cent of all bites observed, and on the reef crest and flat took over 1500 more bites (h(-1) m(-2)) when sediment load was reduced. These findings highlight the role of natural sediment loads in shaping coral reef herbivory and suggest that changes in benthic sediment loads could directly impair reef resilience.
沉积物是所有珊瑚礁的普遍特征，但我们对它们如何影响珊瑚礁上复杂的生态过程的理解是有限的。已表明藻类草皮中的沉积物可抑制高沉积物、低摄食的珊瑚礁平原上的珊瑚礁鱼类的摄食。在这里，我们通过观察底栖沉积物减少后鱼类的摄食行为，研究了沉积物在整个深度梯度（礁底、礁顶和礁坪）上抑制摄食的作用。我们发现，沉积物在所有的珊瑚礁区都抑制了摄食。即使在仅减少礁顶的沉积物（礁顶的沉积物比礁坪少 35 倍），也会导致超过 1800 次的更多摄食（h(-1) m(-2)）。刺尾鱼科（刺尾鱼）负责了超过 80%的所有观察到的摄食，而当沉积物负荷减少时，在礁顶和礁坪上的摄食次数超过了 1500 次（h(-1) m(-2)）。这些发现强调了自然沉积物负荷在塑造珊瑚礁摄食中的作用，并表明底栖沉积物负荷的变化可能直接损害珊瑚礁的恢复力。
