Brooker Rohan M, Brandl Simon J, Dixson Danielle L
School of Marine Science and Policy, University of Delaware, Lewes, DE 19958, USA.
School of Biology, Georgia Institute of Technology, Atlanta, GA 30318, USA.
Sci Rep. 2016 Jan 4;6:18842. doi: 10.1038/srep18842.
Seaweed-dominated coral reefs are becoming increasingly common as environmental conditions shift away from those required by corals and toward those ideal for rampant seaweed growth. How coral-associated organisms respond to seaweed will not only impact their fate following environmental change but potentially also the trajectories of the coral communities on which they rely. However, behavioral responses by coral-associated organisms to seaweeds are poorly understood. This study examined interactions between a guild of obligate and opportunistic coral-feeding butterflyfishes (Chaetodontidae) and scleractinian corals to determine whether fishes continue to interact with corals in contact with seaweed or if they are avoided. Under natural conditions, all species interacted almost exclusively with seaweed-free corals. In a controlled patch reef experiment, fishes avoided corals in physical contact with seaweed, irrespective of dietary preferences. When visual seaweed cues were removed, butterflyfish continued to avoid corals that had been in contact with the allelopathic Galaxaura filamentosa, suggesting that chemical cues produced by coral-seaweed interactions are repellent. These findings suggest that, due to deleterious visual and chemical cues produced by coral-seaweed interactions, coral-associated organisms may struggle to locate resources as seaweed-free corals decline in abundance.
随着环境条件从珊瑚所需的条件转变为有利于海藻大量生长的条件，以海藻为主的珊瑚礁正变得越来越普遍。与珊瑚相关的生物对海藻的反应不仅会影响它们在环境变化后的命运，还可能影响它们所依赖的珊瑚群落的发展轨迹。然而，人们对与珊瑚相关的生物对海藻的行为反应了解甚少。本研究调查了一群专性和机会性以珊瑚为食的蝴蝶鱼（蝴蝶鱼科）与石珊瑚之间的相互作用，以确定鱼类是否会继续与接触海藻的珊瑚相互作用，或者是否会避开它们。在自然条件下，所有物种几乎只与没有海藻的珊瑚相互作用。在一个受控的斑块礁实验中，无论饮食偏好如何，鱼类都会避开与海藻有物理接触的珊瑚。当去除视觉上的海藻线索时，蝴蝶鱼仍然会避开曾与化感作用的丝状乳节藻接触过的珊瑚，这表明珊瑚与海藻相互作用产生的化学线索具有驱避作用。这些发现表明，由于珊瑚与海藻相互作用产生的有害视觉和化学线索，随着无海藻珊瑚数量的减少，与珊瑚相关的生物可能难以找到资源。
