Correspondence between assemblages of coral reef fishes and gradients of water motion, depth, and substrate size off Puerto Rico
Correspondence between assemblages of coral reef fishes and gradients of water motion, depth, and substrate size off Puerto Rico
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波多黎各附近珊瑚礁鱼类群落与水流梯度、深度和基质尺寸之间的对应关系
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发表时间：
1994
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通讯作者：
M. McGehee
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作者：
M. McGehee
在波多黎各西南部的8个珊瑚礁进行了普查，以确定珊瑚礁的组合，并确定水的运动、深度和底物是否与鱼类的分布和丰度相关。通过记录放置在不同深度(从礁顶到平均6米深)的样方中的鱼类种类和丰度以及底物大小，沿着放置在前礁和后礁上的横断面，对每个珊瑚礁进行抽样。水的运动是通过测量石膏块的溶蚀量来检验的，它给出了水在礁体内部和礁间运动的程度的相对指数。分析了在32个样带上收集的14个鱼类斑点的数据以及水运动、礁坡度和4种底物大小的测量结果，以确定物种组并检验生态相关性。分析表明，3个物种组合在礁内(后礁、浅礁和深礁)和礁之间(近岸、中礁和近岸礁)的分布和丰度存在差异。同样，水的运动、深度、礁坡度和底物大小以礁内和礁间明显不同的梯度形式出现。组合1中的鱼类主要包括大西洋眼镜蛇。Dhalassoma biasciatum、Stestes dorsopunicans和小盾齿龙。这些物种在浅海礁石上最为常见，特别是在近海礁石(离陆地最远的珊瑚礁)；这些地点的特点是水运动程度高，礁石坡度平缓，底质大小如巨石。群落2种，分别为金鱼藻、绿背金鱼和红腹海鞘。这些鱼类在深海礁石上最为丰富，特别是在近岸礁石(离陆地最近的地点)，其特点是水运动相对较低，坡度较陡，底物尺寸较小。与前礁相比，组合3中的鱼类最多的是后礁，那里的水运动、坡度和底物尺寸最小。虽然生物变量在决定物种分布方面无疑是重要的，但不同的组合被发现与水的运动、深度和底物类型的变化有关。这3个物理变量以相互关联的梯度形式出现，但分析表明，水运动能量是与物种分布最相关的环境因素。
Censuses were taken at 8 coral reefs in southwest Puerto Rico to identlfy assemblages of flshes and to determine whether water motion, depth, and substrate were correlated with fish distributlon and abundance. Each reef was sampled by recording species and abundance of fishes and substrate sizes within quadrats placed at different depths (from reef crest to an average of 6 m deep) along transects placed on forereefs and backreefs. Water motion was examined by measuring the amount of dissolution of plaster-of-Paris blocks wh~ch gave a relative index of the degree of water movement wlthin and among reefs. Data collected on 14 fish specles and measurements of water motion, degree of reef slope, and 4 sizes of substrate over 32 transects were analyzed to identify species groups and examine ecological correlates. The analyses indicated 3 species assemblages which d~ffered in distnbution and abundance within reefs (backreef, shallow forereef, and deep forereef) and among reefs (nearshore, intermediate, and offshore reefs). Similarly, water movement, depth, reef slope and substrate size occurred as gradients that differed significantly within and among reefs. Fishes in Assemblage 1 included primarily Ophioblennius atlanticus. Thalassoma bifasciatum, Stegastes dorsopunicans, and Microspathodon chrysurus. These species were most common on the shallow forereef, particularly at offshore reefs (those farthest from land); these sites were characterized by a high degree of water motion, gentle forereef slope, and boulder-sized substrate. Assemblage 2 species included Stegastesplanifrons, Hypoplectrus chlorurus, and Holocentrus rufus. These fishes were most abundant on the deep forereef, especially at nearshore reefs (sites closest to land), which were typified by relatively low water movement, steep slope, and smaller substrate sizes. Fishes in Assemblage 3 (Stegastes leucostictus and Malacoctenus macropus) were most numerous in the backreef where water motion, slope inclination, and substrate sizes were minimal compared with the forereef. While biological variables are undoubtedly important in determining species distributions, the different assemblages were found to be correlated with variations in water motion, depth, and substrate type. These 3 physical variables occurred as interrelated gradients, but the analyses suggested that water movement energy was the environmental factor most strongly associated with species distributions.