Coral abundance on the inshore Great Barrier Reef 1998-2013

<em>Study sites: </em>Coral assemblages were surveyed at two depths (shallow: 2-4 m; deep: 5-8 m) at each of four locations on the Great Barrier Reef off Townsville; Nelly Bay (S19.167°, E146.850°) and Geoffrey Bay (S19.155°, E146.861°) on Magnetic Island and Little Pioneer Bay (S18.594°, E146.485°) and southeast Pelorus (S18.560°, E146.500°) in the Palms Island group giving a total of eight sites. <em>Survey method</em>: Between six and nine surveys were conducted at each site between March 1998 and 2013. Between four to six replicate 15 m x 0.5 m belt transects were used at each site on each survey. The abundance of all hard and soft corals (i.e. <em>Scleractinia</em>, <em>Alcyonacea</em> and <em>Hydrocorallina</em>) with a maximum diameter greater than 5 cm within the belt transects was recorded. Coral were identified to genus following Veron (2000). We used colony abundance instead of the more commonly used metric of coral cover because it provides a better estimate of population level mortality.研究样地：研究人员在汤斯维尔外海的大堡礁的4处站位开展珊瑚群落调查，每处站位设置两个水深梯度：浅水区（2~4 m）与深水区（5~8 m）。涉及的站位包括磁岛上的内利湾（S19.167°，E146.850°）、杰弗里湾（S19.155°，E146.861°），以及棕榈群岛的小先锋湾（S18.594°，E146.485°）和佩洛鲁斯东南海域（S18.560°，E146.500°），总计8个调查样地。 调查方法：1998年3月至2013年间，每个样地共开展6~9次调查。每次调查时，每个样地均设置4~6条重复的15 m×0.5 m带状样带。记录带状样带内所有最大直径大于5 cm的硬珊瑚与软珊瑚（即石珊瑚目（Scleractinia）、软珊瑚目（Alcyonacea）和水螅珊瑚类（Hydrocorallina））的丰度。珊瑚的属级鉴定参照Veron（2000）的分类标准。本研究采用群落丰度而非更常用的珊瑚覆盖度作为统计指标，因其可更精准地估算种群水平的死亡率。