Rapid Ecological Assessment (REA) of coral biodiversity and reef health in Manus and New Ireland Provinces, northern Bismarck Sea, Papua New Guinea

Fringing reefs at 19 locations in the Tigak Islands and 17 locations around Manus Island in the northern Bismarck Sea, Papua New Guinea were surveyed in August/September 2006. Locations were selected to provide the broadest range of reef habitat types. At each location, two sites were surveyed (deep: >10m and shallow: An inventory of species, genera and families of sessile benthic taxa was compiled for each site. The inventory included hard corals, soft corals, zoanthids, sponges, macro-algae and other sessile macro-benthos. At the end of each survey, the inventory was reviewed and each taxon was categorized in terms of its relative abundance in the community. For each hard coral taxon present, a visual estimate of the total amount of injury (dead surface area) present on colonies at each site was made in increments of 0.1, where 0 = no injury and 1 = all colonies dead. In addition, for each taxon, the proportion of colonies in each of three size classes (up to 10cm, 10 to 50cm and greater than 50cm colony diameter) was recorded. When identification of hard coral species was not possible, notes and photographs were taken and, if necessary, small samples were collected for later examination. Most specimens were lodged with the local TNC Office for use as a reference collection. Some coral samples were taken to Australia to compare with reference collections in the Museum of Tropical Queensland and the Australian Institute of Marine Science.At the end of each survey, site attributes were recorded based on an assessment integrated over the length of the survey. Attributes included percentage cover of major benthic groups and substrate types, biogenic reef development, exposure to wave energy, depth range, angle of the reef slope, visibility (m) and the presence of any unique or outstanding biological features or evidence of impacts.
1. To conduct a survey of species diversity by identifying hard and soft corals and other benthic marine organisms and by compiling a detailed list of species for each site and for the survey region in general2. To assess coral community types, their current status and health, and the extent of impacts on these reefs from disturbances such as coral bleaching, crown-of-thorns starfish outbreaks, destructive fishing practices, and terrestrial runoff
The method used was similar to that employed during biodiversity assessments for TNC and other agencies in other parts of the Indo-West Pacific, Indonesia and Australia and provides the opportunity for future comparisons of species diversity, composition and community structure of these different areas in terms of their coral communities.

2006年8-9月，研究团队对巴布亚新几内亚俾斯麦海北部的蒂加克群岛（Tigak Islands）19个点位以及马努斯岛（Manus Island）周边17个点位的岸礁（fringing reefs）开展了系统调查。点位遴选原则为覆盖最广泛的礁生境类型。每个点位设置2个调查样地：深水样地（水深>10m）与浅水样地。针对每个样地，研究团队编制了固着底栖生物类群（sessile benthic taxa）的物种、属及科名录，涵盖硬珊瑚、软珊瑚、群体海葵（zoanthids）、海绵、大型藻类及其他固着大型底栖生物。

调查结束后，研究团队对编目结果进行复核，并依据各分类群在群落中的相对丰度进行分类定级。针对每个出现的硬珊瑚类群，以0.1为增量对样地内珊瑚群体的总损伤面积（死亡表面积）开展视觉估算，其中0代表无损伤，1代表所有珊瑚群体均已死亡。此外，针对每个分类群，记录其3个体型等级（群体直径≤10cm、10~50cm及>50cm）的个体占比。若无法鉴定硬珊瑚物种，则拍摄照片、记录备注，必要时采集少量样本用于后续鉴定。多数标本留存于当地大自然保护协会（The Nature Conservancy, TNC）办公室作为馆藏参考标本。部分珊瑚样本被送往澳大利亚，用于与热带昆士兰博物馆（Museum of Tropical Queensland）及澳大利亚海洋科学研究所（Australian Institute of Marine Science）的馆藏标本进行比对鉴定。

每次调查结束后，研究团队基于全程调查评估记录样地属性，属性包括主要底栖类群及底质类型的盖度百分比、生物礁发育状况、波浪能暴露程度、水深范围、礁坡坡度、能见度（单位：米），以及是否存在独特或显著的生物学特征或人类活动影响证据。

本调查的核心目标包括：1. 开展物种多样性调查：通过鉴定硬珊瑚、软珊瑚及其他底栖海洋生物，为每个样地及整个调查区域编制详细的物种名录；2. 评估珊瑚群落类型、当前现状与健康状况，以及珊瑚白化、长棘海星（crown-of-thorns starfish）暴发、破坏性捕捞活动及陆地径流等干扰因素对这些礁体的影响程度。

本次调查采用的方法与大自然保护协会（TNC）及其他机构在印度-西太平洋（Indo-West Pacific）、印度尼西亚及澳大利亚其他区域开展的生物多样性评估方法一致，可为未来对比不同区域珊瑚群落的物种多样性、组成及群落结构提供参照基础。