National Coral Reef Monitoring Program: Stratified Random Surveys (StRS) of Coral Demography (Adult and Juvenile Corals) across Rose Atoll from 2016-05-01 to 2016-05-04 (NCEI Accession 0159167)

The data described here result from benthic coral demographic surveys for two life stages (juveniles, adults) across Rose Atoll in 2016. Juvenile colony surveys include morphology and size. Adult colony surveys record morphology, colony size, partial mortality in two categories - old dead and recent dead, cause of recent dead partial mortality, and non-lesion forming condition including bleaching and disease). A two-stage stratified random sampling (StRS) design was employed to survey the coral reef ecosystems throughout the U.S. Pacific regions. The survey domain encompassed the majority of the mapped area of reef and hard bottom habitats in the 0-30 m depth range. The stratification scheme included island, reef zone, and depth in all regions, as well as habitat structure type in the Main Hawaiian Islands. Sampling effort was allocated based on strata area and sites were randomly located within strata. Sites were surveyed using belt transects to collect juvenile and adult coral colony metrics. These data provide information on juvenile and adult coral abundance (density, proportion occurrence, and total colony abundance), size distribution, partial mortality, prevalence and abundance of recent mortality and cause, prevalence of disease and bleaching, and diversity. The StRS design effectively reduces estimate variance through stratification using environmental covariates and by sampling more sites rather than sampling more transects at a site. Therefore, site-level estimates and site to site comparisons should be used with caution.本文所述数据源自2016年对罗斯环礁（Rose Atoll）两个生活史阶段（幼体、成体）开展的底栖珊瑚种群统计调查。幼体珊瑚群体调查涵盖其形态与尺寸信息；成体珊瑚群体调查则记录了形态、群体尺寸、两类部分死亡情况——旧死亡区域与新近死亡区域、新近死亡部分的致死原因，以及包括珊瑚白化（bleaching）与珊瑚病害（disease）在内的非病灶形成状况。 本次针对美国太平洋区域的珊瑚礁生态系统调查，采用两阶段分层随机抽样（two-stage stratified random sampling, StRS）设计。调查覆盖了0至30米水深范围内绝大多数已测绘的礁体与硬质底栖生境区域。分层方案在所有区域均包含岛屿、礁区与水深维度，在主夏威夷群岛还额外加入了生境结构类型维度。采样分配量依据各层的面积确定，样点在对应层内随机布设。各调查样点采用带状样带（belt transect）法采集幼体与成体珊瑚群体的相关指标数据。 本数据集提供了幼体与成体珊瑚的丰度信息（包括密度、出现比例与总群体数量）、尺寸分布、部分死亡率、新近死亡的流行率与丰度及其致死原因、病害与白化的流行率，以及多样性指数。 两阶段分层随机抽样设计通过利用环境协变量进行分层，以及增加样点数量而非单样点内样带数量的方式，有效降低了估计方差。因此，在使用样点水平估计值以及开展样点间对比时需谨慎。