Occurrence (presence-only) of living Lophelia pertusa reefs in the Irish continental margin

The present data set was used as a training set for a Habitat Suitability Model. It contains occurrence (presence-only) of living Lophelia pertusa reefs in the Irish continental margin, which were assembled from databases, cruise reports and publications. A total of 4423 records were inspected and quality assessed to ensure that they (1) represented confirmed living L. pertusa reefs (so excluding 2900 records of dead and isolated coral colony records); (2) were derived from sampling equipment that allows for accurate (<200 m) geo-referencing (so excluding 620 records derived mainly from trawling and dredging activities); and (3) were not duplicated. A total of 245 occurrences were retained for the analysis. Coral observations are highly clustered in regions targeted by research expeditions, which might lead to falsely inflated model evaluation measures (Veloz, 2009). Therefore, we coarsened the distribution data by deleting all but one record within grid cells of 0.02° resolution (Davies & Guinotte 2011). The remaining 53 points were subject to a spatial cross-validation process: a random presence point was chosen, grouped with its 12 closest neighbour presence points based on Euclidean distance and withheld from model training. This process was repeated for all records, resulting in 53 replicates of spatially non-overlapping sets of test (n=13) and training (n=40) data. The final 53 occurrence records were used for model training.

本数据集被用作栖息地适宜性模型（Habitat Suitability Model）的训练集，其包含爱尔兰大陆边缘现存活体*Lophelia pertusa*礁的仅存在型出现记录，此类记录整合自各类数据库、科考航次报告及已发表学术文献。研究人员共计对4423条记录开展核查与质量评估，以确保其满足以下三项标准：（1）为经确认的活体*Lophelia pertusa*礁记录（因此剔除2900条死珊瑚或孤立珊瑚群落的记录）；（2）源自可实现精准（<200米）地理配准的采样设备（因此剔除620条主要源自拖网、疏浚活动的记录）；（3）无重复记录。最终筛选保留245条出现记录用于后续分析。珊瑚观测点位在科考航次靶向研究区域呈现高度聚集特征，这可能导致模型评估指标被虚高放大（Veloz, 2009），为此研究人员对分布数据进行粗化处理：将分辨率为0.02°的网格单元内除一条记录外的其余所有记录全部删除（Davies & Guinotte 2011）。对剩余的53个点位开展空间交叉验证流程：随机选取一个存在点位，基于欧氏距离将其与12个最邻近的存在点位划为一组，并将该组数据预留作为模型测试数据、不参与训练；将该流程对所有点位重复执行，最终得到53组空间上无重叠的测试集（每组样本量n=13）与训练集（每组样本量n=40），最终保留的53条出现记录即被用于模型训练。