MaineDEP Acadia Seagrass 2025

This dataset contains the seagrass beds delineated in 2025 in the Acadia Region, from Naskeag Point in Brooklin to Kelley Point in Jonesport. Polygons were screen digitized from aerial imagery flown at low tide on June 26 & 27, July 26 & 26, and August 12 & 13. Imagery was captured using a Vexcel Eagle 80-mm Mark 3 aerial camera mounted on a fixed wing aircraft and flown at an elevation of approximately 9,500 feet. Polygons were refined based on field verification efforts that took place between July 29 and September 22, 2025. Field verification was carried out by boat using a Maine DEP vessel (21-foot Maritime Skiff with a 140 horse outboard motor or 12' Tracker with 5 horse outboard motor), SeaViewer Admiral Pro High-Definition (HD) georeferenced underwater videography package with SeaViewer 6000 Sea Drop underwater video camera, and Juniper Systems Geode GNS3S GNSS GPS system capable of submeter accuracy that paired wirelessly to a Samsung Tab Active3 ruggedized field tablet.Each contiguous seagrass bed is named by sequential number, which is provided in the ‘Bed_Name’ column. These beds are further divided into polygons by percent cover. Polygons are labeled with a unique identifier consisting of sequential numbers in the ‘Polygon_ID’ column. A singular bed can consist of several polygons IDs. Percent cover categories and percentages are based on those established by Orth et al. (1991), where 1=0-10% cover (very sparse), 2=10-40% cover (sparse), 3=40-70% cover (moderate), 4=70-100% cover (dense).This seagrass polygon shapefile also contains fields for whether the bed was field verified in 2025 (Y=yes or N=no) and whether there is corresponding underwater video footage (Y=yes, N=no). Field verified beds were verified only in part, meaning one or more transects were placed along the perimeter of the bed to confirm seagrass presence and aerial signatures; bed boundaries were not verified in their entirety. Field verification refers to whether the bed (Bed_Name field) was visited, it does not account for individual parts of the bed (Polygon_ID field) with differing cover classes, though sometimes verification occurred in more than one cover class per bed. Underwater video is present for most of the field verified beds but is lacking in some areas due to technical errors or logistical limitations on deploying video equipment. The video column corresponds to the named underwater video file, which corresponds to transect name. The species identification field is also incorporated in this dataset. Species is only noted if directly observed by underwater video or by visual observations in shallow water. Widgeon grass was observed only in the Blue Hill Salt Pond, which is a tidally restricted water body.本数据集包含2025年在阿卡迪亚区域（Acadia Region）划定的海草床，范围覆盖布鲁克林（Brooklin）的纳斯基亚角（Naskeag Point）至琼斯波特（Jonesport）的凯利角（Kelley Point）。多边形要素通过低潮时段拍摄的航空影像经屏幕数字化提取，影像采集时间为2025年6月26、27日，7月26、27日，以及8月12、13日。所用影像由搭载于固定翼飞机的Vexcel Eagle 80-mm Mark 3航空相机拍摄，飞行高度约9500英尺。多边形要素基于2025年7月29日至9月22日开展的野外验证工作进行了优化。野外验证采用缅因州环境保护局（Maine DEP）的船只开展，包括21英尺长、搭载140马力舷外机的Maritime Skiff，以及12英尺长、搭载5马力舷外机的Tracker艇；配套使用SeaViewer Admiral Pro高清地理参考水下摄像系统，搭配SeaViewer 6000 Sea Drop水下摄像机；同时使用Juniper Systems Geode GNS3S GNSS GPS系统，该系统可实现亚米级精度，并可与三星（Samsung）Tab Active3加固型野外平板无线配对。每个连片海草床按顺序编号命名，编号存储于"Bed_Name"（床名称）字段中。这些海草床进一步按盖度百分比划分为多个多边形要素，多边形要素的唯一标识符由顺序编号组成，存储于"Polygon_ID"（多边形ID）字段中。单个海草床可包含多个"Polygon_ID"。盖度分类及百分比标准采用Orth等人1991年提出的方案：1代表0-10%盖度（极稀疏），2代表10-40%盖度（稀疏），3代表40-70%盖度（中等），4代表70-100%盖度（密集）。本海草多边形形状文件（shapefile）还包含以下字段：海草床是否在2025年完成野外验证（Y=是，N=否），以及是否存在对应的水下视频素材（Y=是，N=否）。野外验证仅针对海草床（"Bed_Name"字段）的部分区域开展，即沿海草床周边布设一条或多条样带以确认海草存在及航空影像特征，并未对床体边界进行全面核验。野外验证状态仅针对海草床（"Bed_Name"字段），未覆盖海草床内不同盖度类别的单个多边形要素（"Polygon_ID"字段），不过部分海草床会在多个盖度类别中开展验证。多数完成野外验证的海草床配有水下视频，但部分区域因技术故障或部署视频设备的后勤限制，未采集到视频数据。"视频"字段对应命名的水下视频文件，该文件与样带名称一一对应。本数据集还包含物种识别字段。仅当通过水下视频或浅水区目视观测直接确认时，才会记录物种信息。川蔓藻（Widgeon grass）仅在蓝山盐沼池（Blue Hill Salt Pond）中被观测到，该区域为受潮汐限制的水体。