Oyster Reef Suitability Layers for the Coast of Virginia

LiDAR-based elevation, water residence time and fetch data layers were used to characterize intertidal lands suitable for oysters in the coastal lagoons on the eastern side of the Delmarva Peninsula in Virginia. Water residence time and fetch serve as proxies for water mean velocity and wave energy from winds, respectively. Three layers, elevation, water residence time and fetch distance were rated as "suitable" or "not suitable" for each location based on the range of values from observed oyster reefs. The number of layers identified as suitable for a location were tallied using a scale of 3-6 where 3 indicated no layers were suitable, 4 indicated one layer was suitable, 5 indicated two layers were suitable and 6 indicated that the location was suitable based on all three input layers. The analysis was conducted using two different elevation ranges for suitability, one based on the elevation of the oyster reef crest and the other the elevation of the tidal flat surrounding oyster reefs. These are provided in layers crest1 and surrounding_el, respectively.本研究借助基于激光雷达（LiDAR）获取的高程、水体停留时间与风区数据图层，对弗吉尼亚州德尔马瓦半岛东侧沿海潟湖内适宜牡蛎栖息的潮间带土地开展特征表征。其中，水体停留时间与风区分别可作为水体平均流速与风力驱动波浪能的替代表征指标。研究基于实测牡蛎礁的数值区间，将各点位的高程、水体停留时间与风区距离三类数据图层分别评定为"适宜"或"不适宜"。针对各点位的适宜图层数量，采用3-6分级量表进行统计：分值3代表无图层达标（即三类图层均不适宜），分值4代表1个图层达标，分值5代表2个图层达标，分值6则代表三类输入图层全部达标，该点位即适宜牡蛎栖息。本次分析采用两套高程适宜性阈值范围：一套以牡蛎礁脊的高程为基准，另一套以牡蛎礁周边潮滩的高程为基准，分别对应crest1与surrounding_el两个数据图层。