Vegetation - Delta Vegetation and Land Use Update - 2016 [ds2855]

The Sacramento-San Joaquin Delta Reform Act of 2009 established the Delta Stewardship Council (DSC) to achieve more effective governance while providing for the sustainable management of the Delta ecosystem and a more reliable water supply, using an adaptive management framework. Vegetation and land use are mapped for the 737,621 acres constituting the Legal Delta portion of the Sacramento and San Joaquin River Delta area. The current effort produced a digital map covering 737,621 acres considered to be the Legal Delta Area. 2016 National Agricultural Imagery Program (NAIP) 1-meter resolution imagery was used to delineate line work and attribute polygons. The 2019 map is a re-map of the 2007 effort. This map retained the line work and attributes of the 2007 mapping when static and was amended in areas where change occurred. Change detection was done comparing 723,426 acres, which were identical in the 2007 (2005 base imagery) and 2019 (2016 base imagery) efforts. GIC utilized the key produced for the 2007 mapping effort, in conjunction with the 2009 Central Valley key, as well as the CNPS membership rules online to determine classification levels and vegetation communities. Vegetation mapping is to alliance level when possible, otherwise it is left at group level (based on the National Vegetation Classification Standard, see http://biology.usgs.gov/npsveg/nvcs.html); land use is mapped to Anderson Level 2 classification (see https://pubs.usgs.gov/pp/0964/report.pdf). The map classification is based on a vegetation classification derived from field data collected in summer and fall of 2005 produced by the Vegetation Classification and Mapping Program (VegCAMP) of the Department of Fish and Wildlife. Membership rules for each alliance can be found at http://vegetation.cnps.org/. 2016 National Agricultural Inventory Program (NAIP) one meter orthoimagery was the baseline imagery used. Google Earth imagery was used as supplemental imagery. Natural vegetation comprises approximately 17% of the Delta study area, 65% is agriculture and pasture, 10% is urban/other and 8% is open water. The minimum mapping unit was 250 acres (100 ha). Link to download report: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=174866.2009年《萨克拉门托-圣华金三角洲改革法案》（Sacramento-San Joaquin Delta Reform Act of 2009）设立了三角洲管理委员会（Delta Stewardship Council, DSC），旨在通过适应性管理框架提升治理效能，同时实现三角洲生态系统的可持续管理与更可靠的供水保障。研究团队对萨克拉门托河与圣华金河三角洲地区的法定三角洲区域（共计737,621英亩）开展植被与土地利用制图，当前成果生成了覆盖该区域737,621英亩的数字化地图。本次制图依托2016年美国国家农业影像计划（National Agricultural Imagery Program, NAIP）1米分辨率影像完成要素线划与面状属性赋值。2019年版地图为2007年制图工作的重新修订版本：保留了2007年制图中未发生变化区域的线划与属性信息，并对存在变化的区域进行修正。本次变化检测比对了2007年（基准影像为2005年）与2019年（基准影像为2016年）制图工作中重合的723,426英亩区域。GIC依托2007年制图所用的分类关键表，结合2009年中央山谷分类关键表以及加州本土植物学会（California Native Plant Society, CNPS）在线会员规则，确定分类等级与植被群落类型。植被制图尽可能细化至群丛级（alliance level），若无法实现则保留至群丛组级（依据《国家植被分类标准》，详见http://biology.usgs.gov/npsveg/nvcs.html）；土地利用制图采用安德森二级分类体系（Anderson Level 2 classification，详见https://pubs.usgs.gov/pp/0964/report.pdf）。本次地图的分类体系基于加州鱼类与野生动物部植被分类与制图计划（Vegetation Classification and Mapping Program, VegCAMP）于2005年夏秋两季采集的野外数据所生成的植被分类方案制定。各植被群丛的会员规则可访问http://vegetation.cnps.org/查询。本次制图采用的基准影像为2016年美国国家农业影像计划（NAIP）1米正射影像，辅以谷歌地球（Google Earth）影像作为补充数据源。三角洲研究区域内，自然植被占比约17%，农业与牧场用地占65%，城市及其他用地占10%，开阔水域占8%。本次制图的最小上图单元为250英亩（100公顷）。数据报告下载链接：https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=174866。