Assessing Nebraska playa wetland inundation status during 1985–2015 using Landsat data and Google Earth Engine
Assessing Nebraska playa wetland inundation status during 1985–2015 using Landsat data and Google Earth Engine
复制标题
DOI：
10.1007/s10661-016-5664-x
复制
发表时间：
2016-11
影响因子：
3
通讯作者：
Zhenghong Tang;Yao Li;Yue Gu;Weiguo Jiang;Yuan Xue;Q. Hu;Ted Lagrange;A. Bishop;J. Drahota;Ruopu Li
中科院分区：
文献类型：
--
作者：
Zhenghong Tang;Yao Li;Yue Gu;Weiguo Jiang;Yuan Xue;Q. Hu;Ted Lagrange;A. Bishop;J. Drahota;Ruopu Li
内布拉斯加州的普拉亚湿地为迁徙水鸟提供了全球重要的栖息地。淹没条件是评价干盐湖湿地功能的重要指标。然而，缺乏对干盐湖湿地的长期连续监测记录。本研究的目的是确定一个合适的指数Landsat图像映射的干盐湖淹没状态在3月和4月在1985年至2015年。四种类型的光谱指数-负归一化植被指数，归一化差异水指数（NDWI），修改后的NDWI，流苏帽湿度绿度差（TCWGD）-进行了评估，以检测干盐湖淹没条件从陆地卫星图像。结果表明，TCWGD是判别干盐湖淹没状态的最佳指标。通过使用Landsat图像和Google Earth Engine，我们绘制了1985-2015年内布拉斯加州干盐湖的春季洪水条件。结果表明：春季迁徙季节，沼泽湿地淹没面积为176.79km2，占沼泽湿地总面积的18.92%。在过去的30年中，有9898个湿地在3月或4月至少被淹没过一次，占33,659个历史湿地总数的29.41%。通过对比历史水文土壤足迹和淹没面积，结果表明，内布拉斯加州大部分干盐湖的水文条件发生了变化。淹没湿地是保护和/或部分恢复的候选者，未淹没湿地需要更多的关注湿地恢复。在过去的几十年里，在春季迁徙季节，保护地役权区的湿地比非保护地役权区的湿地具有显著高的干盐湖淹没状态，这些保护地役权仅占总足迹面积的4.29%，但在过去的30年里，它们贡献了内布拉斯加州20.82%的淹没面积。
Playa wetlands in Nebraska provide globally important habitats for migratory waterfowl. Inundation condition is an important indicator of playa wetland functionality. However, there is a lack of long-term continuous monitoring records for playa wetlands. The objective of this study was to determine a suitable index for Landsat images to map the playa inundation status in March and April during 1985–2015. Four types of spectral indices—negative normalized vegetation index, Normalized Difference Water Index (NDWI), modified NDWI, and Tasseled Cap Wetness-Greenness Difference (TCWGD)—were evaluated to detect playa inundation conditions from Landsat images. The results indicate that the TCWGD is the most suitable index for distinguishing playa inundation status. By using Landsat images and Google Earth Engine, we mapped the spring inundation condition of Nebraska playas during 1985–2015. The results show that the total inundated areas were 176.79 km2in spring migratory season, representing 18.92% of the total area of playa wetlands. There were 9898 wetlands inundated at least once in either March or April during the past 30 years, representing 29.41% of a total of 33,659 historical wetlands. After comparing the historical hydric soil footprints and the inundated areas, the results indicate that the hydrological conditions of the majority of playas in Nebraska have changed. The inundated wetlands are candidates for protection and/or partial restoration, and the un-inundated wetlands need more attention for wetland restoration. Wetlands in areas enrolled in conservation easements had a significantly high level of playa inundation status than non-conserved wetlands during spring migratory seasons in the past decades.These conservation easements only count for 4.29% of the total footprint areas, but they have contributed 20.82% of the inundation areas in Nebraska during the past 30 years.