Map of Riparian Vegetation in Nevada

Project Description

The Map of Riparian Vegetation in Nevada (MRVN) identifies the distribution of riparian vegetation across the entire state of Nevada.  Despite variations in climate and plant species composition across the state, the enhanced vigor of plants in riparian settings during the hot summers of the arid to semiarid climate provides a greenness signal that can be detected in NDVI data derived from Landsat satellites.  By stratifying the landscape of a subregion into units of similar elevation and solar exposure, changes in NDVI due to surface or near surface water availability were differentiated from changes that were due to the amount of vegetation present.  Thousands of calibration points were used to identify the best spatial neighborhood to consider, the step sizes for stratifying elevation and insolation data, the minimum NDVI to be considered as potentially riparian, the magnitude of NDVI anomaly that would be classified as riparian, and a limit on upslope position.  A further enhancement to the map incorporated the areas near perennial streamlines from the NHDPlus product that had the highest NDVI values.  Intensive agriculture (e.g. center pivot) and urban areas were removed by using land ownership maps and manual editing.  The final map was tested with 400 independent test points, and producer’s accuracy (1.0 – errors of omission) for riparian vegetation was 84.6%, and user’s accuracy (1.0 – errors of commission) was 93.5%.

Please use the following citation for the MRVN product:

• McGwire, K., 2019. Optimized Stratification for mapping Riparian Vegetation in Arid and Semiarid Environments, Remote Sensing 11(14):1638. DOI:10.3390/rs11141638

Update 1.1 of the MRVN product includes the raster map of riparian vegetation, and the average and standard deviation of late summer Landsat NDVI datasets that were used in making MRVN (WARNING: statewide NDVI products are 1.04GB).  

• DOWNLOAD MRVN Version 1.1 (FGDC metadata is provided)