Total cover of perennial and annual vegetation are important measures of a number of processes in the Mojave Desert, including soil-moisture availability, stability of biological soil crusts, and the ability of disturbed areas to recover. Perennial vegetation was derived using Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) data coupled with pre-existing field transect data and applying step-wise linear regression techniques. Potential annual vegetation was derived using data mining and exploration techniques to reveal appropriate multi-image calculations applied to MODIS-EVI data that correlate with field data collected 2003 and 2005 at 50 plots. These maps are being used in the Mojave Desert tortoise habitat models and in Mojave Desert dust emissions studies.
In addition, elevation derivatives and topographic roughness metrics were derived from an existing 30m roughness grid for use in the tortoise habitat model.
Publications and Websites:
Nussear, K.E., Esque, T.C., Inman, R.D., Gass, Leila, Thomas, K.A., Wallace, C.S.A., Blainey, J.B., Miller, D.M., and Webb, R.H., 2009, Modeling habitat of the desert tortoise (Gopherus agassizii) in the Mojave and parts of the Sonoran Deserts of California, Nevada, Utah, and Arizona: U.S. Geological Survey Open-File Report 2009-1102, 18 p. http://pubs.usgs.gov/of/2009/1102/
Wallace, C.S.A. and K.A. Thomas, 2008. An Annual Plant Growth Proxy in the Mojave Desert using MODIS-EVI data, Sensors 2008, 8(12), 7792-7808; DOI: 10.3390/s8127792
Wallace, C.S.A., R.H. Webb, and K.A. Thomas, 2008. Estimation of perennial vegetation cover in the Mojave Desert using MODIS-EVI data and pre-existing field data. GIScience and Remote Sensing. 45-2, 167-187
Wallace, C.S.A. and L. Gass, 2008, Elevation derivatives for Mojave Desert Tortoise Habitat models: U.S. Geological Survey Open-File Report 2008-1283, 7 p. [http://pubs.usgs.gov/of/2008/1283/].