ASSESSMENT OF THE IMMEDIATE IMPACTS OF THE 2013-2014 DROUGHT ON ECOSYSTEMS OF THE CALIFORNIA CENTRAL COAST

A methodology was developed to assess the impacts of the historic 2013-2014 drought on ecosystems of California's Central Coast region, using a combination of satellite image analysis and in situ measurements of soil moisture in predominant vegetation types of the region. According to differences in Landsat drought indices for plant water stress and vegetation green cover (NDWI and NDVI, respectively), the geographic areas within the study region that were most severely impacted by the 2013 drought were the inland Carmel Valley in northern Monterey County and the coastal zones around San Simeon Point and Cambria in northern San Luis Obispo County. An expanded area of severe vegetation moisture stress, generally indicated by relative-differenced NDWI values of > 400, was detected by May 2014 in both of these same geographic areas. For more detailed examination of drought impacts, the entire study region was separated into the 3 predominant vegetation types (grasslands, shrublands, and forests) to examine changes in Landsat NDWI and NDVI in the context of differing plant community responses to severe drought. Results confirmed that higher overall drought stress in 2013 and 2014 was detected in grasslands, compared to shrublands and forests, in both years at all elevations and slopes > 200 m and > 5%, respectively.