Oak woodlands of California provide a wide range of societal values and ecosystem services, including forage for livestock, wildlife habitat, recreation, soil conservation, and watershed protection. The future of these ecosystems is threatened by a combination grazing pressure, competition from exotic grasses, wildfire severity, and climate change. Kueppers et al. predicted that by the year 2099 the ranges of California endemic oaks would shrink by over 50% of modern potential range sizes, and would shift northward due to climate warming trends and larger precipitation deficits during the growing season.
The year 2013 was the driest on record in California, with a total of just 30% of average statewide precipitation. The year 2014 was nearly as dry as 2013 on the Central California coast. The geographic areas within the Central California coastal region that were most severely impacted by the 2013 drought included the Carmel River Valley of northern Monterey County. An expanded area of severe vegetation moisture stress was detected by May 2014 in this same watershed.
The objective of this study was to assess the impacts of the historic 2013-2015 drought period on oak woodland ecosystems of the Carmel River drainage in central California using a combination of satellite image analysis and in situ measurements of soil moisture. The novel study approach incorporated more than 15 years of satellite image data (starting in the year 2000) in correlations with precipitation records to understand variations in canopy cover of different oak woodland communities, shrublands, and grasslands