Decadal Changes in a Pacific Estuary: A Multi-Source Remote Sensing Approach for Historical Ecology

In Pacific Coast salt marshes, only color and color IR aerial photography provide the spatial, spectral, and temporal resolution required to conduct long-term historic time series analysis of wetland change at the plant community level. We used historic aerial photographs with manual and automated image classification techniques to discern decadal-scale changes to salt marshes in Elkhorn Slough, California caused by off-farm sedimentation from 1971 to 2001. Change detection identified a process of plant succession that led to arroyo willow encroachment into pickleweed marsh. Changes observed were considered within the context of additional land use changes over a greater regional and time scale.