Elkhorn Slough Research

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Geographical Ecology and GIS
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Geographical Ecology and
Geographical Information Systems (GIS)

Past, Present, and Future Geographic Information Systems technology is helping ESNERR understand the ecological history of the Slough. California's coastal wetlands have undergone dramatic hydrologic modifications and land use changes over the years. At Elkhorn Slough, marshlands were diked and drained and converted to agriculture. In 1947, an artificial opening to the Monterey Bay was constructed that exposed the Slough to increased tidal exchange. By digitizing, rectifying, assembling, and analyzing a chronological sequence of historical maps and aerial photographs, we are beginning to quantify patterns of change to the Slough's wetland habitats and correlate them with historic events. A specific focus for this research program is to measure rates of tidal erosion, changes in tidal creek morphology, and loss of vegetated salt marsh. We hope to determine whether these trends are accelerating or - hopefully - approaching a new equilibrium.

analysis of wetland habitat boundaries	map of habitat types

GIS helps us understand not only Elkhorn Slough's past, but also its present. Using the combination of sophisticated digital image analysis and old-fashioned (GPS-assisted) field survey work, we produce highly accurate habitat and vegetation maps and perform landscape and connectivity analysis. Accurate maps of present conditions and an understanding of historic changes are powerful tools for informed stewardship and conservation. Perhaps the most important role for our GIS-based research is for the future: building an accurate baseline to monitor future habitat changes and to guide restoration.
Spatial Data The Elkhorn Slough NERR, in cooperation with the Elkhorn Slough Foundation, maintains an extensive library of digital aerial imagery of the Slough's wetlands and adjoining upland areas dating from the 1930s through to the present. The California Department of Fish and Game augments the collection with aerial surveys flown every spring and fall.

The Reserve is also assembling a collection of historic and contemporary maps and a variety of other types of raster and vector spatial data including elevation models and vegetation, land use, and soils coverages. GIS Research Program contact: Eric Van Dyke Interested in downloading GIS files? Click here