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A color infrared satellite composite image of the Jenkins Sound study area in Stone Harbor, NJ, showing the location of the four sites surveyed to locate high marsh grasses.

10-m panchromatic Landsat satellite image of the Jenkins Sound, NJ study area.

Satellite image of our study site with three of the four surveyed areas rendered in color infrared images that were collected with our UAV enabled multispectral camera. The inset chart shows the differences in the spectral wavelengths of the primary land cover classifications of concern: open water, developed land, low marsh (Spartina alterniflora) and high marsh (Spartina patens and Distichlis spicata).

Resultant distribution of high marsh grasses in the Jenkins Sound, NJ study area.

Along with survey elevations, the UAV spectral wavelengths were used to locate zones of the high marsh grasses throughout the bay.

Field surveys of the four sites helped locate the typical elevation ranges of high marsh grasses.

Distichlis Sensing

Once the backbone of New Jersey’s agricultural economy, salt marsh grasses (Spartina alterniflora, Spartina patens, and Distichlis spicata) remain an irreplaceable part of the coastal region’s aesthetics, ecosystem health, and storm defense. In particular, high marsh grasses are unique nesting habitats for shorebirds. Rising sea levels and more frequent large storms will increasingly damage or drown these marsh grass communities; however, the extent or rate of loss is poorly understood. National and State Land Cover databases, for instance, use a single classification for all marsh types and exclude important distinctions between low and high marsh. To overcome this limitation in existing datasets, our team surveyed four sites in Jenkins Sound, NJ —each between 4 to 9 hectares—utilizing Unmanned Aircraft Systems (UAS) equipped with multispectral cameras along with GPS field surveys. The information gleaned from this imagery enabled us to identify high marsh areas through the bay.

Led By: Sean Burkholder, Karen M’Closkey and Keith VanDerSys

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Distichlis Sensing

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