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MAPPING EELGRASS SPECIES ZOSTERA ZAPONICA AND Z. MARINA, ASSOCIATED MACROALGAE AND EMERGENT AQUATIC VEGETATION HABITATS IN PACIFIC NORTHWEST ESTUARIES USING NEAR-INFRARED COLOR AERIAL PHOTOGRAPHY AND A HYBRID IMAGE CLASSIFICATION TECHNIQUE
Citation:
Specht, D T., P J. Clinton, AND D R. Young. MAPPING EELGRASS SPECIES ZOSTERA ZAPONICA AND Z. MARINA, ASSOCIATED MACROALGAE AND EMERGENT AQUATIC VEGETATION HABITATS IN PACIFIC NORTHWEST ESTUARIES USING NEAR-INFRARED COLOR AERIAL PHOTOGRAPHY AND A HYBRID IMAGE CLASSIFICATION TECHNIQUE. Presented at 7th International Conference on Remote Sensing for Marine and Coastal Environments, Miami, FL, May 20-22, 2002.
Description:
Aerial photographic surveys of Oregon's Yaquina Bay estuary were conducted during consecutive summers from 1997 through 2000. Imagery was obtained during low tide exposures of intertidal mudflats, allowing use of near-infrared color film to detect and discriminate plant communities. Approximately 90 percent of submerged aquatic vegetation occurs in the intertidal zone at this latitude. The photographs were digitized and orthorectified for image analysis. A hybrid image classification algorithm was developed to allow discrimination of intertidal habitats dominated by the eelgrasses Zostera japonica and Z. marina, the green macroalgae Ulva spp.and Enteromorpha spp., the brown alga Fucus sp., unvegetated areas and various emergent upper-intertidal reeds, grasses and sedges. Application of this algorithm has promise of allowing habitat delineation and change analysis mapping at the sub-meter level over time in Pacific NW estuaries characterized by significant tidally-exposed habitats. Such changes are of interest in the assessment of environmental stresses such as land use management practices (as a typical anthropogenic source), episodic weather events, and long-term (decadal) weather cycles on the resiliency of these plant communities.