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Mapping estuarine distributions of the non-indigenous Japanese Eelgrass Zostera japonica using Color Infrared Aerial Photography
Citation:
YOUNG, D. R., P. J. CLINTON, D. T. SPECHT, T. H. DEWITT, AND H. LEE, II. Mapping estuarine distributions of the non-indigenous Japanese Eelgrass Zostera japonica using Color Infrared Aerial Photography. Presented at Annual Meeting of the Pacific Estuarine Researach Society, Newport, OR, February 28 - March 01, 2008.
Impact/Purpose:
This presentation describes a technique for mapping distributions of the nonindigenous Japanese eelgrass Zostera japonica in estuarine ecosystems of the Pacific Northwest.
Description:
This presentation describes a technique for mapping distributions of the nonindigenous Japanese eelgrass Zostera japonica in estuarine ecosystems of the Pacific Northwest. The relatively broad distribution of this intertidal plant, often on very soft substrate, makes classical ground mapping surveys difficult. We employed color infrared (CIR) aerial photography in conjunction with a new hyprid approach toward digital image classification. In summer 2007 the method was tested in lower Yaquina estuary on the central Oregon coast. More than 75% of the stations known to contain Z. japonica were included in this classification. When the technique was applied to CIR orthophotography of the estuary obtained in summer 1998, a 400% increase in the areal extent of Z. japonica in the lower estuary over the nine year interval was observed. This technique appears to provide a useful new tool in documenting the distribution and expansion of this invasive species in estuarine ecosystems.