Measurement of seagrass standing crop using satellite and digital airborne remote sensing

The standing crop of seagrass is highly sensitive to environmental disturbance. We evaluate 3 optical remote sensing methods for measuring standing crop in the tropical Western Atlantic. Extensive field measurements of standing crop were used to define empirical relationships with imagery from satellite sensors [Landsat Thematic Mapper and SPOT (Systeme Probatoire de l'Observation de la Terre) XS (multispectral)], and the digital airborne imager CASI (Compact Airborne Spectrographic Imager). Predictions of standing crop from processed imagery had high coefficients of determination: 0.74, 0.79 and 0.81 respectively. Using a bootstrap method to measure standard error, the 95% confidence interval of predictions was found to have a similar order of magnitude to quadrat sampling in situ at a precision (standard error/mean) of 10%. Explicit cost-benefit and monitoring considerations are discussed.