A preliminary report on the assessment of wetland productive capacity from a remote-sensing-based model — A NASA/NMFS joint research project

The NASA and the NMFS have undertaken a joint research project to develop Landsat Thematic Mapper (TM) technology for the determination of the value of wetlands to estuarine fish and shellfish production. NASA has developed the remote-sensing-based model to predict wetland productive capacity, a measure of the organic carbon exported to the estuarine food chain. The productive capacity (PC) model uses satellite remotely sensed determinations of vegetation, as the source of carbon, and distance-to-water, shoreline density, and water body type as hydrographic factors influencing carbon export. Regression analyses of aircraft simulated TM (TMS) data showed a stronger relationship with percent vegetation cover than with biomass for estimating the source of organic detritus. Land/water discrimination, fundamental to the measurement of the hydrographic variables, was accomplished more accurately with TMS than with Landsat Multispectral Scanner (MSS) data as compared to a photographic standard. The PC model generates detrital export measurements as input to an estuarine ecosystem model being developed by NMFS. Initial findings show that salinity patterns along with animal interactions affect the utilization of detritus by benthic organisms. The coupling of the two models establishes a technique for estimating the economic value of wetlands with respect to estuarine-dependent fish and shellfish production.