| Contents Notes |
The objective of this report is to provide a literature search-and a short review of wetland functional health determination techniques which are relevant to the NOAA CoastWatch Change Analysis Program and other related programs, e.g., the Environmental Monitoring and Assessment Program (EMAP- Wetlands) of the Environmental Protection Agency. The report also suggests areas where further research is needed. In chapter 2, we review those remote sensing techniques which appear effective for mapping abundance (biomass). We also outline the contributions of remote sensing to early vegetative stress detection, habitat quality, and hydrology. In Chapter 3, we provide an overview of conceptual approaches for the assessment of wetland health, function and value. Then each of the proposed indicators of wetland condition is described in a chapter. Their importance is underlined, the techniques used for indicator sampling and measurement are briefly explained, and the remaining issues that must be resolved are outlined. Complete details of every technique are not discussed in this overview. The reader is encouraged to consult the references in each section for additional information. Our choice of the health indicators is essentially based on conclusions drawn from various interagency reports and planning meetings attended by us and the EMAP-Wetlands major assessment endpoints: productivity and biodiversity defined by the variety of species inhabiting the wetland, and sustain ability defined as the wetland persistence over time. The review includes all the remote sensing techniques that can be substituted for the conventional methods, or that are used in conjunction with them. Some indicators of wetland condition, such as wetland extent and type, habitat structure, and the floral component of wetland productivity, can be studied primarily by means of remote sensing; while others (e.g., vegetation, hydrology, habitat quality) still require the use of more conventional techniques. Satellite and airborne sensors have been used for several decades in wetland mapping, but new remote sensing techniques have recently been developed, that allow researchers to determine wetland biomass production. These new techniques should enhance our ability to determine wetland condition and functional health over large areas and at various repeat intervals. |
