Sensitivity of spectral indices to CO2 fluxes for several plant communities in a Sphagnum-dominated peatland

A study was conducted in which the relationship between spectral indices and carbon dioxide (CO2) fluxes was tested for different communities in a Sphagnum-dominated peatland. This paper focused on the remote sensing approach that was used to directly link spectral indices to CO2 fluxes to highlight the potential of remote sensing for mapping the spatial distribution of CO2 fluxes. Carbon exchange in these ecosystems has become an environmental concern since peatlands play a key role in the global carbon cycle. A portable climate-controlled chamber was used to measure fluxes while simultaneously recording reflectance with a hand-held spectroradiometer. A laboratory experiment was also conducted to find a water-related index that most correlated with Sphagnum water content in order to regulate the normalized difference vegetation index (NDVI) values obtained in the field. The laboratory experiment showed a strong correlation between Sphagnum water content and all spectral indices, notably the water index (WI), normalized difference water index (NDWI), and relative depth index (RDI). The water index was chosen to regulate NDVI values. This paper described the indices that were tested in the field for CO2 flux estimations. NDVI alone was found to be a poor predictor of net ecosystem exchange. The relationship between CO2 fluxes and narrow band chlorophyll indices was reasonably well adjusted. It was concluded that the chlorophyll indices may be the most promising for mapping the spatial distribution of CO2 fluxes in the future. 62 refs., 2 tabs., 4 figs