The spectral behaviour of Sphagnum canopies under varying hydrological conditions

Abstract

We tested the extent to which the spectral response (0.4-2.5 μm) of Sphagnum can be used to indicate changes in near-surface hydrological conditions in northern wetlands. Via laboratory experimentation on three typical Sphagnum species we found that: (1) there is a clear link between (a) a ratio of SWIR/NIR reflectance (ETM+ Ch 5/ Ch4) and (b) the relative depth of the water absorbion feature centred at 1.205 μm (RDI), and near-surface volumetric moisture content (VMC) of the three species, (2) the changes in this ratio seem to be distinct for each species, and (3) data relating to the red-edge inflection point (REIP) for the Sphagnum species may also yield important information on variations in photosynthetic activity with near-surface VMC.