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Towards spatial assessment of carbon sequestration in peatlands: spectroscopy based estimation of fractional cover of three plant functional types
G. Schaepman-Strub1, J. Limpens1, M. Menken1, H. M. Bartholomeus2, and M. E. Schaepman2
1Nature Conservation and Plant Ecology Group, Wageningen University, Wageningen, The Netherlands
2Centre for Geo-information, Wageningen University, Wageningen, The Netherlands
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Abstract. Peatlands accumulated large carbon stocks as peat in historical times.
Currently however, many peatlands are on the verge of becoming sources with
their carbon sequestration function becoming sensitive to environmental
changes such as increases in temperature, decreasing water table and
enhanced nitrogen deposition. Long term changes in vegetation composition
are both, a consequence and indicator of future changes in carbon
sequestration. Spatial continuous accurate assessment of the vegetation
composition is a current challenge in keeping a close watch on peatland
vegetation changes. In this study we quantified the fractional cover of
three major plant functional types (Sphagnum mosses, graminoids, and shrubs) in
peatlands, using field spectroscopy reflectance measurements (400–2400 nm) on
25 plots differing in plant functional type cover. The data was validated
using point intercept methodology on the same plots. Our results showed that
the detection of open Sphagnum versus Sphagnum covered by vascular plants (shrubs and
graminoids) is feasible with an R2 of 0.81. On the other hand, the
partitioning of the vascular plant fraction into shrubs and graminoids
revealed lower correlations of R2 of 0.54 and 0.57, respectively. This
study was based on a dataset where the reflectance of all main plant
functional types and their pure components within the peatland was measured
at local spatial scales. Spectrally measured species or plant community
abundances can further be used to bridge scaling gaps up to canopy scale,
ultimately allowing upscaling of the C balance of peatlands to the ecosystem
level.
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Citation: Schaepman-Strub, G., Limpens, J., Menken, M., Bartholomeus, H. M., and Schaepman, M. E.: Towards spatial assessment of carbon sequestration in peatlands: spectroscopy based estimation of fractional cover of three plant functional types, Biogeosciences Discuss., 5, 1293-1317, 2008. Bibtex EndNote Reference Manager
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