Can Sphagnum traits be used to characterize peatland hydrology?

Background/Question/Methods

Sphagnum is a globally significant genus responsible for carbon sequestration in peatlands. Sphagnum functions as both a living organism as well as a soil and thus affects ecosystem hydrological function. Plant traits can be used to predict ecosystem function and have been used to characterize Sphagnum carbon sequestration, but it has yet to be determined if they can characterize Sphagnum hydrological function. Here we used 48 samples (10 cm diameter, 5 cm tall) of S. fuscum, S. rubellum, and from the S. magellanicum complex collected from four peatlands to relate Sphagnum traits (capitulum dry mass, capitula density, stem dry mass, fascicle density, bulk density, von post hummification) to hydrological functions (saturated hydraulic conductivity and water retention). Capitulum density, bulk density, saturated hydraulic conductivity and water retention were measured for the entire sample. Five individual strands of Sphagnum were taken from each sample to measure capitulum dry mass, stem dry mass, and fascicle density.

Results/Conclusions

Stem dry mass was significantly correlated with fascicle density (r = 0.53, p < 0.05) and capitula dry mass (r = 0.30, p < 0.05). These traits were not as strongly related to the bulk density of the entire sample. Von Post humification did not vary much between samples and so was not significantly related to any other traits. Relationships between the traits measured and hydrological functions are still being explored. These results will determine which functional traits (if any) we can measure as a proxy for hydrological function. Ultimately, using Sphagnum functional traits as a proxy for hydrologic function may allow us to assess peatland hydrology more efficiently.