Bryophytes as key indicators of ecosystem function and structure of northern peatlands

Abstract

Bryophytes play a number of important roles in the functioning and structure of northern peatlands where they form the ground layer of fens and bogs. Sphagnum, dominant in bogs and poor fens, and brown mosses, dominant in rich fens, make up a large percentage of the organic matter that is stored as deep deposits of peat. In this paper we review the mechanisms of resistance to decay in these two moss groups. We then document a case study of a rich fen dominated mostly by Hamatocaulis vernicosus, that has remained stable for over 8000 calendar years. At this site, we use macrofossil abundances, including bryophyte habitat positions on water level and chemistry gradients, to infer past environmental conditions. Lastly, we provide a new ecohydrologic framework for wetland classes centered on bryophyte abundances across water level, nutrient, and salinity gradients and argue that bryophyte species are among the most significant indicators for classifying wetland site-types.