The Effects of Bryophytes on Succession from Alkaline Marsh to Sphagnum Bog

Abstract

The alkaline eastern marsh of Lawrence Lake, a marl lake in southwestern Michigan, USA, was sampled by randomly placed line transects to determine the bryophyte cover and corresponding vascular plant zones. Cluster analysis indicated 3 distinct bryophyte zones designated as: Drepanocladus/Brachythecium, Campylium/Drepanocladus, Campylium/Drepanocladus/Fissidens. These zones correspond with the recognized vascular plant zones cattail/sedge and rose/cattail/sedge, cattail/sedge/Potentilla, and upland Potentilla, respectively. Mosses occupied over 50% of the surface in some areas. Invasion of Sphagnum, vertical zonation of the mosses on hummocks, zonation with distance from the lake, the abundance of non-Sphagnum moss hummocks, and the ability of the non-Sphagnum species to lower the pH of marsh water during laboratory incubations are evidence that non-Sphagnum mosses facilitate succession from alkaline marsh to Sphagnum bog.