Restoration of Raised Bogs: Mechanisms and Case Studies from the Netherlands

Abstract

This chapter discusses and explains various peat bog restoration strategies relating to peat quality, water chemistry and hydrology based on case studies from the Netherlands. Inundation of bog remnants can lead to a rapid redevelopment of (floating) Sphagnum vegetation, usually when poorly humified Sphagnum peat is still present. After inundation, the peat either swells up to the newly created water table or becomes buoyant, in both cases creating a favourable substrate for Sphagnum mosses. Methane production rate and peat chemistry play an important role in the buoyancy of floating peat. The presence of (slightly) calcareous groundwater in the peat base may enhance the development of floating peat by stimulating decomposition processes. Alternatively, the growth of submerged Sphagnum species can also lead to the development of floating rafts. This depends on the availability of light and carbon dioxide in the water layer. Many bog remnants, however, only have strongly humified peat, which does not favour the redevelopment of Sphagnum carpets after deep inundation. On the other hand, most Sphagnum species appear to do very well on surface-soaked strongly humified peat, which is why shallow inundation is to be preferred in such cases. An important prerequisite for the successful restoration of bog remnants is the development of a hydrologically self-regulating acrotelm. Key species involved in this development are Sphagnum magellanicum, Sphagnum papillosum and Sphagnum rubellum. Since these species are usually very slow colonisers, introduction of key species can accelerate the development of a functional acrotelm.