Water is one of the main prerequisites for the development of peatlands. The restoration of peatlands seeks to reestablish a plant cover dominated by Sphagnum or brown mosses depending on the substrate minerotrophy, as well as a hydrological regime typical of peatlands.
Sphagnum-dominated peatlands (bogs and poor fens) are characterized by a strong relationship between vegetation and hydrology. The highly fibric and porous structure of the Sphagnum carpet can store atmospheric water and limits considerably water table fluctuations. In natural bogs, the Sphagnum mosses keep the eco-hydrologic self-regulating systems favorable to their own growth.
In peatland management, it might appear easy to reverse the effects of drainage by simply rewetting. In reality, new soil profile conditions have developed after peat utilization, and these differ significantly from the natural mire soil profile of any former developmental stage. Therefore, restoration actions, especially after peat cutting or agricultural management, should consider the restoration site as a new environment with new physical properties, especially on the upper layer of the soil column.
Restored sites are usually monitored for the return of hydrological functions.