Several functions and values of peatlands make them valuable ecosystems. Although the definitions of functions or values vary according to individual perception and interest, some of them are widely recognized. Their role as a carbon sink has gained visibility recently because of its impact on the greenhouse effect and climate change. Natural peatlands emit greenhouse gases such as methane (CH4), but they also stock a large amount of carbon present in plant debris and peat. Following drainage and extraction, peat is exposed to air and decomposition processes cause the emission of carbon dioxide (CO2), thus contributing to greenhouse gas build-up in the atmosphere.
Biodiversity is another value that gives special status to peatlands. Since they are unique, acidic ecosystems, peat bogs support specific plant communities. A number of plant and bird species are found only in peatlands. Recent studies suggest that large peat bogs have a higher value because they have a greater variety of habitats such as pools, and hence, a larger number of species.
Riparian fens also play a role in regulating water flow: by stocking water, peat bogs act as buffers, in case of abundant precipitation. The importance of this role appears when fens are lost or drained: water that would normally be stocked reaches watercourses more rapidly, thus contributing to higher peak flow.
Peatlands are also used by many people for recreational uses such as fruit picking and hunting. Their aesthetic and educational values are also recognized since more people have access to nature interpretation trails, especially in parks.
The function of peatlands as paleo-archives is well known by scientists. Because of the low rate of decomposition and anoxic conditions, many plant parts, especially seeds and pollen, are preserved in peat for thousands of years. With modern techniques of dating the age of organic matter, it is possible to reconstruct past environment and climate through the identification of seeds and pollen present within the superposed peat layers.
The restoration of functioning peatland ecosystems should allow restored peatlands to play most of their roles and recover some of their value that were lost following peat extraction or other perturbations. A functioning peatland, which is a self-sustaining ecosystem, will restart accumulating carbon, regulate water flow, support a variety of habitats and species and provide recreational activities. However, paleo-archives will be lost forever unless peat cores are taken prior to peat extraction.