Peatland restoration

Peatland restoration is a term describing measures to restore the original form and function of peatlands, or wet peat-rich areas. This landscape globally occupies 400 million hectares or 3% of land surface on Earth. Historically, peatlands have been drained for several main reasons; peat extraction, creation of agricultural land, and forestry usage. However, this activity has caused degradation affecting this landscape's structure through damage to habitats, hydrology, nutrients cycle, carbon balance and more.

Due to peat formation, peatlands are carbon-rich and noted as carbon sinks. It has been projected that climate change, such as increased temperature and alterations of precipitation, affecting these landscapes under current status could increase releases of greenhouse gases (GHGs). Climate projections indicate increased probability and intensity of weather events, which can increase risk of fires and additional GHG release. Peatlands home a variety of native flora and fauna put at risk by projected degradation from climatic or anthropogenic alternation, placing emphasis and need for restoration efforts. Policy for restoration is in action. In June 2002, the United Nations Development Programme launched its Wetland and Ecosystem and Tropical Peat Swamp Forest Rehabilitation Project and in November the International Peatland Society formed, which promotes restoration and balance of demands on peatlands.

Peatland restoration emphasises the reduction of GHG emissions to slow the effects of climate change. With discussion circulating on human impacts of damage from draining and clearing the landscape. As a result, restoration would involve balancing usage of peatlands for human needs and needs of the natural ecosystems. Presently, main methods of restoration circulate on re-wetting, restoring forestry, localised paludiculture and adaption of anthropogenic usage of peatlands.

Peatlands store carbon from dead plants and hence help mitigate climate change. However, draining and degrading peatlands release large amounts of greenhouse gases. Rewetting and restoring peatlands can significantly reduce these emissions by raising water tables which slower down the plant decomposition. The resulting anaerobic decomposition produces the greenhouse gas methane, but since methane does not remain in the atmosphere as long as other GHGs, the net effect on the climate is likely cooling if a long time frame is considered (decades). The strength of this effect varies between different kinds of peatland, but it is generally most significant in tropical and agricultural peatlands. A raised water table also results in a local direct cooling effect, moist vegetation and soil has a higher thermal conductivity and therefore solar radiation is rather used for evapotranspiration than warming the surface.

The goals of peatland restoration in hydrological terms are primarily to improve the quality and regulate the quantity of water. A peatland as an intact ecosystem is a natural water purifier, it filters and stores organic substances, metals or other toxic matter and retains nutrients. These pollutants are stored in the peat for long periods of time, improving the quality of drinking water. The concept of peatlands regulating water quantity has often been compared to the way of a "sponge" works, in times of high availability of water (periods of rainfall) it is sucked up and stored and afterwards, in times of less precipitation, slowly released to the environment. Furthermore, as the water level rises, the risk of peat fire decreases.

In some instances, peatlands may exhibit a comparatively lower number of species. However, in the same biogeographic zone as dryland ecosystems, peatlands contain a greater percentage of specialized and distinctive species. Due to the isolation and heterogeneity of their habitats, peatlands harbor significant populations of endangered and rare species, many of which are unique to peatland environments, and play a role for the conservation of genetic diversity. Restoration seeks to counteract the process of habitat deterioration, which represents the most significant risk to biodiversity. In drained sites there is a tendency for plant diversity to decrease, with mosses (including Sphagnum) facing difficulties in recolonizing such areas. This could be attributed to the hydrological alterations, as well as the loss of the initial soil characteristics.

Due to the formation of peat developing from partial decomposition of vegetation material, there is a high quantity of carbon within this landscape. As a result, peatlands can be seen as a carbon storage. Carbon fluctuations are dominantly impacted by local hydrology within a peatland.

However, these processes are interrupted by anthropogenic usage of peatlands. Peat extractions cause destabilisation of local ecosystems through physical landscape damage of digging, draining and isolation through habitat fragmentation. As a result of drainage and temperature increase, peatlands are becoming drier, which increases the likelihood of severe fires and the risk of larger carbon dioxide emissions.