text: Environmental and ecological issues The distinctive ecological conditions of peat wetlands provide a habitat for distinctive fauna and flora. For example, whooping cranes nest in North American peatlands, whilst Siberian cranes nest in the West Siberian peatland. Palsa mires have a rich bird life and are an EU-red listed habitat, and in Canada riparian peat banks are used as maternity sites for polar bears. Natural peatlands also have many species of wild orchids and carnivorous plants. For more on biological communities, see wetland, bog or fen.
  Around half of the area of northern peatlands is permafrost-affected, and this area represents around a tenth of the total permafrost area, and also a tenth (185 ± 66 Gt) of all permafrost carbon, equivalent to around half of the carbon stored in the atmosphere. Dry peat is a good insulator (with a thermal conductivity of around 0.25 Wm−1K−1) and therefore plays an important role in protecting permafrost from thaw. The insulating effect of dry peat also makes it integral to unique permafrost landforms such as palsas and permafrost peat plateaus. Peatland permafrost thaw tends to result in an increase in methane emissions and a small increase in carbon dioxide uptake, meaning that it contributes to the permafrost carbon feedback. Under 2 °C global warming, 0.7 million km2 of peatland permafrost could thaw, and with warming of +1.5 to 6 °C a cumulative 0.7 to 3 PgC of methane could be released as a result of permafrost peatland thaw by 2100. The forcing from these potential emissions would be approximately equivalent to 1% of projected anthropogenic emissions.
  One characteristic of peat is the bioaccumulation of metals concentrated in the peat. Accumulated mercury is of significant environmental concern.