mires

Mires are a broad category of wetlands distinguished by saturated soils and the accumulation of peat, the partially decomposed remains of originally forest or herbaceous vegetation. This peat buildup creates long-lasting carbon stores and a distinctive hydrology. The term mire is commonly used in peatland research to refer to peat-forming wetlands, especially bogs and fens, though some definitions also include peat-rich swamps and certain marshes. In many regions mires cover extensive areas and influence landscape hydrology and ecology.

Bogs are typically ombrotrophic, receiving most water from precipitation and becoming acidic and nutrient-poor; they are often dominated by Sphagnum moss and ericaceous shrubs, with peat formation maintained by low decomposition rates. Fens are minerotrophic, fed by groundwater or surface inflows, and thus less acidic and more nutrient-rich; their vegetation includes sedges, grasses, mosses and shrubs, and they also accumulate peat, though with different plant communities. Swamps are forested wetlands with standing water that can accumulate peat when organic matter builds up, while marshes are open-water or herbaceous wetlands. Some marshes and swamps can peat-form in cooler climates. Mires influence hydrology by storing water and shaping soil chemistry, and they host specialized flora and fauna adapted to wet, nutrient-poor or variable conditions.

Globally, mires are most extensive in boreal and cool temperate regions, where peatlands can dominate land cover. They are important carbon sinks because peat decomposes slowly under waterlogged, anoxic conditions. Disturbance such as drainage, peat extraction, or climate drying disrupts peat formation and releases stored carbon. Conservation and restoration efforts focus on rewetting drained areas, restoring hydrology, and reestablishing peat-forming vegetation, especially Sphagnum mosses.