Peatlands in the Brazilian Cerrado: insights into knowledge, status and research needs

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Wetlands play an important role for water, carbon storage and biodiversity in the seasonally dry and hot environments of tropical savannas. Peatlands, which are permanent wetlands, are important as the carbon-richest parts of wetland ecosystems with a strong ability to store carbon, retain water and regulate its flow. With this first review on peatlands in the Cerrado we synthesize existing knowledge and gaps on their distribution and types in the biome including, vegetation, soil properties, carbon stocks and hydrogeomorphology. Peatlands are embedded in wetland complexes in valleys, groundwater-fed oligo- to mesotrophic, with wet grass- and shrubland, Vereda or riparian swamp forest vegetation. Average peat depth is 1.4 meters and soil carbon stocks in the first meter can be 9 times higher than in mineral soils under Cerrado dryland vegetation, reaching about 1000 t carbon per hectare. Total soil carbon stock estimates (3.19 Gt C) in peatlands equal 13.3% of the total soil carbon in the Cerrado in only 0.7% of its total area, although large uncertainties exist. Actual peatland occurrence appears to be more abundant than current soil and peat maps suggest. The high rate of transformation of the native vegetation into industrial agriculture and wood plantations, which affects large parts of the Cerrado, is a major cause for the degradation and the loss of peatlands and other wetlands. However, the extent of peatland degradation and resulting carbon losses remain unfathomed. We identified research needs such as better mapping and monitoring, and recommend including peatlands into wetland classification systems in Brazil.