There are less fen peatlands in Latvia than we considered
Without doubt, Latvia's peatlands play an important role in both meeting the country's climate goals and preserving natural diversity. According to the Latvian Centre of Environment, Geology and Meteorology, approximately 10-15% of Latvia's territory is covered by peatlands, which are more precisely defined as deposits. From a current Latvian geological terminology, a peat deposit is defined as an area of at least 2 ha with a peat thickness of at least 30 cm. The 2023 report of the State Audit Office of the Republic of Latvia on "Management of mineral resources in Latvia" states that the lack of data makes it difficult or impossible to fully develop sustainable policies regarding natural recourses.
The same lack of data makes it difficult to predict the extent of peatlands and their potential contribution to climate change mitigation, as only about 60% of peat deposits are identified, and this figure is based on peat stock data obtained from the period 1960 to 1980. It is assumed that in Europe, Latvia ranks 5th in greenhouse gas (GHG) emissions from drained peatland areas.
It should be noted that with lower humidity and higher oxygen content in peat and peat soils, decomposition of organic compounds is faster. Consequently, new inventories of peatlands and peat deposits, as well as the identification of drained areas, can further contribute to sustainable policymaking. It is widely believed that about half of all peatlands in Latvia are fens (wet grass-sedges dominated) and the other half are raised bogs (Sphagnum moss dominated), but is this really the case? Although the Nature Counting project has provided additional information on bog areas, the project in question only surveyed habitats of European Union importance, which does not include an update on the situation of fens.
Given the lack of information on fens, Davis Matskins (student from the University of Latvia supervised by the Prof. Normunds Stivrins) look closer on this topic. He qualitatively assessed the distribution and changes of fens in one of the largest municipalities of Latvia – Ogre. After a feasibility study, 20 fen-type peat deposits were randomly selected and surveyed in the field to determine the type, thickness and characteristics of the peat they contain.
As a result, out of the 20 sites surveyed, only 5 corresponded to a fen peat deposit (with a 30 cm peat layer) and only 1 of these corresponded to a fen peatland also in terms of vegetation and moisture regime. These first results indicated unexpected situation – 75 % of fen peatlands are not anymore there! If similar situation is applicable to the whole territory of Latvia, then the actual numbers are staggering and so off that the official reports to the European Union must be changed according to the real fen distribution and associated GHG, and land use.
It was found that at all five actual fen peatland sites the upper 10 cm contained a lower proportion of organic material than the deeper sediments. These results indicate a potential peat mineralisation process and a more pronounced peat decomposition closer to the surface. Existing fen peat deposits are subject to intensive mineralisation, which means that existing peat layers are decomposing, resulting in GHG emissions and the disappearance of fen peat deposits.
The main conclusion from this study is that there are significantly fewer fen peatlands, as indicated, for example, in the Latvian Centre of Environment, Geology and Meteorology database, and a more detailed analysis of their distribution is needed through inspection and verification in the field at the national level.
Prepared by Normunds Stivrins