Climate change impact on peatland dynamics during the Holocene in Latvia, Northeastern Europe

Abstract

Peatlands are essential ecosystems for climate regulation and biodiversity yet they face increasing threats from human activities and climate change. The geological record of Northeastern Europe, including Latvia, reveals periods of warmer-than-present climatic conditions during the Holocene, offering valuable insights into historical peatland dynamics under changing climates. This study aims to evaluate the initiation and development of peatlands in Latvia during the Holocene, an epoch characterised by distinct long-term climate patterns. We analysed published and unpublished data – including radiocarbon dating, lithology and loss-on-ignition – from fen and raised bog sites in Latvia to assess their characteristics and responses to past climate conditions. Our findings indicate that the earliest peatlands, established approximately 11,000 years ago, were fens. Over the course of the Holocene, Latvian peatlands accumulated an average 4 m of peat, with maximum depths exceeding 8 m. Peat accumulation was most pronounced during the Early Holocene (11,700–8,200 years ago) and the Late Holocene (the last 4,200 years), coinciding with cool and moist hydroclimatic conditions. The highest rates of peat and carbon accumulation were observed during the Late Holocene, whereas peatland establishment was lowest during the Middle Holocene (8,200–4,200 years ago), when the climate was warmer and drier than today. These findings suggest that prolonged warming and drying – similar to Middle Holocene conditions – could significantly slow peat formation and carbon sequestration in Latvian peatlands under future climate warming scenarios.