Peatland initiation in Central European Russia during the Holocene: Effect of climate conditions and fires

Abstract

Peatlands store massive amounts of organic carbon, but the fate of this carbon remains unclear as global climate continues to warm. The age of peatland inception and the main drivers of peat initiation are one of the most important issues in Holocene paleoecology, especially for the numerous but under investigated peatlands in European Russia. This paper introduces new peatland initiation ages for 44 mires in three areas located in the central part of European Russia within the Polesie landscape belt. This region is characterised by waterlogged sandy plains and flat surface topography. Phases of peatland initiation were compared with Holocene fire regime derived from macro-charcoal data as well as with regional climatic reconstructions. We found that peat inception in the region started around 12,000 cal yr BP, but the most active phases of peatland initiation took place during the periods 8500–7500, 7000–6000, 5300–5800, 4000–3500 and 1700–1200 cal yr BP. Expect for rapid peat growth during the early Holocene, peatland initiation mostly coincided with warm climatic periods and increased fire frequency. Forest soil paludification in poorly drained Polesie landscapes was presumably enhanced by reduced evapotranspiration and changes in water balance due to disturbance of forest cover after wildfires. We expect that rising air temperature in the current century will cause higher fire frequencies and may encourage waterlogging of forests and ecosystem transformation.

The ongoing lateral expansion of peatlands in Finland

“…Similar to our findings from the southern sites, charcoal is commonly present in basal peat layers in other studies as well (Foster & Fritz, 1987; Foster & Wright, 1990; Korhola, 1996; Le Stum‐Boivin et al., 2019; Novenko et al., 2021; Pitkänen et al., 1999; Schaffhauser et al., 2017; Tuittila et al., 2007; Turunen et al., 1999) and it has been suggested that in Finland almost two thirds of paludification have been initiated by forest fires (Tolonen, 1983). Low severity fires may benefit peatland expansion by killing trees and reducing evapotranspiration and by promoting light availability creating favourable conditions for Sphagnum moss colonization (Le Stum‐Boivin et al., 2019; Novenko et al., 2021). For instance, in PS area lateral expansion has been promoted by recent fires (Turunen et al., 1999, 2002).…”

“…Similarly, rapid expansion of peatlands can occur in areas with small‐particle size subsoil such as clay or silt that have a large water‐holding capacity and are thus permanently inundated (Foster et al., 1988; Kleinen et al., 2012; Korhola, 1994) while pedogenic processes that decrease soil permeability may lead to increased water tables in peatland margins (Rydin & Jeglum, 2013). Waterlogged conditions in peatland margins may also be caused by disturbances, such as a forest fire or clear‐cutting, in adjacent uphill areas that reduce evapotranspiration due to loss of vegetation (Bauer et al., 2003; Ikonen, 1993; Korhola, 1996; Novenko et al., 2021; Schaffhauser et al., 2017; Simard et al., 2007; Tallis, 1991). In addition, rise of water tables in peatland margins may also be created by autogenic process of peat accumulation as the surface of a typical raised bog rises above the surrounding mineral soils and the runoff from the peatland crest is directed to the peatland margins (Anderson et al., 2003; Foster & King, 1984; Korhola, 1996; Rydin & Jeglum, 2013).…”

Mire plant diversity change over the last 10,000 years: Importance of isostatic land uplift, climate and local conditions

“…In the Northern Hemisphere, three major factors—post‐glacial isostatic uplift, autogenic succession and climate‐induced changes—are usually discussed in connection with mire origin and succession (Hájková et al., 2012; Novenko et al., 2021; O'Reilly et al., 2014; Walker et al., 2012). Even though the study area is small—about 20 × 30 km—the mire succession ‘stories’ of the six mires are rather different.…”

“…The degradation of mires leads to a loss of mire specialist species and reduced ecosystem multifunctionality (Hooijer et al., 2006; Robroek et al., 2017). The ongoing climate change is believed to strongly influence the mires in Northern Hemisphere with a warmer climate accelerating the succession from fen to bog (Novenko et al., 2021; Väliranta et al., 2017) and leading to the encroachment of woody vegetation (Pinceloup et al., 2020).…”

Carbon accumulation dynamics of the Klukva peatland at the southern boundary of broad-leaved forest zone in European Russia

“…Radiocarbon dating of the basal layers showed that the peatland was formed in the Early Holocene -about 9400 cal yrs BP. The comparison of the basal peat ages with the ages of peat initialization of other peatlands within the Central part of European Russia indicates that the peatland Klukva is one of the oldest mires of the Central Russian Upland [51,52]. It allows us to consider the peatland Klukva as a representative object to reconstruct the paleoecological conditions of the Holocene at the southern boundary of the broadleaved forest zone in European Russia.…”