Postglacial peatland vegetation succession in Store Mosse bog, south‐central Sweden: An exploration of factors driving species change

Abstract

Boreal peatlands are facing significant changes in response to a warming climate. Sphagnum mosses are key species in these ecosystems and contribute substantially to carbon sequestration. Understanding the factors driving vegetation changes on longer time scales is therefore of high importance, yet challenging since species changes are typically affected by a range of internal and external processes acting simultaneously within the system. This study presents a high-resolution macrofossil analysis of a peat core from Store Mosse bog (south-central Sweden), dating back to nearly 10 000 cal. a BP. The aim is to identify factors driving species changes on multidecadal to millennial timescales considering internal autogenic, internal biotic and external allogenic processes. A set of independent proxy data was used as a comparison framework to estimate changes in the bog and regional effective humidity, nutrient input and cold periods. We found that Store Mosse largely follows the expected successional pathway for a boreal peatland (i.e. lake ? fen ? bog). However, the system has also been affected by other interlinked factors. Of interest, we note that external nutrient input (originating from dust deposition and climate processes) has had a negative effect on Sphagnum while favouring vascular plants, and increased fire activity (driven by allogenic and autogenic factors) typically caused post-fire, floristic wet shifts. These effects interactively caused a floristic reversal and near disappearance of a onceestablished Sphagnum community, during which climate acted as an indirect driver. Overall, this study highlights that the factors driving vegetation change within the peatland are multiple and complex. Consideration of the role of interlinked factors on Sphagnum is crucial for an improved understanding of the drivers of species change on shortand long-term scales.

Holocene wet shifts in NW European bogs: evidence for the roles of external forcing and internal feedback from a high‐resolution study of peat properties, plant macrofossils and testate amoebae

“…900 cal a bp ), shows a variable degree of peat decomposition above 9 cm and a 4‐cm surface layer of living Sphagnum moss. The ages estimated for the three peat‐stratigraphic boundaries are broadly consistent with those determined for the transitions between the fen and bog stages in the southern bog area by Svensson (1988b), Kylander et al (2013, 2016, 2018), Martínez Cortizas et al (2021) and Ryberg et al (2022). Very low peat‐growth rates (generally <0.5 mm a −1 ) characterize the basal fen peat and the well‐decomposed parts of the Sphagnum peat units, while the lower and more well‐preserved parts of these units show high growth rates in the range 2.0–3.5 mm a −1 (Figure 3).…”

“…C/N mass ratio varies between 27 and 51 in the upper part of the fen peat, while the Sphagnum peat units show values within the range 25-127, with low values within their more decomposed parts and close to the surface. The obtained OMBD, C, N and C/N records are consistent with previous studies (Svensson, 1988b;Malmer et al, 1997;Kylander et al, 2013;Kylander et al, 2016;Martínez Cortizas et al, 2021;Ryberg et al, 2022).…”

Storm chasing: Tracking Holocene storminess in southern Sweden using mineral proxies from inland and coastal peat bogs

“…With isostatic uplift this lake was drained to the southwest leaving a low-lying, exposed lake bottom. This provided an appropriate habitat for the accumulation of peat, which started at the southern end of the bogcomplex at ~9 ka (Ryberg et al, 2022). A recently uncovered map with 2771 peat depth measurements made in 1912 (Eller and Brenner, 1912) shows that the bog complex at Store Mosse is actually composed of several sub-basins with the larger, southernmost basin separated from the rest of the complex by a small stream/wetter area called Blåd€ opet (peat depths shown in Fig.…”

“…1). Based on findings from this earlier work, our studies have focussed on the thickest and oldest sections (5.5e7 m, up to 10,000 years old) in the southern bog complex (SMS 2008 , SMS 2018 ; Kylander et al, 2013Kylander et al, , 2016Kylander et al, , 2018Martínez-Cortizas et al, 2021b;Ryberg et al, 2022). From the GPR profiles that we have collected across Store Mosse and the map from Eller and Brenner (1912), there are clearly several thicker accumulations indicating that the peatland is formed in multiple sub-basins and/or initiation loci.…”

“…1). It has been the subject of numerous studies, particularly in its southern reaches, where the deepest and oldest accumulations have been found (~9000 years recorded in ~6.5 m of peat; Kylander et al, 2018Kylander et al, , 2016Kylander et al, , 2013Ryberg et al, 2022;Svensson, 1988). Store Mosse is unique in that it is not only bisected by a string of sand dunes, but also ringed by aeolian deposits and glaciofluvial sediments, providing abundant local sources of coarser-grained material.…”