The initiation and development of small peat‐forming ecosystems adjacent to lakes in the north central Canadian low arctic during the Holocene

Abstract

Small peat‐forming ecosystems in arctic landscapes may play a significant role in the regional biogeochemistry of high‐latitude systems, yet they are understudied compared to arctic uplands and other major peat‐forming regions of the North. We present a new data set of 25 radiocarbon‐dated permafrost peat cores sampled around eight low arctic lake sites in northern Manitoba (Canada) to examine the timing of peat initiation and controls on peat accumulation throughout the Holocene. We used macrofossils and charcoal to characterize changes in the plant community and fire, and we explored potential impacts of these local factors, as well as regional climatic change, on rates of C accumulation and C stocks. Peat initiation was variable across and within sites, suggesting the influence of local topography, but 56% of the cores initiated after 3000 B.P. Most cores initiated and remained as drier bog hummock communities, with few vegetation transitions in this landscape. C accumulation was relatively slow and did not appear to be correlated with Holocene‐scale climatic variability, but C stocks in this landscape were substantial (mean = 45.4 kg C m−2), potentially accounting for 13.2 Pg C in the Taiga Shield ecozone. To the extent that small peat‐forming systems are underrepresented in peatland mapping, soil organic carbon (SOC) stocks may be underestimated in arctic regions. Mean fire severity appeared to be negatively correlated with C accumulation rates. Initiation and accumulation of soil C may respond to both regional and local factors, and substantial lowland soil C stocks have the potential for biogeochemical impacts on adjacent aquatic ecosystems.

Widespread recent ecosystem state shifts in high‐latitude peatlands of northeastern Canada and implications for carbon sequestration

“…Plant macrofossil assemblages (n = 407) from the 33 peat cores were classified into three peatland vegetation types (Table S2) following an approach similar to that of Camill et al (2009Camill et al ( , 2017 and Treat and Jones (2018). This classification is based on known ecological preferences of the dominant plant taxa (Table S3) in terms of surface wetness and trophic status (Gignac et al, 1991;Gignac, 1992;Mulligan & Gignac, 2001;Vitt & Luth, 2017).…”

Lake–mire ecosystem transformation and its possible forcing mechanisms in volcanic landform regions: a case study in the Gushantun peatland of northeast China

“…Basal peat ages show a good linear relationship with peat thickness ( R 2 = 0.6807) (Figure 4c), indicating that the mean sedimentary rate of peat deposits in most cores is similar to each other. This means that the whole peatland development is synchronous in different parts, and the common influence factors such as regional climate might play an important role in peat accumulation (Ireland et al ., 2013; Camill et al ., 2017).…”

“…However, synchronous evolution features of multi‐cores analysis in peatland most probably is controlled by common factors such as regional climate or common geomorphologic conditions, which can exclude the influence of autogenic process. In contrast, the asynchronous evolution features of multi‐cores analysis in peatland is most probably controlled by autogenic process or local geomorphologic conditions (Camill et al ., 2017; Mathijssen et al ., 2017). Thus, we will use this hypothesis to distinguish the influence of regional climate and autogenic process.…”

Using Relationships Between Vegetation and Surface Soil Biogeochemical Properties to Assess Regional Soil Carbon Inventories for South Baffin Island, Nunavut, Canada

“…The soil cylinder was used to collect mineral soil to a depth of 10 cm and, additionally, from 10 to 20 cm. Because the wet meadow sites were dominated by Sphagnum peatmosses, we used techniques described previously for sampling peat in permafrost soils (Camill et al., 2017). We first extracted a peat monolith with a bread knife to the depth of permafrost, when present, or to the depth of rock or mineral soil (Figure 3c).…”

“…We first extracted a peat monolith with a bread knife to the depth of permafrost, when present, or to the depth of rock or mineral soil (Figure 3c). When permafrost was detected at depths shallower than the depth of peat, a Hoffer corer was used to extract frozen soil to a depth of rock or mineral soil (Camill et al., 2017; Zoltai, 1978). Soil sampling was limited to the top 20 cm in the polar desert and mesic tundra vegetation types due to the difficulty of sampling upland soils containing stones and permafrost.…”