Quantitative landscape reconstruction and erosion history during the past 1,100 years in the Skogaryd Research Catchment, southern Sweden

Abstract

A sediment sequence from a small forest lake in southwestern Sweden was investigated to explore the effects of forestry and land-use on catchment erosion and delivery of organic and minerogenic matter to the lake. Catchment-scale vegetation changes during the last 1,100 years were reconstructed quantitatively at 50-year resolution using pollen analysis and the Landscape reconstruction algorithm (LRA). Variations in terrestrial organic matter input to lake sediments were assessed by total organic carbon (TOC) content and carbon to nitrogen (C/N) ratios. Changes in minerogenic matter were analysed using X-ray fluorescence (XRF) scanning. The results show that Skogaryd was not intensively used for agriculture throughout the past 1,100 years, but its land-use changes were very sensitive to societal changes. Between ca. ad 950 and 1350, local land-use was characterized by small-scale agricultural activities associated with the Medieval expansion, and enhanced soil erosion was recorded by increased K, Ti and Rb deposition. Around ad 1350 much of the farmland was abandoned, most likely in response to outbreaks of plague. The abandonment of farmland caused increased coniferous woodland cover and lower soil erosion. From the 16th century land-use expanded and gradually intensified, concurrent with a population increase documented in the study area between ca. ad 1600 and 1850. Intensive exploitation of the forest led to soil erosion and increased terrestrial organic and minerogenic matter export to the lake. These processes peaked with the artificial drainage of a nearby wetland for agricultural purposes. During the 20th century, modern forestry management started with the plantation of conifers, and soil erosion declined.

Relationships Between Land Use and Terrestrial Organic Matter Transfer to the Baltic Sea Over the Last 500 Years

“…However, as indicated by Λ 8 , the contribution of terrestrial OM was still higher than it was before the 18th century when the catchment experienced minor human impacts. A similar case has also been observed in the sediment of a lake located in southwestern Sweden (Yang et al., 2020, 2021). Many studies have reported an initial loss in soil OM after reforestation partly resulting from pre‐planting disturbances, and the soil carbon stock level is lower in a managed conifer forest than in a comparable natural forest (Bastida et al., 2018 and references therein).…”

A Historical Plankton Index: Zooplankton abundance in the North Sea since 800 CE

“…Non-temperature-related changes in zooplankton abundance as, for example, driven by terrestrial nutrient run-off variability might also be variously modelled using evidence for inter-related changes in settlement, land-cover, storminess and streamflow (e.g. Bunzel et al, 2021; Johansson et al, 2020; Lamb and Frydendahl, 1991; Yang et al, 2020).…”