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

Vegetation History and Archaeobotany https://doi.org/10.1007/s00334-020-00770-6 ORIGINAL ARTICLE Quantitative landscape reconstruction and erosion history during the past 1,100 years in the Skogaryd Research Catchment, southern Sweden Bingjie Yang1 · Anne Birgitte Nielsen1 · Karl Ljung1 · Elise Fahlgren2 · Anne Hormes2 · Dan Hammarlund1 Received: 27 May 2019 / Accepted: 18 January 2020 © The Author(s) 2020 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. Keywords Land-use · Organic matter · Pollen · Landscape reconstruction algorithm · Soil erosion Introduction Human activities including agriculture, forest clearance and industrialization have been the main cause of vegetation changes during the past 1,000 years in Europe. The Communicated by M.-J. Gaillard. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00334-020-00770-6) contains supplementary material, which is available to authorized users. * Bingjie Yang 1 Quaternary Sciences, Department of Geology, Lund University, Sölvegatan 12, 223 62 Lund, Sweden 2 Department of Earth Sciences, University of Gothenburg, Guldhedsgatan 5a, 41320 Gothenburg, Sweden population experienced several phases of growth and decline during this period. Population growth led to the expansion of agricultural land and increased erosion, which resulted in generally increased detrital input to lakes (Williams 2000; Boyle 2001; Koinig et al. 2003; Bragée et al. 2013). The increased detrital input associated with more intensive land use caused eutrophication and increased aquatic primary productivity in lake waters (Neumann et al. 2002; Routh et al. 2004; Köster et al. 2005; Li et al. 2008). During periods of population decrease, lake ecosystems may return to natural conditions, but such recovery can take decades or even centuries (Haas et al. 2019), and if critical thresholds have been crossed, the ecosystem may never return to the preimpact state (Duarte et al. 2009; Randsalu-Wendrup et al. 2016). Long-term records of vegetation and aquatic environmental changes at centennial to millennial time scales are therefore essential for the assessment of ecosystem dynamics in response to early and recent anthropogenic disturbances, 13 Vol.:(0123456789) Vegetation History and Archaeobotany and such data have significance for nature conservation (Willis and Birks 2006; Mazier et al. 2015). Since lake sediments are influenced by terrestrial input, it is possible to reconstruct environmental changes in lake catchments based on multi-proxy analysis of continuous lake sediment records (Koinig et al. 2003; Meyers 2003; Klamt et al. 2017). The long-term history of human impact on vegetation can be reconstructed by means of pollen analysis. However, it is difficult to quantify vegetation dynamics based on pollen percentages without taking the difference in pollen productivity and dispersal into consideration. Thus, the Landscape reconstruction algorithm (LRA) has been developed to quantify vegetation cover based on pollen assemblages, pollen productivity and dispersal (Sugita 2007a, b). The LRA is dependent on two models, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites), which is used to estimate regional vegetation composition (Sugita 2007a), and LOVE (LOcal Vegetation Estimates), which is used to estimate local vegetation composition in the same region (Sugita 2007b). Over the last decade, frequent applications in Europe have shown that LRA gives a better estimate of past land cover and can discriminate between local and regional changes (e.g. Nielsen and Odgaard 2010; Overballe-Petersen et al. 2013; Cui et al. 2013, 2014; Hultberg et al. 2015; Mazier et al. 2015; Mehl et al. 2015; Abraham et al. 2017; Fredh et al. 2017, 2019; Hjelle and Lødøen 2017). Hence, the application of LRA makes it possible to quantify past local land-use changes. The Skogaryd Research Catchment (SRC) station was established with the aim of improving the understanding of the roles of greenhouse gas balances and other biogeochemical cycles for regulating ecosystem services in the forested regions of the hemiboreal zone (https://gvc.gu.se/english/ research/skogaryd). A range of field experiments and monitoring series are in operation to characterize and quantify greenhouse gas balances, including carbon and nitrogen exchange between land and atmosphere (e.g. Klemedtsson et al 2010; Rütting et al. 2014; Tarvainen et al. 2014), land and water (e.g. Chmiel et al. 2016; Campeau et al. 2018) and water and atmosphere (e.g. Kokic et al. 2016; Wallin et al. 2018). However, there is no long-term monitoring data available beyond the last few decades. Documentation of prehistoric remnants, property maps, ownership changes and forestry accounts around the SRC indicate that large changes in land-use have taken place during the recent centuries (Hill 1999), affecting geochemical cycling in the area. It will be beneficial for contemporary studies to understand the history of agriculture and forestry in the SRC, and its consequences for biogeochemical processes, particularly the carbon cycles in a long-term perspective. In this study, we explore how land-use changes (e.g. forestry, agriculture, drainage patterns) have affected soil erosion in the (...truncated)