Soil evidence for historical human-induced land degradation in West Iceland

Abstract

► Environmental change in W-Iceland over the last 2700 years is studied from two soil cores. ► The Norse settlement around AD 870 caused depletion of vegetative coverage and biomass. ► Vegetation degradation induced soil erosion which successively caused a decline in soil quality. Human impacts have been severe on Icelandic soils and vegetation. In order to assess human impact on soils soil quality, soil organic C (SOC), soil bulk density (BD), soil moisture content (SMC), soil mass, and SOC sequestration were measured from two Histosol cores in West Iceland. The cores cover a period from around 665 BC to present, capturing the initial human settlement of Iceland in AD 871. Tephrochronology allowed for a reliable correlation and comparison between the two cores. The initial settlement had profound impacts on the soil quality, causing decreased SOC concentration and SMC, and increased vegetation degradation, soil exposure, eolian deposition, and BD. The total SOC pool was 34.6 kg C m 2 at one of the sites, of which 60.1% was formed during historic times, driven by increased soil mass deposition from surrounding eroded areas. The SOC pool was 43.7 kg C m 2 at the other site, of which 31.4% was formed during historic time, constrained by water cycling and decomposition.