1000 years of environmental change and human impact at Stóra-Mörk, southern Iceland: A multiproxy study of a dynamic and vulnerable landscape

Abstract

Multiproxy pollen, sediment, plant macrofossil and subfossil insect analyses are used to explore environmental change at Stóra-Mörk in southern Iceland between ad 500 and 1500. Previous palaeoecological studies in Iceland have indicated that vegetation and landscape change rapidly succeeded the initial settlement of the island around ad 871, with strong environmental consequences. However, recent high-resolution studies in western and northern Iceland suggest that the timing and amplitude of these changes may be less uniform than previously assumed. The palaeoecological evidence from Stóra-Mörk shows an initially muted anthropogenic signal. Before the early tenth century, the area was characterized by damp birch and willow woodland. Large-scale human impact did not begin until after ad 920 when a change in land use to grazing and crop production is observed in the pollen, insect and plant macrofossil records. Shifts in vegetation and insect taxa and in aeolian deposition indicate that this activity resulted in woodland reduction, increased soil instability, eutrophication and land surface drying. The relatively late appearance of large-scale human impact at Stóra-Mörk is consistent with the tenth-century farm establishment suggested by the historical record, and the delay in settlement at the location may relate to an initial avoidance of labour-intensive woodland clearance and/or management of woodland resources. This paper adds to the emerging body of evidence that suggests that the scale and timing of the initial effect of the human presence on Icelandic environments was influenced by complex and varied climatic, landscape, vegetational and cultural factors.

The impact of past climate change on genetic variation and population connectivity in the Icelandic arctic fox

“…The effects of human settlement in the ninth century AD were exacerbated by hemispheric climate change, both of which led to widespread environmental degradation at an unprecedented rate [1]. Although a great deal of research has focused on the human impacts on soil and vegetation systems [2,3], less is known about the effects of settlement or climate change on the wild animal populations of the island. The arctic fox (Vulpes lagopus) is particularly interesting since it is the island's only indigenous mammal.…”

Assessing the ecological impacts of extensive sheep grazing in Iceland

“…Palaeoand archeological records provide evidence for dramatic human environmental impact shortly after the landnám in some areas (Streeter et al 2015, Eddudóttir et al 2016. The impact was probably most intense in the lowlands, involving extensive clearance of mountain birch woodlands (Betula pubescens) in combination with livestock grazing, resulting in a rapid transition to open grasslands and dwarf-shrub heathlands that were less resilient to natural catastrophes (Dugmore et al 2005, Vickers et al 2011.…”

Late-Holocene land surface change in a coupled social–ecological system, southern Iceland: a cross-scale tephrochronology approach

“…The introduction of grazing animals at Landnám and the creation of persistent areas of aeolian erosion moves SeAR into a new regime of consistently higher SeARs, and there is little overlap between SeARs before and after Landnám (Streeter et al, 2012). This new phase state of elevated SeAR is reached after a rapid transition period (< 64 yrs), which is plausible considering that Iceland was colonised rapidly by a people dependent upon introduced domesticated animals (Vésteinsson and McGovern, 2012) and we know that woodland around farms was cleared rapidly (Halsdóttir, 1996;Vickers et al, 2011). The introduction of wide-ranging herbivorous mammals and the related systematic removal of woodland represents a fundamental shift in the ecology of the island.…”

“…We know settlement of Iceland was rapid (Vésteinsson and McGovern, 2012) and areas around farm sites experienced large ecological changes rapidly after Landnám (Hallsdóttir, 1996;Vickers et al, 2011). Evidence from the wider landscape shows that the change from a purely ecological system to a SES took place over several centuries, as shown by the centuries scale decline in woodland cover Church et al, 2007).…”