Climate change and human settlement as drivers of late-Holocene vegetational change in the Faroe Islands

Abstract

Changes in Faroese land surfaces during the late Holocene reflect intimate interactions between cultural and environmental development. Analyses of fossil wood, pollen and plant macrofossils indicate that the present open landscape replaced shrubby vegetation that was present from c. 6000 BC Up to C. AD 660. Conditions altered during the late Holocene, with loss of woody vegetation and increasing erosion: trends that were initiated prior to human settlement. AMS dating of sub-fossil Betula, Salix and Juniperus found buried in peat profiles from the islands of Su8uroy, Sandoy, Eysturoy, Vagar and Streymoy, revealed that the islands had at least partial woody vegetation cover up to the time of continuous settlement. The settlement horizon, identified in a lacustrine sequence on the island of Eysturoy, dated to c. AD 570. It comprised pollen evidence for the cultivation of Hordeum, cultural macrofossil assemblages, charcoal fragments, diatom assemblage changes indicating lake nutrient enrichment and physical measurements showing increased sedimentation rates. The pollen record showed that heathland development was initiated prior to anthropogenic impact. The ecosystem impacts of settlement were therefore superimposed on landscape changes that began around AD 250. The earlier changes were most likely forced by increased storminess and declining atmospheric temperatures.

The Chironomidae of Gróthúsvatn, Sandoy, Faroe Islands: climatic and lake-phosphorus reconstructions, and the impact of human settlement

“…The islands were extensively glaciated during the last glacial maximum (Humlum et al, 1996), and it is likely that the terrestrial and freshwater biota are made up of Lateglacial and Holocene colonists (Buckland, 1988). The Faroes remained uninhabited until the late first millennium AD, when the Norse colonized the archipelago (Arge, 1993), although there may have been limited earlier settlement by Irish hermits in the sixth to eighth centuries AD (Jóhansen, 1979(Jóhansen, , 1985Hannon and Bradshaw, 2000;Hannon et al, 2005; but see also Buckland et al, 1998). These human settlers brought many plants and animals with them, including barley, sheep, from subfossil assemblages.…”

“…The extent of postcolonization environmental change on the Faroes is not fully known. Most previous studies have been palynological (eg, Johansen, 1985;Hannon et al, 2001Hannon et al, , 2005Edwards et al, 2005;Lawson et al, 2005), and the few other multiproxy studies (eg, Edwards et al, 1998;Vickers et al, 2005) have focused on archaeological sites. This multiproxy study of the palaeolimnology of the lake Gróthúsvatn (Figure 1), near to the Norse period archaeological site of Undir Junkarinsfløtti (Arge, 2001;Church et al, 2005;Lawson et al, 2005), is aimed at obtaining further understanding of the pre-settlement landscape and the impacts of colonization.…”

The Vikings were not the first colonizers of the Faroe Islands

“…Barley is not indigenous to the Faroes and so must have been either grown or brought to the islands by humans. The possibility of small-scale barley cultivation is strengthened by the barley-sized pollen grains first appearing in the Faroes palaeoecological record in the mid first millennium AD (Hannon et al, 2000(Hannon et al, , 2005Edwards et al, 2005;Figure 1a). …”

“…* measured on-line on AMS. Table 1) for archaeological contexts from Á Sondum compared to the time of appearance of barley-type pollen from Hov and Heimavatn (Hannon et al, 2005 (X to Y on trench plan). A, B and C denote the sample positions for the radiocarbon dates displayed in Figure 2a.…”

“…Previous research on the contemporary literary source of De Mensura Orbis Terrae written by the Irish monk Dicuil c. AD 825, attested to ecclesiastical anchorites settling remote North Atlantic islands (Tierney, 1967), but the specific identification of the Faroes in the text is a subject of debate (Arge 1991;Debes, 1993;Thorsteinsson, 2005;Dugmore et al, 2010). Palaeoenvironmental reconstruction in the form of close-interval pollen analysis (Jóhansen, 1985;Hannon et al, 2000Hannon et al, , 2001Hannon et al, , 2005Edwards et al, 2005;Edwards and Borthwick, 2010), has also suggested that small-scale human settlement may have occurred in 5 th -6 th centuries cal AD. This early settlement was proposed through the 14 C dating of sediment layers containing the first appearance of barley-type pollen, at sites such as Heimavatn in the north of the island chain and Hov in the south (see Figures 1 and 2a).…”