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

Abstract

cattle, goats and pigs , and these would have modified the natural environment through grazing across the Faroese landscape. 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.It has been demonstrated that in general the most important environmental variable affecting chironomid composition is temperature (Brooks and Birks, 2001). With the temperature optima of most species known, it is possible to estimate past temperatures Abstract: Chironomids were examined as part of a multiproxy palaeolimnological study of Gróthúsvatn, Sandoy, Faroe Islands. A total of 37 taxa was found in the top 1 m of the core. Chironomid-inferred total phosphorus and temperature reconstructions indicate that after landnám (the Norse settlement period) total phosphorus levels rose slightly, then peaked at a temperature minimum (interpreted as the 'Little Ice Age'). Total phosphorus levels subsequently fell to only slightly above pre-settlement levels at the sediment surface. Little indication of increased erosion in the catchment after landnám was found, and it is likely that the impacts of human settlement on Gróthúsvatn and its catchment were slight. We therefore propose that the temperature decrease caused the increase in the lake's productivity.

Within-lake variability of subfossil chironomid assemblage in a large, deep subtropical lake (Lugu lake, southwest China)

“…In Lugu lake, higher concentration nearshore may be also primarily due to the fact that large amounts of submerged macrophytes were distributed within the shallow parts of the lake at less than 11 m of depth (Wang and Dou, 1998), which in turn support large invertebrate communities. The taxa associated with macrophytes, such as P. penicillatus-type, Ablabesmyia, Cricotopus sylvestris-type, Paramerina, Dicrotendipes nervosus-type (Brodersen et al, 2001;Langdon et al, 2010;Gathorne-Hardy et al, 2007), were restricted to the near-shore locations at a depth less than 11 m. This also confirms the relationship between macrophytes and the chironomid fauna in Lugu lake. Furthermore, Fig.…”

The Vikings were not the first colonizers of the Faroe Islands

“…Therefore, the scant early remains would have been truncated and built over by successive generations of Faroese builders, either destroying the evidence completely or sealing it under metres of occupation debris capped by modern buildings, again rendering the evidence archaeologically invisible. Thirdly, the insubstantial remains would be susceptible to natural eroding and accreting forces, such as coastal aeolian erosion and soil movement and landslides, which routinely occur in the low-lying coastal valleys of the Faroes Gathorne-Hardy et al, 2007;Lawson et al, 2005;2008). A systematic and very detailed archaeological examination of the base of known coastal erosion sections containing archaeological remains similar to Á Sondum may be the best way to find other early settlement sites in the islands.…”