A REVIEW OF LICHEN GROWTH AND APPLIED LICHENOMETRY IN SOUTHWEST AND SOUTHEAST GREENLAND

摘要

This paper presents a critical review of previous lichenometric and lichen growth studies in southern parts of West and East Greenland. These studies include classic work from around S circle divide ndre Str circle divide mfjord, Sukkertoppen, Sermilik and Angmagssalik. Particular emphasis is placed on those studies examining the role played by climatic continentality on the growth rate of crustose lichens in Greenland. The latter part of the paper presents new data on lichen growth rates from Sermilik, between 2001 and 2006, in 22 different lichen species. Measurements show that different species grow at different rates and growth rates vary from site to site. In this study Rhizocarpon geographicum generally grows slowly (< 0.2 mm a-1) while other species such as Pseudephebe minuscula grow more rapidly (1.0 mm a-1) in the same environment. Comparison with other studies shows that taxa-specific growth rates are slightly greater in West than in East Greenland - probably as a result of the slightly more favourable climate and higher precipitation levels. It is suggested that recent climate change, most marked in southern Greenland, will probably result in changed growth curves (over time) for species such as Rhizocarpon geographicum. However, only more precise growth curves and lichenometric dating curves can demonstrate such a phenomenon.