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Green, T. G. A./ L. Brabyn/ C. Beard/ L. G. Sancho 2012: Extremely low lichen growth rates in Taylor Valley, Dry Valleys, continental Antarctica. - Polar Biology 35(4): 535-541. [RLL List # 226 / Rec.# 33642]
Keywords: Antarctica/ Extreme environment/ Lichenometry/ Radial growth/ Ross Sea/ Snow
Abstract: Estimates of lichen growth rates based on the measurements of several thalli at any site do not exist for continental Antarctica. However, the very limited existing data suggest that lichen growth rate may be a good indicator of climate change in Antarctica. We present measurements made on thalli of the lichen Buellia frigida Darb. growing in the Dry Valleys, Southern Victoria Land, continental Antarctica, which appear to have some of the slowest radial growth rates yet measured. Photographs of thalli at three different sites were analysed for growth over a 25-year period using nano-GIS techniques. At one site, Mt. Falconer Summit, the lichens had a mean growth rate of 0.0052 mm year with one individual as low as 0.0036 mm year. Thalli at the other two sites had significantly higher mean growth rates, 0.0136 mm year at Mt. Falconer Ridge and 0.0118 mm year at Rhone Bench. Assuming a constant growth rate, thalli at Mt. Falconer Summit had a mean age of 5,367 years, whilst the thalli at the other two sites were much younger, 840-1,026 years. We suggest that the different ages represent the appearance of new substrate for colonisation following climate changes in the Dry Valleys that altered the amount and duration of snow. The results confirm that lichen growth rate differs by almost two orders of magnitude over a latitudinal range of 15 degrees from south to north across Antarctica. © 2011 Springer-Verlag.
URL: http://dx.doi.org/10.1007/s00300-011-1098-7
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