Department of Geography and Centre for Polar Ecology, University of South Bohemia, 370 05 České Budějovice, CZECH REPUBLIC.
The ecology of widespread and abundant lichen Usnea sp. present on James Ross Island in the Antarctic is studied in this thesis. The complex approach was used to study the phenomenon of this species in the Antarctic terrestrial ecosystem. The method for nondestructive estimation of lichen biomass was developed. The method is based on simple field measuring with the use of modified botanical square and digital photography of the experimental plots. The method can be used on similar lichen communities. Furthermore, the focus of other work was on lichen dispersal over the James Ross Island mesas. For this purpose, the simple field experiment was established on Berry Hill and Lachman Crags mesa in the vicinity of newly deglaciated parts. It was found out that even very young deglaciated bare grounds are slowly settled by lichens. For better understanding of microclimate and humidity changes on particular Antarctic cryptogam communities caused by recent climate changes, the long-term experiment simulating temperature increase and humidity changes was established on Johnson mesa. Open-top chambers were used as a reliable method for simulating these changes. Snow barriers were used for the first time in the Antarctic terrestrial ecosystem.