Tall moss turf subformation, whose developed forms are called moss banks (MB), play an important role in the structure of vegetation communities in the maritime Antarctic. In the present research, we studied the spatial distribution, moss banks thickness, area, species amount, dependence between these parameters, and species composition of the 44 MB on Galindez Island, Argentine Islands, Graham Coast. To select indicators for the monitoring of communities affected by climate change and biotic disturbance we compared the key parameters of the largest moss bank on Galindez Island (Smith moss bank) with measurements received for this moss bank 46 years ago. Galindez moss banks’ bryophyte flora included 13 species of mosses and three species of liverworts. There was no correlation between the species richness and the area of MB, but the species richness positively correlated with moss banks’ thickness. We supposed species diversity of MB depended presumably on the age of the moss bank and micro-conditions than on the area. Abundance of some moss species correlated with moss bank thickness. A comparison of results obtained in this study and in 1976, revealed an increase in the amount of brown- and black-coloured curtains of Polytrichum strictum, no significant changes in the ratio of Chorisodontium aciphyllum and a decrease in the lichen incrustation. These results show that the ratio of P. strictum’s colour morphotypes, C. aciphyllum and liverworts’ abundance can be used to evaluate the condition of MB in the long-term monitoring.