The sizes of glacial lakes of the Ukrainian Carpathians without surface water runoff (Brebeneskul, Nesamovyte – the last 130 years, Verhne Ozirne, Nyzhne Ozirne – the last 50 years) and surface water runoff lakes Dogyaska (the last 30 years) has not substantial changes. The lakes Maricheyka and Vorozheska considerably decreased in area (20–40 % of previous squares), obviously, due to the erosion of rocky moraines-damages. Comparison of photos lakes Nesamovyte (1935–2008) has not showed changes of the outlines of the water area, the sedge-sphagnum alloy and the coastal thickets of the debris. The small glacial lakes Breskul has reduced its bed, because the sedge-sphagnum alloy overgrown with ray herbs, but the open water area is stable during the last 67 years. There are some increase alkalinity water of Brebeneskul and Verhne Ozirne and acidification of the Nesamovyte during the last 60 years. Unidirectional changes in the acid-alkaline balance of glacial lakes waters are not noted. The shrub covered decreases its area in basins of the all glacial lakes of Ukrainian Carpathians every year as a result of the cuttings of tourists for the campfires. For example, the number of the hearths in the Nesamovyte basin has decreased from 7 in the 2001 to the 80 in the 2017 years. The most intense in this process is in the basins of Nesamovyte and Brebeneskul. The number of tourists stopping for a night in the basins of high mountain lakes increased by 7–10 times according to the calculation of foci traces during 2001–2017 years. The clogging of shores and water areas of the glacial lakes and the formation of random garbage increases in the last two decades. The number of the oligosaprobic crustaceans species decrease and mesosaprobic are growing, appear polisabrobic species. The saprobic status of water lakes with the greatest recreational influence (Nesamovyte, Brebeneskul, Dogyaska) has a tendency to increase during the last 17 years. The loss of stenobiontic crustaceans species from glacial lakes (Streblocerus serricaudatus (Fischer, 1849), Mixodiaptomus tatricus (Wierzejski, 1883) and some others), the penetration of non-typical hydro- and amphibiontic species into highlands waters (Pohlia nutans (Hedwig) Lindberg, 1879, Bufo bufo (Linnaeus, 1758), Simocephalus vetulus (O. F. Müller, 1776) and others), and the increase in the rate of mass, mezosaprobic and eurybionts species in the total number of water groups are noted. Verhne Ozirne was the last untouched glacial lake of the Ukrainian Carpathians, but after the introduction of its basin to the Ramsar Convention there was laid a path there and today we will observe intensification of tourist and pasture influence on its ecosystem. The most anthropogenic negative influence has recreation (clogging, cutting, trampling, automotourism and other factors). Mountain tourism is one of the most dangerous types of anthropopression in high-altitude areas, as it is in the lakes located on permanent tourist routes and water catchments which is the place for overnight tourists, the degradation of populations and groups of mountainous species of hydrobionts has been noted. Moderate pastoral influence (up to thirty heads of cattle per hectare per day) does not make significant changes from the hydrobionts communities of the glacial lakes. The most effective mechanism for preventing the negative processes of anthropogenic transformation of ecosystems of the glacial lakes of the Ukrainian Carpathians is to determine the buffer number of tourists visiting basins of unique aquatic glacial ecosystems of Ukraine and the strict control over compliance by visitors with the rules of conduct regulated by environmental organizations.
