AIR-POLLUTION-MEDIATED CHANGES IN ALPINE ECOSYSTEMS AND ECOTONES

Soil biological parameters (e.g., Collembola), soil types, soil chemic al parameters (pH, humus substances), and plant communities were studi ed in different ecosystems and ecotones in alpine, subalpine, and spru ce forest zones in the Tatra National Park, Slovak Republic. The preli minary, selected data, based on a long-term research program, showed a high sensitivity of some alpine ecotones and ecosystems to long-dista nce transported acid deposits. The changes in different ecosystem para meters since 1977 were more extensive in alpine grasslands on limeston e than on granite. The greatest soil pH decrease was in the plant comm unities Festucetum versicoloris (- 1.5 pH), Geranio-Alchemilletum crin itae (- 1.32 pH), and Saxifragetum perdurantis (- 1.25 pH), which are restricted to places with snow accumulation and water runoff gullies. In these ecosystems the greatest changes occurred in the leaching of h umus substances. Some formerly less abundant and rare soil animals res tricted to acid bedrock became dominant in some ecosystems on limeston e as well as on granite; other formerly dominant species disappeared f rom the entire study area (e.g., Folsomia alpina). The aerial extent o f some ecosystems changed substantially since 1977, and their surround ing ecotones moved into the space formerly occupied by one of the adja cent ecosystems. These changes are detectable by remote-sensing method s. In Central European mountains, strongly affected by global and regi onal industrial air pollution (e.g., Krusne Hory, Krkonose, Beskydy), spruce forests started to die back from higher to lower mountain eleva tions. The effects of air pollution on alpine and subalpine vegetation were not studied there. Strong alterations in alpine ecosystems and e cotones were detected by the author during long-term studies in the Hi gh Tatra Mountains, and I suggest that subalpine and mountain forest b elts will be affected here in the near future as they were in the more polluted Central European mountains. The ecosystems and ecotones in h igher alpine zones are likely to be affected earlier than the ecosyste ms at lower altitudes. Detection of ecosystem alteration in the alpine zone may be used for prediction of acidification processes and global change in ecosystems at lower altitudes. The consequences of global c limate change are predictable by monitoring changes in the extent of s ome ecosystems located in discrete mountain geomorphological units (e. g., karstic sinkholes, water runoff gullies, wind shadows, ridges expo sed to wind, etc.) and ecotones among them because of their dependence on duration of snow cover, water supply, wind and frost exposure, and other abiotic and biotic factors.