This paper describes the effects of 1,020 passages of snowmobiles, made over two winters, on three regularly winter-snow-free alpine tundra plant communities. A cushion-plant community on a 7-degrees slope showed a 31% reduction in total living plant coverage due to snowmobile impact. Destruction was greatest to soil lichens, rock lichens, and the cushion-plants Arenaria obtusiloba, Arenaria fendleri, Paronychia sessiliflora var. pulvinata, Silene acaulis, Eritrichium aretioides, and Phlox pulvinata. Graminoids generally survived to increase in importance. On a flat site, a cushion-plant community with Kobresia myosuroides as its most important species, showed the greatest loss of living-plant coverage, namely 46%. This was due primarily to the destruction of Kobresia, although Selaginella densa, Arenaria obtusiloba, Hymenoxys acaulis, and Eritrichium aretioides, also showed heavy losses. In a Kobresia turf community, destruction was decidedly less severe than in the cushion-plant communities, reduction in total living plant coverage being only 19%. It is suggested that the closed nature of the Kobresia turf, with its stiff tussocks, enables it to absorb impact well. It is recommended that snow-mobile travel be confined to Kobresia or similar turfs, when such travel is necessary under snow-free conditions.
Response of plant community composition and productivity to warming and nitrogen deposition in a temperate meadow ecosystem
