No abstract

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Snow cover and its spatio-temporal changes play a crucial role in the ecological functioning of mountains. Some human activities affecting snow properties may cause shifts in the biotic components of ecosystems, including decomposition. However, these activities remain poorly understood in subalpine environments. We explored the effect of human-modified snow conditions on cellulose decomposition in three vegetation types. Snow density, soil temperature, and the decomposition of cellulose were studied in Athyrium, Calamagrostis, and Vaccinium vegetation types, comparing stands intersected by groomed ski slope and natural (outside the ski slope) stands. Increased snow density caused the deterioration of snow insulation and decreased the soil temperature inside the ski slope only slightly in comparison with that outside the ski slope in all vegetation types studied. The decomposition was apparently lower in Athyrium vegetation relative to the other vegetation types and strongly (Athyrium vegetation) to weakly lower (other vegetation types) in groomed than in ungroomed stands. Wintertime, including the melting period, was decisive for overall decomposition. Our results suggest that differences in decomposition are influenced by ski slope operations and vegetation type. Alterations in snow conditions appeared to be subtle and long-term but with important consequences for conservation management.

No abstract

Three isolated massifs in the Sudetes, Central Europe, are elevated sufficiently high to allow for the development of the treeline ecotone. These are the Karkonosze/Krkonoše in the West Sudetes and Hruby Jeseník and Masyw Śnieżnika/Králický Sněžnik in the East Sudetes. The upper limit of closed tree stands (i.e. timberline) is located at c. 1250 m a.s.l. on average in the Krkonoše, but with significant variability spanning more than 500 m. In the East Sudetes the respective elevation is higher, above 1300 m a.s.l., and the variability is smaller. While temperature is the primary factor governing the uppermost tree stands, second-order climatic factors play an important role in shaping treeline ecotone position, particularly wind and snow accumulation patterns. Active surface processes such as debris flows and snow avalanches force the timberline to descend and account for its locally very irregular course. There is a history of long-term human impact on the position of the timberline, with its peak in the 17-19th centuries when high-mountain meadows were extensively used for grazing and haymaking. In the last century the overall trend of timberline ascent associated with abandonment of agricultural land and temperature rise has been interrupted by the episode of catastrophic forest decline due to air pollution.