Short-term signals of climate change along an altitudinal gradient in the South Alps

Abstract

Short-term changes in plant species number, frequency and composition were studied along an altitudinal gradient crossing four summits from the treeline ecotone to the subnival zone in the South Alps (Dolomites, Italy). Large-scale (summit areas) and small-scale patterns (16 plots of 1 m 2 /summit) were monitored. After 5 years, a re-visitation of the summit areas revealed a considerable increase of species richness at the upper alpine and subnival zone (10% and 9%, respectively) and relatively modest increases at the lower alpine zone and the treeline ecotone (3% and 1%, respectively). At the small scale, the results were partly different, with species richness decreasing at the lower summits and increasing at the higher summits. The changes can most likely be attributed to climate warming effects and to competitive interactions. The main newcomers at the lower three summits were species from the treeline and the lower altitudinal zones. Only at the highest summit, the newcomers came from the alpine species pool. At the treeline ecotone, the abundance of Pinus cembra, of dwarf shrubs and clonal graminoid species increased. Here, displacements of alpine species may be predicted for the near future. At the higher summits, expansions of the established alpine species and further invasions of species from lower altitudes are forecasted.

The Impact of Climate Change on Recent Vegetation Changes on Dovrefjell, Norway

“…However, the conditions at the study summits in the Alps and at the study summits at Dovrefjell are difficult to compare. For instance, the total number of vascular species at most of the summits analyzed by Erschbamer et al [26] is much higher than at the study summits at Dovrefjell.…”

“…In similar studies from the Alps, the largest increase in species richness was found in the upper alpine and subnival zone [26] and in the subnival/nival zone [13]. Erschbamer et al [26] even found that the species richness decreased at the lower summits.…”

“…Erschbamer et al [26] even found that the species richness decreased at the lower summits. Hence, the results from the Alps are contrary to the results from Dovrefjell with respect to at what altitude the changes are more pronounced.…”

“…Erschbamer et al [26] found an increase in species richness in mountain summit areas over a five year period in the Dolomites.…”

Regional-scale identification of three-dimensional pattern of vegetation landscapes

“…Many studies have investigated vegetation types and patterns along altitudinal gradients in the mountains (Kitayama, 1992;Lovett, 1996;Kessler, 2000;Hemp, 2006). The three-dimensional pattern of vegetation landscapes are usually been related to the species diversity and distribution (Körner, 2000;Kitayama and Aiba, 2002;Wang el al., 2002;Bhattarai and Vetaas, 2003;Wang et al, 2007;Batllori et al, 2009;Sang, 2009 (Daniels and Veblen, 2003;Gian-Reto et al, 2005;Walther et al, 2005;Erschbamer et al, 2009;Odland, 2009;Wang et al, 2009). Identifying the three-dimensional pattern of vegetation landscapes could improve their ecological interpretation (Kitayama, 1992;Miehe, 1994;Fang et al, 1996;Tang and Ohsawa, 1997;Leuschner, 2000;Hörsch, 2003;Tang, 2006;Proctor et al, 2007).…”