Upward shift in elevational plant species ranges in Sikkilsdalen, central Norway

Abstract

Phytosociological studies are an important tool to detect temporal vegetation changes in response to global climate change. In this study, we present the results of a resurvey of a plot-based phytosociological study from Sikkilsdalen, central Norway, originally executed between 1922 and 1932. By using a detailed phytosociological study we are able to investigate several aspects of elevational shifts in species ranges. Here we tested for upward and downward shifts in observed upper and lower distribution limits of species, as well as changes in species optima along an elevational gradient, and related the observed range shifts to species traits that could explain the observed trends. More species shifted upwards than downwards, independently of whether we were investigating shifts in species' upper or lower distribution ranges or in species optima. However, shifts in species upper range margins changed independently of their lower range margins. Linking different species traits to the magnitude of shifts we found that species with a higher preference for prolonged snow cover shifted upwards more in their upper elevational limits and in their optima than species that prefer a shorter snow cover, whereas no species traits were correlated with the magnitude of changes in lower limits. The observed change in species ranges concord both with studies on other mountains in the region and with studies from other alpine areas. Furthermore, our study indicates that different factors are influencing species ranges at the upper and lower range limits. Increased precipitation rates and increased temperatures are considered the most important factors for the observed changes, probably mainly through altering the pattern in snow cover dynamics in the area.

Impact of climate change on alpine vegetation of mountain summits in Norway

“…This observation was consistent with previous studies, indicating an upward distribution shift and increased species richness of alpine vegetation in several Scandinavian (e.g. Klanderud and Birks 2003;Kullman 2007;Felde et al 2012;Kapfer et al 2012) as well as other European mountain areas (e.g. Grabherr et al 1994;Pauli et al 2007;Parolo and Rossi 2008;Holzinger et al 2008;Lenoir et al 2008;Pauli et al 2012).…”

Alpine vegetation along multiple environmental gradients and possible consequences of climate change

“…Felde et al (2012) found an upward elevation expansion of species dependent upon long snow duration in a mountain area in central Norway, likely a response to increased precipitation at high elevations. As the climate scenarios used as basis for our predictions were coarse, we did not include varying changes in snow cover duration along the altitudinal gradient (discussed in the ''Materials and methods'' section).…”

Changes in alpine vegetation over 21 years: Are patterns across a heterogeneous landscape consistent with predictions?

“…While alpine plants are well adapted to their ''harsh'' environment, environmental filtering (minimum temperatures, wind) generally restrict non-alpine species from establishing in alpine tundra Mooney 1968, Korner 2003). More recent directional environmental change is leading to an upslope movement of tundra and non-tundra plant species in many locations around the world (Lenoir et al 2008, Felde et al 2012) and may be permitting the persistence of a wider range of functional strategies (increased functional diversity) and in turn higher numbers and a greater diversity of species (e.g., the physiological tolerance hypothesis: Currie et al 2004) due to the relaxation of this ''strong'' environmental filtering. While abiotically structured environments such as alpine may first experience an increase in diversity with directional climate change due to the range expansion of species previously unable to establish, longer-term directional change may decrease diversity as alpine species lose optimal habitat as increasing temperature shift their niche optimum further and further up slope (Gottfried et al 2012, Pauli et al 2012.…”

“…Indeed, many studies have found that the alpine flora is moving upwards likely as a result of climate warming (Grabherr et al 1994, Walther et al 2005, Jurasinski and Kreyling 2007, Lenoir et al 2008, Parolo and Rossi 2008, Felde et al 2012. However, variability in responses across mountain systems has caused some to challenge the assumption that climate change will cause a general uphill migration of plant species (Randin et al 2009, Engler et al 2011, Malanson et al 2012.…”