Background
The authors write that "mountain ecosystems are particularly susceptible to climate change," and, therefore, they say that "characterizing intraspecific variation of alpine plants along elevational gradients is crucial for estimating their vulnerability to predicted changes."

What was done
To test for plant adaptation to its elevation of origin, Frei et al. collected seeds of three nutrient-poor montane grassland species - Ranunculus bulbosus L., Trifolium montanum L. and Briza media L. - from across the Swiss Alps in the summer of 2008 at elevations of 1200 and 1800 meters above sea level (m a.s.l.), after which they established a reciprocal transplant experiment with experimental gardens located at 600, 1200 and 1800 m a.s.l.

What was learned
The five Swiss scientists report that they found "no evidence for local adaptation to elevation of origin and hardly any differences in the responses of low and high elevation populations." And they state that "the consistent advanced reproductive phenology observed in all three species shows that they have the potential to plastically respond to environmental variation."

What it means
Quoting Frei et al., "our findings support the conclusion of a recent meta-analysis including 32 other plant species that local adaptation is less common than generally assumed (Leimu and Fischer, 2008)." And they go on to state that "since plant populations were not adapted to their respective elevations of origin, we conclude that, for our study species, the expected upward shift of optimal climatic conditions will not necessarily lead to a shift of population and species ranges to higher elevations in the context of climate change," since "plasticity will buffer the detrimental effects of climate change."

Reference
Leimu, R. and Fischer, M. 2008. A meta-analysis of local adaptation in plants. PLOS ONE 3: e4010.