Population stasis in a high-elevation herbaceous plant under moderate climate warming

Densities of differing life history stages of two Ranunculus glacialis L. populations were monitored for 12 years in permanent plots of an alpine fellfield from 1986 to 1997. Results of repeated measures ANOVAs indicated no significant spatial or temporal variation in the densities of total or flowering adult shoots, or of juvenile individuals. Seedling densities were however fourfold higher on thermally favorable South-facing slopes and year-to-year variation was also considerable. However, the densities of none of the observed life history stages were correlated with climatic data, although herbivory was negatively correlated with growing season temperature. The observed populations of R. glacialis have remained remarkable stable, despite a consistent warming trend during the last decade. These results in conjunction with growing evidence from experimental studies on climate warming effects should be incorporated in scenarios concerning the responsiveness of high-elevation plants to climatic change.