High-elevation plant species exhibit limited morphological variability across elevations, contrary to species with a wider elevational distribution

Abstract

Plants along mountain slopes experience strong environmental variation, particularly declining air temperature with increasing elevation. Investigating intraspecific variation in morphological traits and biomass allocation across elevational gradients can reveal how plants adjust their life-history strategies to climatic conditions, improving our understanding of their resilience to climate change. We analysed variation in overall morphology and biomass allocation in two high-elevation species: Campanula alpina and Doronicum stiriacum, both centred in the alpine belt. Their elevational responses were compared with three species exhibiting wider elevational occurrence: Soldanella carpatica (lower montane to subnival belt), Bellidiastrum michelii (lower montane to alpine belt), and Senecio subalpinus (lower montane to subalpine belt). All five species showed decreasing plant height with increasing elevation. However, high-elevation species maintained stable aboveground biomass and reproductive allocation, while species with wider elevational occurrence exhibited more than 50% reduction in aboveground biomass, and two of them showed significant decline in flower biomass with elevation. Our findings confirm that species with wider or lower elevational ranges exhibit greater trait variation than high-elevation specialists. These patterns suggest that mountain generalist species, with lower elevational preferences and wider elevational occurrence, may respond more strongly to rising temperatures, potentially increasing aboveground biomass and plant height under future climate change. In contrast, high-elevation species demonstrated the ability to persist across a wide temperature range while maintaining stable biomass, indicating physiological tolerance and potential to withstand warming in alpine environments. Further research is needed to understand how high-elevation specialists maintain stable growth and reproductive output, particularly their eco-physiological adaptations.