Understanding Long-Term Abundance Shifts in European Alpine Plants Through the Lenses of Functional Seed Trait Ecology

Abstract

Aim: Understanding the resilience and adaptability of alpine flora under climate change is crucial for biodiversity conservation. While functional traits are key to predicting alpine plants' responses to climate change, the role of regeneration traits remains underexplored. We hypothesised that alpine species thriving under climate change produce seeds with higher dispersal ability, longer soil persistence, lower dormancy requirements, and faster germination, while declining species would show opposite traits. Location: Twenty-three summits across six mountain ranges in Central and Southern Europe: Sierra Nevada, Northern and Central Apennines, and Northeastern, Central, and Southern Alps. Methods: We analysed long-term data on frequency and abundance changes and eight seed traits related to dispersal, establishment, and soil persistence for 177 alpine species using linear mixed-effect models. Results: Over two decades, alpine plant populations remained stable, with nearly 90% of species showing minimal frequency change and 70% showing minimal abundance change. However, abundance shifts varied by region: 16%–25% of species declined in Sierra Nevada, the Central Apennines, and the Southern Alps, while the Northeastern Alps and the Northern Apennines showed the largest increases (27% and 17%, respectively). Significant but limited relationships between seed traits and population dynamics were captured, primarily in the Central and Northern Apennines. Species with lower potential for epizoochory or anemochory were more likely to increase in abundance, while smaller seeds were linked to ‘winners’ in some regions. Germination traits, such as broader temperature requirements and slower germination, characterised species with increased abundance in the Northern Apennines. Main Conclusions: Seed traits had limited predictive power in distinguishing ‘losers’ and ‘winners’ of climate change among European alpine plants. This likely reflects the longevity of alpine plants, short observation periods, and potential mismatches between seed-level microenvironmental conditions and broader climatic trends.