Format: ORAL

Andrea Mondoni1, Sergey Rosbakh2, Margherita Tognela1, Graziano Rossi1, Silvano Lodetti1, Simone Orsenigo1, Francesco Porro1, Fiona White1

1 Department of Earth and Environmental Science, University of Pavia, Pavia, (Italy) 2 Plant and Environmental Sciences, University of Copenaghen, Copenaghen (Denmark)

Alpine habitats are threatened by climate change because their cold-adapted species are experiencing some of the fastest rates of warming. In response, alpine plants have altered their performance, population dynamics, community structure and geographic distribution, ultimately affecting the functions and services alpine ecosystems provide. Yet, there is a general lack of mechanistic explanations about these complex responses. In this context, application of functional traits, that is morphological, physiological, phenological or behavioural characteristics impacting individuals fitness,has been considered as a promising approach in assessing climate change vulnerability of alpine plants. In particular, seed traits are expected to have a good predictive power in explaining the observed patterns of alpine species migration, adaptation, and persistence, as seeds are the main plant organ fulfilling these functions. Here, we investigated whether species with contrasting long-term population dynamics differ in their seed traits related to germination, dispersal, and persistence. Specifically, we correlated data on 20-yr population dynamics collected within the GLORIA network (https://www.gloria.ac.at/) for 146 alpine species occurring in temperate, sub-Mediterranean and Mediterranean mountain ranges with seed traits (mass, shape, number, dormancy, germination time, base temperature for germination, anemochory and epizoochroy potential) measured following standardised protocols. We revealed that the focal species displayed mountain range-specific changes in abundance, with Mediterranean and sub-Mediterranean ranges having the largest variations. The relationship between seed traits and abundance change were significant only in the sub-Mediterranean ranges. Here, species that increased in abundance exhibited weaker dormancy (e.g. shorter cold stratification period), required higher temperatures for germination, and produced larger seeds, all traits that enable long-distance dispersal and improved performance under a warmer climate. Our results show that seed traits may explain differences in recently observed population dynamics and highlight important insights for assessing extinction risk and predicting future community structure.