Regional Mountain Conference

Mountain ecosystems are highly sensitive to the impacts of climate change. Nevertheless, our knowledge of critical biogeochemical processes—key to understanding how these ecosystems cope to shifting environmental conditions—remains limited.

This study investigates and compares turbulent carbon dioxide (CO₂) fluxes measured using the eddy covariance (EC) technique at two high‑elevation Italian sites: Torgnon and Nivolet in the Western Alps. These locations belong to the ICOS (Integrated Carbon Observatory System) network as Associated stations IT‑Tor (Torgnon) and IT‑Niv (Nivolet). Both are unmanaged subalpine grasslands situated at 2050 m and 2750 m a.s.l., respectively, and host distinct plant community compositions. Snow typically persists from late October to late May at IT‑Tor, and until June at IT‑Niv, resulting in a growing season of roughly four to five months. Continuous EC measurements of CO₂ fluxes have been collected at IT‑Tor since June 2017 and at IT‑Niv since June 2019.

This work compares CO₂ fluxes from the two sites under similar meteorological conditions to highlight ecophysiological differences between the two grassland canopies. Furthermore, phenological dynamics are examined to assess how each ecosystem responds to extreme weather events, including the 2022 summer drought, the most intense episode recorded over the past 17 years.

Our findings highlight how vulnerable mountain ecosystems are to climate change, stressing the importance of sustained monitoring efforts to improve their understanding and management. Differences in ecophysiological responses between the two sites will be explored in connection with their elevation, species composition, and past management practices.

Ongoing research, combining long-term data with advanced modeling approaches will be crucial for developing a more comprehensive understanding of how climate extremes affect mountain ecosystems across Europe.