Vegetation and climate change

Climate change, which is clear to everyone at every latitude, does not end with a "simple" rise in average temperatures, but also manifests itself through the alteration of the amount of rainfall and the increased frequency of exceptional events, such as prolonged periods of extreme heat, drought, floods and tornadoes. These changes, which are perceptible even on a small scale, do not spare mountain and alpine ecosystems. Here, the constant retreat of glaciers is the most notable consequence and also has the greatest impact on the environment. This phenomenon is controlled by the Gran Paradiso National Park Surveillance Corps which, in collaboration with the Italian Glaciological Committee, has been monitoring and measuring the park’s 57 glaciers for over 25 years.  

Like animals, plants are significantly affected by climate change, especially in relation to the spatial distribution of individual species (shrinking areas and increase in altitudinal limits) and the temporal variations of the various phases that characterize their lifecycle. Phenology is the science that studies and records these recurrent phases: sprouting, foliating, flowering, fructification, dissemination, senescence and leaf fall are the main phenological phases related to the trend of some climate factors, such as temperature, humidity and solar radiation. In order to assume scientific relevance, phenological observations must cover the long term (10-50 years).

Historically, phenology was mainly concerned with agriculture, in order to optimize cultivation practices with respect to plant development phases. In recent decades, numerous phenological networks, including some international ones, have been set up to try to understand and predict how the different plant communities will react to the current climate changes. The aim is twofold - to assess the potential effects on biodiversity and to assess how they will change the ecosystem services the environment provides free of charge to the community.

In the park, since 2009 observations have been carried out on the phenology of 6 tree species at 15 permanent stations (3 in each valley); the data obtained are included in the Phenoclim European network that covers the entire Alpine arc. To monitor high-altitude grasslands, in collaboration with "ARPA Valle d'Aosta" (climate change unit), recording stations have been set up at three different locations. These are equipped with automatic instrumentation (webcam and NDVI), which mainly record the greening and senescence of grassy sward.