02-10-2024
Chronicle of a foretold death: the Névé plant communities of the Pyrenees as indicators of climate change
Vulnerable ecosystems under climate pressure: the plant communities in the snowbed areas of the Pyrenees are undergoing significant transformation due to rising temperatures and competition with other species.
According to Estela Illa Bachs Biodiversity Research Institute scientist: "The alpine plant communities of the Pyrenees are clear indicators of climate change"
The vegetation of the snow zones in the Pyrenees: A natural laboratory for climate change
The plant communities that inhabit the areas of snowbed, where snow accumulates for much of the year, have been a refuge for alpine and arctic species since the end of the glaciations. In these environments, which in the Pyrenees are small in size and are scattered throughout the mountain range, the main limiting factor for plants is the short period of growth. Only snowbed species are able to complete their reproductive cycle in such little time. Currently, however, these communities are undergoing significant change due to the pressure of climate change and competition with the species of the surrounding alpine meadows. IRBio's GEOVEG research group researcher Estela Illa Bachs, specialized in the ecology of alpine plant communities, who has devoted more than 20 years to studying the plants of the snow areas of the Catalan Pyrenees, explains it to us.
The plant communities of snowbed zones are particularly vulnerable to climate change: their vegetation is dependent on the duration of the snow cover, and very sensitive to the increase in temperatures and the decrease in precipitation. "Plants in these areas are small and highly dependent on moisture; earlier snowmelt and a reduction in summer precipitation can seriously affect these species," explains Estela.
As temperatures rise and winter precipitation decreases, snow melts earlier, increasing the time available for plant growth. This allows plants from the alpine meadows surrounding the snowbed zones to colonize these areas, displacing the weaker species. This process puts at risk the conservation of the plant communities of the snowbeds, although individually the species can take refuge in small cold and shady places, with favorable conditions.
The field studies carried out both in the National Park of Aigüestortes and Estany de Sant Maurici, as well as in the entire Pyrenean mountain range, allow the distribution and composition of these communities to be monitored over time. This, in some cases, indicates a drastic reduction of the species adapted to these extreme conditions. For 20 years, scientific teams have established permanent plots in various areas of the Pyrenees to monitor changes in vegetation. The data collected indicate a clear tendency towards the early melting of the snow and a progressive alteration in the plant communities. This constant monitoring makes it possible to quantify the speed of climate change and its effects on high mountain ecosystems.
Conservation projects and future challenges
According to Illa, coordinated action is urgent to conserve ecosystems and stop the loss of biodiversity. The plant communities of snowbed areas can be a model ecosystem to learn how vegetation can evolve in mountain areas. "But we can't do anything about it, the only thing we can do is witness and verify the disappearance of a large part of their localities", she alludes to the title of Gabriel García Márquez's book: Chronicle of a foretold death. In the highest and snowiest parts of the mountain range where there are practically no alpine meadows at the moment, there does not seem to be a short-term risk. However, in the rest of the territory the strong competition with meadow species means that these plant communities are at risk of disappearing.
"The future of these habitats is at stake, and their continuous monitoring offers us key data to understand the speed and scope of the changes we are experiencing," concludes Dr. Illa.