Survey on future distribution of South-Western Alps’ endemic species Gentiana ligustica R.Vilm. & Chopinet

Gentiana ligustica is an endemic species of the south-western Alps, protected by European laws, with populations growing under both alpine and mediterranean climates. Their Conservation Status is assessed ad “Good”, with a stable trend for alpine populations; meanwhile, for the Mediterranean populations, their Conservation Status is assessed as “Inadequate”, with an unknown trend due to insufficient studies and a habitat degradation that is still in progress and that can bring about the disappearance of the population to the point of species extinction.

To evaluate the impact of climate change on the species, we projected the potential distributions of G. ligustica under two different RCP scenarios (SSP3-7.0 and SSP5-8.5) for the years 2070-2100 by using two different sets of variables downloaded from the CHELSA database. The first set had five bioclimatic variables, which are considered physiologically important for the species even if they are correlated with each other, and the second set had three uncorrelated variables. Models were run in the R package “biomod2” by using 12 algorithms.

Under both scenarios and by using both sets of bioclimatic variables, the models suggest that the southernmost populations growing under a Mediterranean climate will be strongly negatively affected by climate change, facing extinction due to the loss of habitat suitability. Moreover, the habitat suitability will strongly decrease in the alpine region, shifting in the northern direction toward high-elevation areas, resulting in a high extinction risk for a large part of the alpine populations as well.

This study underlines the need for proactive conservation plans and assisted colonization strategies in suitable areas to preserve Gentiana ligustica in the face of climate change.