Globalization has led to an increase in introductions of species outside of their natural range. Just like the Asian hornet in France, the introduction of so-called invasive species leads to a decline of certain local species: biological invasions represent one of the most important factors of loss of biodiversity on a global scale and the first cause of the level of island territories.
Until now, studies of biological invasions have focused mainly on the number of endangered species. The study carried out by scientists from CNRS1 and Université Paris-Saclay allows us to go further by determining and quantifying the profiles of endangered bird and mammal species.
The researchers have thus shown that a total of 11% of the phylogenetic diversity of these two groups, in other words their accumulated evolutionary history, is threatened by biological invasions. They have also shown that the impact of invasive species is even greater on the ecological strategies of these groups – the means at their disposal to feed, live, function and defend themselves from other species. Biological invasions threaten 40% of the diversity of ecological strategies of birds and 14% of that of mammals.
This work confirms that birds are a particularly vulnerable group to invasions. Indeed, many birds, especially in island ocean regions, are less able than their continental counterparts to adapt their strategies to more generalist invasive species.
For example, the crested kagou, an emblematic species of New Caledonia which is unique from a phylogenetic point of view, since it is the only representative of the Rhynochetidae family, is threatened in particular by the rat. Indeed, this bird does not fly and feeds only on the ground. It is therefore unable to adapt to a new terrestrial predator such as the rat. Other bird species, including pollinators and seed dispersers, are also endangered from biological invasions. The disappearance of these species would therefore have consequences on the functioning of ecosystems of which they are active elements.