Biodiversity Loss: Political Actions Are Required, Not Additional Scientific Knowledge
Their initial conclusion is indisputable: the remaining threats to biodiversity today were already identified nearly 40 years ago, when they were quoted the “evil quartet.” They are (i) habitat destruction (ii) overexploitation of resources, i.e., overhunting or overfishing for example; (iii) introduction of invasive species; and (iv) co-extinctions that may be triggered by these factors. To these four well established threats we may add the concern of climate change, which further destabilizes natural environments. And it is not “exotic” biodiversity alone that is endangered: most research has focused on European ecosystems, showing that populations of common species and habitats are also suffering. This is, for example, the case for birds in the French countryside**.