Located to the east of Madagascar, the bountiful, volcanic French island of Réunion has sometimes been called a sister to Hawaiian volcanoes because of the similarity in their climate and geographical nature. Those familiar with its seemingly pristine vegetation may be surprised to find out that half of the plants there were introduced by humans, even though they arrived on the island in the 16th century. So how and why did some species arrive and not others?
Those are the questions that a team of five scientists from the University of Paris Saclay, China’s Ocean University and the Institute for Biodiversity Research in Berlin have set out to answer. Humans have long ferried species around the world, prompting scientists to wonder about the impacts of these movements. The United Nations’ scientific body tasked with studying biodiversity, IPBES, have situated the global number of non-native species to hover around 37,000. Every year, an estimated 200 species enter new territories, prompting 1,215 local species to go extinct.
Humans are the first cause of the introduction of non-native species throughout the living world, whether they crawl, climb, swim or fly. Indeed, perhaps counter-intuitively, we have played a decisive role in shaping island bird communities. While native species have taken millions of years to adapt to these islands’ very specific climatic, geological and environmental constraints, our arrival has drastically disrupted these communities within a few hundred years alone, both at ecological and genealogical levels.
