On the island Of Reunion, tourism endangers a unique flora in the world

Unique in the world, the flora of the island of Reunion, a French department located in the Indian Ocean, is largely threatened with disappearance. The fault is climate change, human pressure, but above all invasive species encroaching on hitherto preserved natural spaces. “Look at this shrub with its yellow flowers: it is very beautiful. But it would be much better on the Breton coasts», in the west of mainland France, exclaims Dominique Oudin, director of the Mascarin National botanical conservatory (CBNM). On the Maïdo massif, in the heart of the Réunion National Park, the European gorse seems at home in places, threatening the endemic flora.

The meeting “is a unique environment in the world, but it is invaded», summarizes Dominique Oudin. The most emblematic exotic species above 1000 meters of altitude, the European gorse is not the most invasive: the butterfly vine, coming from Asia, smothers the last dry forests of the island. The Gabonese tulip tree has invaded agricultural land. The thousands of visitors who visit this site every day, offering a breathtaking view of the Mafate cirque, classified as a large part of the island as a UNESCO intangible heritage site, pass by without paying attention.

Hikers’ soles cleaned at the park entrance

The exceptional nature of the flora of Reunion Island is partly what earned it its UNESCO listing. Of the 963 species of “native” plants recorded on the island, 382 are endemic to the sub-region (the Mascarene archipelago, with the islands of Mauritius and Rodrigues), including 230 unique to Reunion. “230 is also the number of endemic plants in all of mainland France», specifies Dominique Oudin. But at the end of 2023, the International Union for Conservation of Nature (IUCN) re-evaluated its Red list of threatened species, the result of work carried out under the coordination of the CBNM. The result is worrying: between 2010 and 2023, the rate of threatened species increased from 30% to 41%. Around forty plants have already disappeared.

Among the threats, drought and human pressure are cited, while Reunion welcomed more than 550,000 visitors in 2023, a record according to the Regional Tourism Observatory. But exotic species remain enemy number one. It’s not all hopeless. “You still have spaces preserved from invasion», assures Janik Payet, head of the western branch of the Réunion National Park. From Maïdo, a path leads to the Grand Bénare massif: “We call it the golden triangle because up there, there is still exceptional biodiversity”, with few invasives and “more than 80% endemicity“.

To access it, the Park has installed biosecurity devices cleaning the soles of hikers, which may carry seeds. But the fight against invasive plants, a threat identified at the end of the 1970s, has long been carried out in a disorderly manner and was not “up to the challenge”, summarizes Janik Payet.

“If we do nothing, it’s a heritage that disappears”

It took an electric shock for the island to mobilize: the classification in 2017 by UNESCO of Reunion among the sites giving rise to “important concern» due to its poor state of preservation. An action program involving communities and biodiversity stakeholders in Reunion, called ReMiNat (for “restoration of natural environments”), was then put in place. Priority action areas have been defined and different restoration techniques are being studied. This is what is being done at Maïdo, where an accidental fire in 2020 paradoxically made it possible to “start from scratch» on this site considered lost.

“But people who live and come to Reunion must participate.“, insists Dominique Oudin, hoping for a “awareness“. What Jacques Fournel is trying to achieve: at an altitude of 1,100 meters, this former botanist only cultivates endemic plants, some of which will be used to replant the Maïdo. In recent years, several nursery growers have launched into this segment. Red tan, pepper wood, yellow flowers… “Everything that comes from Reunion, I plant it», explains Jacques Fournel. “You have to be active. Because if we do nothing, our heritage will disappear.»