Herbarium
The flora of Reunion, like that of other intertropical oceanic islands, is the result of slow and selective immigration (indigenous species*), and of speciation processes that, although recent in geological terms, have given rise to significant endemism.* Lacking mobility, plants naturally disperse their seeds passively: via sea currents (sea vector), winds and cyclones (wind vector) or even via birds (animal vector). Isolated in the middle of the Indian Ocean, Reunion has remained a difficult destination to reach! Only certain species were able to make the journey and become established. The original plant colonisation relied on the closest continental areas (nearly 70 per cent of the flora comes from Madagascar and East Africa).
The spontaneous flora of Reunion currently includes** 1,730 vascular plant species, including 1,478 spermatophytes*** (85.4%) and 252 pteridophytes (14.6%). It is divided into:
* 848 indigenous species (of which only 86 are likely to be native), or about half (49%) of the spontaneous flora. Among these species:
* 237 (28%) species that are strictly endemic to Reunion
* 153 (18%) regional endemics, also growing in the other Mascarene Islands (Mauritius and Rodrigues)
* 458 (54%) simply indigenous species, which can also be found in their country of origin
* 829 exotic species,* approximately the other half (48%)
* 53 cryptogenic species,* or 3%.
Vegetation linked to the history of the island
When humans settled on the island in the mid-17th century, Reunion’s flora was enriched by exotic plants that gradually became more and more established as the population of Reunion grew. Their wide range of uses (agricultural, forestry, economic, medicinal, ornamental, etc.) and the increase in trade in goods and people led to the voluntary and involuntary introduction of several thousand species from both tropical and temperate regions around the world. A number of these species have today become a real threat to the native flora.
Endangered species
Today, 256 species are considered endangered in Reunion (according to IUCN criteria), or 30.7 per cent of the native flora. Of these endangered species, 125 are now critically endangered (at least in the wild). Sustainable development projects are therefore crucially important.
Knowledge of the native flora and the environments and their fragility is key to promoting their preservation. Developing tourism that respects Reunion’s natural environment requires that everyone play their part in safeguarding this unique heritage.