Record numbers of Wright’s gardenia, one of the world’s rarest and most fragrant trees, have been counted on the tiny tropical island of Aride in Seychelles.
The only place in the world where the critically endangered tree occurs naturally is on the 72-hectare granite island in the Indian Ocean. The tree was once found on other, larger islands in the Seychelles archipelago but its sturdy wood was harvested for firewood, leading to its disappearance from everywhere except Aride.
A team of eight staff and volunteers for the Island Conservation Society of Seychelles, which manages Aride for biodiversity, spent 272 hours scouring the challenging terrain of the island to identify and count the rare trees.
They found 2,913 trees, nearly 1,000 more than in the previous census in 2017. Some trees had more than 1,000 seedlings nearby, indicating that the species is now thriving on the island.
Conservation ranger Steve Esther, a Seychellois who is stationed on the island, said: “It’s an evergreen tree which was originally on most of the granitic islands of the Seychelles but then it disappeared from the main islands. On Aride it thrived but it is a critically endangered species – at extremely high risk of extinction in the wild.”
The conservationists on Aride are not certain why the tree is doing so well again but according to the conservation manager Emma Cotton, one reason is that invasive fern species have been removed, increasing the area of ground on which it can grow.
“It’s really nice to see the tree’s rising population after the effort we put in to count all the trees,” she added.
According to Esther, the Wright’s gardenias are also benefiting from a wetter climate in recent seasons on Aride, which was named by the French for being drier than the other islands.
“We often sit on the beach and see that it’s raining on all the other islands but not here,” he said. “But it’s been raining a lot more in the past few years than before.”
The tree’s orchid-like white flowers decorated with small dots of purple and magenta bloom after the rains and spread their fragrance across the island – and the ocean.
Rob Lucking, the chair of the Island Conservation Society UK charity, said: “It’s a lovely little tree. It flowers 10 days after heavy rainfall and it is very, very fragrant. You can be coming back to Aride on the boat and you can smell it half-a-mile out at sea, it’s incredible.”
The rangers on Aride regularly monitor a sample of the trees to check for signs of disease, attack by insect or invasive pathogens.
Trees have been grown on other islands in the Seychelles archipelago to provide backup if the trees on Aride ever suffered from a catastrophe but the tree does not seem to thrive in the wild on other islands.
There are hopes that it will continue to spread and prosper on Aride even more now that Aldabra giant tortoises have been translocated to the island. Ten were brought back nearly a decade ago as part of an conservation programme to re-establish these herbivorous ecosystem engineers on the island. They’ve recently been joined by 50 smaller young individuals of a long-lived species.
The tortoises play a key role in dispersing seeds, including those of the Wright’s gardenia, and as they forage bird species follow in their path to catch insects and invertebrates that they expose. The tortoises also excavate small wallows on the arid island, improving water retention and opening up water sources to birds, invertebrates and lizards.
