- Scientists have described a new species of flower that appears to only grow in a small forest patch on the slopes of a mountain range in Guinea, West Africa, where extensive open-cast mining for iron ore is set to begin soon.
- There are thought to be as few as 100 of the Gymnosiphon fonensis flowers in existence in the Boyboyba Forest, which is part of the Pic de Fon classified forest reserve in the southeast of the country.
- Mining firm Rio Tinto has pledged to protect the Boyboyba Forest and the plants and animals that live in it.
- But Boyboyba makes up only a tiny fraction within a mosaic of forests and grasslands whose ecological integrity depends on linkages extending across Simandou’s 100-kilometer (60-mile) length.
Martin Cheek first entered the Boyboyba Forest in southeastern Guinea in September 2022 to look for an extremely rare plant whose entire population is estimated to number just 100. The weather, though, had dampened his enthusiasm.
“You’re a long way from anywhere that’s dry, and you’re going to be here all day, and it’s pouring with rain, and it’s not going to be very comfortable,” the plant taxonomist from the U.K.’s Royal Botanic Gardens, Kew, recalls.
All that changed when Cheek and his Guinean colleagues found a patch of the extremely rare snow-white flowers growing on the forest floor. “You forget about any discomfort you might be feeling: just the excitement of confronting these amazing plants takes that all out of your mind,” he says.
The plants are a species of Gymnosiphon, a genus that comprises a few dozen species scattered across Africa, Madagascar, Asia and Central and South America.
Another group of scientists had noted these flowers growing in the very same spot in Boyboyba 14 years earlier, but they were misidentified as Gymnosiphon bekensis, a species that only grows more than 2,000 kilometers (1,200 miles) away to the east, in Cameroon and the Central African Republic.
Cheek has now corrected that, identifying Boyboyba’s plants as a new-to-science species, Gymnosiphon fonensis, named in honor of the Pic de Fon classified forest, a partially protected reserve at the southern end of the Simandou mountain range.
Like all Gymnosiphon species, the Fon gymnosiphon, as Cheek says the plant will likely be called in English, is mycoheterotrophic: it lacks chlorophyll, the green pigment needed to make food from sunlight, and depends instead on a fungus to survive.
Even on sunny days, little light penetrates to the floor of the Boyboyba Forest, so the Fon gymnosiphons are thought to attract a fungus to their roots to help them extract nutrients from the soil.
“As these plants develop more roots, so you get more colonization of the roots by the fungi, and the plant grows underground until it gets to the point that it can reproduce, and then it puts a flower above the ground,” Cheek says.
When it flowers, the Fon gymnosiphon produces the largest flowers of all Gymnosiphon species in West Africa. “You can’t miss it,” says Cheek, likening the plant’s size above ground to those of well-known garden ones such French marigolds (Tagetes patula), or one of the dahlias.
But the species of fungus that sustains the Fon gymnosiphon is still a mystery, meaning there would currently be no way of cultivating the plants in places like Kew Gardens as an insurance policy against extinction in the wild.
Given their scarcity — and imminent plans by mining firms to extract billions of tons of high-grade iron ore from the Simandou mountains — the task of pinpointing that fungus is now an urgent one.
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In the meantime, the discovery of the plants has spared Boyboyba from mining activities. The forest, in a deep hollow on the side of a ridge, had been designated as a dumpsite for rock waste. Rio Tinto, one of the mining firms with concessions in Simandou, has now decided against this.
“The discovery of this species, and populations of other species that will be threatened when they are assessed if they are not already, means they’ve turned their decisions around; they’re now protecting that forest, and they’ve signed up to do it,” Cheek says.
He says he’s hopeful this will give him and other plant taxonomists time to identify the plants’ fungal partner, and gather insights into how the species reproduces. “Nothing is known on pollination, on seed production, on establishment for any Gymnosiphon in the world.”
Gymnosiphons are “furtive plants,” easily overlooked, and likely signal more diversity just waiting to be discovered, says Daniel Nickrent, a professor of plant biology at Cornell University, U.S., who wasn’t part of Cheek’s team.
In 2020, Nickrent described a new species of Gymnosiphon — G. syceorosensis — from Mount Hamiguitan in the Philippines. It was the second Gymnosiphon to be identified in the Philippines in recent years.
Nickrent and his team were on a general plant-collecting expedition, and were unable to stay longer to observe pollinators, seed dispersers or “any other factors that impinge upon the life history of this species,” he says.
It underscores the importance of protecting Boyboyba so Cheek and his Guinean colleagues can study the Fon gymnosiphon in its natural habitat.
The Boyboyba Forest is home to four other species of mycoheterotrophic plants, including two other gymnosiphons, making it the site with the highest diversity of these plants in West Africa. It also holds the biggest global population of a critically endangered liana unique to Guinea, Keita deniseae, that has evolved different types of climbing hooks to help it grapple its way up trees.
Boyboyba is expected to yield additional plants new to science, Cheek and his co-authors write in their recent paper describing the Fon gymnosiphon. Range-restricted animal species potentially new to science are also being researched in Boyboyba, they write.
The biological richness, and fragility, of the Pic de Fon was highlighted 22 years ago when another group of 13 international and Guinean scientists was sponsored by Rio Tinto to carry out a rapid biodiversity assessment to help inform the mining firm on future environmental and social impacts. The scientists assessed not just plants, but also birds, insects, mammals, amphibians and reptiles.
They recorded nearly 800 different species, including some amphibians and insects new to science. Other notable species documented were critically endangered forest-dwelling western chimpanzees (Pan troglodytes verus), endangered Diana monkeys (Cercopithecus diana), and grassland birds like endangered Sierra Leone prinias (Schistolais leontica).
The team’s plant survey revealed more than 400 species, including 32 endangered or vulnerable tree species.
“The potential damage to the Pic de Fon habitat from open cast mining should be carefully considered,” the team said in a 248-page report it published afterward, although it also identified shifting agriculture, and the cultivation of coffee by farmers within the boundary of the reserve, as equally pressing threats.
In a response to questions about its imminent mining operations in Simandou, Rio Tinto, which operates in Guinea under the name Rio Tinto SimFer, told Mongabay in 2024 that it was making “significant strides in the implementation of the biodiversity mitigation hierarchy to avoid, minimize, restore and offset [its] impacts to biodiversity.”
Setting aside Boyboyba as a protected area may preserve a vital piece of Simandou’s evergreen forests, but it may not be enough to safeguard rare flora like the Fon gymnosiphon.
Nickrent, the Gymnosiphon expert at Cornell, says that plants like parasites and mycoheterotrophs that depend on other plants or fungi for their survival sit at the top of a precarious food pyramid. “Any perturbations on the habitat — especially their host plants — is very likely to severely impact their ability to persist in that environment,” he says. “In a way, they can be viewed as a very sensitive ‘canary in the coal mine.’”
Populations and individual plants are often widely scattered, and gene flow between them is essential to maintain genetic integrity, Nickrent points out, adding that this is as true for gymnosiphons as it is for other parasitic tropical plants such as the famous stinking corpse lilies from the genus Rafflesia that are native to Southeast Asia.
“It is good to hear that the Boyboyba forest is to be protected, but likely other areas in the Simandou mountains would require protection as well if G. fonensis is to survive,” he says.
Genevieve Campbell, the head of the ARRC Task Force, part of the Primate Specialist Group at the IUCN, the global wildlife conservation authority, says Rio Tinto’s mining footprint is currently restricted to the northern part of the Pic de Fon, meaning there will still be forest left in the southern portion of the reserve.
This southern portion, however, will be subject to indirect impacts: noise, new roads and railways, the influx of workers and their families, among others. “The fate of that area will depend on how effective Rio Tinto is at managing and mitigating its indirect impacts,” she says.
Campbell and her task force colleagues visited the Pic de Fon mining site in May 2024. They found that while Rio Tinto’s team on the ground was “motivated and well-intended,” the implementation of biodiversity-related management and monitoring plans was lacking. The team gave Rio Tinto until the end of 2024 to follow through with its recommendations, which include setting up arboreal camera traps to monitor Diana monkeys and endangered king colobus monkeys (Colobus polykomos), and implementing biodiversity offsets to compensate for the mining operation’s impacts on chimpanzees.
Rio Tinto says it’s considering or working on these and a number of other recommendations.
Banner image: Gymnosiphon fonensis, Boyboyba Forest, Guinea. Image courtesy Martin Cheek.
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Citations:
Cheek, M., Burgt, X. M., Tchiengué, B., Thiam, A., Molmou, D., Doré, T. S., & Magassouba, S. (2024). New discoveries of plants from Republic of Guinea, W. Africa, including Gymnosiphon fonensis Cheek, sp. nov. (Burmanniaceae), a new Critically Endangered species from Simandou. Adansonia, 46(10), 89-101. doi:10.5252/adansonia2024v46a10
Nickrent, D. L. (2020). Gymnosiphon syceorosensis (Burmanniaceae), the second new species for the Philippines. PhytoKeys, 146, 71-87. doi:10.3897/phytokeys.146.48321
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