A team of researchers has taken to Xishuangbanna Tropical Botanical Garden (XTBG)to study, log and preserve species under serious threat from human incursion, Chen Liang reports. 

Pink shower tree (Cassia nodosa) blossoming in XTBG (Image by ZHAO Jinli) 

Because of habitat loss and illegal trade, many species of wild orchids are endangered in Xishuangbanna. 

The sixth mass extinction is coming, with nearly half of all living species on the planet likely to disappear by the end of this century, according to recent scientific studies. How to prevent it? Scientists around the world have been trying to figure that out. 

At Xishuangbanna Tropical Botanical Garden in Menglun, Yunnan province, professor Chen Jin and professor Richard Thomas Corlett have worked out their own solution. 

Together with more than 20 researchers, and PhD and graduate students, they launched a project three years ago they dubbed Zero Extinction and have been working to put all of Xishuangbanna’s plant species under protection. 

Although botanical gardens have a cumulative capacity in plant conservation, XTBG director Chen Jin said, their contribution to conservation is still very limited, mainly through off-site conservation. But botanical gardens can also contribute to on-site conservation, which protects species diversity in natural habitats and ecosystems, he said. 

Different from many well-known botanical gardens in major cities of developed countries, such as Kew Royal Botanic Gardens in the United Kingdom and the Brooklyn Botanic Garden in New York, which are usually in temperate zones and cover comparably small areas, XTBG is in the biodiversity-rich tropical area and contains a large number of indigenous species, Chen said. 

“Through efficient environmental education to build up a long-term partnership with local communities, we can help the communities’ ecological restoration,” he said. “By focusing on conservation, we can develop XTBG into a conservation leader in the whole (Asian tropical) region and a model for the world’s new botanical gardens.” 

Zero Extinction is a key project of the development strategy. 

According to professor Corlett, who is also director of the garden’s center for integrative conservation, Xishuangbanna is extremely important for the country’s biodiversity even though it covers “a tiny area” of China. “It has 15 percent of all China’s plant species,” said the professor from the UK, who has been working with the botanical garden for three years under the auspices of the Chinese Academy of Sciences but “has been working in tropical Asia for 35 years”. 

The species are under serious threat, he said. 

“The forest, which was here 30, 40 years ago, is now being replaced by rubber, by tea in high-altitude areas, or by banana in valleys,” he said. 

The project has three aims, said the professor, who taught at universities in Singapore, Thailand and Hong Kong before signing a five-year contract with the botanical garden. 

One is “to basically find out what is the current status of plants recorded from Xishuangbanna”. 

They have a list of plant species recorded in Xishuangbanna over the last 50 years. It’s about 4,500 species. They tried to assess their current status. 

“Are they OK, critically endan- gered, endangered or vulnerable?” Corlett explained. 

They held an expert meeting, went through the whole list, and researchers were sent to conduct field surveys. Then they had a preliminary assessment. “We found that Xishuangbanna only has about 4,100 species overall,” Corlett said. “A lot (of historical records) turned out to be wrong. Three are probably extinct in Xishuangbanna — two are orchids, (which) nobody saw in 10 years.” 

Among them, about 150 species are critically endangered, nearly 200 endangered, and about 700 vulner- able. “Roughly 8 percent of plant species, about 350 species, are endangered,” Corlett said. “It means they (either) have only a few individuals left (in the wild) or they are living in narrow areas that are rapidly being destroyed.” 

Stage two of the project is to protect them. 

A lot of endangered species are distributed in the region’s nature reserves. They have already been protected well, Corlett said. 

However, many other endangered species, living in small habitats, are not under any protection. “Ideally, we expect to protect them in their natural habitats,” the professor said. “If we can’t, as a backup plan, we will protect them in the botanical garden. For some species, it is possible to dry the seeds to freeze them and store them for a long time. For many, we have to cultivate them in XTBG and try to make sure they won’t go extinct.” 

Of the 4,100 species, Chen said, about 1,600 species have already been collected and cultivated in the botanical garden. 

“Of the 350 endangered species, however, only 30 percent of them can be found here,” he said. “In our future works we will make sure to collect all of them and put them under certain protection in our garden.” 

The third stage is education, Corlett said. 

On one of the sacred forested hills that are believed to be the resting place of the spirits of the Dai ethnic group’s ancestors, at Mengyangguang village near Jinghong city in Xishuangbanna, researchers and students from the garden reintroduced and planted 67 species of indigenous trees there. As a regular environment education and ecological restoration program started last year, the treeplanting event also had the participation of the Dai villagers and students from a local primary school. 

After the plants, Corlett said, similar methods will be used to assess the status of Xishuangbanna’s other groups of living species. 

Meanwhile, as a key member of Chinese Union of Botanical Gardens, which has a membership of nearly 90 botanical gardens around the country, XTBG is promoting the Zero Extinction project’s idea and methodology to more botanical gardens. 

“Through similar projects by the other botanical gardens, more plant species of the country can be put under better protection,” said Chen, who is also president of the organization established in 2013. (China Daily)

Flower of Cola nitida (L) and slipper orchid (R) (Images by XTBG)