'You could be stepping on an endangered species': Why hikers need to be careful in S'pore's forests

SINGAPORE – X marked the spot on the edge of Clementi Forest where we were to meet the researchers from the National Parks Board (NParks) last Wednesday morning (April 28) .

The 85ha Clementi forest is a piece of state land that has been reclaimed by the wilderness as it awaits redevelopment. As the overgrown plot is not a designated park or nature reserve, there are no trails nor entry points to serve as landmarks. Instead, we relied on Google map coordinates that had been sent to us earlier.

We were not there for a hike though. This was a “rescue mission”.

The 85ha Clementi forest is a piece of state land that has been reclaimed by the wilderness as it awaits redevelopment. PHOTO: SCREENGRAB FROM GOOGLE MAPS

Our targets: Dienia ophrydis and Zeuxine clandestina – two rare orchid species, whose numbers have dwindled sharply following an influx of hikers there.

Collecting the remaining individuals, and then nurturing them at the Singapore Botanic Gardens, could help to ensure the continued survival of both species.

Dienia ophrydis and Zeuxine clandestina are ground-dwelling orchids, with roots that extend into the earth. Many other orchids – including Singapore’s national flower, the Vanda Miss Joaquim – are epiphytes, growing above ground on tree branches and getting their moisture from air or from water that flows along the branches and tree trunk when it rains.

Unlike their showy cousins in the orchid family, both target species are inconspicuous. When not in bloom – and they were not – they look like mere grass to the untrained eye. That makes them very likely to be trodden on by the unsuspecting hiker.

The Zeuxine clandestina, also known as the hidden zeuxine, looks like grass when it isn’t flowering. ST PHOTO: MARK CHEONG

The common snout orchid (Dienia ophrydis) is collected during an NParks salvaging trip on April 28, 2021. ST PHOTO: MARK CHEONG

Both species are critically endangered in Singapore, and have been so even before the influx of people into Clementi Forest.

But their situation became more dire at the end of last year, when people were drawn to the forest after footage depicting it in its early morning splendour spread on social media.

Clementi Forest sits on land that is zoned for residential use. The Government said in January that the site will still be earmarked for this purpose, although there is no immediate need to develop it. Nature enthusiasts hope the plot can be rezoned as a nature park.

Despite the lack of proper trails or entrances, people have ventured into forest’s folds to soak in the sights and smells of nature.

A hiker stands at one of the unofficial entrances of Clementi Forest on April 28, 2021. ST PHOTO: MARK CHEONG

But Singapore residents could be loving the forest to the demise of its inhabitants.

“People enjoy Singapore’s nature areas for their ambience,” acknowledged Mr Lua Hock Keong, deputy director of NParks’ National Biodiversity Centre, and one of the researchers on the salvage expedition.

“But many are often not aware that these green spaces have biodiversity too.”

Sensitive things

The common snout orchid (Dienia ophrydis) was presumed nationally extinct, until it was rediscovered in Clementi Forest in 2011 by an NParks team, including Mr Lua, during a biodiversity survey .

Today, Clementi Forest and the Nee Soon Swamp Forest are the only places where this orchid is known to exist.

But human impact is taking a toll on its numbers.

Being state land, there are no trails in Clementi Forest. An old railway line there has served as an informal one. But hikers widen established paths when they skirt puddles or avoid fallen trees.

A hiker walks “off-trail” in Clementi Forest on April 28, 2021. The old railway line running through the forest serves as an informal trail. ST PHOTO: MARK CHEONG

Before people turned up in droves, Mr Lua had counted about 50 Dienia ophrydis individuals clustered at one site in the forest. But once the hikers came, he went back and found fewer than 20. By March, just one remained.

As for the other orchid, Zeuxine clandestina, also known as the hidden zeuxine, its numbers fell from more than 50 to 14. This species can also be found in other spots within Singapore’s central nature reserves, but is still considered rare.

It had rained the day before the rescue mission, and the NParks staff and researchers were geared up for it. Mr Lua even wore diving booties, typically worn by scuba divers or snorkellers. It was perfect for going through puddles, instead of around it.

NParks National Biodiversity Centre deputy director Lua Hock Keong wading through ankle-high mud as he looks for the two rare orchids at Clementi Forest during a salvaging trip on April 28, 2021. ST PHOTO: MARK CHEONG

Into the woods

Mr Ang Wee Foong dons two hats at NParks.

As centre director of the Seed Bank and deputy director of nursery management, he makes regular trips out to Singapore’s forests and nature areas to source for material like seeds or plant cuttings that will allow him and his team to nurture future generations of native plants. On those trips, parent plants are left behind.

NParks Seed Bank centre director Ang Wee Foong during a salvaging trip in Clementi Forest on April 28, 2021. ST PHOTO: MARK CHEONG

But last Wednesday, their aim was to get as many orchids as they could find.

Mr Lua and Mr Ang identified the orchids at a glance, while the rest of us pointed out green shoots to them that turned out to be something else completely.

NParks National Biodiversity Centre deputy director Lua Hock Keong looking for the two rare orchids along train tracks belonging to the Old Jurong Railway Line on April 28, 2021. ST PHOTO: MARK CHEONG

The plainness and size of both orchids make them the wallflowers of their natural habitats. A tropical rainforest assaults the senses – birds call, humidity clings to the skin, plants outdo one another with large, showy leaves, and streams gleam with an oily sheen.

This, we learnt from NParks group director of conservation Lim Liang Jim, was “forest kombucha”. Microbes in the water break down organic matter such as dead leaves, making these nutrients available once again to the rest of the forest. The oil on the surface is a byproduct of these processes, he explained.

The first orchid we saw during our foray into the forest was the Zeuxine clandestina, growing right on the “trail”.

With each orchid that they came across, Mr Lua and Mr Ang used their bare hands and a small trowel to loosen the earth around it. Then, they scooped up the entire plant and placed it into a plastic box.

NParks’ National Biodiversity Centre deputy director Lua Hock Keong (right) and Seed Bank centre director Ang Wee Foong salvaging two rare orchids on April 28, 2021. ST PHOTO: MARK CHEONG

The orchids were dislodged easily as their roots are shallow and extended only into the leaf litter and the top few centimetres of soil.

It was easy to see why high human traffic could kill them.

These terrestrial orchids develop a rhizomatous stem bearing short roots that worm their way through this topmost layer of fallen plant debris before reaching the soil, Mr Ang explained.

The constant pounding of feet onto this layer of topsoil can compact them – with disastrous consequences for the plants that depend on this layer to gain a foothold in the forest. Plants may also get trampled on by hikers as they make their way through non-designated trails, resulting in damage to the stems, roots, or sometimes entire plants for the smaller species.

Ground orchids also rely on mycorrhiza – a type of fungus invisible to the naked eye – to help them thrive in the forest environment, Mr Lua explained.

It is a symbiotic relationship – a quid pro quo for both fungus and orchid. The fungus helps the orchid germinate, and absorb water and mineral nutrients from the soil when the plant is developing into an adult with leaves. In return, the orchid supplies the fungus with the food it makes through photosynthesis.

So the NParks staff make sure they take a little bit of the soil back with them.

Two rare orchids, the hidden zeuxine (Zeuxine clandestina), and the common snout orchid (Dienia ophrydis), are collected in a container during the salvaging trip on April 28, 2021. ST PHOTO: MARK CHEONG

The next steps

Last week’s rescue mission was not their first rodeo. The NParks staff had started making trips to the forest to collect the orchids ever since Mr Lua noticed a decline in their numbers.

Some of their earlier “rescues” are now bearing seed pods.

The common snout orchid (Dienia ophrydis) is seen in a tank at the NParks Seed Bank on April 28, 2021. ST PHOTO: MARK CHEONG

NParks has a few strategies to ensure the continued survival of the species. The first is to observe if these seeds are viable and can germinate into new plants via tissue culture in a laboratory.

Another strategy is to propagate the orchids vegetatively by dividing the clumps when they grow to a suitable size. NParks is also working to transplant the orchids to other suitable sites around Singapore to establish new populations.

Efforts are ongoing to ensure that these two orchid species can continue to survive amid the surging interest in the Clementi Forest.

But their situation reflects a broader issue for Singapore: In a City in Nature, how can we encourage appreciation for nature, in a way that will not negatively affect wildlife?

Healthy leaf litter (right) seen side by side with compacted soil on the trail which hikers walk through along Clementi Forest on 28 April, 2021. ST PHOTO: MARK CHEONG

Dienia ophrydis and Zeuxine clandestina are unlikely the last of Singapore’s native wildlife to bear the consequences of a growing love for the Republic’s green spaces.

NParks’ Mr Lim, the group director of conservation, said the country was now enjoying the fruits of founding Prime Minister Lee Kuan’s Yew vision of a green Singapore. Nature has bloomed all around the island, he said, and NParks has seen surges in visitorship numbers in the places that it manages.

For instance, visitorship to Sungei Buloh Wetland Reserve has doubled from the average of 110,000 visits a year, to more than 220,000 last year. Likewise for Bukit Timah Nature Reserve. About 700,000 people last year made a visit to the grand old dame, the Bukit Timah Hill, compared with the usual 400,000.

Visitorship to the Sungei Buloh Wetland Reserve doubled last year. PHOTO: NPARKS

“We hope people understand that green spaces have biodiversity, and how people visit these places will have an impact on plants and animals,” said Mr Lim. Shy, forest species that can be found here include critically endangered animals like the Sunda pangolin and Raffles’ banded langur.

Last June, Singapore Botanic Gardens researchers discovered another species of orchid (Nervilia singaporensis) found only in Singapore and nowhere else in the world at the Bukit Timah Nature Reserve.

Will it suffer the same fate?

The Nervilia singaporensis was discovered last year. PHOTOS: NPARKS

Nature guide Ivan Kwan said visitors should keep to existing trails.

“Even within Clementi Forest and other unofficial hiking areas, paths have already been created trampling. If people keep to these paths, the impact from high visitorship can be lessened,” he said People should also not litter, or feed or harass wildlife.

Mr Kwan added: “It’s great that more people are taking the time to enjoy nature in Singapore, but we need to be careful and make sure that we don’t love our green spaces to death.”

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