Originally published in Habitatnews 2003-09 19 April 2003. Revised, 24th August 2003
FOSSIL FERNS FOUND
The discovery of Dipteris conjugata on Pulau Sarimbun,
Western Johor Straits, 4 March 2003
'It grows also on the sea cliffs at Labrador in Singapore Island
(formerly also at Kranji)'.

So wrote the late Prof R.E. Holttum in his Flora of Malaya, Volume II, Ferns - first published in 1954.

As a keen student of indigenous flora, I hung on to his words tenaciously, especially his references to former localities of rare ferns. A fern so rare presently, that only a few privileged researchers have so far been blessed to see the isolated individuals growing in what are now off-limit military areas of Pulau Tekong and Poyan Reservoir.

Fate has since dealt a fatal blow on the large Dipteris colony on the cliffs of Labrador. In his book, "Common Ferns and Fern-allies of Singapore", published in 1984, Prof Wee Yeow Chin lamented that "Today, its presence at Labrador has yet to be established, as the original large colony of the plants on the cliff fronting the beach is there no more. No doubt, it may still exist somewhere within the area, struggling desperately to survive."

A few black and white photos are what that is left for present students to appreciate the fern's past glory in this most celebrated site. One such picture (circa 1960s) can be found in the book "Rhythm of the Sea, The Life and Times of Labrador Beach", published in 1994. Readers are left in no doubt about the fern's historical significance on Labrador. Prof Leo W.H. Tan (et al), the author, had succinctly revealed at the beginning of his introduction that "The original 4 hectares of cliff-side vegetation at Labrador was set aside for conservation in order to protect the habitat of the primitive fern, Dipteris conjugata."

He was, of course, referring to the Nature Reserve Ordinance enacted in 1951, under which the fern was originally protected. Since then, the conservation status of Labrador had undergone a long roller-coaster ride. But recent re-designation of Labrador as a Nature Reserve in November 2001 gave hope and a place of permanence for the survival of the few remaining Dipteris there. A rare photograph of the 'last clump' can be found in "A Guide to the Threatened Plants of Singapore" by Prof Hugh Tan (published in 1995).

Where else can one find Dipteris in Singapore then? How about Kranji - the district mentioned by Prof. Holttum and where Sungei Buloh Wetland Reserve is situated now?

While other rare plants had been discovered from time to time in Sungei Buloh, Dipteris had remained illusive by far - that is, not until we chanced upon Pulau Sarimbun (an island west of Sungei Buloh) while surveying shorebirds in the Western Johor Straits on 4 March 2003. It was a day we shall never forget for the rest of our lives!

We were simply overwhelmed by the sight of the Dipteris. They were everywhere! We could see them all around the island, draping extensively over the steep slopes, like some Mesozoic 'butterflies' flapping their paired leafy 'wings' triumphantly in the wind. The Dipteris colony is simply huge.

Had it not been for our recent acquisition of a 15-foot motorboat "Mangrovian" and our newfound mobility at sea, we would have remained in the dark even now. We felt incredulous that it is only now (since Sungei Buloh became a park in 1993) that we finally solved Holttum's Kranji puzzle. Until now, the ferns were "so near and yet so far".

But it is precisely the nature of this 'nearness' that brings home to us the importance of adjacent ecosystems that mutually benefit each other as seed areas as well as sites for trans-migration of marine animals, such as the otters, and avifauna.

Paradoxically, it takes the island of Pulau Sarimbun to remind us that Sungei Buloh does not exist as 'an island' by itself. The river of life that links us to the mangroves and mudflats at Mandai and Lim Chu Kang, as well as the Horseshoe Reef near Pulau Sarimbun helps to ensure the continuous exchange of genetic material from one community of plants and animals to another.

Given that we have no control over nature areas being removed for development immediately across our narrow straits, it is up to us to mitigate adverse ecological changes by retaining as much of our own adjacent ecosystems to the left and right of Sungei Buloh Wetland Reserve. This is particularly true for Mandai mudflats which "are a major feeding area for birds that roost at Sungei Buloh" an important revelation provided by the study of Profs. Murphy D. H.& J. B. Sigurdsson in "Birds, Mangroves and Man: Prospects and Promise of the New Sungei Buloh Bird Reserve" published in 1990.

But one thing for sure, our discovery has definitely re-opened a brand new site for the ecology studies of Dipteris conjugata as well as other floristic works. Perhaps, one day someone might even find the inspiration to study the genetic link between Dipteris here and those thriving atop Gunong Pulai, which on a clear day, looms large over Pulau Sarimbun.

Yes, why not. I believe dear Prof Holttum is smiling from the heavens right now!

Joseph Lai is a freelance writer and a former conservation officer of Sungei Buloh Wetland Reserve (SBWR). This article is dedicated to former colleagues in SBWR, especially co-discoverers - James Gan, Soon Lian, Ramakrishnan and Supaidi.

Pulau Sarimbun


A cliff face with Dipteris conjugata.


Close up of the Dipteris conjugata

Next - more on Dipteris conjugata.
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