Bio­di­ver­sity : a tragedy with many play­ers

The fol­low­ing arti­cle is the report of an inter­view that two jour­nal­ists, Carina Den­nis and Peter Ald­house, had 2004 with Prof. Peter Ng, one of the best ichthy­ol­o­gists of Sin­ga­pore uni­ver­sity who described some species of licorice gouramis, too. It was orig­i­nally pub­lished in Nature 430, 396398 (22 July 2004)

Bio­di­ver­sity: A tragedy with many players

Peter Ng is a man with a mis­sion: to cat­a­logue the huge diver­sity of life dwelling in habi­tats long dis­missed as unin­ter­est­ing. It’s a race against time, he tells Carina Den­nis and Peter Ald­hous.

A trop­i­cal peat swamp is not a wel­com­ing place. Its acidic waters sting every tiny scratch on your body. Hold your hands just beneath the sur­face and you can’t see them through the tannin-​laden water. The only bonus is that leeches don’t fancy the murk. But Peter Ng, a tax­on­o­mist and con­ser­va­tion biol­o­gist at the National Uni­ver­sity of Sin­ga­pore, loves get­ting up to his armpits in the mire.

Ng has dis­cov­ered that the peat swamps of south­east Asia are teem­ing with rare species of fish and crus­taceans, many of which are new to sci­ence. “Peat swamps have been badly neglected,” says Ng, who pulls out novel spec­i­mens on nearly every dip into these hos­tile waters. His team has found a trea­sure trove of bio­di­ver­sity in other unlikely places too, includ­ing the bro­ken rub­ble of dead coral found off trop­i­cal beaches.

Now Ng is engaged in a race to cat­a­logue these neglected fau­nas before many of them are wiped out by Asia’s relent­less eco­nomic devel­op­ment. The peat swamps, in par­tic­u­lar, are being drained as fast as he can sam­ple them, some­times for urban or agri­cul­tural devel­op­ment, at other times — in a bit­ter irony — under the guise of ‘envi­ron­men­tal improve­ment’.

The rich fau­nas found in such neglected habi­tats under­line a grow­ing real­iza­tion that con­ser­va­tion biol­o­gists really know very lit­tle about our planet’s bio­di­ver­sity (see ‘Hyper­di­ver­sity, or hype?’). But Ng’s quest is dri­ven by more than aca­d­e­mic inter­est. “Sci­en­tists and envi­ron­men­tal man­agers need to know these habi­tats exist and that they deserve to be con­served,” he says. “If they are lost through igno­rance or mis­in­for­ma­tion, then it will be a ter­ri­ble tragedy.”

Ng’s excite­ment about peat swamps was first fired in the early 1990s, when his sur­veys of the North Selan­gor swamp in Malaysia turned up some unex­pected finds. Wad­ing through the muck, his team stum­bled on sev­eral species of an elu­sive genus of cat­fish called
Ench­e­loclar­ias1. The last time any­one reported find­ing such a fish was in the 1930s.

The pH of such swamp waters can be as low as 3 — about the same as vine­gar. “Until recently, peat swamps were assumed to be hos­tile, acidic places where the bio­di­ver­sity was low,” says Ng. “But that’s because no one had actu­ally jumped in.” After tak­ing the plunge into numer­ous swamps on the Malay Penin­sula and the islands of Bor­neo and Suma­tra, Ng’s team has found some 80 fish new to sci­ence, bring­ing the esti­mate of the total num­ber of species in the swamps to 200300. “My stu­dents say they have too much to study,” he says. A high pro­por­tion of the species are exclu­sive to the peat-​swamp envi­ron­ment

Hide and seek

It isn’t easy pulling these crea­tures from the mire. Many of the fish and crus­taceans hide in crevices in the peat, rather than swim­ming in the watery chan­nels that run through it. Ng has to wade into the murky water hold­ing a net, while his larger col­league, Mau­rice Kot­te­lat, jumps up and down on the banks. “Mau­rice does his rain dance,” says Ng — and that’s enough to star­tle the crea­tures out of the peat. If Ng wants to sam­ple all of the species present, includ­ing amphib­ians, he has to col­lect at night as well. Wad­ing in a swamp in pitch dark­ness isn’t for the eas­ily spooked, he says.

“I’m inter­ested in fish in places where peo­ple haven’t been,” says Kot­te­lat, who is pres­i­dent of the Euro­pean Ichthy­olog­i­cal Soci­ety and is based in Cornol, Switzer­land. Some of the fish they have found in the swamps — includ­ing colour­ful species of Betta fight­ing fish, pop­u­lar with the aquar­ium trade
3 — have thrown up some intrigu­ing mys­ter­ies. “Why they should be so colour­ful in such black water is the million-​dollar ques­tion,” Ng says.

Ng doesn’t spend all his time in the field wad­ing chest-​deep in fetid swamps. Some­times his trips take him to much more pleas­ant des­ti­na­tions, includ­ing the idyl­lic sandy beaches of the US-​controlled island of Guam, some 2,000 kilo­me­tres east of the Philip­pines. There he stud­ies another over­looked habi­tat: the piles of bro­ken coral rub­ble that lie just a few tens of metres from the shore.

If you swim from a trop­i­cal beach to its fring­ing reef, you first pass over expanses of this rub­ble, cre­ated by storms and the rav­ages of time. Many nat­u­ral­ists make this jour­ney time and again, lured by the stun­ning array of fish and other ani­mals in the reef itself. But few pause to give the rub­ble a sec­ond thought. “It looks like a desert, almost,” says Ng.

The rub­ble piles might still be dis­missed as a desert, were it not for the obses­sive curios­ity of Harry Con­ley, who began div­ing off the beaches of Guam in the early 1980s after retir­ing from the US Air Force. Conley’s ini­tial inter­est was in col­lect­ing seashells. Real­iz­ing that they were present in large quan­ti­ties in the rub­ble, he started to exca­vate the piles by hand. “The holes he dug looked like bomb craters,” says Ng.

Rub­ble rousers

By the 1990s, Conley’s inter­ests had expanded to the crabs and other crea­tures that his digs dis­turbed. He teamed up with researchers at the Uni­ver­sity of Guam led by Gus­tav Paulay, who was con­duct­ing a sur­vey of the island’s marine bio­di­ver­sity4. Ng joined the team in 2000, when he was asked to help iden­tify crabs pulled from the rub­ble.

Sadly, Conley’s work came to an abrupt end in 2002 when he was killed by a gun­shot to the head — prob­a­bly self-​inflicted — after an argu­ment in which another man was shot and wounded. Friends describe Con­ley as a gen­er­ous yet trou­bled indi­vid­ual. “Harry was always a loner,” recalls Bruce Henke, who accom­pa­nied him on many col­lect­ing trips. “He was very com­pet­i­tive. If you found some­thing, he had to find some­thing bet­ter.”

Henke, who works in Guam as an air-​traffic con­troller, con­tin­ues to col­lect sam­ples from the rub­ble piles. Now 50, he has dived recre­ation­ally since his teens and is an accom­plished under­wa­ter pho­tog­ra­pher. In shal­low waters, each dive might last for two hours, con­sum­ing sev­eral tanks of air. Larger pieces of rub­ble have to be prised away with a crow­bar. “It can be dan­ger­ous,” says Henke. “It’s not some­thing that I would rec­om­mend to just any­body.”

Like the peat swamps, the rub­ble piles fas­ci­nate Ng because many of the species present have been found in no other envi­ron­ment. The crabs alone include about half-​a-​dozen gen­era and dozens of species that were pre­vi­ously unknown to sci­ence
5. Those that live deep within the rub­ble look sim­i­lar to crabs that are found in caves, with no pig­ments and shrunken eyes6. “It’s a whole new world,” says Ng.

Paulay, who is now at the Uni­ver­sity of Florida in Gainesville, believes that the rub­ble piles sup­port a sim­i­lar range of crea­tures to those that live in crevices deep within the coral reef itself. “This ‘crypto­fauna’ rep­re­sents the bulk of the reef’s bio­di­ver­sity,” argues Paulay, who views the rub­ble as a win­dow through which to study crea­tures that oth­er­wise could be

reached only by destroy­ing the reef.

Hid­den depths

There could be even more life inside the rub­ble than has been found so far — includ­ing faster-​moving crea­tures that dart away from the dig sites before they can be caught. “I would expect to find prawns, gob­ies and worms of all sorts,” says Ng. Sam­pling the sites more thor­oughly is a huge chal­lenge, though. One way would be to deploy a heavier-​duty ver­sion of the vac­uum pumps that marine archae­ol­o­gists use to suck up silt to sift through for frag­ments of arte­facts. But such devices don’t yet exist.

Other parts of the marine ecosys­tem, such as the steep walls that fall away from the reef into deeper waters, are even harder to reach. Scuba divers can’t descend below 100 metres and the walls are too steep to be dredged. With­out access to a sub­mersible, the only means of sam­pling the area is to throw a net blindly into the depths and cross your fin­gers.

Guam’s rub­ble fauna isn’t under imme­di­ate threat, so there is oppor­tu­nity to think about how to improve sam­pling. But time is run­ning out for many of Ng’s field sites, which include exten­sive sys­tems of lime­stone hills and caves found across south­east Asia. Water seep­ing down from the dense for­est there cre­ates moist grooves and crevices in the rock that host a wide assort­ment of plants and ani­mals.

These ‘karst’ sys­tems haven’t been entirely over­looked — they include the Gunung Mulu National Park in Malaysian Bor­neo, granted World Her­itage sta­tus for its bio­di­ver­sity and geo­log­i­cal fea­tures. But their fau­nas are poorly stud­ied
7. “Lime­stone hills are hotspots of rich­ness, but this has only really been appre­ci­ated recently,” says Tony Whit­ten, a bio­di­ver­sity spe­cial­ist with the World Bank, based in Wash­ing­ton DC.

The forests that grow above the lime­stone are rapidly being cleared, which dries out the rock, destroy­ing its sub­ter­ranean ecosys­tem. Ecol­o­gists study­ing the caves often find them­selves side-​by-​side — lit­er­ally — with devel­op­ers or cement com­pa­nies min­ing the hills for raw mate­r­ial. “We’ll be care­fully col­lect­ing our sam­ples, try­ing not to dam­age the habi­tat, and a few hun­dred metres fur­ther on, there’s a guy busy with a chain­saw,” says Jaap Ver­meulen, a col­lab­o­ra­tor of Ng’s at the Sin­ga­pore Botanic Gar­dens, who spe­cial­izes in the tax­on­omy of snails.

Van­ish­ing world

Liv­ing in the con­crete jun­gle of Sin­ga­pore, Ng knows all too well the con­se­quences of unfet­tered devel­op­ment. Last year, he pub­lished a paper in Nature8 that used the detailed records made by British colo­nial nat­u­ral­ists to doc­u­ment the extinc­tions that have occurred since most of Singapore’s forests were cut down. Extrap­o­lat­ing from these data, Ng and his col­leagues con­cluded that up to 42% of the species cur­rently in south­east Asia’s forests will dis­ap­pear over the next cen­tury if habi­tat destruc­tion con­tin­ues at its present rate. About half of these will be global extinc­tions, as the species are not found else­where.

The race to cat­a­logue bio­di­ver­sity before it dis­ap­pears is par­tic­u­larly intense in the peat swamps, which are dis­ap­pear­ing at a fright­en­ing rate. The drainage is even affect­ing neigh­bour­ing bits of for­est; dried peat bogs have fuelled huge fires that have razed some areas.

When he talks about the threats to the peat ecosys­tems, Ng’s nat­ural enthu­si­asm can’t hide a deep melan­choly. He has become a reluc­tant ambu­lance chaser, rush­ing in to sam­ple sites ear­marked for devel­op­ment. The col­lect­ing meth­ods that Ng’s team uses in such cases are severe and destruc­tive. “We call them sal­vage oper­a­tions,” he says. “We catch what­ever is sci­en­tif­i­cally valu­able, know­ing full well that there is no tomor­row. It is a very rot­ten feel­ing.”

Ng hopes his work will counter the igno­rance that under­lies the blasé destruc­tion of these habi­tats. Offi­cials and devel­op­ers argue that there is no point con­serv­ing the swamps because there is ‘noth­ing’ there. “These places don’t have big, sexy ani­mals,” Ng con­cedes. “But in almost all cases, when they say a place is species-​poor, they’re wrong.”

He remains gloomy about the chances of pro­tect­ing the remain­ing swamps from the tide of devel­op­ment. But at the very least, Ng is deter­mined to reveal for future gen­er­a­tions the true mag­ni­tude of the dev­as­ta­tion that is now being wrought. “The story is much more tragic once you know the char­ac­ters,” he says.

1 Carina Den­nis is Nature’s Aus­tralasian cor­re­spon­dent
2 Peter Ald­hous is Nature’s chief news & fea­tures editor.


1. Ng, P. K. L. & Lim, K. K. P. Ichthyol. Explor. Fresh­wa­ters 4, 2137 (1993). | Article |

2. Ng, P. K. L. Wal­lacea 73, 15 (1994).

3. Kot­te­lat, M. & Ng, P. K. L. Ichthyol. Explor. Fresh­wa­ters 5, 6578 (1994).

4. Paulay, G. Micronesica 3536, 325 (2003). | ISI |

5. Paulay, G., Kropp, R., Ng, P. K. L. & Eldredge, L. G. Micronesica 3536, 458517 (2003). | ISI |

6. Ng, P. K. L. & Takeda, M. Micronesica 3536, 419432 (2003). | ISI |

7. Ver­meulen, J. & Whit­ten, T. Bio­di­ver­sity and Cul­tural Prop­erty in the Man­age­ment of Lime­stone Resources – Lessons From East Asia (World Bank, Wash­ing­ton DC, 1999).

8. Brook, B. W., Sodhi, N. S. & Ng, P. K. L. Nature 424, 420423 (2003). | Arti­cle | PubMed | ISI | ChemPort |

9. Boucher, G. & Lamb­shead, P. J. D. Con­serv. Biol. 9, 15941604 (1995). | Arti­cle | ISI |

10. Lamb­shead, P. J. D. et al. BMC Ecol. 3, 1 (2003). | Arti­cle | PubMed |

11. Lamb­shead, P. J. D. & Boucher, G. J. Bio­geogr. 30, 475485 (2003). | ISI |

12. Gray, J. S. Mar. Ecol. Prog. Ser. 112, 205209 (1994). | ISI |


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