With its iconic skylines and waterfront vistas, Singapore is today a bustling city-state with one of the highest population densities in the world. Two centuries ago, before the British chose to build the port city in 1819, Singapore was covered by rainforests, mangrove forests and swamp forests. In the two centuries that followed, these forests were cleared to make way for people, plantations and concrete structures, and iconic species like tigers and leopards vanished.
A new study estimates that Singapore has lost more than a third of its species in this transition. It uses observational data from more than 3,000 species from 10 major taxonomic groups, including mammals, birds, reptiles, amphibians, plants and insects. Using mathematical models, the study, published in Proceedings of the National Academy of Sciences (PNAS), estimates the species extinction rate over time. The analysis also considers “dark extinctions” — extinction of species that are yet to be discovered.
“The number we came up with, which was 37%, is quite a lot but it’s about half that of a previous estimate,” says theoretical ecologist and lead author Ryan Chisholm from the National University of Singapore.
The previous estimate Chisholm refers to comes from a 2003 study, which found a whopping 73% species extinction rate in Singapore. That study assumed species in Peninsular Malaysia, which borders Singapore, were also present in similar habitats in Singapore, an assumption the current study’s researchers say is flawed. Because the area of Singapore is tiny — just 1% of Peninsular Malaysia — not all species occur here, they say.
The author of the 2003 study, ecologist Barry Brook, now at the University of Tasmania, tells Mongabay he agrees with the statistical approach used in the current research. “They used an improved method that better accounted for uncertainties and sourced improved data,” he says via email, adding that the revised calculation “nicely illustrates how science advances.” Brook was not involved in the research but did serve as one of the editors for the resulting PNAS article.
Better data and improved models yield realistic predictions
Singapore’s extinctions began in the mid-19th century when large swaths of forests made way for plantations, leading to the extinction of many plants and vertebrates. Hunting also contributed to the loss of large mammals, such as tigers and leopards. By the mid-20th century, rapid urbanization wiped out many butterflies and birds.
The researchers of the current study painstakingly dug through more than 50,000 observational records — including plant specimens from as early as 1796, museum specimens collected by Alfred Russel Wallace in the 1800s, published literature, recent observations submitted by citizen scientists such as the current Prime Minister Lee Hsien Loong, media reports and news of species rediscovered. Using newer and more robust mathematical models than previous such studies, the researchers calculated the extinction rates for each species and grouped them based on their taxonomy.
“The previous standard has been just to use the first and the last [sighting]. All the information in between [is] discarded,” says plant ecologist Joseph Wright from the Smithsonian Tropical Research Institute, who was not involved in the study. He points out that this study represents a “breakthrough” as it uses every observation record for every species from when it was first sighted to its last known sighting.
The study found that in the last two centuries, nearly half of butterflies, nine out of 10 forest-dwelling birds and more than two-fifths of bees have gone extinct. Among mammals, nearly 60% of large mammals (weighing more than 10 kilograms, or 22 pounds) have vanished — including charismatic ones such as tigers and leopards. More than two-thirds of orchids have also become extinct.
Surprisingly, amphibians, considered the most vulnerable to habitat loss, seemed to have fared reasonably. “One thing which really bamboozled us a bit was that there were no recorded amphibian extinctions for Singapore,” says Chisholm. He posits it could be because their data size of observations was small, or that droughts before 1819 may have already wiped out many of the amphibians on the island before record-keeping began.
Extrapolating their data, the researchers predict that by 2100, about 18% of all species in Southeast Asia could go extinct if the current rate of forest loss and degradation continues. The 2003 study estimated a 42% extinction rate for Southeast Asian species.
New estimates provide a glimmer of hope
Although 1% of the original primary forests remain in Singapore today, the study finds that extinction rates have now leveled off for most species. The remaining patches of forests in the city are now protected and serve as a haven for existing biodiversity, as there’s no threat of poaching. Conservation efforts targeting specific species, such as the oriental pied hornbill (Anthracoceros albirostris), once locally extinct, have brought them back from extinction.
“We recommend that conservation in the region focus more on charismatic species rather than necessarily on large numbers of species going extinct,” says Chisholm. “I think it’s more likely to generate public support.” Since charismatic species, like pangolins (Pholidota), need large reserves, conserving them can also help protect other species in the same habitat.
Wright points out that the study’s findings show that the future of the tropics could be like that of Europe, where most species have adapted and thrive in human-modified landscapes instead of going extinct. “The study should force a rethink of the idea that we are precipitating the sixth mega extinction,” he says, adding that the findings could “revitalize policy and conservation in the tropics.”
As for Singapore’s future, Chisholm says there’s a significant chance some species could emigrate from Malaysia independently or with human assistance and recolonize the city. “All that depends on government policy,” he says. “We produce the numbers, and it’s up to people to decide what they actually want to do.”
Brook, B. W., Sodhi, N. S., & Ng, P. K. L. (2003). Catastrophic extinctions follow deforestation in Singapore. Nature, 424(6947), 420–423. doi.org/10.1038/nature01795.
Chisholm, R. A., Kristensen, N. P., Rheindt, F. E., Kwek Yan Chong, Ascher, J. S., Kelvin, Peter, Darren, Meier, R., Heok Hui Tan, Xingli Giam, Yen Shing Yeoh, Seah, W. W., Berman, L. M., Hui Zhen Tan, Sadanandan, K. R., Theng, M., Faridah, W., Jain, A., & Huertas, B. (2023). Two centuries of biodiversity discovery and loss in Singapore. Proceedings of the National Academy of Sciences of the United States of America, 120(51). doi.org/10.1073/pnas.2309034120g/10.1073/pnas.2309034120.
This article by Spoorthy Raman was first published by Mongabay.com on 22 December 2023. Lead Image:Conservation efforts targeting specific species, such as the oriental pied hornbill (Anthracoceros albirostris), once locally extinct, have brought them back from extinction. Image by Sipuwildlife via Wikimedia Commons (CC BY-SA 4.0).
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Singapore, kwa sababu ya mandhari yake ya kifahari na mandhari ya pwani, leo ni mji-jimbo wenye shughuli nyingi na mojawapo ya miji yenye idadi kubwa zaidi ya watu ulimwenguni. Tangu Uingereza ilipoanzisha mji wa bandari mwaka 1819 Singapore ilikuwa na misitu ya mvua, misitu ya mangrove na misitu ya mabwawa. Katika karne mbili zilizofuata, misitu hiyo ilikatwa ili kufanyiza njia kwa ajili ya watu, mashamba na majengo ya saruji, na spishi maarufu kama vile simbamarara na chui zilipotea. Uchunguzi mpya unaonyesha kuwa Singapore imepoteza zaidi ya theluthi moja ya spishi zake katika kipindi hiki cha mabadiliko. Kwa mujibu wa utafiti huo, kuna spishi zaidi ya 3,000 kutoka vikundi vikuu 10 vya jamii, ikiwa ni pamoja na mamalia, ndege, wanyama wanaotambaa, amfibia, mimea na wadudu. Kwa kutumia mifano ya hisabati, utafiti huo, uliochapishwa katika Proceedings of the National Academy of Sciences (PNAS), unakadiria kiwango cha kutoweka kwa spishi kwa muda. Uchambuzi pia unafikiria "kuangamia kwa giza" - kutoweka kwa spishi ambazo bado hazijagunduliwa. "Nambari tuliyopata, ambayo ilikuwa 37% ni nyingi sana lakini ni karibu nusu ya makadirio ya awali", anasema mtaalamu wa ikolojia na mwandishi mkuu Ryan Chisholm kutoka Chuo Kikuu cha Taifa cha Singapore. Chisholm alitaja kwamba utafiti uliofanywa mwaka 2003 ulionyesha kuwa idadi ya spishi za wanyama nchini Singapore imepungua kwa asilimia 73. Utafiti huo ulidhani spishi katika Peninsula ya Malaysia, ambayo inapakana na Singapore, pia zilikuwapo katika makazi kama hayo huko Singapore, dhana ambayo watafiti wa utafiti wa sasa wanasema ni mbaya. Kwa sababu eneo la Singapore ni dogo - ni 1% tu ya Peninsula ya Malaysia - sio spishi zote zinapatikana hapa, wanasema. Mwanasayansi Barry Brook, ambaye sasa anafanya kazi katika Chuo Kikuu cha Tasmania, anasema kwamba anaamini katika utafiti huo. "Walitumia njia iliyoboreshwa ambayo ilichukua uhakika bora na data iliyoboreshwa ya chanzo, ""anasema kupitia barua pepe, akiongeza kwamba hesabu iliyorekebishwa ""inaonyesha vizuri jinsi sayansi inavyoendelea.""" "Hata hivyo, ""data bora na mifano iliyoboreshwa hutoa utabiri wa kweli"" - kutoweka kwa Singapore kulianza katikati ya karne ya 19 wakati misitu mikubwa ilipofanya njia kwa mashamba, na kusababisha kutoweka kwa mimea na wanyama wengi wenye uti wa mgongo." Uwindaji pia ulichangia kupotea kwa mamalia wakubwa, kama vile simbamarara na chui. Kuanzia karne ya 20 na kuendelea, ukuzi wa miji ulifanya viumbe wengi wa asili wa dunia waangamie. Watafiti wa utafiti huu walichunguza kwa bidii zaidi ya rekodi 50,000 za uchunguzi, ikiwa ni pamoja na sampuli za mimea kutoka mapema kama 1796, sampuli za makumbusho zilizokusanywa na Alfred Russel Wallace katika miaka ya 1800, fasihi iliyochapishwa, uchunguzi wa hivi karibuni uliwasilishwa na wanasayansi wa raia kama vile Waziri Mkuu wa sasa Lee Hsien Loong, ripoti za vyombo vya habari na habari za spishi zilizogunduliwa tena. Kwa kutumia mifano mpya na yenye nguvu zaidi ya hisabati kuliko masomo ya awali kama hayo, watafiti walihesabu viwango vya kutoweka kwa kila spishi na kuziweka kwa msingi wa taxonomy yao. <unk>Kiwango cha awali imekuwa tu kutumia kwanza na ya mwisho [kuona]. Habari zote zilizo kati [za] kutupwa, "anasema mtaalamu wa mazingira ya mimea Joseph Wright kutoka Taasisi ya Utafiti wa Tropiki ya Smithsonian, ambaye hakuhusika katika utafiti huo. "Anasema utafiti huo ni ""mwisho"" kwa sababu unatumia rekodi zote za uchunguzi kwa kila spishi tangu ilipoonekana kwa mara ya kwanza hadi ilipoonekana mara ya mwisho." Katika karne mbili zilizopita, karibu nusu ya vipepeo, ndege tisa kati ya kumi wanaoishi misitu na zaidi ya nusu ya nyuki wametoweka. Kati ya mamalia, karibu 60% ya mamalia wakubwa (wenye uzito wa zaidi ya kilo 10 au pauni 22) wametoweka - ikiwa ni pamoja na wale wenye kuvutia kama vile simbamarara na chui. Zaidi ya thuluthi mbili za okidi pia zimepotea. Kwa kushangaza, amfibia, wanaochukuliwa kuwa walio hatarini zaidi kwa sababu ya kupoteza makao yao, walionekana kuwa wamefanikiwa kwa kadiri fulani. "Kitu kimoja ambacho kilitushangaza sana ni kwamba hakukuwa na rekodi za kutoweka kwa amfibia huko Singapore", anasema Chisholm. "Anasema, ""Inawezekana kwa sababu data zao zilikuwa ndogo, au kwa sababu ukame uliotokea kabla ya mwaka 1819 ulikuwa umeharibu wanyama wengi wa baharini na baharini kabla ya kuanza kurekodi.""" Watafiti hao wanakadiria kuwa kufikia mwaka 2100 asilimia 18 ya spishi zote za mimea na mimea ya Asia Kusini-Mashariki zitakoma ikiwa kiwango cha sasa cha uharibifu wa misitu kitaendelea. Uchunguzi wa mwaka 2003 ulikadiria kiwango cha kutoweka kwa spishi za Asia ya Kusini Mashariki kuwa asilimia 42 ya spishi zote za dunia. "Hata ingawa asilimia moja ya misitu ya awali ya asili bado iko nchini Singapore leo, utafiti huo unagundua kuwa viwango vya kutoweka vimepungua kwa spishi nyingi.""" Sehemu zilizobaki za misitu katika mji sasa zimelindwa na hutumika kama kimbilio kwa utofauti wa kibiolojia uliopo, kwa kuwa hakuna tishio la uwindaji haramu. Jitihada za kuhifadhi spishi fulani, kama vile antracoceros albirostris, ambayo wakati mmoja ilikuwa imepotea mahali hapo, zimewaokoa wasiondolewe. "Tunapendekeza kwamba uhifadhi katika mkoa huo kuzingatia zaidi juu ya spishi charismatic badala ya lazima juu ya idadi kubwa ya spishi kwenda extinct, "anasema Chisholm. "Nafikiri ni uwezekano mkubwa wa kupata msaada wa umma. ""Kwa kuwa spishi zenye kuvutia, kama vile pangolins (Pholidota), zinahitaji hifadhi kubwa, kuzihifadhi pia zinaweza kusaidia kulinda spishi nyingine katika mazingira sawa. """ Wright anasema matokeo ya utafiti huo yanaonyesha kuwa wakati ujao wa maeneo ya kitropiki unaweza kuwa kama ule wa Ulaya, ambapo spishi nyingi zimebadilika na kusitawi katika mazingira yaliyobadilishwa na binadamu badala ya kutoweka. "Utafiti huo unapaswa kulazimisha kufikiria tena wazo kwamba tunaharakisha kutoweka kwa mega ya sita, ""anasema, akiongeza kwamba matokeo yanaweza ""kuamsha sera na uhifadhi katika kitropiki. ""Kuhusu siku zijazo za Singapore, Chisholm anasema kuna nafasi kubwa kwamba spishi zingine zinaweza kuhamia kutoka Malaysia kwa kujitegemea au kwa msaada wa binadamu na kuanzisha tena jiji hilo. """ "Hiyo yote inategemea sera ya serikali", anasema. "Tunazalisha nambari, na ni juu ya watu kuamua nini wao kweli wanataka kufanya. "" Brook, B. W., Sodhi, N. S., & Ng, P. K. L. (2003). Maangamizi makubwa ya wanyama hufuata ukataji-miti huko Singapore. Nature, 424 (6947) na 420 (423) (Dai.org 10.1038.nature.org) "Kristo, R.A., Kristensen, N.P., Rheindt, F.E., Kwek Yan Chong, Asher, J.S., Kelvin, Peter, Darren, Meier, R., Heuk Tan Hui, Xingli Giam, Yen Shing Yeoh, Seah, W.W., Berman, L.M., Hui Zhen Tan, Sadanandan, K.R., Theng, M., Faridah, W., Jain, A., na Huertas, B.""" (2023) (k) Ni nini kinachohusika? Karne mbili za uvumbuzi na upotezaji wa utofauti wa kibiolojia huko Singapore. Proceedings of the National Academy of Sciences, 120 (51) (P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S. P.S Makala hii ya Spoortier Raman ilichapishwa kwa mara ya kwanza na Mongabay mnamo Desemba 22, 2023. Kwa mfano, katika nchi za mashariki, aina ya mnyama anayeitwa anthracoceros albirostris, ambaye alikuwa ameangamia, ameokolewa. Picha ya Sipuwildlife kupitia Wikimedia Commons (CC BY-SA 4.0). Unaweza kusaidia kuokoa wanyama wa porini kwa kutoa mchango mdogo kama $ 1 kwa dakika moja tu.