Lin Y., L.S. Wijedasa & R.A. Chisholm, 2017. Singapore’s willingness to pay for mitigation of transboundary forest-fire haze from Indonesia. Environmental Research Letters [free online version].
“Southeast Asian haze pollution caused by forest and peatland fires in Indonesia has caused adverse health effects, impacted regional economies and let to tensions between ASEAN nations. One of the solutions proposed is payments for ecosystem services. This could take the form of richer nations aiding better land management and restoration by making regular payments.
In this study, we assessed the willingness of Singaporeans to pay for haze mitigation in Indonesia. We surveyed a diverse set of individuals from different income groups, genders and locations throughout the country to quantify the willingness to pay (WTP) for haze mitigation.
Our estimate of mean individual WTP was 0.97% of annual income (n=390). This amounted to a total WTP estimate of US$643.5 million per year (95% CI [US$527.7 million, US$765.0 million]). This estimate is comparable in magnitude to previously estimated impacts of Indonesia’s fires and also to the estimated costs of peatland protection and restoration. We recommend that our results be incorporated into future cost–benefit analyses of the fires and mitigation strategies.”
Grad student K S Seshadri is working on threatened amphibians in the Western Ghats for his PhD dissertation, focusing on the ecology and behaviour of bamboo nesting frogs. His research is supported by the Mohamed bin Zayed Species Conservation Fund and Chicago Zoological Fund. He updates us about news of a discovery of another new species of frog from the area:
“I’m happy to share with you the news of a new species of frog that we discovered from the West Coast of India. We described it as Euphlyctis karaavali, named after the local name of the west coast in Kannada language.
We chanced upon this frog entirely by serendipity. The frog call is very similar to that of the white throated kingfisher, commonly found in India. Mr. C. R. Naik, a forester with the state forest department brought this frog to our attention during his surveys along the coastal plains. We got him on board and wrote this paper along with him. This discovery is significant considering a forest department official with no formal training in research made the discovery and is an author of this contribution to science.
The frog is already threatened and we suggest that it be listed as Endangered under the IUCN redlist. The paper was published in Asian Herpetological Research, and is openly accessible.
Chang, C. C., H. Y. Teo, Y. Norma-Rashid & D. Li, 2017. Predator personality and prey behavioural predictability jointly determine foraging performance. Scientific Reports, 7: 40734 [pdf].
Predator-prey interactions play important roles in ecological communities. Personality, consistent inter-individual differences in behaviour, of predators, prey or both are known to influence inter-specific interactions. An individual may also behave differently under the same situation and the level of such variability may differ between individuals. Such intra-individual variability (IIV) or predictability may be a trait on which selection can also act. A few studies have revealed the joint effect of personality types of both predators and prey on predator foraging performance. However, how personality type and IIV of both predators and prey jointly influence predator foraging performance remains untested empirically.
Here, we addressed this using a specialized spider-eating jumping spider, Portia labiata (Salticidae), as the predator, and a jumping spider, Cosmophasis umbratica, as the prey. We examined personality types and IIVs of both P. labiata and C. umbratica and used their inter- and intra-individual behavioural variation as predictors of foraging performance (i.e., number of attempts to capture prey).
Personality type and predictability had a joint effect on predator foraging performance. Aggressive predators performed better in capturing unpredictable (high IIV) prey than predictable (low IIV) prey, while docile predators demonstrated better performance when encountering predictable prey. This study highlights the importance of the joint effect of both predator and prey personality types and IIVs on predator-prey interactions.
From Ted Webb, “PhD student Matti Niissalo suggests that many of the gingers of Singapore are under immediate threat of extinction or have an unpaid extinction debt; but that the prolonged period before extinction provides a window of opportunity for conservation action.”
Niissalo, M. A., J. Leong-Škorničková, G. S. Khew & E. L. Webb, 2017. Very small relict populations suggest high extinction debt of gingers in primary forest fragments of a tropical city. American Journal of Botany,104(1): 182-189 [journal link]
Tropical plant communities in fragmented forests are likely to experience an extinction debt, i.e., the habitat cannot support as many species as are present due to reduced habitat size and connectivity. There are few estimates of the number of species that represent extinction debt, and the number of extinctions over time has rarely been recorded. We recorded population sizes to assess threats and extinctions in gingers (sensu Zingiberales) in fragmented rainforest in Singapore, ca. 200 yr after fragmentation began.
We surveyed extant diversity and population sizes of gingers and used the results to estimate species survival. We critically assessed historic specimens to estimate initial extinctions and extinctions realized in present habitats.
We recorded 23 species, including five species previously presumed nationally extinct and four species omitted from the national checklist. The revised extinction rate is much lower than previously reported (12 vs. 37%). Most gingers have very small populations or miniscule ranges, implying that extinction debt has not been paid off.
Ginger diversity remains high, but the number of species at immediate risk of extinction outnumber recorded extinctions. Although tropical forest fragments remain arks of plant diversity for a long time, extinction debt may be prevalent in all plant groups in Singapore. Slow relaxation of extinction debt should be explicitly identified as a conservation challenge and opportunity. For conserving plant diversity in tropical fragments, relaxation must be reversed through restoration of degraded landscapes and, where feasible, targeted ex situ conservation and planting.
Yee, A. T. K., K. Y. Chong, L. Neo & H. T. W. Tan, 2016). Updating the classification system for the secondary forests of Singapore. Raffles Bulletin of Zoology Supplement No. 32: 11-21 [pdf].
In this paper, the authors examine dryland secondary forests of Singapore with a defied tree canopy layer (i. e. not scrubland). They classify these secondary forests based on their land-use histories into three forest types:
Native-dominated secondary forests – forests regrown on land cleared before the 1950s, and dominated by native tree species.
Abandoned-land forests – forests regrown over abandoned plantations or kampungs, with mature trees largely intact.
Waste-woodlands – forests regrown over land cleared usually after the 1960s, and dominated by exotic tree species. Species composition derived from seed source of the surroundings at the time of clearance, and succession. Reclaimed land forest (technically primary succession) is structurally similar to waste-woodlands with a species composition likely derived from the fill material.”
The authors remind us that land-use history of a single patch of secondary forest can be heterogeneous, and would require a mixed classification to best describe it.
See also, Yee, A. T. K., R. T. Corlett, S. C. Liew & H. T. W. Tan, 2011. The vegetation of Singapore—an updated map. Gardens’ Bulletin Singapore, 63(1&2), 205-212 [pdf].
“Vegetation covers 56% of Singapore’s total land area: 27% is actively managed (parks, gardens, lawns, etc.) and 29% is spontaneous vegetation. Primary lowland dipterocarp forest and freshwater swamp forest cover only 0.28% and is confined to the Bukit Timah and Central Catchment Nature Reserves. The majority of the non-managed vegetation is secondary forest of various kinds, dominated by native or alien trees.”
Abstract – The origin of novel traits remains an outstanding question in evolutionary biology. In particular, it is largely unknown how these novel traits originate via modifications in development. Butterfly eyespots are complex novel traits that originated once, from simpler coloured spots, within the family Nymphalidae. Although several genes associated with eyespot development have been identified, the underlying gene regulatory network and function of eyespot genes still remains largely unknown.
Using a transcriptome analysis, I first identified 186 genes that were differentially expressed in wing tissues that develop eyespots in Bicyclus anynana compared to wing tissues that don’t. Many of these genes were involved in wound healing, suggesting that butterfly eyespots may have originated with the co-option of the wound healing gene regulatory network. Second, I investigated the genetic basis of eyespot number variation using an eyespot number mutant, Spotty, with two additional eyespots. Only a handful of the 461 genes that were differentially expressed between Spotty and wild-type butterflies overlapped with genes from the eyespot gene regulatory network, indicating possible targets for Spotty. Finally, I tested the function of wingless, a gene previously implicated in eyespot development, by down-regulating it in transgenic B. anynana butterflies via RNAi. Transgenic butterflies showed significant reductions in the size of eyespots and wings, compared to wild-type controls, indicating that wingless is a positive regulator of eyespot and wing development in B. anynana butterflies.
“Comparative and experimental approaches to understanding sexual selection in Sepsidae (Diptera)”
Speaker: Tuan Jia Min Mindy
(Graduate Student, Dept. of Biological Sciences ,NUS)
Date: 13 January 2017, Friday
Time: 10 am
Venue: DBS Conference Room (S3 Level 5)
Supervisor: Professor Meier, Rudolf
All are welcome
Abstract – Natural history and discovery science has taken a back-seat as hypothesis-testing using model species has become a standard approach in biology. This is one reason why the vast majority of described species are severely data-deficient and very little is known is known about their behaviour, interactions with other species, and ecosystem functions. In my thesis, I explore the behavioural diversity within black scavenger flies (Diptera: Sepsidae) which have ca. 350 described species. Sepsidae include a few “model species” (e.g., Sepsis cynipsea, Sepsis punctum, and a few species of Themira, Archisepsis and Microsepsis), but little is known about the remaining taxa. In my thesis, I use a comparative approach to explore the behavioural diversity space of Sepsidae by studying the mating behaviour of 49 species and use comparative and experimental approaches to document and understand the behaviour.
I find that sepsids are one of the few insects that perform “sensory kissing”, which is significantly different from the nuptial kissing observed in other dipterans or the kissing performed by drosophilids to assess females’ receptivity before mating. Sepsids also evolved a variety of ways to terminate copulations. For example, some species use a novel “twisting” motion that allows the male to “pivot” clock- or anti-clockwise in order to separate from the female. Data analysis suggests that this new behaviour is adaptive because it allows for faster and more predictable separation times. Similarly variable is copulation time. The copulation time of sepsids varies 5 minutes to 5 hours and I show through ancestral state reconstruction and sensitivity analyses that copulation time undergoes considerable amounts of evolution. Furthermore, I used experimental reciprocal crosses between separated conspecific populations to determine which sex controls copulation duration. Experimental perfuming of females using osmeterium secretions from males were also performed to test whether the secretion possessed an anti-aphrodisiac function. Finally, I detailed the repertoire, action patterns and phases for 24 species of sepsids.
This work revealed interesting and rare behaviours, as well as widespread polymorphism within species, which would have remained hidden if only model species had been studied. This illustrates the importance of comparative research on the natural history of many species. It both broadens and deepens our knowledge of animal diversity.
Distribution and bionomics of Anopheles sinensis, and its role of the malaria transmission in Singapore
Speaker: Pang Sook Cheng (Graduate Student Dept. of Biological Sciences, NUS)
Date: 13 January 2017, Friday
Venue: DBS Conference Room II (S1 Level 3, mezzanine)
Supervisor: Assoc Prof Li Daiqin
All are welcome
Abstract – Research on Anopheles mosquitoes has always been of low priority due to the malaria free status of Singapore since 1982. However, Anopheles sinensis were persistently found in localized malaria outbreaks in 2009 and kick started the investigation on the distribution, bionomics and the role of malaria transmission of this species. In this study, we confirmed the presence of A.sinensis Form A and the possible absence of Form B in Singapore.
Anopheles sinensis Form A was experimentally incriminated as a Plasmodium vivax vector and were found to be anthropophilic. Being the most widespread anopheline, they were present in a third of the total investigated sites and were actively seeking host throughout the night, especially before 1.00am. In the wild, their abundance positively correlative with the average and minimum temperature, but not rainfall.
Basic biological characteristics of A. sinensis were also pursue to further understand the fundamental knowledge to epidemiology of malaria. This study has revealed that A. sinensis could pose a malaria threat in urban Singapore, if the risks are not managed.