Fri 05 Sep 2014: 3.30pm @ DBS Conf Rm 2: Toh Tai Chong on “The use of sexually propagated scleractinian corals for reef restoration”

PhD Defense Seminar cum Oral Examination

“The use of sexually propagated scleractinian corals for reef restoration”

Toh Tai Chong
Graduate Student,
Dept. of Biological Sciences, NUS
Supervisor: Prof Chou Loke Ming

Fri 05 Sep 2014: 3.30m
DBS Conference Room II (S1 Level 3, Mezzaine)

All are welcome

Abstract – 

“Increasing anthropogenic pressures coupled with global climate change have resulted in the rapid degradation of coral reefs, necessitating the implementation of active measures to assist the recovery process. Recent advancements have facilitated the use of sexually propagated scleractinian corals to supplement reef restoration initiatives, by capitalizing on the ability of corals to produce large numbers of genetically diverse propagules. The main objectives of my thesis were to assess and improve the feasibility of using sexually propagated scleractinian corals for reef restoration.

Attempts at transplanting sexually derived corals are limited and have been restricted to the use of the fast-growing species. This is the first study to rear two species of slow-growing Faviid corals from larvae through to transplantion to the reef. My results demonstrated that this technique is technically viable for reef restoration and the key bottleneck of this approach resided in the initial ten months of the ex situ mariculture phase, which had the highest juvenile coral mortality rate.

To improve the feasibility of this approach, I have demonstrated that introducing the sea urchin Salmacis sphaeroides and the gastropod Trochus maculatus as biological control agents were useful in regulating macroalgae proliferation and augmenting the post-settlement growth and survival of coral juveniles in mariculture facilities. Subsequently, I have showed that nutritional enhancement significantly increased the ex situ growth of coral juveniles. This had significant flow-on effects even after transplantation to the reef, as coral transplants which were fed had higher growth and survival rates than those which were not.

Taken together, my research provided key empirical evidence to support the use of sexually propagated corals as source material for transplantation to degraded reefs. The initatives proposed in this study can be incorporated into future reef restoration programmes to improve the feasibility and cost-effectiveness of transplanting sexually propagated corals.”

Mon 25 Aug 2014: 9.00am @ DBS Conf Rm 1: Lucas Garrett Gibson on “The fate of biodiversity in modified tropical forests”

PhD Defense Seminar cum Oral Examination

“The fate of biodiversity in modified tropical forests“

Lucas Garrett Gibson
Graduate Student,
Dept. of Biological Sciences, NUS
Supervisor: Asst Prof Bickford, David Patrick

Mon 25 Aug 2014: 9.00m
DBS Conference Room (S3 Level 5)

All are welcome

Abstract – 

“Tropical forests hold half of all species on the planet, but are being rapidly lost or disrupted by agricultural expansion, logging, and other human enterprises. In my thesis, I examined the fate of biodiversity in modified tropical forests in three original ways. First, I compiled data from published studies around the global tropics and used a meta-analysis to assess the relative biodiversity value of regenerating, logged, and other disturbed forests. Second, I surveyed small mammal communities in forest fragments over multiple time periods to measure the rate of species loss – and thereby gauge the time available to avert extinctions in fragmented forest landscapes by implementing conservation actions. Third, I modeled projected biodiversity impacts of various scenarios combining different levels of deforestation and forest restoration to assess the potential of regenerating forests to offset biodiversity loss due to deforestation. My results highlight the vulnerability of tropical forests to substantial and rapid biodiversity loss and also identify the best strategies to stem this loss – by preserving remaining expanses of undisturbed forest, protecting modified forests with highest biodiversity value (e.g., logged forests), and rapidly restoring forest connectivity in fragmented landscapes.”

Undergrad part-time lab volunteers wanted for phytoplankton research (April-Dec 2014)

Do you have an interest in freshwater fauna?
Want to learn about more about phytoplankton research techniques?

Picture taken from Singapore Biodiversity: Freshwater Ecosystems by Yeo & Lim (2011)

Project description: Sampling and experimental work on toxic cyanobacteria isolated form Singapore’s reservoirs.

Two or more part-time volunteers are required for sample processing (cell counting) from September 2014 to February 2015.

What you will learn

1. Sample processing (cell counting) of samples collected from previous experiments
2. Using of Sedgwick Rafter and compound microscopes
3. Learning to do basic phytoplankton identification
4. Learn more about Singapore’s freshwater fauna

Candidates should be:

1. Be able help out over the semester break and during term time
2. Willing to learn new techniques

Contact

Please contact Maxine Mowe, Graduate student, Freshwater and Invasion Biology Laboratory, Department of Biological Sciences, National University of Singapore. Update (16 Jan 2015): Thank you for your interest. The researcher has recruited enough volunteers for the project.

Tue 26 Aug 2014: 3.30pm @ DBS CR2 – Aloysius Teo on Carbon and nutrient cycling in litterfall in Singapore

Department of Biological Sciences, NUS
Qualifying Examination

“How biodiversity and forest succession affect ecosystem functioning: carbon and nutrient cycling via litterfall in Singapore”

Teo Xian Yao Aloysius
Graduate Student,
Dept. of Biological Sciences
National University of Singapore

Tue 26 Aug 2014: 3.30pm
DBS Conference Room (S3 level 5)
Supervisor: Assoc Prof Theodore A. Evans

All are welcome

Abstract: – Pervasive deforestation and land-cover changes within the tropics have led to the formation of large tracts of tropical secondary forests. While the loss of species within secondary forests is well-recognised, it remains unclear if the decline in biodiversity is associated with a decline in the level of ecosystem functioning. It is imperative that the provision of essential ecosystem processes and services within secondary forests – in particular carbon and nutrient cycling, be better characterised.

The production and decomposition of vegetative litter is a vital ecosystem process, forming one of the main pathways for carbon and nutrient cycling. These processes are regulated by a range of biotic and abiotic factors – the diversity of the decomposer community, the diversity of plants, the chemical quality of litter produced and the physical environment. However, few studies have characterised the mechanistic linkages of these factors with the litterfall and decomposition processes in secondary forests.

In Singapore, secondary forests dominate the forested landscape. However, there remains a paucity of studies to describe the secondary forests from a functional perspective. Specifically, no studies have been conducted to assess the efficiency of carbon and nutrient cycling via the litterfall and decomposition processes. Henceforth, this study aims to investigate the relative roles of forest succession, the decomposer community, and abiotic factors in determining fine litterfall productivity and litter decomposition rates, as well as the associated fluxes of carbon and nutrients. The phenological patterns of litterfall will be identified too.

Preliminary results revealed that litterfall productivity in mature secondary forests did not approach that of primary forests, despite the former having more than a century of regeneration. Wood wastelands, which had less than 50 years of regeneration, produced significantly more fine litterfall and were characterised by a markedly elevated level of nitrogen and phosphorus cycling.

The monthly production of fine litterfall was found to exhibit an inverse relationship with precipitation. Reproductive litter production did not appear to be influenced by precipitation, except in primary forests, where the drought-triggered masting of Dipterocarps likely contributed to a spike in the quantity of reproductive litter recorded.

Decomposition rates of fine litter remained relatively similar across forest types. Litter nitrogen content and soil moisture levels were strong determinants of decomposition rates. Further studies will investigate the dynamics of coarse litter decomposition and evaluate the relative roles of microbial and invertebrate decomposers experimentally.

Recycle your E-waste at Blk S2 and at Utown (From 20 to 27 Aug 2014, 11am)

This one-week E-waste recycling exercise is part of Dr Amy Choong’s efforts for her GEK1515 Environmental Biology students.  To make it convenient to staff as well, she has invited Cimelia staff to install two bins at these two locations (Utown Education Resource Centre and between S2 & S3) for a week so that you can also dispose of your e-waste.

Please make use of this opportunity to get rid of broken appliances.

Wed, 27 Aug 2014: 1.00pm @DBS Conf Rm II: Low Bi Wei on “The invasion biology of the African sharptooth catfish in Southeast Asia”

Qualifying Examination

“The invasion biology of the African sharptooth catfish, Clarias gariepinus, in Southeast Asia“

Low Bi Wei
Graduate Student,
Dept. of Biological Sciences, NUS
Supervisor: Asst Prof. Darren Yeo
Co-supervisor: Dr Tan Heok Hui

Wed 27 Aug 2014: 1.00pm
DBS Conference Room II (S2 Level 3, Mezzaine)

All are welcome

Abstract – “The African sharptooth catfish, Clarias gariepinus, is a highly invasive species with known severe impacts, including native species declines through ecological (e.g. competition, predation) and genetic interactions (e.g. introgressive hybridization). The species is widely introduced and established across Southeast Asia, particularly in disturbed rural to urban environments, but despite its potential far-reaching consequences on native ecosystems, little is known about its life history and impacts in the region.

My study aims to address these knowledge gaps, and elucidate the potential risks and impacts of this invasive species on freshwater communities in Southeast Asia. Specifically, I review and analyze evidence suggesting that C. gariepinus has adversely affected populations of native Clarias species in Singapore, and address taxonomic problems in the Clarias batrachus species complex, a group that is similarly associated with anthropogenic systems, which in recent years has faced severe declines owing to uncontrolled introductions of C. gariepinus. Environmental niche models are used to investigate niche conservatism of C. gariepinus outside its native range and its invasion potential.

At the regional level, I will investigate the trophic and habitat ecology of introduced and native Clarias species in Southeast Asia, and examine the mechanisms and consequences of interspecific interactions. I will also utilize genome-wide genetic markers to elucidate the landscape genetics of C. gariepinus across the region, and determine the extent of genetic impacts on native counterparts. Besides furthering our understanding of various ecological and evolutionary processes, knowledge gained from this study will also contribute towards informing policy and management of aquatic invasive species across Southeast Asia.”

Fri 22 Aug 2014: 2.30pm @ LT31 – Prof Ken Hinchcliff on “Horses for Courses: Controlling Equine Influenza in Australia”

Professor Ken Hinchcliff, Dean of Veterinary and Agricultural Sciences at the University of Melbourne is in town for a talk and to chat with prospective graduate students of the Doctor of Veterinary Medicine programme they offer.

All are welcome – join us at LT31 on Froday 22 Aug 2014: 2.30pm!

For directions, see NUS PEACE.

Thanks to Shannon Heo for hosting the talk on behalf of NUS PEACE & NUS DBS.

LSM1103 TAs ready for action as first years introduce themselves to group mates

Blue day!

 

 

 

L-R: Jose Mendoza (Bachelor of Environmental Studies lecturer, N. Sivasothi aka Otterman and Gavan Leong (FTTA General Biology & EVB)

Thu 28 Aug 2014: 10.00am @ DBS Conf Rm I: Goh Seok Ping on “Sociality of spiders of the Genus Anelosimus”

PhD Defense Seminar cum Oral Examination

“Sociality of spiders of the Genus Anelosimus (Araneae: Theridiidae), with focus on species in Southeast and East Asia“

Goh Seok Ping
Graduate Student,
Dept. of Biological Sciences, NUS
Supervisor: Assoc Prof Li Daiqin

Thu 28 Aug 2014: 10.00m
DBS Conference Room (S3 Level 5)

All are welcome

Abstract – 

“The genus Anelosimus (Araneae: Theridiidae) consists of 64 nominal species, of which six are social, 14 subsocial and five solitary, while the sociality of the remaining species are unknown. Although intensive work has been conducted on spiders of this genus in North and South America, little is known about Anelosimus in Asia. As a model system, a comprehensive study of spiders of this genus would further the understanding of sociality in spiders. Therefore, the goal of this thesis was to supplement the knowledge of Anelosimus, with concentration on species found in Southeast and East Asia and to explore factors affecting the evolution of sociality in this genus.

The findings of this study includes nine newly described species. Eleven previously described species were also included and supplemented with photographs, updates of missing male/female descriptions and information on natural history. The natural history of ten species of Anelosimus collected from China, Malaysia and Singapore were also examined, with special focus on traits such as habitat and colony structure, maternal care, cooperative behaviour, dispersal and a number of reproductive traits. Seven of these species were determined to be solitary, while the remaining three species are subsocial. Examination of the sensory receptors in subsocial and solitary species also revealed that subsocial species have a lower density of mechanoreceptors, which may result in lowered sensitivity towards conspecifics, promoting aggregation.

An analysis of the worldwide distribution of 35 Anelosimus species revealed that solitary species tend to occur in habitats with high rainfall and temperature, subsocial species occur in areas with low rainfall and temperatures while social species are commonly found in areas with high rainfall and intermediate temperatures. This may be associated with the ability of web structure to withstand rain damage, prey abundance and effects of temperatures on metabolism and growth of spiders.

Finally the prevalence of parasites in nests of eight Anelosimus species and the presence of the endosymbiotic bacteria Wolbachia 37 species of Anelosimus were tested. Results obtained suggest that cooperative web maintenance from juveniles in subsocial species may aid in reducing the number of parasites in the bigger nests of subsocial spiders. Meanwhile due to solitary spiders’ preference in constructing webs on small wildflowers, there are higher numbers of parasitic organisms such as mites, lepidopteran larva and hymenopterans in their nests. Wolbachia infection was also not found to be widespread amongst Anelosimus species tested. However, infection appears to be more prevalent in social species.

Overall, this study has revealed a high concentration of solitary species and an absence of social species in Southeast and East Asia. Factors such as mechanoreceptor densities, rainfall, temperature and Wolbachia infection have also been found to affect the development of sociality in Anelosimus.”