Thu 26 April 2018: 10.00am [QE] – Kenny Chua on “Freshwater fish diversity and ecosystem functioning in Southeast Asia”

Department of Biological Sciences, NUS
Qualifying Examination

Freshwater fish diversity and ecosystem functioning in Southeast Asia

Speaker:    Kenny Chua Wei Jie (Graduate Student, Dept. of Biological Sciences, NUS)
Date:            26 April 2018, Thursday
Time:              10am
Venue:             DBS Conference Room  (S3 Level 5, #05-01)
Supervisor:     Asst Prof Darren Yeo Chong Jinn

Abstract: – The highly diverse ichthyofaunas of Southeast Asian fresh waters are threatened by land-use change, resulting in declines in species richness. Given the ecological importance of freshwater fishes, the loss of their diversity is expected to alter ecosystem functioning—i.e., pools and fluxes of biogeochemical resources—but these potential impacts remain poorly understood in Southeast Asia. To address this knowledge gap, I aim to elucidate the relationship between freshwater fish diversity, ecosystem functioning and land-use change in Southeast Asia.

By characterising and analysing the variation in functional traits of freshwater fishes, my work will investigate mechanistic links between freshwater fish diversity and the ecosystem functions mediated by them. I will also conduct both cross-sectional and longitudinal field studies across Southeast Asia to quantify the impacts of land-use driven fish diversity losses on the functioning of flowing fresh waters in the region. Since ecosystem functions ultimately underpin ecosystem services that are essential for human well-being, knowledge gained from this study will help illuminate the potentially far-reaching and reflexive consequences of anthropogenic biodiversity loss.

All are welcome

Fri 13 Apr 2018: 10.00am [PhD defense] – Muhammad Izuddin Bin Mohamad Rafee on “Conservation of epiphytic orchids in urbanised tropical environments”

PhD Defense Seminar cum Oral Examination

ConservIzuddin.jpgation of epiphytic orchids in urbanised tropical environments

Speaker:       Muhammad Izuddin Bin Mohamad Rafee (Graduate Student Dept. of Biological Sciences, NUS)
Date:             13 April 2018, Friday
Time:             10am
Venue:          DBS Conference  Room (S3 LEVEL 5, #05-01)
Supervisor:   Assoc Prof Edward L. Webb

Abstract – 

“As urban expansion persists, preserving biodiversity becomes progressively difficult. Yet, ex situ methods can facilitate biodiversity conservation in urban spaces. However, species-specific niche requirements—particularly in urbanised environments—remain largely unknown, making ex situ conservation programmes ineffectual. Using native epiphytic orchids as a study system, I assessed two primary ecological barriers to orchid regeneration in urban habitats, namely availability of orchid mycorrhizal fungus / fungi (OMF) as well as the niche requirements of OMF and native orchids.

First, I assessed the availability of OMF on urban trees and the orchid-site suitability of various orchid species by conducting metabarcoding and next-generation sequencing on tree bark and orchid samples. I also identified biophysical factors that influenced OMF presence and richness on urban sites.

Second, I investigated the germination niches—i.e. compatible OMF and suitable biophysical conditions—of four orchid species by conducting orchid mycorrhizal fungal baiting and seed sowing experiments. I then assessed the potential for aboveground orchid seed banks (seed longevity) using seed viability tests on post-experimental, non-germinated seeds.

Third, I evaluated the effectiveness of managed relocation of multiple native orchid species in various urban habitats via long-term planting experiments, as well as identified species post-germination niche requirements that influenced the long-term survival and growth of translocated orchids.

My results indicated that OMF are present on urban trees. However, presence, diversity, and distribution of OMF were primarily constrained by biophysical factors. Urban trees can support germination niches for native epiphytic orchids as well. I also found evidence of seed bank formation on epiphytic microsites. Based on the long-term study, majority of the species showed survival and positive growth. Overall, this thesis demonstrates how species-specific niche requirements can be evaluated / quantified and how the information gained can benefit ex situ, as well as in situ, orchid conservation.”

All are welcome


Mon 23 April 2018: 11.00am [QE] – Lionel Ng on “Functional characterisation of coral species for enhancing reef restoration”

Department of Biological Sciences, NUS
Qualifying Examination

Functional characterisation of coral species for enhancing reef restoration

Speaker:              Ng Chin Soon Lionel (Graduate Student, Dept. of Biological Sciences, NUS)
Date:                   23 April 2018, Monday
Time:                   11am
Venue:                DBS Conference room  (S3 Level 5)
Supervisor:        Asst Prof Huang Danwei
Co-Supervisor:  Prof Chou Loke Ming

Abstract: – The global decline of coral reefs has necessitated active management strategies in the form of restoration and rehabilitation. Despite the emphasis on reinstating taxonomic diversity on degraded reefs, there is limited understanding on how such actions and the species used collectively contribute to reef ecosystem functioning. This could be addressed by adopting a trait-based approach to reef restoration, but this is hampered by a general paucity of available information on coral traits.

My thesis focuses on characterising the functional traits of reef stony corals to prioritise species for the rehabilitation of Singapore’s degraded reefs. Broadly, I aim to: 1) establish species distributions across Singapore’s coral habitats, 2) investigate species responses to bleaching, 3) quantify coral growth rate and skeletal density, and 4) examine stakeholder inputs towards reef restoration. The data obtained will be incorporated into a decision-making framework so that relevant and effective restoration strategies can be formulated.

The research is expected to enhance coral reef management in Singapore, and is applicable to other coastal cities seeking to optimise their habitat rehabilitation strategies.

All are welcome

Fri 20 Apr 2018: 2.00pm [QE] – Jenny on “Competitive interactions between scleractinian corals and macroalgae on heavily impacted reefs”

Department of Biological Sciences, NUS
Qualifying Examination

Competitive interactions between scleractinian corals and macroalgae on heavily impacted reefs

Speaker:              Jenny (Graduate Student, Dept. of Biological Sciences, NUS)
Date:                    20 April 2018, Friday
Time:                    2pm
Venue:                 DBS Conference Room II (S1, Level 3, mezzanine
Supervisor:          Assoc Prof  Peter A. Todd
Co-Supervisor:   A/P Suresh Valiyaveettil

Abstract: – Coral reef ecosystems are in global decline with macroalgae commonly replacing many scleractinian corals. On heavily impacted coral reefs where nutrients are elevated and herbivory is low, high levels of competitive interactions between corals and macroalgae are predicted. Macroalgae are able to suppress coral survival, growth, and reproduction, which can potentially lead to phase-shifts from coral- to algae-dominated reefs. The dynamics of coral–macroalgal interactions and the mechanisms involved, however, remain poorly understood.

My PhD thesis aims to (1) assess the spatial–temporal patterns of coral–macroalgal interactions on Singapore’s reefs, (2) examine the effects of macroalgal competition on coral physiology and microbiomes across various coral–macroalgal pairings, and (3) investigate the allelopathic effects of macroalgae as the potential mechanism mediating coral–macroalgal competition. My research will help improve our understanding on processes regulating coral–macroalgal competition and hence the long-term benthic community structure on impacted coral reef ecosystems.

All are welcome

Thu 12 Apr 2018: 3.00pm [QE] – Wong Boon Hui on “The evolution of enlarged chelicerae in the ant-mimicking jumping spiders”

Department of Biological Sciences, NUS
Qualifying Examination

The evolution of enlarged chelicerae in the ant-mimicking jumping spiders

Speaker:            Wong Boon Hui
Date:                  12 April 2018, Thursday
Time:                 Time: 3pm
Venue:               S3-05 DBS Conference Room
Supervisor:      Assoc Prof Li Daiqin

Abstract: – Exaggerated weapons have persisted through the animal evolutionary tree, having evolved on multiple occasions. This study is to examine the evolution of weapons, which are the enlarged chelicerae, in the ant-mimicking jumping spiders, Myrmarachne spp., through the analysis of its allometry, trade-off, compensation, and selection mode across the phylogeny, with focus on the family Salticidae, followed by the genera Myrmarachne. As we established the evolutionary history, I will proceed to evaluate the cost and benefit of developing and carrying such weapon. Food resources and moulting behaviour are proposed as the cost while sexual selection, comprising male-male competition and female mate choice, is proposed as the benefit.

As to verify enlarged chelicerae being an honest signal, which is limited by cost, I will conduct experiment to show that nutritional level of the spider diet will affect the size of the chelicerae. As the spiders only carry weapons after their final moult, I will also investigate whether weapon size affects moulting duration, as moulting is known to be an energetically costly process.

As for the benefit, male-male competition is tested by pairing size-matched males against each other in contest experiments to test whether chelicera size affect contest outcome. Pairs of males will then be presented to females to see if female spiders have a preference over males with different chelicera sizes. These two experiments will indicate whether enlarged chelicerae are employed as honest signal for resource holding potential (RHP) and/or as mate potential.

All are welcome

Thu 01 Feb 2018: 3.00pm [PhD Defense] – Francesca Louise Mcgrath on “How payments for ecosystem services impact social equity”

PhD Defense Seminar cum Oral Examination
Department of Biological Sciences, NUS

How payments for ecosystem services impact social equity

Speaker:      Francesca Louise Mcgrath (Graduate Student Dept.of Biological Sciences, NUS)
Date:           1 Feb 2018, Thursday
Time:           3pm
Venue:        DBS Conference Room 1
Supervisor: Asst Prof Carrasco T L Roman

Abstract –  “Payments for Ecosystem Services (PES) schemes have become an attractive and widely used instrument for environmental conservation. Ensuring that PES schemes are equitable, fair and just for all involved is of growing interest in the PES literature and to practitioners. In my PhD, I identify the mechanisms (social, spatial, institutional) that can negatively influence equity outcomes and propose ways to overcome them. Each of my PhD chapters broadly discusses either in part of fully, four key areas related to equity namely: 1. how participants are engaged, 2. information dissemination, 3. social impacts and 4. potential trade-offs.

My first chapter investigates the relationship between scheme characteristics and equity outcomes, found within real-life case studies. In my second chapter, using a well-established PES scheme in Sumberjaya, Indonesia, I explore the relationship between farmer characteristics and their perceived auction fairness/satisfaction and impacts on the community social dynamics. My third and fourth chapters use a longstanding PES scheme in Cidanau, Indonesia, as a case study. In this third chapter I explore the differences in social capital between participants and non-participants. While In my fourth chapter, I investigate the implications of spatially targeting PES participants based on equity, understanding, perceptions, and compliance. The results from this thesis can help academics, PES proponents and organizers understand the complex relationships between PES and equity.”

All are welcome


Thu 25 Jan 2018: 10.00am [Phd Defense] – Seshadri Kadaba Shamanna on “Discovery, parental care and conservation of frogs in the Western Ghats of India”

PhD Defense Seminar cum Oral Examination
Department of Biological Sciences, NUS

“Discovery, parental care and conservation of frogs in the Western Ghats of India”

Speaker:            Seshadri Kadaba Shamanna  (Graduate Student, Dept. of Biological Sciences, NUS)
Date:                  25 Jan 2018, Thursday
Time:                  10am
Venue:               DBS Conference room  (S3 Level 5, #05-02)
Supervisor:        Asst. Prof. Frank E. Rheindt

Abstract –  Amphibians are a diverse group of vertebrates that are relatively understudied with nearly 30% of them being discovered only in the last decade. Globally, a third of all amphibians are already threatened with extinction and the need to rigorously document their natural history and ecology is imperative. Thus, my thesis is focused on bridging our knowledge gaps about frogs. It was undertaken in the Western Ghats of India, a renowned biodiversity hotspot where amphibians are underrepresented in research.

Specifically, I report the discovery of two hitherto undescribed species belonging to two families and reappraise the descriptions of three other extant frogs. I then document a novel behaviour in two species wherein the adult frogs of Raorchestes ochlandrae and Raorchestes aff. chalazodes (Rhachophoridae) enter bamboo stalks via narrow openings and lay direct developing eggs and provide parental care to developing embryos inside the bamboo internodes. This behaviour is unique among all extant anurans and is described as a novel reproductive mode.

Subsequently, I focused on the behaviour of R. aff. chalazodes and to do so, required an effective tool for which, I undertook a mini-review of methods used to study animals dwelling in cavities. This enabled me to choose endoscopes to study the behaviour of R. aff chalazodes.

I then established the evolutionary significance of parental care behaviour in R. aff chalazodes using insitu adult removal experiments and found that conspecific males cannibalized unattended eggs. Unattended eggs were also eaten by ants, parasitized by flies, and died from fungal infections or drowned. Thus, male parental care behaviour in form of egg attendance, egg guarding and, oviposition site defence increases offspring survivorship.

With an ultimate goal of conserving R. aff chalazodes, I predicted the potential geographic distribution using species distribution modelling. Finally, my contributions are summarized in the context of existing knowledge about diversity and reproductive ecology of amphibians to identify avenues for further research.

All are welcome