PhD Defense Seminar cum Oral Examination
Bridging in situ and ex situ conservation with genomics and stakeholder management: case studies of the Southern River Terrapin (Batagur affinis) and the Burmese Roofed Turtle (Batagur trivittata)
Speaker: Cilingir Fatma Gozde (Graduate Student Dept.of Biological Sciences, NUS)
Date: 8 December 2017, Friday
Venue: Seminar Room 1 (S2 Level 4 #04-14)
Supervisor: Asst Prof Rheindt, Frank E
Abstract – Turtles are one of the most endangered vertebrates suffering from the effects of human-caused extinction wave currently underway. Batagur affinis and Batagur trivittata are among the World’s 25 most endangered freshwater turtle species. The major portion of B. affinis is currently found in the Peninsular Malaysia. The only remnant Indochinese population was found in Southern Cambodia. For more than a decade the wild eggs were collected from this population and were reared in captivity. I amplified 10 microsatellite markers, obtained >2000 Single Nucleotide Polymorphisms (SNPs) via Double Digest Restriction Associated DNA Sequencing (ddRAD-seq) and amplified two mtDNA markers aiming to determine genetic structure and diversity of this population, estimate the number of active wild breeders, to compare the performance of the traditional and the genomic markers regarding these aims.
My results showed that Indochinese portion of the species comprises of only 4 kinship groups as of 2012, and the entire offspring were sired from <10 individuals in the wild. I demonstrated an obvious decrease in genetic contributions of the breeders in the wild from 2006-2012, identified high-value breeders with the outperformance of the genomic markers against the traditional ones and genetically managed the contemporary genetic stock of the species. Unlike B. affinis, only one wild population of B. trivittata remains in Myanmar. I sampled ~40% of the turtles’ remaining global population, applied ddRAD-Seq, and obtained ~1500 SNPs. Individuals fell into 5 distinct genetic clusters, four of which represented full-sib families. I inferred a low effective population size (≤10 individuals) but did not detect signs of severe inbreeding, possibly because the population bottleneck occurred recently. Two groups of 30 individuals from the captive pool that were the most genetically diverse were reintroduced to the wild, leading to an increase in the number of fertile eggs (n=27) in the wild. Another 25 individuals, selected based on the same criteria, were transferred to the Singapore Zoo as an assurance colony. Obviously, the biological extinction of B. trivittata will be achieved by in situ and ex situ conservation efforts, should they be combined with the support of local people.
Accordingly, I visited 29 villages located along the upper Chindwin River, where the wild population of B. trivittata occurs. I conducted semi-structured surveys designed to examine local perceptions, attitudes, and awareness towards B. trivittata conservation, and understand local patterns of turtle/egg consumption. My findings indicate that more than half of the respondents can correctly identify B. trivittata, and the majority has some sense of decline occurred >15 years ago due to collection of eggs and hunting adults. No cases of B. trivittata egg consumption in the last 10 years and no information about their sale in the local markets were reported. The majority are willing to contribute toward turtle conservation, and 95% do not think that turtle conservation efforts restrict their daily lives. Therefore, I concluded that there is no significant cost for local people to oppose B. trivittata conservation.
I believe that this study is a great example of how academic study may translate into actual conservation efforts supported by local people. This multi-disciplinary approach promises to enhance current conservation practices of the other endangered turtles and guide future conservation efforts for other endangered species.”
All are welcome