The endangered Formosan flying fox – the largest bat found in Taiwan – was once abundant on Green Island. Using genomic tools, the research group led by Dr. Wen-Ya Ko from the Department of Life Sciences and Institute of Genome Sciences at National Yang Ming Chiao Tung University (NYCU) showed that the effective population size of the Formosan flying fox in Taiwan could be as small as 200. The population has declined dramatically under severe ecological pressure during the last few decades.
Collaborated with Dr. Masako Izawa from the University of the Ryukyus (UR), Dr. Teruo Kinjo from the Okinawa Zoo and Museum, Dr. Shiang-Fan Chen from the National Taipei University, and Dr. Hsi-Chi Cheng from the Endemic Species Research Institute, the NYCU research group successfully obtained sufficient genetic variants from three samples of Formosan flying fox (provided by Taipei Zoo) and four samples of Orii’s flying fox.
Based on the allele frequency spectrum constructed from genomic data, the effective population size of Formosan flying fox was estimated to decline from 2324 to 223 about 28 years ago, which suggests that hunting pressure or habitat loss in the past had caused a severe population decline on Green Island rather than habitat abandon by the Formosan flying fox.
In contrast, the Orii’s flying fox on Ryukyu Island has expanded their population about five times (from 2110 to 9547) thousands of years ago. The distinct demographic history of these two closely related populations delineates the urgent conservation threat of the Formosan flying fox. “Population sizes of these two populations were estimated to be similar in the past, it is evident that the critically endangered conservation status of the Formosan flying fox was caused by anthropogenic threats that was relatively small in the Ryukyus,” commented by Dr. Wen-Ya Ko, who led this research project.
Dr. Wen-Ya Ko is an assistant professor at NYCU. He said that it is quite a challenge to infer the demographic history based on such small sample size, especially given that there is no reliable reference genomic sequences for this endangered species. The methods developed in this work can also be applied to other endangered species that is hard to collect samples. This research is supported by the Ministry of Science and Technology and the Forestry Bureau, Council of Agriculture, Taiwan and published on the peer-reviewed journal “Journal of Heredity”.