The use of non-invasive molecular techniques to confirm the presence of mountain bongo Tragelaphus eurycerus isaaci populations in Kenya and preliminary inference of their mitochondrial genetic variation
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The mountain bongo antelope Tragelaphus eurycerus isaaci has rapidly declined in recent decades, due to a combination of hunting, habitat degradation and disease. Endemic to Kenya, mountain bongo populations have shrunk to approximately 100 individuals now mainly confined to the Aberdares mountain ranges. Indirect observation of bongo signs (e.g. tracks, dung) can be misleading, thus methods to ensure reliable species identification, such as DNA-based techniques, are necessary to effectively study and monitor this species. We assessed bongo presence in four mountain habitats in Kenya (Mount Kenya National Park, Aberdare National Park, Eburu and Mau forests) and carried out a preliminary analysis of genetic variation by examining 466 bp of the first domain of the mtDNA control region using DNA extracted from faecal samples. Of the 201 dung samples collected in the field, 102 samples were molecularly identified as bongo, 97 as waterbuck, one as African buffalo and one as Aders’ duiker. Overall species-identification accuracy by experienced trackers was 64%, with very high error of commission when identifying bongo sign (37%), and high error of omission for waterbuck sign (82%), suggesting that the two species’ signs are easily confused. Despite high variation in the mtDNA control region in most antelope species, our results suggest low genetic variation in mountain bongo as only two haplotypes were detected in 102 samples analyzed. In contrast, the analysis of 63 waterbuck samples from the same sites revealed 21 haplotypes. Nevertheless, further examination using nuclear DNA markers (e.g. microsatellites) in a multi-locus approach is still required, especially because the use of mitochondrial DNA can result in population overestimation as distinct dung samples can potentially be originated from the same individual.
KeywordsBongo antelope Non-invasive genetics Endangered species Genetic diversity mtDNA control region
We thank the Kenya Wildlife Service (KWS) for permission to collect samples and the University of Nairobi, Cardiff University and International Livestock Research Institute for facilitating the study. The Bongo Surveillance Team (BST) led by Michael Prettejohn and the BSP trackers on whose expertise and knowledge of the bongo habitats enabled the collection of the samples, are also thanked. Olivier Hannote and Doreen Adhoch both from International Livestock Research Institute assisted in organizing and shipment of the samples to Cardiff. Katherine Dunbar carried out the preliminary testing of the bongo sequences. The study was funded by the African fund for Endangered Wildlife (AFEW), Rhino Ark Charitable Trust and the Rare Species Conservatory Foundation (RSCF). This study was a part of GDK’s MSc thesis.
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