Assessment of genetic variation for conservation implications in the Critically Endangered Bawean Deer Axis kuhlii Temminck, 1836  (Mammalia: Artiodactyla: Cervidae)

Abstract

The Bawean Deer Axis kuhlii, endemic to the small Indonesian island of Bawean, is listed as ‘Critically Endangered’ with fewer than 250 mature individuals remaining in the wild. The first genetic assessment of captive A. kuhlii populations using 13 microsatellite markers were conducted. Samples included individuals from Bawean, multiple Indonesian zoos, and a European zoo. The goals were to assess genetic diversity and to test for potential hybridisation with Rusa unicolor and Rusa timorensis, due to frequent mixed-species housing in Javan facilities. STRUCTURE analysis revealed no evidence of hybridisation and identified three genetic clusters within A. kuhlii, likely reflecting drift and kinship effects. Genetic diversity was low across all A. kuhlii samples, but slightly higher in the Bawean population. Some alleles present in Java zoo populations were absent from Bawean. These findings suggest that while inbreeding may be a concern, managed translocation between captive and wild populations could enhance genetic diversity without introducing hybridisation risk. Targeted integration of ex-situ individuals and the inclusion of wild-caught stags into the Bawean breeding program are recommended to support genetic rescue efforts and long-term population viability.