Belambangan Biosphere Reserve supports wildlife corridors: Evidence from population genetics of Rusa deer (Cervus timorensis) in Java, Indonesia

Faculty of Forestry, Universitas Gadjah Mada, Jl. Agro No.1 Bulaksumur, Sleman, Yogyakarta 55281, Indonesia

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Abstract

The conservation of genetic diversity within a biosphere reserve requires landscape connectivity. Recent assessments focus mainly on gene exchange studies. Here, we present the population genetics of an endemic Rusa deer (Cervus timorensis) in the Belambangan Biosphere Reserve (BBR), Indonesia. This research evaluated variation, population structure, and genetic admixture using microsatellite markers from non-invasive samples collected in 2022 at Baluran, Meru Betiri, Alas Purwo, and Bali Barat. DNA amplified at seven loci, with amplicon length as an allele identifier. Results showed high genetic variation, with no linkage disequilibrium, high polymorphism, and a heterozygote deficit. The deer's genetic diversity was low to moderate (H_e=0.28-0.59; H_o=0.02-0.34; N_a=1.86-3.43), likely due to population declines evidenced by a bottleneck test. Shared alleles across subpopulations indicated gene flow, with low differentiation (F_st = 0.15). Migration and admixture helped maintain diversity and prevent allelic loss, restoring genetic variation after declines. This study improved conservation genetics in the reserve and highlights the importance of promoting landscape connectivity within the BRR.