Demographic history of the fragmented yellow-throated bulbul (Pycnonotus xantholaemus) population in the Deccan Peninsula, India

Abstract

The yellow-throated bulbul (YTB) is an endemic passerine restricted to scrub forests along hill slopes with exposed rocky outcrops in the Deccan Peninsula, India. It is found in small, discontinuous populations and is vulnerable to extinction due to ongoing habitat loss and subsequent population decline. To assess the genetic connectivity and past demography, we sequenced 1050 nucleotide base pairs of the mitochondrial control region of 60 individuals that represent distinct populations in the geographic range of the species. We recovered 39 haplotypes defined by 81 variable sites. Haplotype diversity was high with low nucleotide diversity, suggesting rapid population growth from a founder population with a small effective population size. The negative values of Tajima's D and Fu's Fs and small positive value of Ramos-Onsins and Rozas’ R2 suggest deviation from neutrality and population expansion. The haplotype network and demographic expansion parameters further suggest historical population expansion. Mismatch analysis statistics and Bayesian skyline plots estimate population expansion during the late Pleistocene. Al though the species presently occurs in small, disconnected we found no structuring of the population. Dispersal events are the most likely explanation for the absence of genetic structuring in the YTB population. These results represent important data for the design of a conservation plan for this endemic and globally threatened species.