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

A Jha,K Vasudevan

doi:10.3354/esr01062

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’sDand Fu’sFsand small positive value of Ramos-Onsins and Rozas’R2suggest 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. Although 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.

Highlights

The yellow-throated bulbul Pycnonotus xantholaemus (YTB) is a habitat specialist, threatened passerine endemic to peninsular India
It has been described as a rare and sedentary species (Subramanya et al 2006). Such species are likely to show population structuring due to limited genetic exchanges between populations. They face the threat of stochastic extinction due to small population size effects
Our data show that YTB has high genetic diversity and there is no structure in the populations

Summary

Introduction

The yellow-throated bulbul Pycnonotus xantholaemus (YTB) is a habitat specialist, threatened passerine endemic to peninsular India. It is predominantly associated with scrub forests on hill slopes with exposed rocky outcrops and has patchy distribution across its geographical range (Ali & Ripley 1987, Subramanya et al 2006). Molecular markers provide important measures to explore population genetic structure and geographic differentiation (Avise 1994). They have been employed to understand evolutionary processes and suggest appropriate conservation measures (Avise 1994). There have been few studies on Pycnonotus bulbuls utilizing variation in mtDNA sequences to understand the genetic structure in the population (olive-winged bulbul P. plumosus; Tang et al 2016, and light-vented bulbul P. sinensis; Song et al 2013)

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Results

Conclusion