Population structure and loss of genetic diversity in the endangered white-headed duck, Oxyura leucocephala

Abstract

The white-headed duck is a globally threatened species native to the Palaearctic with a range extending from Spain in the west to the western edge of China in the east. Its populations have become fragmented and undergone major declines in recent decades. To study genetic differences between populations across the range and change in genetic diversity over time, we sequenced a portion of the mitochondrial DNA control region from 67 museum specimens (years 1861-1976) as well as 39 contemporary samples from Spain and seven from Greece (years 1992Greece (years -2003. In the historical sample, we found a lack of significant genetic structure between populations in different areas. We found evidence that the species experienced a rapid expansion in the past, perhaps from glacial refugia centred around the Mediterranean following the last ice age. In Spain, the population went through a dramatic bottleneck in the 1970s and early 1980s, when only a few dozens individuals remained in the wild. Although population size has since recovered to a few thousand individuals, we found a highly significant loss of mitochondrial haplotype diversity between the historical and contemporary samples. Given ongoing declines in other areas, losses in genetic diversity that may reduce the adaptive potential of white-headed ducks in the future are a continuing concern throughout the geographic range of this species.

Species-Specific Population Structure in Rock-Specialized Sympatric Cichlid Species in Lake Tanganyika, East Africa

“…One sample (T. moorii from Katoto) was about twice as large as the other population samples, and the effect of large sample size on diversity indexes was assessed by random resampling of 30 haplotypes (1000 iterations) from the full sample and recalculation of the diversity indexes. The significance of interspecific differences in diversity was addressed by a Mann-Whitney rank sum test (SIGMASTAT 3.9; SPSS Inc.); differences among populations within species were tested against a null distribution obtained by randomizing haplotypes between populations and recalculation of the indices (Mun˜oz-Fuentes et al 2005). Haplotype genealogies were reconstructed using a statistical parsimony approach with a 95% cutoff as implemented in TCS (Clement et al 2000).…”

Single base errors in PCR products from avian museum specimens and their effect on estimates of historical genetic diversity

“…Museum specimens are valuable sources of DNA whenever sampling of fresh tissue is not possible (e.g., Culver et al 2000;Payne and Sorenson 2002) and for comparisons of current and historical genetic variation (Vallianatos et al 2002;Godoy et al 2004;Johnson et al 2004;Muñ oz-Fuentes et al 2005). Low concentration and quality of DNA, however, can make the genotyping of such samples difficult (Glenn et al 1999;Sefc et al 2003).…”

Spatial and temporal patterns of genetic diversity in an endangered Hawaiian honeycreeper, the Hawaii Akepa (Loxops coccineus coccineus)

“…Such a result has also been seen in coconut crabs (Lavery et al 1996), white-headed ducks (Muñoz-Fuentes et al 2005), and cerulean warblers (Veit et al 2005). In these situations, it seems the historical pattern of growth is fairly robust to further changes in population size, and the population declines have occurred too recently for a new genetic equilibrium to be reached (Lavery et al 1996).…”