Genetic and morphological differentiation between remnant populations of an endangered species: the case of the Seychelles White‐eye

Abstract

The Seychelles White‐eye Zosterops modestus is a critically endangered species that survives in two remnant populations on the islands of Mahé and Conception. Multilocus minisatellite DNA fingerprinting and morphometric measurements were used to assess the levels of variation between these populations. Mahé White‐eyes are on average significantly larger than Conception birds, as are males compared to females. The mean level of bandsharing (c. 60%) indicates low levels of genetic variability within both populations. Bandsharing is significantly lower between populations (32%), suggesting that the two populations are genetically isolated from each other, and that one is not a subsample from the other. Both populations should therefore be considered as equally important genetic reservoirs that deserve to be safeguarded. Although each population appears locally adapted to its particular island environment, such limited differentiation is not considered of major taxonomic significance. Recombining genetic variation by mixing individuals from both populations may be beneficial for the species in view of future island transfers. This illustrates the importance of investigating differentiation between remnant populations of a threatened species to orientate future conservation and management measures.

Genetic variation in two endangered Acrocephalus species compared to a widespread congener: estimates based on functional and random loci

“…This estimate is in line with previous data from this species (Komdeur, Kappe & van de Zande, 1998;Richardson & Westerdahl, 2003). Similar low levels of variation have been found in populations of some other endemic island species, for example, Californian channel island foxes, Urocyn littoralis (Gilbert et al, 1990), Laysan finch, Telespitza cantans (Tarr, Conant & Fleischer, 1998), Mariana crow, Corvus kubaryi (Tarr & Fleischer, 1999) and Seychelles white-eye, Zosterops modestus (Rocamora & Richardson, 2003; see also studies reviewed therein). It is plausible that most of the genetic variation was depleted during the recent bottleneck that the SW went through (Komdeur et al, 1998;Richardson & Westerdahl, 2003), but also earlier undocumented bottlenecks are very likely to have occurred in the isolated and fragmented island habitat provided by the Seychelles islands.…”

Genetic and Morphological Differences Among Populations of the Bonin Islands White-eye in Japan

“…These observations suggest that open habitats, as well as water, can be a dispersal barrier for the Bonin Islands White-eye. Although a low frequency of over-sea dispersal has been indicated for the Australian White-eye, Z. lateralis, and the Seychelles Grey White-eye, Z. modestus (Degnan and Moritz, 1992;Degnan, 1993;Rocamora and Richardson, 2003), this is the first time such restricted migration between such close islands has been detected in white-eyes.…”

Giraffe translocation population viability analysis

“…Few studies have thoroughly monitored source and translocated populations for changes in genetic parameters such as heterozygosity, allelic richness, and the rate or level of inbreeding (Groombridge et al 2012, Puckett et al 2014. Ideally, genetic variability should be assessed in source populations in advance of translocations to use genetic information to guide translocation plans and to provide a contrast to posttranslocation genetic studies (Rocamora & Richardson 2003, Biebach & Keller 2010. This is particularly important if there is reason to assume that the source population already has low genetic diversity, for example, because it was established through translocations or because it was a long-isolated population of only a few hundred individuals.…”