| Abstract |
- Aim: The ecological effects of biological invasions are well documented, but little
is known about the effects of invaders on the genetic structure of native
species. We examined the phylogeography, genetic variation and population
structuring of two galaxiid fishes, Aplochiton zebra and A. taeniatus, threatened
by non-native salmonids, and whose conservation is complicated by misidentification
and limited knowledge of their genetic diversity.
Location: Chile and the Falkland Islands.
Methods: We combined microsatellite and mitochondrial DNA (16S rDNA and COI) markers to compare genetic diversity, effective population size and gene flow of Aplochiton spp. populations differentially affected by salmonid presence.
Results: We identified two 16S rDNA haplotypes among A.zebra - one dominant in coastal populations and another dominant in inland populations. Populations living on the island of Chiloe displayed a mixture of coastal and inland haplotypes, as well as high microsatellite diversity, as one would expect if the island had been a refugium during the Last Glacial Maximum, or a contact zone among populations. Microsatellite data revealed strong population structuring, indicative of current isolation patterns, and a negative correlation between the genetic diversity of A.zebra and the relative abundance of invasive salmonids.
Main conclusions: Our study indicates that population structuring of A.zebra reflects the influence of historical patterns of migration, but also the current levels of reduced gene flow among watersheds. Invasive salmonids, known to compete with and prey on native galaxiids, may have had negative impacts on the genetic diversity of Aplochiton spp. The low genetic variation found in some populations, coupled with potential biases in abundance estimates due to species misidentification, highlight the urgent need for more research into the conservation status of the two species of Aplochiton.
- Keywords: phylogeography, salmonids, mtDNA, post-glacial colonization, Aplochiton, biological invasions, microsatellites, gene flow
- Keywords: phylogeography, salmonids, mtDNA, post-glacial colonization, Aplochiton, biological invasions, microsatellites, gene flow
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