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Advisor(s)
Abstract(s)
Population genetic structure and diversity and phylogeographical dispersal routes were assessed for the Azorean
endemic grass Deschampsia foliosa using AFLP markers. This species occurs on seven islands in the archipelago
and a sampling of populations from the three main geographical groups of islands was used, covering its known
distribution. Principal coordinates analyses (PCoAs), Bayesian analyses and phylogenetic networks revealed different
degrees of admixture for the central group (C) populations and a clear differentiation for the western group (W) and
São Miguel island (in the eastern group, E) populations. The best K values corresponded to nine and 11 genetic
groups, which were also confirmed by analysis of molecular variance. A low but significant correlation between
genetic data and geography was observed, with most relevant barriers to gene flow generally placed between sub archipelagos. We suggest a west-to-east isolation by distance dispersal model across an island age continuum with
Flores–Corvo (W) and Pico (C) at the extremes of the dispersal path. An alternative scenario, also supported by the
genetic data, implies an initial colonization of São Jorge (C), dispersal within C and following bidirectional dispersal
to the W and E. The phylogeographical framework detected might be related to island age and to highly destructive
volcanic events, and it supports the occurrence of cryptic diversity within D. foliosa. Genetic diversity estimators were
highest for Pico island populations (C), lowest for São Miguel (E) and Flores (W) populations, and more divergent
for the Corvo population (W). Conservation measures should be taken to preserve the genetic structure found across
sub-archipelagos and islands.
Description
Keywords
Azores (Portugal) Açores (Portugal) Conservation genetics Microevolution Phylogeography . Faculdade de Ciências da Vida
Citation
Moura, M., Catálan, P., Brehm, A., & Sequeira, M. M.(2019). Colonization routes, microevolutionary genetic structure and conservation concerns in a remote widespread insular endemic grass: the case of the Azorean tussock grass Deschampsia foliosa. Botanical Journal of the Linnean Society, 191(3), 365-380. https://doi.org/10.1093/botlinnean/boz059
Publisher
Linnean Society of London