Within-population spatial genetic structure in four naturally fragmented species of a neotropical inselberg radiation, Alcantarea imperialis, A. geniculata, A. glaziouana and A. regina (Bromeliaceae)

Autor: Thelma Barbará, Simon Joseph Mayo, Michael F. Fay, Christian Lexer, Gustavo Martinelli, Myriam Heuertz
Přispěvatelé: Jodrell Laboratory, Royal Botanic Garden , Kew, Instituto de Pesquisas, Herbarium, Royal Botanic Gardens, Université libre de Bruxelles (ULB)
Rok vydání: 2008
Předmět:
Zdroj: BASE-Bielefeld Academic Search Engine
Heredity
Heredity, Nature Publishing Group, 2008, 101 (3), pp.285-296. ⟨10.1038/hdy.2008.65⟩
ISSN: 1365-2540
0018-067X
DOI: 10.1038/hdy.2008.65
Popis: International audience; Studies of organisms on 'terrestrial islands' can improve our understanding of two unresolved issues in evolutionary genetics: the likely long-term effects of habitat fragmentation and the genetic underpinnings of continental species radiations in island-like terrestrial habitats. We have addressed both issues for four closely related plant species of the adaptive radiation Bromeliaceae, Alcantarea imperialis, A. geniculata, A. regina and A. glaziouana. All four are adapted to ancient, isolated inselberg rock outcrops in the Brazilian Atlantic rainforest and are thus long-term fragmented by nature. We used eight nuclear microsatellites to study within-population spatial genetic structure (SGS) and historical gene dispersal in nine populations of these species. Within-population SGS reflected known between-species differences in mating systems. The strongest SGS observed in A. glaziouana (Sp=0.947) was stronger than literature estimates available for plants. Analysis of short- and long-distance components of SGS identified biparental inbreeding, selfing and restricted seed dispersal as main determinants of SGS, with restricted pollen dispersal by bats contributing in some localities. The ability of Alcantarea spp. to colonize isolated inselbergs probably stems from their flexible mating systems and an ability to tolerate inbreeding. Short-ranging gene dispersal (average sigma=7-27 m) is consistent with a loss of dispersal power in terrestrial island habitats. Population subdivision associated with sympatric colour morphs in A. imperialis is accompanied by between-morph differences in pollen and seed dispersal. Our results indicate a high potential for divergence with gene flow in inselberg bromeliads and they provide base-line data about the long-term effects of fragmentation in plants.
Databáze: OpenAIRE