Flora of the Galapagos Islands

Wiggins, Ira L.; Porter, Duncan M.; Anderson, Edward F.

doi:10.2307/1219253

Cited by 153 publications

(151 citation statements)

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“…Isabela is the largest island (more than 4000 km 2 ) and could be considered highly complex ecologically, or at least equally as complex as the older islands, since each volcano contains all ecological/ vegetation zones found on Santa Cruz and San Cristobal ( Wiggins & Porter 1971;Peck 1991Peck , 1996bPeck , 2005. However despite its area, Isabela does not contribute to Galapaganus species diversity through intra-island speciation but by being colonized multiple times.…”

Section: Discussion (A) Colonization Patternsmentioning

confidence: 99%

Nuclear and mitochondrial sequences confirm complex colonization patterns and clear species boundaries for flightless weevils in the Galápagos archipelago

Sequeira

Sijapati

Lanteri

et al. 2008

Phil. Trans. R. Soc. B

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Nuclear sequence data were collected from endemic Galápagos species and an introduced close relative, and contrasted with mitochondrial DNA sequences, continuing investigation into the colonization history and modes of diversification in the weevil genus Galapaganus. The current combined phylogeny together with previously published penalized likelihood age estimates builds a complex picture of the archipelago's colonization history. The present reconstruction relies on submerged platforms to explain the early divergence of the young southern Isabela endemics or the Españ ola or San Cristobal populations. Diversity is later built through inter-island divergence starting on older islands and continuing on two simultaneous tracks towards younger islands. The amount of diversity generated through intra-island processes is skewed towards older islands, suggesting that island age significantly influences diversity. Phylogenetic concordance between nuclear and mitochondrial datasets and well-supported monophyletic species in mitochondrial derived topologies appear to reject the possibility of inter-species hybridization. These clear species boundaries might be related to the tight host associations of adult weevils in discrete ecological zones. If shared hosts facilitate hybridization, then host-or habitat-promoted divergences could prevent it, even in the case of species that share islands, since the altitudinal partitioning of habitats minimizes range overlap.

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Section: Discussion (A) Colonization Patternsmentioning

confidence: 99%

Nuclear and mitochondrial sequences confirm complex colonization patterns and clear species boundaries for flightless weevils in the Galápagos archipelago

Sequeira

Sijapati

Lanteri

et al. 2008

Phil. Trans. R. Soc. B

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“…(1996); Falkland Islands, Moore (1968), Lawrence et al. (1999); Galapagos Islands, Wiggins & Porter (1971), Hamann (1981), Perry (1984); Hawaiian Islands, Wagner & Funk (1995), Wagner et al. (1999); Juan Fernandez Islands, Skottsberg (1953), Stuessy et al.…”

Section: Methodsmentioning

confidence: 99%

Anagenetic evolution in island plants

Stuessy¹,

Jakubowsky²,

Gómez³

et al. 2006

Journal of Biogeography

176

229

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Aim Plants in islands have often evolved through adaptive radiation, providing the classical model of evolution of closely related species each with strikingly different morphological and ecological features and with low levels of genetic divergence. We emphasize the importance of an alternative (anagenetic) model of evolution, whereby a single island endemic evolves from a progenitor and slowly builds up genetic variation through time. Location Continental and oceanic islands. Methods We surveyed 2640 endemic angiosperm species in 13 island systems of the world, both oceanic and continental, for anagenetic and cladogenetic patterns of speciation. Genetic data were evaluated from a progenitor and derivative species pair in Ullung Island, Korea, and Japan. Results We show that the anagenetic model of evolution is much more important in oceanic islands than previously believed, accounting for levels of endemic specific diversity from 7% in the Hawaiian Islands to 88% in Ullung Island, Korea, with a mean for all islands of 25%. Examination of an anagenetically derived endemic species in Ullung Island reveals genetic (amplified fragment length polymorphism) variation equal or nearly equal to that of its continental progenitor. Main conclusions We hypothesize that, during anagenetic speciation, initial founder populations proliferate, and then accumulate genetic variation slowly through time by mutation and recombination in a relatively uniform environment, with drift and/or selection yielding genetic and morphological divergence sufficient for the recognition of new species. Low‐elevation islands with low habitat heterogeneity are highly correlated with high levels of anagenetic evolution, allowing prediction of levels of the two models of evolution from these data alone. Both anagenetic and adaptive radiation models of speciation are needed to explain the observed levels of specific and genetic diversity in oceanic islands.

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“…Published floras or checklists exist for most oceanic islands, including most of our nine focal archipelagos (e.g. Wiggins and Porter, 1971;Lawesson et al, 1987;Acebes-Ginové s et al, 2004;Silva et al, 2005a;Sá nchez-Pinto et al, 2005;Jardim and Sequeira, 2008 DNA sequence data and other non-morphological traits may be critical for producing more objective classifications. This is especially important for endangered populations, whose taxonomic rank may affect their legal conservation status.…”

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confidence: 99%