Colonization Sequence (colonization + sequence)

Distribution by Scientific Domains


Selected Abstracts


Colonization history, ecological shifts and diversification in the evolution of endemic Galápagos weevils

MOLECULAR ECOLOGY, Issue 4 2008
A. S. SEQUEIRA
Abstract Mitochondrial DNA sequence data were obtained for eight species of flightless Galapaganus endemic weevils and one winged close relative in order to study their colonization history and modes of diversification in the Galápagos Archipelago. Contrary to most other insular radiations, the phylogeny estimates we recovered for Galapaganus do not follow the progression rule of island biogeography. The penalized likelihood age estimates of colonization of the archipelago exceed the age of the emerged islands and underscore the potential role of now sunken seamounts for the early evolution of Galapaganus. The phylogeny proposes one intra-island origin for Galapaganus endemics, but monophyly tests suggest a larger contribution of in-situ speciation on older islands. Generalist habitat preferences were reconstructed as ancestral while shifts to highland habitats were reconstructed as having evolved independently on different islands. Magnitudes and patterns of diversification rate were found to differ between older and younger islands. Our analyses reveal that the colonization sequence of islands and timing of colonization of Galapaganus could be linked with the geological and volcanic history of the islands in a rather complex scenario. Even though most islands appear to have been colonized soon after their emergence, there are notable deviations from the pattern of sequential colonization expected under the progression rule when considering only the extant emerged islands. Patterns of diversification rate variation on older and younger islands correspond to the volcanic activity or remnants of such activity, while the pattern of independent evolution of restricted habitat preferences in different islands suggests that habitat shifts could also have contributed to species diversity in Galapaganus. [source]


Tracking island colonization history and phenotypic shifts in Indian Ocean bulbuls (Hypsipetes: Pycnonotidae)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2005
BEN H. WARREN
Molecular phylogenies of island organisms provide useful systems for testing hypotheses of convergent or parallel evolution, since selectively neutral molecular characters are likely to be independent of phenotype, and the existence of similar environments on multiple isolated islands provides numerous opportunities for populations to evolve independently under the same constraints. Here we construct a phylogenetic hypothesis for Hypsipetes bulbuls of the western Indian Ocean, and use this to test hypotheses of colonization pattern and phenotypic change among islands of the region. Mitochondrial sequence data were collected from all extant taxa of the region, combined with sequence data from relevant lineages in Asia. Data are consistent with a single Hypsipetes colonization of the western Indian Ocean from Asia within the last 2.6 Myr. The expansion of Hypsipetes appears to have occurred rapidly, with descendants found across the breadth of its western Indian Ocean range. The data suggest that a more recent expansion of Hypsipetes madagascariensis from Madagascar led to the colonization of Aldabra and a secondary colonization of the Comoros. Groupings of western Indian Ocean Hypsipetes according to phenotypic similarities do not correspond to mtDNA lineages, suggesting that these similarities have evolved by convergence or parallelism. The direction of phenotypic change cannot be inferred with confidence, since the primary expansion occurred rapidly relative to the rate of mtDNA substitution, and the colonization sequence remains uncertain. However, evidence from biogeography and comparison of independent colonization events are consistent with the persistence of a small grey continental bulbul in India and Madagascar, and multiple independent origins of large size and green plumage in insular island populations of the Comoros, Mascarenes and Seychelles. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 271,287. [source]


Colonization of an island volcano, Long Island, Papua New Guinea, and an emergent island, Motmot, in its caldera lake.

JOURNAL OF BIOGEOGRAPHY, Issue 11-12 2001

Abstract Biogeographical context Long Island, in Vitiaz Strait, is 55 km north of New Guinea, 60 km from Umboi Island and 125 km from New Britain. After its explosive caldera-forming eruption in about 1645, Long is being recolonized by animals and plants. Through renewed volcanic activity in the 1950s a new island emerged from Long's caldera lake, 4 km from the nearest lake shore and was recreated by eruptions in 1968. Long Island thus provides the opportunity to study a nested pair of natural colonization sequences. The geological background, eruptive history, course and results of the seventeenth century eruption, and the geographical features and climate of Long Island are summarized. Existing knowledge of Long's recolonization, confined almost entirely to surveys of its avifauna in 1933 and 1972, is reviewed. The geological history of Motmot is outlined, and published knowledge of its colonization by animals and plants from 1968 to 1988 is summarized. The 1999 expedition and aims An expedition to Long Island and Motmot in 1999 set out to investigate the hitherto little-known flora and present vertebrate fauna of Long Island and to survey the entire flora and fauna of Motmot for comparison with the results of previous surveys. The methods used in the 1999 survey are described, and the papers setting out the results briefly introduced. [source]


Colonization of an island volcano, Long Island, Papua New Guinea, and an emergent island, Motmot, in its caldera lake.

JOURNAL OF BIOGEOGRAPHY, Issue 11-12 2001

Abstract Location, Aim Long Island, 55 km north of New Guinea, erupted explosively in the seventeenth century and has been recolonized by animals and plants. Effectively in 1968, an island, Motmot, emerged from Long's 13 km-diameter fresh-water caldera lake, about 4 km from the nearest shore. A nested pair of colonization sequences is thus available for study. Long Island has been recolonized by birds, and Motmot has been colonized, presumably from the surrounding ring of Long Island. In order to monitor further colonization of Long Island following bird surveys in 1933 and 1972, and to survey the birds of Motmot, Motmot and the western parts of Long were visited for 15 days in 1999. Results In the last 66 years one species probably has become extinct; in the past 27 years three species have colonized and three, present in 1972, were not recorded in 1999. We assess the present number of nonmigrant land bird species as fifty. On Motmot, we recorded eight species, three breeding, and found two more only as prey remains (three raptor species were seen on the island). Main conclusions Long Island's avifauna still has youthful features. Species with good colonizing ability predominate, and there are no island-endemic subspecies. There is a persistently high proportion of supertramps; none of the ten supertramps has been replaced by later-colonizing ,high-S' species. A quasi-equilibrium of about fifty species, fourteen fewer than the predicted equilibrium number for the island, has persisted for at least seven decades and may be seen as that appropriate to the present prolonged stage of Long's floral and vegetational development. Compared with the younger avifauna of Krakatau, Long's avifauna has a higher proportion of nectarivores, predators of large invertebrates and small vertebrates, and ground-foraging insectivore-herbivores, and a lower proportion of the insectivore-frugivore guild. Motmot's small avifauna consists predominantly of species obtaining subsistence from outside the island. [source]