The tales of two geckos: does dispersal prevent extinction in recently fragmented populations?

Marion Hoehn, Stephen Sarre, Klaus Henle

    Research output: Contribution to journalArticle

    73 Citations (Scopus)

    Abstract

    Although habitat loss and fragmentation threaten species throughout the world and are a major threat to biodiversity, it is apparent that some species are at greater risk of extinction in fragmented landscapes than others. Identification of these species and the characteristics that make them sensitive to habitat fragmentation has important implications for conservation management. Here, we present a comparative study of the population genetic structure of two arboreal gecko species (Oedura reticulata and Gehyra variegata) in fragmented and continuous woodlands. The species differ in their level of persistence in remnant vegetation patches (the former exhibiting a higher extinction rate than the latter). Previous demographic and modelling studies of these two species have suggested that their difference in persistence levels may be due, in part, to differences in dispersal abilities with G. variegata expected to have higher dispersal rates than O. reticulata. We tested this hypothesis and genotyped a total of 345 O. reticulata from 12 sites and 353 G. variegata from 13 sites at nine microsatellite loci. We showed that O. reticulata exhibits elevated levels of structure (FST=0.102 vs. 0.044), lower levels of genetic diversity (HE=0.79 vs. 0.88), and fewer misassignments (20% vs. 30%) than similarly fragmented populations of G. variegata, while all these parameters were fairly similar for the two species in the continuous forest populations (FST=0.003 vs. 0.004, HE=0.89 vs. 0.89, misassignments: 58% vs. 53%, respectively). For both species, genetic structure was higher and genetic diversity was lower among fragmented populations than among those in the nature reserves. In addition, assignment tests and spatial autocorrelation revealed that small distances of about 500 m through fragmented landscapes are a barrier to O. reticulata but not for G. variegata. These data support our hypothesis that G. variegata disperse more readily and more frequently than O. reticulata and that dispersal and habitat specialization are critical factors in the persistence of species in habitat remnants
    Original languageEnglish
    Pages (from-to)3299-3312
    Number of pages14
    JournalMolecular Ecology
    Volume16
    Issue number16
    DOIs
    Publication statusPublished - 2007

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    Lizards
    Gekkonidae
    Ecosystem
    extinction
    habitat fragmentation
    Genetic Structures
    Population
    genetic variation
    habitats
    autocorrelation
    habitat destruction
    Spatial Analysis
    persistence
    woodlands
    population genetics
    Biodiversity
    conservation areas
    Population Genetics
    demographic statistics
    microsatellite repeats

    Cite this

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    title = "The tales of two geckos: does dispersal prevent extinction in recently fragmented populations?",
    abstract = "Although habitat loss and fragmentation threaten species throughout the world and are a major threat to biodiversity, it is apparent that some species are at greater risk of extinction in fragmented landscapes than others. Identification of these species and the characteristics that make them sensitive to habitat fragmentation has important implications for conservation management. Here, we present a comparative study of the population genetic structure of two arboreal gecko species (Oedura reticulata and Gehyra variegata) in fragmented and continuous woodlands. The species differ in their level of persistence in remnant vegetation patches (the former exhibiting a higher extinction rate than the latter). Previous demographic and modelling studies of these two species have suggested that their difference in persistence levels may be due, in part, to differences in dispersal abilities with G. variegata expected to have higher dispersal rates than O. reticulata. We tested this hypothesis and genotyped a total of 345 O. reticulata from 12 sites and 353 G. variegata from 13 sites at nine microsatellite loci. We showed that O. reticulata exhibits elevated levels of structure (FST=0.102 vs. 0.044), lower levels of genetic diversity (HE=0.79 vs. 0.88), and fewer misassignments (20{\%} vs. 30{\%}) than similarly fragmented populations of G. variegata, while all these parameters were fairly similar for the two species in the continuous forest populations (FST=0.003 vs. 0.004, HE=0.89 vs. 0.89, misassignments: 58{\%} vs. 53{\%}, respectively). For both species, genetic structure was higher and genetic diversity was lower among fragmented populations than among those in the nature reserves. In addition, assignment tests and spatial autocorrelation revealed that small distances of about 500 m through fragmented landscapes are a barrier to O. reticulata but not for G. variegata. These data support our hypothesis that G. variegata disperse more readily and more frequently than O. reticulata and that dispersal and habitat specialization are critical factors in the persistence of species in habitat remnants",
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    The tales of two geckos: does dispersal prevent extinction in recently fragmented populations? / Hoehn, Marion; Sarre, Stephen; Henle, Klaus.

    In: Molecular Ecology, Vol. 16, No. 16, 2007, p. 3299-3312.

    Research output: Contribution to journalArticle

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    AU - Hoehn, Marion

    AU - Sarre, Stephen

    AU - Henle, Klaus

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    AB - Although habitat loss and fragmentation threaten species throughout the world and are a major threat to biodiversity, it is apparent that some species are at greater risk of extinction in fragmented landscapes than others. Identification of these species and the characteristics that make them sensitive to habitat fragmentation has important implications for conservation management. Here, we present a comparative study of the population genetic structure of two arboreal gecko species (Oedura reticulata and Gehyra variegata) in fragmented and continuous woodlands. The species differ in their level of persistence in remnant vegetation patches (the former exhibiting a higher extinction rate than the latter). Previous demographic and modelling studies of these two species have suggested that their difference in persistence levels may be due, in part, to differences in dispersal abilities with G. variegata expected to have higher dispersal rates than O. reticulata. We tested this hypothesis and genotyped a total of 345 O. reticulata from 12 sites and 353 G. variegata from 13 sites at nine microsatellite loci. We showed that O. reticulata exhibits elevated levels of structure (FST=0.102 vs. 0.044), lower levels of genetic diversity (HE=0.79 vs. 0.88), and fewer misassignments (20% vs. 30%) than similarly fragmented populations of G. variegata, while all these parameters were fairly similar for the two species in the continuous forest populations (FST=0.003 vs. 0.004, HE=0.89 vs. 0.89, misassignments: 58% vs. 53%, respectively). For both species, genetic structure was higher and genetic diversity was lower among fragmented populations than among those in the nature reserves. In addition, assignment tests and spatial autocorrelation revealed that small distances of about 500 m through fragmented landscapes are a barrier to O. reticulata but not for G. variegata. These data support our hypothesis that G. variegata disperse more readily and more frequently than O. reticulata and that dispersal and habitat specialization are critical factors in the persistence of species in habitat remnants

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