Mostrando recursos 1 - 5 de 5

  1. Spatial Variation in Density and Total Size Estimates in Fragmented Primate Populations: The Golden-Crowned Sifaka (Propithecus tattersalli)

    Quemere, E.; Champeau, J.; Besolo, A.; Rasolondraibe, E.; Rabarivola, C.
    The golden-crowned sifaka (Propithecus tattersalli) is an endangered lemur species found only in the Daraina region, a very restricted area in north-eastern Madagascar. Its forest habitat is highly fragmented and expected to suffer from significant changes in the near future. The species is poorly known and only one census study, carried out in 2000, has ever been published. It is thus crucial to update the conservation status of the golden-crowned sifaka. before major anthropogenic environmental changes take place. Using the line-transect approach, we estimated the species density in the main forest fragments located in both the peripheral and central parts...
    - 30-oct-2013

  2. The utility of existing passerine microsatellite markers for genetic studies in endangered species: as demonstrated for a critically endangered forest bird endemic to Réunion Island, the Réunion cuckooshrike (Coracina newtoni)

    Salmona, J.; Dawson, DA.; Fouillot, D.; Ghestemme, T.; Thebaud, C.; Chikhi, L.; Salamolard, M.
    Genetic data are increasingly recognized for their utility in conservation programs. However, many endangered species belong to families that have been understudied. Due to the urgency of their conservation status it is important to quickly identify polymorphic microsatellite loci from available resources. We show for the Re´union Cuckoo shrike Coracina newtoni, that this strategy can be very useful. Using 110 passerine microsatellite primer sets we identified eighteen polymorphic loci and tested them in 25 C. newtoni individuals. Following a Bonferroni correction one pair of loci displayed linkage disequilibrium
    (application/pdf) - 01-oct-2010

  3. Landscape genetics of an endangered lemur (Propithecus tattersalli) within its entire fragmented range

    Quemere, E.; Crouau-Roy, B.; Rabarivola, C.; Louis, EE.; Chikhi, L.
    Habitat fragmentation may strongly reduce individuals' dispersal among resource patches and hence influence population distribution and persistence. We studied the impact of landscape heterogeneity on the dispersal of the golden-crowned sifaka (Propithecus tattersalli), an endangered social lemur species living in a restricted and highly fragmented landscape. We combined spatial analysis and population genetics methods to describe population units and identify the environmental factors which best predict the rates and patterns of genetic differentiation within and between populations. We used non-invasive methods to genotype 230 individuals at 13 microsatellites in all the main forest fragments of its entire distribution area. Our...
    - 30-oct-2013

  4. 2BAD: an application to estimate the parental contributions during two independent admixture events

    Bray, TC.; Sousa, VC.; Parreira, B.; Bruford, MW.; Chikhi, L.
    Several approaches have been developed to calculate the relative contributions of parental populations in single admixture event scenarios, including Bayesian methods. In many breeds and populations, it may be more realistic to consider multiple admixture events. However, no approach has been developed to date to estimate admixture in such cases. This report describes a program application, 2BAD (for 2-event Bayesian ADmixture), which allows the consideration of up to two independent admixture events involving two or three parental populations and a single admixed population, depending on the number of populations sampled. For each of these models, it is possible to estimate...
    - 30-oct-2013

  5. Signals of recent spatial expansions in the grey mouse lemur (Microcebus murinus)

    Schneider, N.; Chikhi, L.; Currat, M.; Radespiel, U.
    Pleistocene events have shaped the phylogeography of many taxa worldwide. Their genetic signatures in tropical species have been much less explored than in those living in temperate regions. We analysed the genetic structure of a Malagasy primate species, a mouse lemur with a wide distribution (M. murinus), in order to investigate such phylogeographic processes on a large tropical island. We also evaluated the effects of anthropogenic pressures (fragmentation/deforestation) and natural features (geographic distance, rivers) on genetic structure in order to complement our understanding of past and present processes of genetic differentiation.
    - 30-oct-2013

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