Résumé
The greater horseshoe bat (Rhinolophus ferrumequinum) is among the most
widespread bat species in Europe but it has experienced severe declines,
especially in Northern Europe. This species is listed Near Threatened in
the European IUCN Red List of Threatened Animals and it is considered to
be highly sensitive to human activities and particularly to habitat
fragmentation. Therefore, understanding the population boundaries and
demographic history of populations of this species is of primary
importance to assess relevant conservation strategies. In this study, we
used 17 microsatellite markers to assess the genetic diversity, the
genetic structure and the demographic history of R. ferrumequinum colonies
in the western part of its distribution. We identified one large
population showing high levels of genetic diversity and large population
size. Lower estimates were found in England and northern France. Analyses
of clustering and isolation by distance suggested that the Channel and the
Mediterranean seas could impede R. ferrumequinum gene flow. These results
provide important information to improve the delineation of R.
ferrumequinum management units. We suggest that a large management unit
corresponding to the population ranging from Spanish Basque country to
northern France must be considered. Particular attention should be given
to mating territories as they seem to play a key role in maintaining the
high levels of genetic mixing between colonies. Smaller management units
corresponding to English and northern France colonies must also be
implemented. These insular or peripheral colonies could be at higher risk
of extinction in a near future.