Molecular ecology of Round Island petrels
Round Island is a small islet off the north coast of Mauritius and is
of international importance in conservation biology, with the removal
of exotic species and habitat reconstruction underway. Our links with
the Mauritius Wildlife Foundation have allowed us access to the island,
to contribute to the ongoing conservation and biological research.
Round Island Petrels were only distinguished in the 1940's, and this
population is unique for several reasons: it is closed; it is on just
one island; most of the birds are ringed and nearly all of the nest
sites are known and marked.
The petrels on Round Island usually nest in the open, in groups
(clusters), and extensive ringing data suggests that birds form
long-term pair bonds. They also display a high degree of site fidelity
despite frequently being close to vacant sites with hollows that are
thought to have much higher hatching success. Part of the explanation
for this spatial pattern of nests may involve attacks on eggs and young
by conspecific intruders. Another puzzling aspect of their reproductive
behaviour is that only a proportion of the population is breeding at
any one time. We are using genetic markers (mtDNA and microsatellites), along
with the ringing records and systematic observation, to evaluate the
relatedness of group members and aggressors, and their contribution to
attack and defence. Parentage analysis will also enable us to evaluate
the mating system, and to investigate a skew in reproductive
success, which may be related to habitat saturation.
We are also conducting a survey of mitochondrial DNA (mtDNA)
haplotypes present in the population, to distinguish and identify the
species present and their relationships. In conjunction with
microsatellite markers we will evaluate the extent of cross-breeding
(hybridization) between these putative species, and the extent to which
this leads to genetic mixing. This genetic groundwork will provide the
fundamental information for evaluating the taxonomic and conservation
status of these petrels, and for drafting guidelines for appropriate
management.
Round Island petrel
Round Island
