Population expansion, current and past gene flow in Gould’s Petrel: implications for conservation
Résumé
Seabird life-history traits such as long generation
time, low annual fecundity and delayed sexual maturation
make them more prone to population loss and consequently
to extinction; petrels are indeed amongst the most threatened
birds. Based on coalescence and multiloci inference
this study examines the extent of genetic differentiation of
a vulnerable New Caledonia (caledonica) and Australia
(leucoptera) subspecies of Pterodroma leucoptera
(Gould’s Petrel), and whether the genetic relationship
between them results from the influence of past events like
variation in sea level, or is dominated by contemporary
gene flow. Sequences of two mitochondrial genes and five
nuclear introns were obtained from 86 individuals from
both populations. Haplotype networks were used to infer
relationships between the haplotypes of both populations.
The demographic history of the P. leucoptera complex was
studied using neutrality tests and Extended Bayesian Skyline
Plots. A weak population differentiation was revealed.
The Extended Bayesian Skyline plot suggested a population
expansion approximately 80,000 years before present
(bp) for caledonica and 30,000 years bp for leucoptera.
The split was dated to 30,000 years bp by means of multilocus
inference through *BEAST. Despite genetic similarity
of the two taxa, we advocate to consider them as
independent units for conservation management, given
their strong ecological distinctiveness (foraging distribution,
winter distribution, breeding phenology and breeding
distribution).