Genetic differentiation between Príncipe Island and mainland populations of the grey parrot (Psittacus erithacus), and implications for conservation

Abstract

The range of the grey parrot (Psittacus erithacus), one of the most heavily harvested bird species for the international pet trade, spans the forest belt of Central and West Africa and includes the oceanic island of Príncipe (Gulf of Guinea). Morphological variation led to the recognition of two mainland subspecies (P. e. erithacus and P. e. timneh). The population from Príncipe was originally described as a separate species (P. princeps) but is currently included in the nominate race. We used 1932 bp of the mitochondrial genome to clarify the genealogical affinities between the two currently-recognized mainland subspecies and the Príncipe population. Sampling included 20 individuals from Príncipe, 17 from P. e. erithacus, and 13 from P. e. timneh. We found that the two mainland subspecies form two independent lineages, having diverged up to 2.4 million years ago (Ma), and that the Príncipe population is composed of two lineages that diverged in allopatry. The most common lineage is descended from the first colonizers and evolved in isolation for up to 1.4 Ma. Contrary to current understanding, this 'Príncipe lineage' is more closely related to the timneh than to the erithacus subspecies. The second lineage consists of P. e. erithacus birds from the nearby mainland that colonized the island in recent times. The evolutionary dynamics of the grey parrot population of Príncipe are primarily characterized by isolation, with new genetic variation being added through rare immigration events. The heavily harvested Príncipe grey parrot population should therefore be treated as an independent conservation unit.

Habitat preferences of the forest birds on the island of Príncipe, Gulf of Guinea

“…However, modelling the combined observations of the threatened species suggested that they are sensitive to disturbance as they were more likely to occur at greater distances from roads. A similar pattern was found for the grey parrot, which, historically has been hunted in large numbers for the pet trade (Juste, 1996; Melo & Ryan, 2007). Although such trade is now illegal in São Tomé and Príncipe, its impacts remain apparent.…”

Conservation Concern for the Deteriorating Geographical Range of the Grey Parrot in Cameroon

“…Factors within any given habitat act either singly or together to influence the presence of wildlife species within the habitat [5,10]. The vegetation distributional maps show that the Grey Parrot mostly inhabits lowland rainforest areas within Cameroon, with elevation from Limbe (5 m) through Ndikinemiki (829 m) up to Nkolakie (1038 m).…”

Phylogenetic relationships of the Gulf of Guinea Alcedo kingfishers

“…This is well documented for the mitochondrial genome: because it is not linked to the nuclear genome, which contains most loci that determine individual fitness, it can penetrate the genome of a foreign population with very low levels of hybridization (Takahata & Slatkin 1984). This explains the introgression of mtDNA across species borders in many animal groups, and has been described in the Grey Parrot Psittacus erithacus population from Príncipe Island (Melo & O'Ryan 2007). In birds, this phenomenon is facilitated by their potential for hybridizing successfully after millions of years of separation (Price & Bouvier 2002).…”