Evaluating the demographic history of the Seychelles kestrel (Falco araea): Genetic evidence for recovery from a population bottleneck following minimal conservation management

An important requirement for biologists conserving vulnerable species of wildlife and managing genetic problems associated with small population size is to evaluate existing evidence regarding what is known of a species' recent population history. For endemic island species in particular, current genetic impoverishment could be due to either a recent population crash or a consequence of an evolutionary history of sustained isolation and small effective population size. Interpreting any given case can often be further complicated by incomplete or contradictory evidence from historical field surveys that might suggest a very different demographic history. Here, we use the case of the Seychelles kestrel (Falco araea), an island endemic previously listed as critically-endangered but now relatively common, to illustrate how genetic data from microsatellite genotypes of 100-150-year-old museum specimens reveals a recent and severe population crash since the 1940s to approximately eight individuals, before the population recovered. We re-interpret the historical population trajectory of the Seychelles kestrel in the light of the minimal intervention required for this species to recover. We examine different ecological explanations for the decline and apparently unassisted recovery of the Seychelles kestrel, review the evidence for similarly unaided recoveries elsewhere and discuss the implications of unaided population recoveries for future species conservation programmes. Demographic profiles from historical genetic signatures can provide highly informative evidence when evaluating past and future recovery efforts for endangered species. (C) 2009 Elsevier Ltd. All rights reserved.