The impact of serial translocation bottlenecks on the genetic diversity of Anegada Rock Iguanas (Cyclura pinguis) in the British Virgin Islands
摘要
The use of animal translocation as a conservation strategy is growing, and translocations involve founder events. Because resultant populations pass through genetic bottlenecks, it is anticipated that they should maintain less genetic variation than their source populations. In addition to the reduced evolutionary potential associated with decreased genetic variation, founder events can lead to increased expression of the genetic load due to inbreeding and give rise to inbreeding depression. Here, we describe the effects of serial translocations on the genetic diversity of critically endangered Anegada Rock Iguanas (Cyclura pinguis) in the British Virgin Islands in the 1980s and 1990s. Very few founders were involved (N = 8, N = 4) but they were extremely fecund and census sizes in these translocated iguana populations increased quickly. This implies a genetic paradox because these translocations were successful from a demographic perspective despite the fact that they are inbred. To quantify genetic variation in these bottlenecked populations, blood samples were collected from the source population and two translocated populations. Genetic diversity at 21 microsatellite loci was significantly lower in the translocated populations than that in the source population. However, statistical methods designed to detect molecular signatures of genetic bottlenecks failed to do so. Estimates of internal relatedness by age class suggest that inbreeding depression may be elevated in the translocated populations, likely reflecting the small initial population sizes. Anecdotally, our work shows that translocations may result in subtle genetic erosion, even when census size indicates demographic success.