Evaluating a potential source of founders for ex situ conservation efforts: genetic differentiation between disjunct populations of the Endangered red siskin Spinus cucullatus

ABSTRACT: Captive breeding and reintroduction can be effective conservation tools, but the origin of founders for such programs is key for success. The red siskin Spinus cucullatus, a bird from northern South America, is Critically Endangered in Venezuela due to decades of trapping for the illegal wildlife trade. As a result, many red siskins are held in captivity worldwide, but several potential problems with captive birds make considering founders from the wild more desirable. A recently discovered population of red siskins in Guyana presents such an opportunity, but, due to its disjunct distribution from the main range, the possibility of genetic differentiation is a concern. We used a variety of standard and novel analyses of amplified fragment length polymorphism (AFLP) and mitochondrial (mtDNA) markers to evaluate genetic divergence of the Guyana (GU) population, using 5 individuals from GU and 13 captive birds of presumed Venezuelan (‘VE’) origin. All analyses of nuclear loci revealed 2 clusters separating GU from ‘VE’ individuals, with FST values varying from 0.15 to 0.24, depending on assumptions about individual relatedness. Furthermore, all 5 GU birds shared an mtDNA haplotype that differed by 2 or more substitutions (0.11%) from the 3 ‘VE’ haplotypes. The GU population thus appears to be differentiated from the ‘VE’ population in both nuclear and mtDNA. While further genetic evidence is needed, these data suggest that the GU population is not an optimal source of founders for recovery efforts in Venezuela, and should be treated as a separate elemental conservation unit until additional data are available.