Non-invasive sampling reveals low mitochondrial genetic diversity for a
Critically Endangered island endemic species
Abstract
As an island endemic with a decreasing population, the Critically
Endangered Grenada Dove Leptotila wellsi is threatened by
accelerated loss of genetic diversity resulting from ongoing habitat
fragmentation. Small, threatened populations are difficult to sample
directly but advances in molecular methods mean that non-invasive
samples can be used. We performed the first assessment of genetic
diversity of populations of Grenada Dove by a) assessing mtDNA genetic
diversity in the only two areas of occupancy on Grenada, b) defining the
number of haplotypes present at each site and c) evaluating evidence of
isolation between sites. We used non-invasively collected samples from
two locations: Mt Hartman (n=18) and Perseverance (n=12). DNA extraction
and PCR were used to amplify 1,751 bps of mtDNA from two mitochondrial
markers: NADH dehydrogenase 2 (ND2) and Cytochrome b (Cyt b). Haplotype
diversity (h) of 0.4, a nucleotide diversity (π) of 0.4 and two unique
haplotypes were identified within the ND2 sequences; one haplotype was
identified within the Cyt b sequences. Of the two haplotypes identified;
the most common haplotype (haplotype A = 73.9%) was observed at both
sites and the other (haplotype B = 26.1%) was unique to Perseverance.
Our results show low mitochondrial genetic diversity, a non-expanding
population and clear evidence for genetically isolated populations. The
Grenada Dove needs urgent conservation action, including habitat
protection and potentially augmentation of gene flow by translocation in
order to increase genetic resilience and diversity with the ultimate aim
of securing the long-term survival of this Critically Endangered
species.