Data from: Critically endangered island endemic or peripheral population of a widespread species? Conservation genetics of Kikuchi’s gecko and the global challenge of protecting peripheral oceanic island endemic vertebrates

Aim: To highlight the significant conservation challenge of evaluating
peripheral endemic vertebrates in island archipelago systems and to assess
empirically the complexities of approaches to conservation genetic studies
across political and biogeographic boundaries. To demonstrate the poignant
need for international collaboration and coordination when species
delimitation problems with high conservation concern involve island
endemics with biogeographically peripheral ranges. Location: Southeast
Asia, Lanyu Island, Taiwan, and the Philippines. Methods: Genetic samples
were collected and sequenced for one mitochondrial gene and five nuclear
loci for species of the Gekko mindorensis-G. kikuchii species complex in
Southeast Asia. We used maximum likelihood and Bayesian phylogenetic
methods and coalescent-based species delimitation analyses to estimate
phylogeographic relationships, construct multilocus haplotype networks and
test putative species boundaries. Results: Phylogenetic and population
genetic analyses suggest that Kikuchi's Gecko may represent a
peripheral population of a widespread species distributed from the
northern Philippines to Taiwan. However, we identify a discrepancy between
inferences of species boundaries resulting from methods based on allele
frequencies versus coalescent-based methods that incorporate evolutionary
history. Coalescent-based analyses suggest that G. kikuchii may be a
distinct evolutionary lineage. Our study underscores the need for
coalescent-based methods in conjunction with population genetic approaches
for conservation genetic assessments of widespread species. Main
conclusions: This study joins a few recent works suggesting that
Philippine-derived anomalies in the fauna of Lanyu (and possibly greater
Taiwan) are worthy of careful reconsideration. Determining whether each is
the result of recent human-mediated introduction or (possibly more
ancient) natural dispersal should be the goal of future studies on this
seldom-conceived biogeographic relationship. Isolated species endemic to
islands on the outer periphery of biogeographic and political regions
represent particular conservation challenges. This is especially true if a
species occurs on an isolated island that is allied biogeographically with
one nation, but politically administered by another.