Recent extinctions among Little Spotted Kiwi (Apteryx owenii) and the origin of extant populations

Little Spotted Kiwi (LSK; Apteryx owenii) have the lowest genetic
diversity of five currently recognised kiwi species apparently due to a
bottleneck when at most five individuals were translocated to Kapiti
Island in 1912. Ancient DNA analyses show that LSK also had the lowest
genetic diversity of kiwi species historically, possibly due to population
bottlenecks during Pleistocene glaciation. We compare genetic diversity
between LSK from Kapiti Island (extant), D’Urville Island (extinct) and
the South Island of mainland New Zealand (extinct) at 495 bp of the
mitochondrial control region (mtDNA) and 15 nuclear microsatellite loci
(nDNA). Despite higher sample sizes in extant (n = 31 mtDNA, 97 nDNA) than
recently extinct (n = 10 mtDNA, 9 nDNA) populations, extant LSK have at
least 78% fewer mtDNA haplotypes and 52% fewer microsatellite alleles than
recently extinct LSK. Extant LSK were strongly divergent from historical
LSK for both mtDNA and nDNA (FST = 0.237 to 0.480), but showed greatest
similarity with historical samples from Fiordland near the putative source
population of Kapiti founders. Microsatellite data suggest that Kapiti LSK
could have arisen from as few as three birds and our mtDNA data show that
at least two of the founders were female. Our results indicate that
substantial genetic diversity has been lost with the recent extinctions of
remnant populations. Locating and protecting any last surviving
individuals in presumed extinct populations will require intensive
conservation efforts, but could also provide an invaluable source of
genetic diversity for the species.