Genetic variation, systematics and management of kiwi (Apteryx spp.)

Kiwi (Apteryx: Struthioniformes) are a family of ratite birds confined entirely to New Zealand. Since 1813, at least ten species have been described. Recent taxonomy has accepted three species: A. owenii (little spotted kiwi), A. haastii (great spotted kiwi) and A. australis (brown kiwi). Apteryx australis has three subspecies: A. a. australis (South Island); A. a. mantelli (North Island); and A. a. lawryi (Stewart Island). We undertook a survey of genetic variation of all known types of kiwi. Between 1984 and 1992, blood samples were collected from populations of all presumed taxa of kiwi from 32 locations. The objectives of this survey were to: (a) describe patterns of geographic variation in blood proteins (allozymes); (b) assess competing taxonomic hypotheses for Apteryx; and (c) identify management units and populations of special conservation significance. Cluster analysis of allozyme variation revealed four genetic groups differentiated at the species level: (a) northern brown kiwi from the North Island and Okarito on the West Coast of the South Island, corresponding to A. mantelli; (b) tokoeka or southern brown kiwi from Haast, Fiordland and Stewart Island, corresponding to A. australis; (c) little spotted kiwi; and (d) great spotted kiwi. Within these major groups, three populations of special interest were revealed: (a) Okarito brown kiwi; (b) Haast tokoeka, which may be specifically distinct; and (c) Little Barrier Island brown kiwi. Tokoeka from Fiordland and Stewart Island show high levels of genetic similarity. Populations of great spotted kiwi show moderate levels of genetic divergence with no apparent geographic pattern. The two populations of little spotted kiwi, on Kapiti and D’Urville Islands, are genetically very similar. Kapiti Island brown kiwi are of a hybrid A. mantelli × A. australis origin, and a single bird from Franz Josef was a hybrid A. australis × A. owenii. Other hypotheses regarding the latter bird are discussed. Present theory recommends conservation of the entire range and geographic pattern of genetic variation. This study identified seven fundamental management units for kiwi, corresponding to genetically and geographically distinct populations or metapopulations. Management priority of these units should be determined by ecological factors such as rarity and immediate threats to survival. Translocations between management units should be prohibited. Research should be undertaken to resolve remaining taxonomic uncertainties.