Conservation genetics of island takahe (Porphyrio mantelli)

Abstract

General introduction:

Conservation of biodiversity is one the most important contemporary global problems faced by humanity. Human activity has caused the extinction of more than a thousand vertebrate species over the last century (Altukhov, 1994), with many more currently on the verge of extinction. As remaining natural areas continue to decline in size and become fragmented, an increasing number of species will require monitoring and management to ensure their persistence.

New Zealand contains 11% of the world's endangered bird species (Reed and Merton, 1990). For many of these species, management options are limited to preserving relic populations and their habitats on the mainland, and/or maintaining a number of small populations on predator-free offshore islands. New Zealand has over 500 offshore islands, a large proportion of which are designated sanctuaries or nature reserves (Mortimer et al., 1996).

Over the last decade, awareness and concern over genetic problems potentially faced by small populations has grown considerably. Issues of particular concern are the maintenance of genetic variation and effects of inbreeding. This project constitutes an investigation into genetic issues related to the management of the takahe (Porphyria mantelli), a large, flightless rail endemic to New Zealand. Presumed extinct until their "rediscovery" in 1948, just one relict population of -120 individuals remains in the Murchison Mountains, Fiordland. In addition, four small populations have been established on predator-free islands since 1984 (Crouchley, 1994).

This project consists of two separate but inter-related chapters. Chapter One addresses the mating system and levels of genetic variation of takahe breeding on islands. Chapter Two assesses the effects of inbreeding on the reproductive success of island takahe. Conclusions and management recommendations are considered in the final part of this report. Some repetition is a consequence of this approach.