Threats and conservation All the restricted-range species are considered threatened or Near Threatened, owing largely to introduced predators and competitors. Porphyrio mantelli has declined through competition for food from red deer Cervus elaphus and predation by stoats Mustela erminea. Apteryx haastii is declining in some areas owing to predation by introduced mammals (possums, mustelids, cats and dogs). Mohoua ochro- cephala has periodic population crashes in response to the stoat irruptions that follow major beech-mast production and subsequent mice plagues; it has disappeared from some of the best habitat in northern South Island, perhaps because of introduced wasps which compete for 'honey dew' (an important food source in beech forest). Anarhynchus frontalis is subject to predation by stoats and cats, but also suffers from a decline in the quality of nesting habitat owing to encroachment of weeds as hydroelectric schemes reduce seasonal flooding of riverbeds. The many other threatened landbirds in this EBA were historically widespread, although many have very restricted ranges today. They include Brown Kiwi Apteryx australis (Vulnerable; the race australis which occurs in Fiordland and on Stewart Island is treated as a full species by Baker et al. 1995, Little Spotted Kiwi A. owenii (Vulnerable; only Long Island in this EBA), Australasian Bittern Botaurus poiciloptilus (Endangered), Blue Duck Hymenolaimus malacorhynchus (Vulnerable), Himantopus novaezelandiae (Critical; see 'Restricted-range species', above), New Zealand Kaka Nestor meridionalis (Vulnerable) and Strigops habroptilus (Extinct in the Wild; see above). Several threatened seabirds are largely endemic to this EBA when breeding, including Hutton's Shearwater Puffinus huttoni (Endangered; Kaikoura Range), Fiordland Penguin Eudyptes pachyrhynchus (Vulnerable), Westland Petrel Procellaria westlandica (Vulnerable), New Zealand King Shag Phalacrocorax carunculatus (Vulnerable; stacks in the Marlborough Sounds) and Black-fronted Tern Chlidonias albostriatus (Vulnerable). There has been much conservation action within this EBA (see, e.g., Lambert and Moritz 1995) and c.40-50% of the total area lies within protected areas, notably Fiordland and Kahurangi national parks. Major conservation programmes involving captive breeding and release, introductions and predator control are targeted at Porphyrio mantelli, Himantopus novaezealandiae and Strigops habroptilus (e.g. Clout and Craig 1995). There is growing concern, however, about the fragmentation of habitat and the impact of this on small relict populations with little or no gene flow between them. Increased tourism is expected to act to the detriment of surviving wild areas, and consequently there is a need to balance the desire for people to enjoy wildlife with the need to protect vulnerable species from excessive disturbance (D. Cunningham in litt. 1995). |