threatened species

Impacts of introduced mammalian predators on New Zealand’s alpine fauna

Alpine zones are threatened globally by invasive species, hunting, and habitat loss caused by fire, anthropogenic development and climate change. These global threats are pertinent in New Zealand, with the least understood pressure being the potential impacts of introduced mammalian predators, the focus of this review. In New Zealand, alpine zones include an extensive suite of cold climate ecosystems covering c. 11% of the land mass. They support rich communities of indigenous invertebrates, lizards, fish, and birds.

Persistence of biodiversity in a dryland remnant within an intensified dairy farm landscape

The lowland Canterbury Plains of New Zealand have been extensively modified since human occupation, but with recent conversions to irrigated dairy farming very few remnants of native dryland vegetation remain in the region. We investigated soil chemistry, plant distribution and soil invertebrates along transects in Bankside Scientific Reserve, a small (2.6 ha) remnant. The vegetation is a mosaic of native woody shrubs, predominantly Kunzea serotina (kanuka, Myrtaceae) and Discaria toumatou (matagouri, Rhamnaceae), and dry grassland.

Impacts of introduced mammalian predators on indigenous birds of freshwater wetlands in New Zealand

The impacts of introduced mammalian predators on the viability of bird populations in forest, river and coastal habitats in New Zealand are well known. However, a common understanding of their impacts in freshwater wetlands is lacking. We review evidence for impacts of introduced mammalian predators on freshwater birds, particularly specialist species restricted to wetlands, and use this information to make predictions about freshwater species likely to be vulnerable to predation.

Diet of hedgehogs (Erinaceus europaeus) in the upper Waitaki Basin, New Zealand: Implications for conservation

European hedgehogs (Erinaceus europaeus) have recently been identified as a conservation threat in New Zealand. Hedgehogs were kill-trapped at 14 wetland and braided riverbed sites in the upper Waitaki Basin between late October 1997 and early February 1998 and their gut contents described. The most commonly eaten prey were Coleoptera (present in 81% of 192 guts), Lepidoptera (52%; n = 192), Dermaptera (49%; n = 192), Hymenoptera (42%; n = 192) and Orthoptera (31%; n = 319).

Growth and survival of nestlings in a population of red-crowned parakeets (Cyanoramphus novaezelandiae) free of introduced mammalian nest predators on Tiritiri Matangi Island, New Zealand

The negative effects of introduced nest predators on the breeding success of endemic New Zealand parrots are well documented, as is their role in the general decline of these species. In contrast, little is known about the intrinsic intra-brood dynamics responsible for modulating fledging success in parrots breeding at sites free of introduced nest predators. We studied red-crowned parakeets over two breeding seasons on Tiritiri Matangi, an offshore island free of introduced mammalian predators.

Habitat associations and detectability of the endemic Te Paki ground beetle Mecodema tenaki (Coleoptera: Carabidae)

Te Paki Ecological District in Northland is regarded as a New Zealand biodiversity hotspot, but habitat loss and forest fragmentation have adversely affected many of its endemic species. We investigated the distribution and habitat associations of Mecodema tenaki (Coleoptera: Carabidae), a Te Paki endemic ground beetle whose threat status was recently changed from ‘Nationally Critical’ to ‘Declining’. Manual searching and pitfall trapping (live-capture and lethal) were used to detect the species at 46 sites in three habitat types: native forest, pine plantation and shrubland.

Are introduced takahe populations on offshore islands at carrying capacity? Implications for genetic management

Translocation to island reserves is a common strategy in New Zealand and elsewhere for safeguarding species against introduced predators. When successful, however, the closed nature and relatively small size of many island sanctuaries can result in populations quickly reaching their carrying capacity, which in itself can present further challenges such as reduced productivity and population growth rates associated with density-dependent effects as well as increased rates of inbreeding.