Urbanisation causes fragmentation of natural habitats, which results in loss of biodiversity, while promoting an environment that can facilitate invasive species. However, forest fragments are an important refuge for native species and therefore understanding and mitigating threats in fragments is critical.
Managed pine plantations now constitute a large portion of mainland New Zealand. Despite many native birds inhabiting these exotic habitats, their value for biodiversity conservation is unclear. Although numerous studies have quantified densities of native bird species in pine plantations, it is unknown whether these individuals constitute self-sustaining populations. Here we address this question for North Island robins (Petroica longipes) in a Pinus radiata plantation in the central North Island.
Recently introduced mammalian predators have had devastating consequences for biotas of archipelagos that were isolated from mammals over evolutionary time. However, understanding which antipredator mechanisms are lost through relaxed selection, and how they influence the ability of prey to respond to novel predatory threats, is limited. The varying effects on native lizard populations of the relatively recent and patchy history of mammalian introductions to New Zealand’s islands provide an opportunity to examine the consequences of relaxed selection.
Many of New Zealand’s 104 lizard taxa are restricted to the country’s main islands where they are vulnerable to a range of threats. Information on population trends and basic ecological data are lacking for most species, hampering conservation efforts. We monitored a population of scree skinks (Oligosoma waimatense; conservation status: Nationally Vulnerable) in an alluvial stream bed in O Tu Wharekai Wetland in the mid-Canterbury high country over 10 years (2008−2018) to understand aspects of the population’s ecology, and to clarify potential threats and options for management.
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.
Feral pigs (Sus scrofa) are a threat to New Zealand’s biodiversity. Predation of frog species by feral pigs is a notable problem in other countries where pigs have been introduced. Our study aimed to determine through analysis of stomach contents if feral pigs are consuming frogs in the Waitakere Ranges, Auckland. Auckland Council contract pig hunters collected 274 feral pig stomach samples. Of these samples, 184 were screened for frog consumption via both dissecting microscope and DNA analyses.
Invasive house mice (Mus musculus) have detrimental effects on biodiversity, but their impacts can be difficult to detect and are often unquantified. We measured their effects on survival of a translocated population of an endangered lizard in New Zealand. Twelve captive-reared Otago skinks (Oligosoma otagense) were translocated to a 0.3-ha area of grassland/shrubland cleared of invasive mammals and surrounded by a mammal-resistant fence. Sixteen more skinks were released 2 years later but this was followed by an incursion of mice for c. 160 days.
Studies of waterfowl productivity at the Pukepuke Lagoon Wildlife Management Reserve have shown high mortality amongst young ducklings. This has been found in other studies in which it has often been attributed to predation. (Evans and Wolfe 1967, Balser et al. 1968, Urban 1970, Schranck 1972). Areas of pasture, cut-over pine forest, and dunes outside the reserve were also included in the trapping area.
There are currently many attempts in New Zealand to restore native ecosystem functioning through the intensive control of introduced mammalian predators. One system that is faltering is bird pollination of endemic mistletoes (Peraxilla tetrapetala) by bellbirds (Anthornis melanura), apparently because of stoat (Mustela erminea) predation. We used a paired-catchment experiment in Nothofagus solandri var. cliffortioides forest at Craigieburn, central South Island, to measure whether stoat control could restore bellbird densities and mistletoe pollination.
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).