predation

Stable isotope analysis reveals variable diets of stoats (Mustela erminea) in the alpine zone of New Zealand

The alpine zone of New Zealand covers c. 30% of public conservation land and is home to a high diversity of endemic species. Predation by introduced stoats (Mustela erminea) is identified as a major threat to alpine fauna. However, a lack of biological information, such as what stoats eat in different settings, hinders efforts to focus control measures in time and space in order to achieve the greatest conservation gains. We used a biochemical tool, stable isotope analysis, to estimate stoat diet across three time-periods in the alpine zone of three national parks.

The role of pine plantations in source-sink dynamics of North Island robins

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.

Does evolution in isolation from mammalian predators have behavioural and chemosensory consequences for New Zealand lizards?

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.

Ecology of scree skinks (Oligosoma waimatense) in O Tu Wharekai Wetland, mid-Canterbury high country, New Zealand

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.

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.

Feral pig (Sus scrofa) predation of a green and golden bell frog (Litoria aurea)

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.

Impacts of invasive house mice on post-release survival of translocated lizards

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.

Aspects of the biology of the ferret (Mustela putorius forma furo L.) at Pukepuke lagoon

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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.

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