Kararehe Kino Issue 30
December 2017: Emerging and neglected pests.
In this issue
Editorial: Emerging and neglected pests
Across the history of colonisation, humankind brought 32 terrestrial mammal species to Aotearoa, alien to this land, that managed to establish self-sustaining populations. We are all aware of how devastating these introductions have been for our native biodiversity, through depredation, herbivory, resource competition and disease impacts. What is astounding, however, is that the breadth and depth of these impacts are such that we are still discovering new ones today.
Explaining Vespula wasp population structure in the Hauraki Gulf
Invasive Vespula (common and German) wasps have a negative impact on the environment throughout New Zealand, preying on native invertebrates and competing with native nectar-feeding birds and invertebrates for the honeydew produced by native scale insects in beech forests.
Flying beneath the radar: New Zealand’s ‘minor’ wild ungulates
For a country that prehistorically had no native land mammals other than bats, New Zealand is now home to a surprising variety of ungulates. If moose are not yet extinct, and with wapiti now classed as separate from red deer, there are 15 species of ungulate (including local feral populations of ‘domestic’ sheep, cattle and horses) that still have one or more viable wild population.
Hedgehogs: recent evidence of their impacts on native fauna
It seems the more we look, the more we find when it comes to the impacts of invasive pests. European hedgehogs are no exception.
Are large arboreal invertebrates threatened by possum control?
A common phenomenon in vertebrate pest control is an increase in the number of one pest species when another competing pest species is controlled. A good example of this in New Zealand is the increase in the abundance of rats following the poisoning of possums: in some forests, rat populations recover quickly over several months following poisoning, while possum populations are much slower and take several years to recover.
Norway rats in rural and urban New Zealand
The vision of a predator-free New Zealand by 2050 is usually about possums, stoats and rats. While possums and stoats are single species, there are three species of rat in New Zealand. In order of arrival – and of increasing distribution around New Zealand – they are the kiore or Polynesian rat (Rattus exulans), the Norway or brown rat (Rattus norvegicus), and the ship, black or roof rat (Rattus rattus).
When pets go rogue: the link between the wildlife trade and exotic species
Mounting evidence reveals the key role played by the pet trade in shaping the new national pool of exotic species. Globally a large variety of species are traded to supply and meet the demand for pets. This demand is causing significant environmental problems. In their native range the exploitation of populations is leading to over-harvesting and population declines; in the recipient regions some of the imported and traded species may pose an untenable risk of becoming invasive species.
Emerging invasive threats: the alpine newt
There is a growing appreciation globally of the occurrence and ecological impacts of herpetological invasive species. New Zealand has historically suffered relatively few such incursions or establishments due to its relative isolation, yet as cross-border freight volume grows so too have the rates of interception of reptiles and amphibians. The Biosecurity Act 1993 provides effective justification for border management and controls on importation, yet incursions have still occurred. One such incursion is the alpine newt.
Feral pigeons – the problem and its management
The feral or rock pigeon is well established throughout New Zealand and is a common sight in cropping regions, cities and large towns. Some people enjoy seeing and feeding pigeons, particularly in urban areas, whereas others view them as vermin equivalent to rats.
Expanding wallaby populations
Six species of wallabies were introduced into New Zealand during the late 1800s, either for recreational hunting or as part of the then desire to acclimatise exotic species. Four of these species are found on Kawau Island, with dama wallaby also found around Rotorua, and Bennett’s wallaby found in South Canterbury / North Otago. Populations of both these species continue to spread on the mainland and have negative impacts on primary production and indigenous biodiversity.