001.jpgAotearoa New Zealand is a pretty special place. We have a huge number of endemic species (species found only in New Zealand). For example all our bat, amphibian and reptile species, over 80% of our native plants and at least 70% of our birds are endemic. If any of these species become extinct they are lost forever from New Zealand and the world. Native plant and animal species are vulnerable to the impact of humans and the new species we bring with us. Extinctions caused by humans began over 750 years ago, first with the arrival of Maori ancestors who hunted native species and brought kiore (the Polynesian rat), and the dog. Later, the arrival of Europeans increased the rate of extinctions as they introduced many new plants and animals, as well as bringing about major habitat change through clearing forests and draining wetlands.

Many introduced plants and animals adapted well to New Zealand’s temperate climate and the modified environments. Of the 30,000 or more introduced plant species, over 2,500 have become naturalised – able to live and reproduce in the wild. Of these naturalised plants more than 300 have become environmental weeds impacting detrimentally on New Zealand’s indigenous plant communities, waterways and animals. Native land animals evolved within ecosystems dominated by birds, but with the introduction of mammalian predators (e.g. rats, stoats and cats) and introduced species (e.g. rock pigeons, starlings and wasps), these native animals now experience intense predation and competition for habitat and food. Combined, these changes have so greatly altered New Zealand’s ecosystems that many species can no longer survive without human intervention. Extinction rates are already high in New Zealand, and many living species are listed as endangered or vulnerable. The most damaging introduced animal pests in New Zealand include rats (kiore, ship and Norway), mustelids (stoat, ferret and weasel), possum, deer, goat and pig.
Student booklet (print a class set or order from education@ecan.govt.nz) in which story 'Pests Galore' is found

Presentation (ppt and pdf version) Session 6: The impact of pest species over time.