The threat of tahr
The sensitive Mount Cook lily
Why are they a problem?
New Zealand's native plants evolved during 80 million years of isolation without any large mammal browsers. This makes them particularly vulnerable to damage from introduced mammals. Herding browsers such as tahr and chamois cause two-fold damage; firstly by eating native plants; secondly by trampling large areas of vegetation and compactable soils, when herds of animals gather together.
Tahr graze at high altitudes, in alpine grasslands and sub-alpine shrublands where they feed most intensively on tall snow tussock and can kill entire plants. Chamois eat a similar diet to tahr, but prefer more woody plants, particularly native brooms (Carmichaelia spp.), and herbs such as the Mount Cook lily (Ranunculus lyallii). Both animals are a major threat to the sensitive ecosystems of alpine regions, as their social nature increases pressure in localised areas.
Tahr and chamois are remarkably fast and agile in steep and rugged terrain. Their hooves are specially designed for surefootedness, with a combination of hard and soft surfaces to give excellent grip. Both tahr and chamois are classified as pests in New Zealand.