Himalayan tahr and chamois were introduced to New Zealand in the early days of European settlement for sport. Both animals have found the Southern Alps of the South Island ideal habitat, but have become a major threat to the ecosystems in these alpine areas.
Himalayan tahr (Hemitragus jemlahicus) are large goat-like animals, native to the central Himalayan ranges of India and Nepal. In New Zealand tahr are found in the central Southern Alps between about the Rakaia and Whitcombe valleys in the north to about Lake Hawea in the south.
Tahr are generally found in the alpine grassland zone, where they graze on snow tussocks, alpine herbs and sub-alpine shrubland plants.
Tahr are remarkably fast and agile in steep and rugged terrain. Their hooves are designed for surefootedness, with a combination of hard and soft surfaces to give excellent grip.
The male tahr’s summer coat is a reddish-brown, females a medium brown, both turning dark brown in winter. The bull tahr has an impressive mane of long hair around the neck and shoulders.
Tahr are popular with recreational and tourist hunters. Their horns and the male's striking mane are sought-after trophies.
Tahr are social animals and form easily recognisable groups. Adult females, juveniles and kids gather together. Mature males over four years form bachelor groups, and younger males hang out together in separate, smaller groups. Males mix in with the females in their range over the winter breeding season but during the summer months they often travel long distances away from the female groups.
As tahr have no natural predators in New Zealand their population can increase unchecked, unless there is regular control from hunters or DOC. Large groups can form and damage plants which provide vital food and shelter for native animals.
Threat to native plants
Zora Canyon, Landsborough in 1999 (left) and 2020 (right) showing the impact of tahr
New Zealand alpine ecosystems evolved over millions of years in isolation without any large mammal browsers (such as tahr), and many alpine plants have no defence mechanisms (such as toxins or spines) to discourage tahr from eating them.
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, and browse on native plants that birds, lizards and insects use for feeding, nesting and shelter. The tahr diet includes some large, succulent herbaceous species including alpine buttercups and mountain daisies. Some of these species are ranked as Threatened or At Risk by the New Zealand Threat Classification System.
Tahr also feed on snow tussock and shrub species which are the dominant vegetation in many of New Zealand’s subalpine and alpine environments. Tahr are a major threat to the sensitive ecosystems of alpine regions as their social nature increases pressure in localised areas. In extreme situations, large groups of tahr can transform tall tussocks and subalpine shrublands to a grassy turf or bare ground.
Tahr damage to the Mount Cook lily – before (left) and after (right)
Threats to native animals
The changes tahr can cause to the alpine and sub-alpine plant communities affect the native animals that live there by reducing their access to food and shelter. Over time, they may disappear from these sites.
This is because rare native birds, such as kea and rock wren, may no longer find enough shelter or food. Tahr may also be directly competing with threatened alpine scree wētā, since both animals feed on alpine buttercups.
Monitoring is undertaken to follow trends in the tahr population and to understand the impacts of tahr on the alpine environment, both of which help inform management actions.
Assessing the impact
DOC has been recording the impacts of Himalayan tahr on alpine and subalpine biodiversity since the early 1990s by monitoring a network of 117 permanent plots in alpine grasslands within the tahr management units. New research since 2011 has established that there is less shrub cover in the tahr management areas than in the tahr exclusion zones (the areas to the north and south of the tahr feral range).
High tahr numbers have led to a drastic change in the vegetation around the Makawhio River, South Westland, with tall snow tussocks in some places almost gone.
Reports on impacts of Himalayan tahr:
- Long-term impacts of an introduced ungulate in native grasslands: Himalayan tahr in New Zealand’s Southern Alps (PDF, 801K)
- Impact of Himalayan tahr on snow tussocks in the Southern Alps, New Zealand (2014) (PDF, 964K)
- Impact of Himalayan tahr on snow tussock grasslands in the Southern Alps (2004) (PDF, 12,131K)
- Potential of Tier 1 and alternative monitoring networks to assess the ecological integrity of alpine vegetation exposed to tahr grazing (PDF, 3,999K)
Aerial surveys have been carried out over recent years to estimate the density and abundance of Himalayan tahr on public conservation land in each of the seven management units and two exclusion zones in the Southern Alps.
After three summer seasons of tahr population monitoring, the total abundance of tahr on public conservation land between 2016 and 2019 was estimated to be 34,478 animals (95% confidence interval: 26,522–44,821). This estimate does not include tahr herds on other land tenures.
The current estimate is an average abundance over the three seasons of data collection using aerial surveys in the tahr management areas on public conservation land. This means we effectively average over any additions (tahr births) or losses (tahr deaths due to control operations and natural causes) to the population during this period.
The assessment from Autumn 2019 is included below along with a factsheet and a previous report.
Population monitoring reports:
- Factsheet: Estimating Himalayan tahr numbers in New Zealand (PDF, 886K)
- Estimates of Himalayan tahr abundance in New Zealand September 2019 (PDF, 1,741K)
- Estimates of Himalayan tahr abundance in New Zealand 2015-2018 (PDF, 1220K)
Managing tahr numbers
DOC's management policy for tahr is to control numbers in sites of high conservation value. Recreational and commercial hunters as well as DOC contribute to tahr control.
Legislation allows for a managed population of up to 10,000 tahr across Crown pastoral leases, private land and public conservation land to co-exist with our native species.
There are very few tahr in the exclusion zones, as all tahr present in these areas are targeted for removal to prevent the tahr feral range from expanding.
DOC is aiming for population control, not eradication. There’s no intention or risk of tahr being eradicated now or in the future, but we do need to meet the objectives of the Himalayan Thar Control Plan 1993.
The Himalayan Thar Control Plan 1993 is prepared under the Wild Animal Control Act 1977, and guides DOC’s annual Tahr Control Operational Plans. The annual plans are designed to manage tahr in areas throughout the feral range where they remain at high densities, and to move the tahr population towards goals of the 1993 plan.
If you see tahr in areas outside their feral range (PDF, 306K), let the local DOC office know.
Hunters play a pivotal role in helping to manage tahr numbers and protect our alpine ecosystems.
Take part in a hunt – you will have a great outdoor adventure and contribute to keeping tahr or chamois numbers down. Just make sure you have your hunting permit.
Find tahr hunting ‘hotspots’
DOC is mapping the locations of tahr observed on public conservation land.
Use our tahr sightings maps to plan hunts on conservation land, or find areas where you can hunt tahr and other wild animals.