Threats
The Te Urewera Mainland Island (TUMI) has two key management approaches:
- The Background Area is where possums are reduced to low densities. Control is undertaken on an ongoing rotational basis.
- The Core Areas are where continuous intensive control of other animal pests in addition to possums is undertaken.
There are five Core Areas currently established within TUMI: Otamatuna, Mangaone, Onepu, Pakoakoa and Waikokopu.
The threats
New Zealand's native species are very vulnerable to many introduced species due to their long isolation from other landmasses where predatory mammals evolved. TUMI controls a range of introduced pests.
Possums
The Australian brush-tailed possum was introduced into New Zealand in 1837 to establish a fur trade. In Te Urewera National Park, possums are largely responsible for the decline of rata, kamahi and pirirangi, and have contributed to the declines in many bird species such as kokako, kaka and kereru.
Possums are being controlled by skilled and dedicated contractors on a rotational basis throughout 50,000 hectares of northern Te Urewera. Control is undertaken by a combination of trapping and cyanide poisoning.
Stoats
Stoats are ferocious predators, and being agile climbers have had a devastating effect on many indigenous species, particularly birds. They prey on both adult birds and chicks and can also raid nests for eggs. Kiwi, being flightless, are particularly vulnerable to stoat predation when weighing less than 1000 grams.
Stoats are being controlled by trapping over 7,215 hectares within the 5 core areas. Traps are baited with food that is familiar and attractive to stoats, such as hen eggs.
Rats
Ship rats are omnivores and capable of eating a wide range of plants and animals, including eggs and young birds. They have directly caused or contributed to the extinction of many species of wildlife including birds, reptiles and invertebrates.
Rats are controlled throughout the year within the five core areas of TUMI. Many threatened species (e.g. kokako and robins) are especially sensitive to rat predation.
Rats are trapped using snap traps set in plastic corflute tunnels, with more than 5,000 traps used in TUMI. Traps are baited with peanut butter or white chocolate. Rats are controlled within all the Core Areas, an area totalling approximately 1,550 hectares.
Deer
Deer were introduced into New Zealand for hunting. Like possums and mustelids, deer have no natural predators in New Zealand. They pose a long term threat to indigenous forest, by limiting understory regeneration, and deprive native animals of essential food.
Intensive deer control has been undertaken by contract hunters in a a 2,500 hectare area at Otamatuna. This project aims to determine if it is possible for ground hunters to reduce deer numbers sufficiently for deer-palatable understory plants to become re-established at Otamatuna.
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