M. bovis - we need to be vigilant
From November 1, 2023, Ministry for Primary Industries’ Mycoplasma bovis Eradication Programme has been contracted out to disease management agency OSPRI, as it enters a long-term surveillance phase.
It's another step in eradicating bovine tuberculosis from New Zealand, says Ospri (formerly Animal Health Board).
The proposed TBfree operation is supported by the Department of Conservation, and community consultation and public meetings are scheduled to determine the exact size of the control area, water supplies and exclusion zones.
The proposed area includes the East Harbour Regional Park where the Eastbourne Forest Rangers have been killing possums since 1933, and the Orongorongo Valley, where community groups such as the Moa Conservation Trust have worked hard on voluntary possum kills. The wider southern Rimutaka area has not been treated by air before.
The farming region of South Wairarapa on the eastern fringe of the southern Rimutaka has a history of TB in cattle herds going back 30 years, and the link with tuberculous wildlife is well established.
Possums are the main 'vector' (transmitter) of TB among cattle. Possum surveys in 2008 by the Animal Health Board (now Ospri) and more recently by Landcare Research found TB-infected possums in the forest park.
Ospri, which manages the TBfree programme, aims to eradicate bovine TB in livestock by 2026 and in wildlife by 2040. To eradicate bovine TB, possum numbers need to be kept extremely low – one to two possums in every 10ha.
DOC says the conservation values of the area, including lowland forest and threatened bird species, make southern Rimutaka an important target area. It is used extensively by walkers, runners, trampers and hunters and the owners of the park's network of huts.
DOC Kapiti-Wellington operations manager Rob Stone says the operation will knock down the possum population and will slash rat and stoat numbers. Among the species to benefit are rata, kiwi, kakariki and NZ falcon. Possums, stoats, ferrets and rats, wreck the habitat that supports these native birds.
Large rata trees dominate the forest canopy in the Orongorongo Valley. "These ancient trees are seriously threatened by possums which show strong preferences for browsing this species," says Stone.
Kiwi have been re-introduced to Rimutaka Forest Park, but protecting them against mustelids requires constant control work.
Rugged terrain is difficult country in which to trap possums. GPS navigation equipment will be used to ensure accurate drops of 1080.
OSPRI's chief operating officer, Matthew Hall, says aerial drops achieve fast and accurate kills, and ground-based control has benefits for protecting kiwi and other native species.
The effectiveness of the operation will be monitored via a survey of wild pigs in the area. The absence of bovine TB in captured pigs will guide the next steps in the TB eradication scheme.
