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Published: 2009-09-07 00:00:00

Trapping, ground-based bait stations and aerially applied baits have all been used in a highly successful possum control operation over more than 17,000 hectares west of Otorohanga in the Waikato.

The work in steep and rugged native bush, and farmland areas, of the Hauturu-Awaroa priority possum control area (PPCA) was funded by Environment Waikato and the Department of Conservation, and was carried out by EcoFX Ltd. The area is a PPCA because of its vast stands of native bush, which support indigenous bird and animal life.

Local landowner Fiona Scott, a member of the steering group which oversaw the work, said: "The operation was carried out in a very professional way – the results reflect this."

Environment Waikato has been working alongside landowners in the area since 1998 to control possums.

Half of the area is in private ownership and the other half administered by DoC. In the past, 1080 has been used to successfully control possums on the DoC-administered land and some private land. Other farmland has previously been controlled using ground-based methods and was largely carried out by landowners, who had problems getting pest numbers down to the required level.

A change to EW’s possum control policies in 2007-08 meant that the council would fund the project from rates and carry out possum control on behalf of landowners within PPCAs. This meant that control on the DoC and private land in the Hauturu-Awaroa could be carried out at the same time this year.

EcoFX Ltd used helicopters to apply baits over about 8,800 hectares of DOC and private land, while the remaining 8,725 hectares of private land was treated using bait stations filled with toxins such as brodifacoum and cholecalciferol in conjunction with encapsulated cyanide. Some trapping was also used. All work was carried out with no incidents or controversy over 1080 which reflects the strong level of community support, and the effective consultation undertaken by EW and EcoFX Ltd.

Subsequent monitoring, which measured the number of possums caught in traps, showed EcoFX had exceeded their performance targets, achieving results of:

· 0.36 per cent residual trap catch (RTC) in the aerial operation (this equates to four possums caught from over 1100 trap nights)

· 2.06 per cent RTC for the ground control operation (or 14 possums caught from 690 trap nights).

DoC spokesman Dave Smith said the results were good news for native trees and animal life. "The monitoring results after the aerial operation equated to only four possums being caught in more than 1000 trap nights. That’s great news for trees and bird nests in particular.

"On top of that, DoC has recently taken more than 3000 feral goats out of the area. Goats can be particularly damaging to a range of palatable plants on the forest floor."

EW project manager Brett Bailey said the operation had clearly delivered good results for the investment made over the last decade. "The work we have done around Pirongia and west of Otorohanga is about supporting a key area for native birds and trees in our region. Controlling pests such as possums in these parts of the Waikato makes a big contribution to protecting our natural heritage in the region."