Watch out for wallabies is the message as Environment Canterbury considers the viability of fencing to stop the spread of the pests across the Tekapo River.
ECan and the Otago Regional Council have joined forces to control wallabies as the Ministry for Primary Industries (MPI) warns that, left unchecked, they could cover a third of New Zealand over the next 50 years.
MPI estimates the economic impact of wallaby spread, including lost farm production, could reach $84 million by 2025.
Wallabies are considered a pest under regional pest management plans because of the harm they cause to biodiversity and productive land.
Both councils have erected signs along their borders urging anyone has seen a wallaby outside the containment area to report the sighting.
Canterbury has a containment area for wallabies that includes 900,000ha of land in South Canterbury.
In Otago, wallabies are listed as an eradication species with all efforts focused on the complete removal of them from the region.
To do this, the regional councils need the public to report sightings outside of the Canterbury containment area, ECan wallaby programme leader Brent Glentworth said.
This refers to all locations south of the Waitaki River, north of the Rangitata River and westwards from the Lake Tekapo River system.
Glentworth said the regional council is exploring the feasibility of up to 55km of wallaby fencing to stop the spread of the pests across the Tekapo River system into the Mackenzie Basin.
The fencing would also be rabbit-proof.
“We have got to get good facts around the cost and what the fence would look like and for that we are seeking registrations of interest to get a more accurate idea,” he said.
Initially the council is looking at the cost of materials and construction for 15km of fencing with the fence extended each year as fund permit. The fencing, while only marginally bigger than a stock fence, will require consent.
Mackenzie Mayor Graham Smith applauded the fencing proposal.
“Our council is right behind this. Wallaby is a pretty troublesome pest, they eat a lot of food and are very destructive to farming,” he said.
The number of wallabies in the Mackenzie district has risen substantially and it is important to protect the Aoraki/Mt Cook National Park from the spread, Smith said.
“There has been a fence in the past, a rabbit fence, but it has fallen into disrepair and is no good for wallaby so we are keen to see a new fence going forward and one that is both wallaby and rabbit proof makes good sense.”
The Mackenzie District Council is hopeful the fence will run up the eastern side of Tekapo up to 6000 feet, between Lake Benmore and Tekapo.
“We have told ECan we don’t want Tekapo cut in half.”
Smith said currently wallaby is a risk not a problem in the region “but we don’t want the problem”.
“If we have a chance with the river as the boundary, and a fence to reinforce that, with our focus being to protect our national parks and the Mackenzie Basin, then we are right behind that chance,” Smith said.
“Obviously, it has got to fit our district plan and will require consent accordingly.”
The Bennett wallaby, the species that is the focus of eradication efforts, was introduced into New Zealand for recreational hunting in the 1870s.
The animals have been steadily increasing in density and geographic range since user-pays control was adopted in 1992.
The $27m MPI-led, four-year National Wallaby Eradication Programme (NWEP) launched in July 2020 is a partnership programme that includes regional councils, the Department of Conservation, Land Information NZ, iwi and Federated Farmers.
ECan holds the funds for the control work within the Canterbury region, but the number of wallabies spotted beyond the containment area is growing rapidly.
Last year there were 630 reported sightings, up from 405 in 2020 and 307 in 2019.
Meantime Glentworth said programme control continues, with the primary control measures being ground hunters and dogs, thermally equipped drones and aerial surveillance with dog teams and shooting.
“However, longer-term solutions will require some deeper thought with the farming community at the heart of these discussions.”