DNA from deer droppings aids eradication plan

27 May 2021, 1:34 PM

Droppings from a herd of several dozen deer living in and around the Russell Forest are being collected for DNA analysis as part of a plan to eradicate the animals within the next three years.

Iwi, DOC and the Northland Regional Council share a vision of a deer-free Northland and central to that is eradicating the wild offspring of sika deer (Cervus nippon) illegally released into the Russell Forest in the late 1980s and other deer also thought to have been unlawfully set free there since.

Despite ongoing – and successful – efforts to reduce their environmental impacts and prevent the deer spreading to other parts of the region, officials have been unable to eradicate them altogether, estimating there are now 50 to 60 deer living in the forest and surrounding farmland.

Two men in a forest. One is holding a sample of deer droppings.Professional hunter Jordan Munn, of Upper Hutt, with a sample of droppings collected for DNA analysis. Watching on is Rawhiti local Andre Witehira.

Jack Craw, Chair of the regional council’s Biosecurity and Biodiversity Working Party, says with that number of animals, it’s estimated the herd could double in size in the next three years unless they’re eradicated, which is where the DNA testing has an important role to play.

“The DNA survey at a large property in the Russell area is the first step to eradicating sika deer from the area via the Russell Sika Eradication Programme.” “It will be a ‘proof of concept’ to provide costs and effort data which can be modelled for the wider Russell forest sika eradication.”

The farm was chosen because it is known to have sika living and potentially breeding there. The survey involves collecting sika scat/pellets along set transect lines across the roughly 700 hectare property.

“Sika pellets are collected, and each sample is recorded on a GPS. The samples are then sent to lab to be analysed.” “The DNA from the pellets will be able to tell us the number of individual sika, the sex and the home range of each sika on the property.”

Councillor Craw says the methodology for the survey is based on “science, expert technical advice and advice from Norm MacDonald, deer eradication expert from the Department of Conservation who has international experience in large mammal eradications”.

The council says the project also aims to empower ngā hapu in their kaitiaki role in Russell and ensure their sustained involvement in keeping pests, particularly wild deer out of the ngahere (forest).

Biosecurity Manager Don McKenzie says 30 years ago there were no known feral deer in Northland, but they’re now thought to be living in the wild in more than half a dozen locations; most the legacy of farm escapes, the balance illegal liberations sourced from other parts of the country.

Feral deer are officially classed as an ‘eradication species’ in the north and while overall their combined numbers aren’t huge, ‘they’re definitely not wanted here” and it’s illegal to release or move wild deer in or around the region.

He says community leaders and local hapū have made it clear through correspondence and hui that wild deer are not wanted in Russell or in Northland.

“Letters of support and endorsement for the latest operation have also been received from the Northland and Te Hiku Conservation Boards and DOC’s Director General.”

Councillor Craw says feral deer are an issue because they’re selective browsers, targeting particular forest species over others which can substantially alter a forest’s make-up, along with associated negative impacts on the fauna that rely on those plants.”

As well as destroying the understorey of native forest by browsing, grazing, bark stripping and trampling (which can all increase soil erosion) feral deer can also damage crops and exotic forests and have been implicated in the transmission of bovine tuberculosis.

“Similarly, our kauri forests are already at risk from kauri dieback and wild goats and pigs – and in some places wild cattle – are adding to that pressure; we don’t want another large hooved animal like deer spreading soil and disease through our forests.”

The regional council is urging anyone who sees or hears wild deer to immediately call a 24/7 Deer Hotline ‘0800 FIND DEER’ (0800 346 333).

Meanwhile, it says more information about feral deer is available online from www.nrc.govt.nz/pestcontrolhub