A SIKA deer and fawn in the Kaimanawas. What is apparent is the complete lack of understory in the background, a sign of overpopulation.
THE Department of Conservation (DOC) is being told by Forest and Bird (F&B) to step up and massively increase control of deer, goats, pigs and possums to reduce the methane from these animals. By doing so, it’s expected to protect New Zealand’s massive carbon storage on public conservation land.
NO EMISSIONS TAX While farmers are facing taxes for the methane emissions of the animals they raise, DOC faces no emissions tax on the growing feral numbers on the DOC estate. The Department of Conservation’s current approach puts farming deer on behalf of hunters ahead of protecting nature, meeting New Zealand’s climate change goals or preventing deer from invading neighbouring properties, F&B chief executive Nicola Toki said. It’s time for a fresh approach and better funding, she said. The details of the amount of methane released by wild deer, goats and possums listed in a Forest & Bird commissioned report released in 2021 estimated wild deer produced 16.5 kg of methane per animal per year, while individual feral goats produced around 10kg CH4(methane)/yr. This was equivalent to around 410kg CO2e/animal/yr and 250kg CO2e/animal/yr respectively. The numbers of feral animals was not known, but it was growing according to local hunters and F&B. One Te Kūiti-based deerstalker said he no longer considered himself a deerstalker, he was just a deer culler. F&B’s concern was the damage the wild herbivores were doing to the country’s natural carbon sink, the bush. A report: Protecting Our Natural Ecosystems’ Carbon Sinks by Kevin Hackwell & Maitland Robinson for F&B in June 2021, said more than 6500 million tonnes of carbon was sequestered in natural vegetation and soils. Nearly 1500 million tonnes was stored in the above-ground vegetation of natural ecosystems (mostly native forests). The sheer size of the stocks meant that even small changes in their condition, either positive or negative, could have a significant impact on the profile of the country’s greenhouse gas emissions.
DECLINE Kāmahi-podocarp forest – the native forest type that makes up 10% of all native forest – underwent a significant decline in stored carbon between 2002 and 2014. Herbivores are blamed as the most likely cause. The annual loss of carbon from the kāmahi-podocarp forests was equivalent to 3.4 million tonnes of CO2 – three times the 2018 domestic air-travel emissions, or 80% of the extra annual sequestration that the Climate Change Commission hoped could be generated in the medium term by new native forest plantings. Feral herbivores produce an estimated methane equivalent to 3.1 million tonnes of CO2 each year, the study said. The F&B study estimated the mid-point figure for carbon sequestration reductions due to browsing damage was a further loss of 8.4 million tonnes of CO2e per year – equivalent to nearly 15% of 2018 net greenhouse gas emissions, or nearly 60% of 2018 road transport emissions.
THREATS “If you have introduced animals that are destroying your forests – at a cost of up to 15% of our 2018 net carbon emissions – you don’t ‘manage’ them. You treat them as threats, just like rats and possums,” F&B’s chief executive, Nicola Toki said. Forest & Bird, along with farmers, foresters and QEII covenant landowners, were spending millions to control feral animals which were overflowing from public conservation land and threatening to destroy these efforts overnight. “Treating New Zealand’s native forests as a free lunch for deer, pigs and goats is such a missed opportunity for wildlife and the climate, and it’s gutting for all the community groups putting in the hard yards to protect nature,” Nicola said. “Forest & Bird’s local members have had to take extreme action to protect our own reserves from invading herds of feral deer spilling out of conservation land. “We’ve erected a deer fence around a Hawke’s Bay reserve and employed professional hunters in our reserve in Southland. “The department in charge of public forests needs to do its job and put in place a framework that actually sets out how it will control the wild animals destroying our forests and undermining New Zealand’s collective efforts to tackle carbon emissions. “All New Zealanders are being asked to do their bit to tackle climate change. We need DOC to play its part and look after our key native forest carbon sinks.” DOC said it does not collect information on how many deer and goats are present on its estate.
