Deer Oh Deer
Deer Oh Deer
By Helen Bain
Kerry Hogan’s not sure what he’s done to deserve having most of the deer in the North Island on his patch, but it is a problem that is increasingly worrying him.
Hogan’s beat as technical support manager for the Department of Conservation’s East Coast-Hawkes Bay Conservancy covers nearly 600,000 hectares of conservation land, including Te Urewera National Park and Raukumara, Kaweka and Ruahine Conservation Parks. And deer are a growing problem in much of the huge, rugged expanse of forest here.
As with most other parts of the country where there are feral deer, deer numbers in East Coast-Hawkes Bay have increased since the collapse of the commercial helicopter deer-hunting industry early this decade.
Hogan shows us an area of the Raukumara Forest Park where deer numbers are low – “deer got here late and choppers got here early” – and the forest floor is thick with leaf litter, ferns and other low-growing plants, and a wide variety of seedlings grow up among the trunks of the mature trees.
In contrast, the forest he shows us at Wahaatua in the Urutawa Forest, north-west of Gisborne, where deer numbers are high, has virtually no seedlings present and the understorey is totally absent – all you can see are bare trunks and dirt below the canopy.
DOC’s exclosure plots – which fence off areas of forest to monitor the difference between browsed and unbrowsed forest – show a stark contrast: inside the fence is a lush profusion of greenery; outside the ground is bare.
Hogan says the deer strip the forest of the palatable species they prefer, such as pate, broadleaf, mahoe, hen and chicken fern and lancewood, reducing the forest to just a few non-palatable species.
The entire understorey of leafy shrubs vanishes, along with the tree seedlings that would have eventually replaced the mature canopy trees. Ground-covering plants and leaf litter is also gone, leaving the forest floor exposed to the impact of rainstorms and erosion. The food sources of fruit, seeds, insects and leaves that would feed native birds disappear; so does habitat for the birds and the myriad invertebrate species of the forest floor.
The forest Hogan shows us at Otamatuna Mainland Island in Te Urewera National Park, where intensive control of deer and other pests is conducted over 2500 hectares, is in good health. Palatable species such as native fuchsia, which wouldn’t stand a chance against high deer numbers, are thriving.
Monitoring of faecal pellet indexes (more commonly known in DOC parlance as “shit lines”) show that if deer control is intensive enough it will allow recovery of the shrub tier.
Hogan and the East Coast-Hawkes Bay region are not alone in facing an increasing deer problem. Senior technical support officer at DOC, Keith Briden, says the last estimate of New Zealand’s feral deer population was made in about 2000, and put numbers then at 250,000 nationally.
There have been wild deer in New Zealand since they were liberated here in the 1850s. From the 1950s-1970s, the Government paid deer cullers to shoot deer from the ground, till the commercial deer-hunting industry shooting deer from helicopters effectively took over.
Commercial deer-hunters were killing 18,000-20,000 deer a year, but since international venison markets slumped, the industry has been taking just 1000-3000 deer a year. Last year the take was up slightly to 5483, but the industry is virtually at a standstill.
DOC doesn’t have figures on how many deer recreational hunters take: NZ Deerstalkers Association spokesman Hugh Barr says a study in the late 1980s put the figure at 50,000 a year.
Briden is reluctant to hazard a guess at how much the deer population has increased since commercial deer hunting ceased, but he says deer population increases are a concern, particularly in Fiordland, South Westland and the Urewera Ranges.
However, the amount of deer control being carried out is negligible: publicly funded deer control is carried out on just 1.3% of the area where feral deer are found.
Briden explains that DOC priorities mean that pest control resources go first to target predators, particularly where they threaten to push endangered species to extinction. Deer, further down the ladder of priorities, miss out.
However, he says paying hunters to kill deer would only result in deer being removed from the most accessible country, leaving deer in the more inaccessible back country.
Briden agrees tenders could be sought for hunters to shoot deer in specific areas, but Government policy dictates that “market forces”hold sway, and paying people to kill deer is viewed as “subsidies”and therefore a no-go.
Briden is hoping for the recovery of venison markets, and says DOC is “holding off” for another year or so for that much-hoped-for revival, though he admits that pinning the fortunes of deer control to a boom-and-bust industry is not the most reliable long-term solution.
Hogan is wary of the “wait and see” approach. “It’s not panic stations yet, but we need to start making decisions about what we are going to do. The problem isn’t going away.”
He suggests “incentives” for the deer industry could support a solution that produces gains for both conservation and the industry.
The current price of venison at $2.50 a kilogram (down from a peak of more than $8) means commercial hunting simply isn’t financially viable – but if the price reached around the $5 mark, the helicopters could be whirring back into action.
Hogan suggests that top-up payments to commercial hunters could fund effective deer control at a fraction of the estimated cost to DOC of $150 per deer if it undertook deer control on its own. To avoid the deer hunters taking literally only the easy meat, payments could be conditional on hunters taking out a guaranteed number of animals from a specific area.
Hogan is optimistic about the chances of recovery of forests if deer are reduced.
“In just about every exclosure plot I have ever seen, there is a huge variety of species that come back - I am amazed by the resilience of the seed sources. But the longer you wait, the more you put that at risk.”
DOC remains unconvinced that recreational hunters can play a major role in controlling deer, particularly on the rugged back country. Hogan – a former deer culler himself – says he had a quota of 20 deer a month, while commercial hunters with helicopters would take 10 times that many.
However, the Deerstalkers Association believes recreational hunters can play a valuable complementary role in controlling deer, particularly in more accessible hunting spots.
Barr says claims that deer numbers are dramatically increasing and causing serious damage are “significantly overblown”. And he says deer hunters don’t want high deer numbers – deer are in poor condition when populations are high and make poor eating – and as much as conservationists they want to see a management regime introduced.
Forest & Bird Advocacy Manager Kevin Hackwell is increasingly worried by the fact that there has not been any effective control of deer for several decades.
“We know the damage is serious and is getting worse. Walking into many of our forests is like entering an empty cathedral –while there may be a fine canopy overhead, below there is just empty space.”
In some forests we are already starting to see total forest collapse caused by deer, Hackwell says.
“If we don’t move on deer control, the longer we wait the harder it is going to be to achieve recovery of the forests.”
Hackwell says increasing financial pressure on New Zealand to meet its international obligations to reduce greenhouse gas emissions may be the catalyst that sees deer control become not only affordable but a financial necessity.
Reducing the amount of forest destroyed by deer (and other browsers) would greatly increase the amount of carbon stored in our forests. Cutting deer numbers could significantly reduce New Zealand’s greenhouse gas liabilities, potentially saving the country hundreds of millions of dollars That would pay for the cost of deer control many times over.
“It’s not a case of ‘can we afford to control deer?’ It’s a case of “we can’t afford to NOT control deer’.”