health & science

Hello cows, bye-bye rare beetle

Search for Eyrewell Forest on Google Maps and you won’t find a forest. In fact, what you see looks similar to surrounding Canterbury farm land.

What was once a forest is now home to 14,000 dairy cows. Satellite photographs show a tell-tale pattern of circles where centre-pivot irrigators are busy creating grass where trees once stood.

The forest was home to a small, dark brown beetle commonly known as the Eyrewell ground beetle. Globally, only 10 have ever been found. All were found amongst trees in Eyrewell Forest, the last in 2005.

The beetles’ home was returned to Ngāi Tahu as part of a treaty settlement in 2000. Since then the 6700 hectares of plantation pines have steadily disappeared and dairy cows have taken over.

“The success and effectiveness of Ngāi Tahu Farming is connected to the health and wellbeing of the lands, waterways, plants and animals under our care which is central to our kaitiakitanga values.”

The march of chainsaws, shredders and pivot irrigators continued despite eight years of effort by the Department of Conservation (DOC) to convince Ngāi Tahu Farming to save some the beetles’ habitat in reserves.

In October 2018 Ngāi Tahu Farming told Stuff  the last of the forest would be removed for the intensive dairy conversion. Its CEO Andrew Priest said the organisation turns to Ngāi Tahu values guide their farming.

“The success and effectiveness of Ngāi Tahu Farming is connected to the health and wellbeing of the lands, waterways, plants and animals under our care which is central to our kaitiakitanga values.”

According to him 120 hectares of plantation pine has been retained. From aerial photographs it appears this has been done only in one area where beetles were possibly found. Other areas where beetles were found are treeless, one area has a small amount of scrub.

Priest said Lincoln University has been surveying the likely remaining spots of the beetle since 2013. No beetles have been found. He said search efforts will be abandoned in 2020.

The risk of extinction is so extreme one scientist, Eckehard Brockerhoff, who found five of the 10 collected beetles, is considered penning an obituary.

If he does, the obituary will be scant on detail of the beetle as so little is known about it. It’s a bit over 1cm long, nocturnal, and scientists think it lives for two years.

Wingless and described as a “moderate” runner it has managed to move from the kānuka it inhabited in the 1920s to the plantation pine which replaced it. It could even be called tenacious, as it also survived repeated rounds of removing and replacing areas of plantation pine as areas of forest were progressively logged and replanted.

Whether its tenacity could survive the dairy conversion is another matter according to Brockerhoff who spent thousands of trapping days attempting to find the beetle in the early 2000s. His efforts netted five beetles.

“It [the dairy conversion] involves felling all the trees, ripping out the root stock and then pretty much mulching the coarser woody material which is left behind into small chips. They took like a giant shredder over it. It was a very effective method of not only shredding any plant matter, but any invertebrates that are larger than a pinhead. I didn’t think the beetles would have stood much of a chance to survive in those converted areas.”

In the views of the scientists, setting aside a reserve of plantation pine where beetles were found in the 6700 ha property could have given the beetle a fighting chance.

Eyrewell Forest. Red dots show approximate locations where Eyrewell beetles were found by Brockerhoff. Yellow dots are probable locations of previously found beetles. Image: Google Maps

Failed talks

Brockerhoff sums up Ngāi Tahu Farming’s reception to the idea of establishing a reserve to save the beetles habitat as “a bit reluctant.”

Documents attained under the Official Information Act show repeated efforts were made by DOC between 2005 and 2013 to promote the creation of a reserve.

Emails exchanges started off cheerfully. A 2009 email from DOC to Ngāi Tahu’s rural manager reads: “Just been chatting to [redacted name] here at DOC re the possibility of setting up a reserve at Eyrewell – the same chat we had about two years ago I’m sure you recall!!!”

Once trees started to be cut down and with no formal agreement about the creation of a reserve the tone grew more urgent. In internal DOC emails frustration is clear.

“It’s fine for private landowners to develop their land, however it seems absurd for us a community to be allowing the unplanned clearance of much of the forest when this will knowingly cause the extinction of Holcaspis [Eyrewell ground beetle] …”

A plan by Ngāi Tahu Farming to reserve 150ha of pine forest was called “commendable”, however, the location of the reserve was not in the area where the beetle had been found. Restoration planting Ngāi Tahu Farming was planning to undertake was also not considered to be a solution which would save the beetle.

“… preserving a small amount of their habitat before it is gone will give us a great chance of saving these species from global extinction and regional extinction respectively, and one that is far more effective than some-how recreating their habitat … some minor changes to the location and size of the reserves would effectively save these species from extinction.”

DOC staff listed their attempts at finding a way to save the beetles’ habitat through the district and regional council pathways. A judicial review was suggested, although it was noted this was with some nervousness as there would be several “legal fish hooks”.

There was no judicial review. After 2013, the emails stopped.

DOC Mahaanui operations manager Andy Thompson said he understood Ngāi Tahu Farming commissioned Lincoln University to help with restoration efforts after 2013. Thompson was not aware of what the outcome has been and whether DOC’s eight years campaigning for a reserve had any effect.

“DOC would have loved to have seen a reserve created and an Eyrewell ground beetle population flourishing. The reality is we can only provide advice for managing biodiversity values on private land or advocate through consent processes and district council plans.

“We don’t have the ability to directly manage private land.”

“The fact that most of the forest has gone and now no beetles are being found means they've likely already been driven extinct, and a couple more years of trapping will probably confirm that.”

Ngāi Tahu Farming’s response

Priest said the plight of the beetle was an issue of importance to Ngāi Tahu Farming.

“Since 2013, Lincoln University has been surveying the Eyrewell Forest area at the request of Ngāi Tahu and has found no beetles. They have surveyed in the likely remaining sites using the same techniques as the original survey and have not found any beetles after searching for approximately 30,000 trap days. These annual surveys will continue until 2020 at this stage.

“In this area, approximately 120ha of pine forest has been retained and at least another 100ha of land has been set aside for native kānuka shrub land restoration. The pine forest in the central section of the development has not been cleared away, which is important to note because it is in this area that Canterbury Beetles [Eyrewell beetles] were once recorded.”

Ngāi Tahu Farming have been asked to clarify where these areas are on an aerial map but did not respond prior to publishing.

Wikipedian-at-large and keen entomologist Doctor Mike Dickison has expressed concern over the plight of the beetles for several months. He was not impressed by Ngāi Tahu Farming’s efforts.

“The preferred habitat of the beetle is pine forest, and they've removed 98.3% of the pine forest, chipped and mulched what's left, and turned it into dairy pasture.”

With only one of the areas the beetle has been found in left as forest he suspects it will never be seen again.

“The fact that most of the forest has gone and now no beetles are being found means they've likely already been driven extinct, and a couple more years of trapping will probably confirm that.”

Mike Dickison visited Eyrewell Forest February 9. Photo: Mike Dickison

He’s not reassured by the claims of restoration efforts. During a recent visit to the area he saw planting in the corners of centre-pivot irrigated paddocks with dead plants.

A Lincoln University website show what it calls a “distributed forest” as being proposed for the farm. Concept drawings show thin rings of native trees surrounding centre-pivot irrigators.

Brockerhoff said when he was in talks with Ngāi Tahu Farming it hoped shelter belts which were going to be established between irrigated paddocks would provide enough habitat for the beetles. 

“We suggested a single row of trees in the landscape established after the habitat conversion would probably not do the trick.”

He was unsurprised at the news no beetles have been found since he found the last one in 2005.

“I think the surveys done from 2013 onwards was after the pine forest had been cleared.”

He said while guesswork was involved, it’s probable no beetles have been found because the forests gone: “The shredding and the mulching would not have left a lot of invertebrates behind.”

While 120ha might sound like a large area it’s still a limited habitat according to Brockerhoff.

“Even if there is a population there, there’s no guarantee they can actually survive there.”

"The decision to convert Eyrewell Forest to pasture has been driven by an economic assessment of profitability, with little consideration of biodiversity values."

Why can’t we save a beetle?

Insects on private land don’t have much protection. The only exception is if they are listed as protected under the Wildlife Act. Despite being on a DOC list of 150 conservation priority species, the Eyrewell ground beetle is not on the list of protected insects.

A draft policy for indigenous biodiversity has been written which could cover insects in the future, however, there’s disagreement about plantation forests. The Forest Owners’ Association and Federated Farmers want a special exclusion stopping any plantation forest from being classed as being worthy of protection, regardless of what threatened species might live there.

While most don’t think of commercial pine forests as hotbeds of biodiversity they’ve become home to a surprising number of New Zealand’s threatened species. A 2010 article published in the New Zealand Journal of Ecology found 118 species listed as threated live in plantation forests. These include birds such as kiwi and falcons, bats, fish, plants, and invertebrates like the Eyrewell ground beetle.

The article makes special mention of the Eyrewell forest:

“However, this forest, along with several others in this area, is currently being converted to pasture, primarily for dairying. The decision to convert Eyrewell Forest to pasture has been driven by an economic assessment of profitability, with little consideration of biodiversity values. If the conversion is implemented without setting aside adequate areas of suitable habitat for H. brevicula [Eyrewell beetle] (i.e. plantation forest or restored kānuka forest) then this species is likely to become extinct in the near future.”

Brockerhoff’s most optimistic view of the likelihood the beetles’ tenacity might help it survive the dairy conversion is far from inspiring.

“The chances aren’t too good but it’s difficult to say.”

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