Grant Guilford: Dung beetle plan a risky gamble

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Proposal to introduce the insect has been poorly thought out and the impact of such a move underestimated.

Dung beetles hasten the burial of livestock dung but the risk they pose to human and animal health has not been researched. Photo / Supplied
Dung beetles hasten the burial of livestock dung but the risk they pose to human and animal health has not been researched. Photo / Supplied

A controversial decision by the environment authority to approve the introduction of 11 new species of dung beetle to this country has exposed serious weaknesses in our biosecurity processes.

Doubts about the proposed benefits and concerns about potential risks have been voiced by knowledgeable staff from the Auckland Council, Auckland Regional Public Health Service, Crown research institutes, farming organisations and universities here and in Australia.

These concerns have arisen because the science behind the approval was inadequate, the approval process substandard and the scale and potential impact of the introduction underestimated.

The goal is to hasten the burial of livestock dung by establishing "millions" of dung beetles in all regions, flying day and night through all seasons. These large beetles can fly long distances, some species are attracted to lights, and all are vulnerable to predation. Not surprisingly, they carry faecal pathogens like E.

coli and salmonella, and they appear capable of transmitting these pathogens from farm to farm across regions as well as to urban communities, wildlife and companion animals. This prospect raises many important questions. For example, how often will large numbers of beetles be drawn to the lights of houses?

This already occurs in one small area of Northland thanks to the earlier establishment of Mexican dung beetles. Infestation in this region can be so heavy that shaking dung beetles out of your boots has become part of the morning ritual. What are the risks to children if they handle the pathogen-laced beetles?

Could the beetles complicate control of bovine tuberculosis or Johne's disease, impair food security and trade by spreading feared pathogens like E. coli 0157:H7, or impact on our ability to contain exotic disease incursions? What effect will eating contaminated beetles have on free-range poultry and pigs, companion animals and iconic wildlife like moreporks? These questions, and many more like them, remain unanswered.

Assurances that dung beetles have been shown to be safe in Australia have proven to be incorrect. Experts there admit that nobody has actually looked at the role (if any) dung beetles play in the thousands of undiagnosed gastroenteritis cases that occur daily. Similarly, the claim that the risks will be offset by reduced fly numbers has been quashed because, unlike Australia, we don't have the troublesome flies that breed in dung. Rapid, shallow burial of dung may not be as beneficial as speculated and may actually increase levels of some pathogens and parasites in soils because of their protection from the sanitising effects of sunlight and drying.

The assumption that dung beetles won't add to existing transmission pathways ignores distinctive features of dung beetle biology including their upwind flights, role as a parasite host, and periodic abundance - at times flying in their thousands. And on the debate goes, fuelled by uncertainty and untested assumptions.

So why would the EPA approve an "experiment" of this unprecedented scale before establishing the significance of the risks and the magnitude of any benefits in the New Zealand context? The EPA is a small group. To make good decisions it relies on three critical factors: an application supported by independent, high quality science free of advocacy; effective consultation by the applicant; and supportive relationships with other government agencies that have relevant knowledge. None of these factors was present in this particular case.

The relationship between the Landcare Research scientists, farmers and others in the Dung Beetle Release Strategy Group (DBRSG) became so intertwined that the identity of the applicant was unclear to the EPA. The enthusiastic scientists in Landcare Research fell into the trap of advocacy - something scientists must guard against to maintain objectivity. The result was an application to the EPA that exaggerated claims of benefit and understated risk. Stakeholder consultation by the applicant was ineffective. Those farming groups that were consulted were sold the upsides and not informed of the downsides - another feature of advocacy.

As a result, key risk managers in - for example - the dairy industry weren't brought into the discussion until after the EPA approval. The public health and veterinary professions along with whole sectors of the animal industries that bear some of the risk, including deer, pork, equine and poultry, were largely in the dark, as were pet owners. Lastly, the EPA had great difficulty in getting effective engagement from other government ministries. The result of all of this was a deeply flawed decision to release dung beetles "without controls" - reversing MAF's previous stance.

New Zealand's biosecurity deserves better protection. The EPA must improve its performance. Recent steps to add veterinary and public health expertise have been welcome changes. However, the authority must be absolutely sure of the independence of its scientific advice and the larger ministries must be prepared to more meaningfully engage with the EPA. Accountability will be better served if applications from informal groups like the DBRSG are discouraged and if all approvals for field release are followed by careful monitoring.

In this particular case, a technical committee has been belatedly formed to initiate at least some of the omitted research. Unfortunately, it is convened by the DBRSG and lacks the legal authority of the EPA. As a result, the dung beetles can now be released into our environment at the whim of the DBRSG.

If the beetles are released before the uncertainties are adequately resolved by research, we will be relying on luck to avoid yet another national biosecurity misadventure. No matter what the outcome of such a gamble, those who have put our biosecurity at unnecessary risk by their actions, or by their inaction, deserve censure.

Professor Grant Guilford, is Dean of Science at the University of Auckland.

- NZ Herald

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