This story was originally published on Newsroom.co.nz and is republished with permission.

The University of Auckland's Dr Cate Macinnis-Ng makes a case for why we can't leave our vulnerable native species to fend for themselves in forests where predators roam

OPINION: Debate on Newsroom this week has explored different sides of the 1080 debate, asking us to consider animal suffering when weighing up use of toxins to control predators. There are two points I would like to make about 1080 use that I don't think have been fully addressed in a debate that can feel very polarising at times.

As a scientist, I understand that science doesn't happen in a vacuum, it happens within a community and a society where many things come into play, not least things like values and beliefs. It is important for scientists to listen carefully to community concerns and take time to reflect on how the science message is received in the wider population.

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I am not an expert in pest control or invasive species management but in my role as President of the New Zealand Ecological Society (NZES), I have had to inform myself about the science and social climate of this issue because invasive species pose the greatest threat to our treasured biodiversity.

I have met people working on the front lines of conservation. People involved in projects aimed at conserving our most endangered birds, committing their time and effort into managing and building native species' population numbers to ensure their ongoing survival.

Without pest control of all kinds, these conservation programmes would fail. Conservation in Aotearoa New Zealand simply wouldn't happen without intervention by a wide range of organisations and people including government agencies, communities, neighbourhoods and individuals.

I've also met people working on alternative methods and approaches to protecting our native species. An excellent piece on 1080 alternatives by the Director of New Zealand's Biological Heritage National Science Challenge, Dr Andrea Byrom, lists some of the novel pest control technologies in development.

All of the people I have met working in conservation and new methods of control are thoughtful, caring and compassionate. Nobody I have talked to enjoys using 1080 and everyone I've talked to wishes there were a viable alternative.

What is important to emphasise, and something I worry the public doesn't fully understand, is that 1080 is not used 'indiscriminately', its use is carefully planned according to stringent regulations and communication protocols.

While we can always have more communication and further research, it's important we acknowledge that 1080 is one of the most effective tools in our pest-control arsenal and until better methods are developed and widely available, we simply cannot leave our vulnerable native species to fend for themselves in forests where predators roam.

We hear of threats to Department of Conservation staff on the 1080 issue and while understanding that different views are strongly held, this cannot be okay for people who are being paid to do their job.

The second point I would make has to do with existing alternatives. Many opponents of 1080 suggest using traps instead. Our 2017 Te Tohu Taiao award winner (the NZES prize for outstanding contributions to Ecology) was Graeme Elliott of the Department of Conservation. In his plenary address at our annual conference in Wellington last year, Dr Elliott presented data comparing trapping versus aerial 1080 approaches for a 70,000 ha site in the rugged West Coast Paparoa Ranges.

For stoat control, best practice is one trap per 10 ha which equates to 316 m of track per trap. For rats, its one trap per ha, equating to 100 m of track per trap. The track distance is how far a person needs to travel between traps to set them up or check them. So, for rats in the Paparoa, it would require 70,000 rat traps, 7000 km of track and at least 700 person days to get around to each trap just once (in good weather).

For DOC's planned one million ha of 1080 for 2019, they would need one million traps and 100,000 km of tracks to service them, which would require 10,000 person days. Remember, that's just for rats. Stoats would be extra work on top of that.

So we can see this approach would be prohibitively expensive. More to the point, in highly rugged and mountainous terrain like the Paparoa Ranges, it is practically impossible in terms of health and safety and the practical limits of DoC staff and their time. Even where terrain is more accommodating, trapping causes trampling of bush and creates pathways for dispersal of weeds and pathogens like kauri dieback.

Aside from these facts, the SPCA has raised its concerns about the humane death of species we are trying to control. Many people have contributed to this aspect of the debate and it is entirely understandable the SPCA is concerned. But we are fooling ourselves if we think that death by predator is a somehow quicker or more humane death than poison. Predators, particularly rats and possums, are rarely humane when they kill their prey - they often start eating before they kill.

As well, pest populations explode when food supplies are plentiful during mast years when trees produce high amounts of seed that drop to the ground to be eaten by predators such as rats, stoats and possums. As food supplies from the mast event dwindles, these pests turn to native wildlife as an increasing part of their diet.

After a mast event, large populations of rats, stoats and possums can no longer be sustained, resulting in death by starvation. It's worth noting that Dr Elliott is not convinced deaths caused by 1080 are better or worse than dying of starvation in the middle of winter, or being killed by a predator.

This debate can seem polarising at times and I think it's important we do our best to remain open-minded and respectful when others express views that don't align with our own. The SPCA is of course right that we need more research to find and develop new approaches. But as a scientist and ecologist, I support the use of 1080 as the best tool we have at this time, and until we have other options, we need to use it because our endemic species cannot afford to wait.

This story was originally published on Newsroom.co.nz and is republished with permission.