By Jamie Steer and Rowan Taylor
Scientists tend to shape our beliefs about wildlife in New Zealand, and particularly how we think of introduced species. But what are we to think when scientists disagree?
Conservation biologists, for example, tell us that introduced wildlife are invasive environmental and economic pests while fisheries and waterfowl biologists tell us that they are valued additions to our environment and economy.
The question one of us asked in a recent article in the New Zealand Science Review is: Which view is correct? That article took a look back at the history of scientific research on introduced species in this country and found some surprises.
First, scientists’ views on wild exotic plants and animals in New Zealand have changed quite a bit, so can we be confident that the current views will be any more durable? When early European settlers were importing new bird, mammal and fish species in the mid-19th century, most scientists were pretty keen on it. They were happy to see the familiar species from home added to the rather drab New Zealand wilderness Darwin had described as gloomy and silent when The Beagle visited in the 1830s.
When, in the late 1800s, Acclimatisation Societies were set up to run the introduction business, local scientists were among their foremost members. At the time, these scientists thought it inevitable that the weaker native species would be replaced by more robust European ones. Conservation of natives, where it was considered, was largely restricted to preserving dead specimens for posterity – hence much effort was devoted to shooting them, stuffing them, classifying them, and propping them up in museums.
To be fair, most scientists at the time were more in the vein of gentlemen poets – typically hobbyists and generalists rather than lab-coated specialists. They were not conservationists in the modern sense of the world. The wilderness they sought was a vigorous hybrid of the native and the new in which the introduced species would add colour, variety, and recreational and economic opportunities – making the now vilified Australian brush-tailed possum, for example, seem like the perfect addition.
In the latter part of the 19th century, however, scientists’ attitudes started to shift more toward those we would recognise today. This change seems to have been driven more by cultural values and fashions than by scientific research. As the first wave of overseas-born settlers gave way to New Zealand-born second and third generations, nostalgia for Europe was replaced by a new found pride in their southern home. Native species started to be celebrated and introduced ones denounced, especially if they appeared to compete with or prey upon native species.
This new attitude applied mainly to native birds and the species that threatened them, but introduced fish maintained their privileged status. Acclimatisation Societies, for example, waged regular pogroms against several native species that competed with trout, notably shags and eels. The goal was to preserve the New Zealand native landscape, but to stock it with exotic fauna for rich tourists to hunt.
From around the 1930s, wildlife management as a scientific discipline began to develop in New Zealand and, with it, more rigorous scientific methodologies. Most of this research was initially directed toward showing how to produce ever-greater numbers of introduced fish and game animals. But as people became increasingly convinced of the superiority of natives, more and more conservation science was directed toward demonstrating this as well.
This direction became further entrenched after the development of restoration ecology in the 1980s with its crushingly nostalgic focus on a pure and pristine New Zealand wilderness. Today, there’s a lot of advocacy science going into showing the positive aspects of our native birds and plants and the negative aspects of introduced species – except for fish, game and farmed species.
Much of this research is now used to justify the spending of millions of taxpayer dollars on pest control, even while one of the main pests, the possum, does not always live up to its wicked reputation. A deep belief in conservation circles, for instance, is that possum herbivory is a prime cause of native tree canopy loss. However, the only long-term study designed to confirm this found just the opposite – no difference at all over a decade between possum-infested and possum-controlled plots and no adverse possum impacts on tree health, size or abundance.
Studies like this are rare, however. We don’t get much research investigating the potential benefits of wild introduced species, nor for that matter, the impacts of game species on natives. There’s a lot of research showing how desirable past ecosystems were but very little looking at how we might move on to desirable novel ecosystems in the future. The reason for that is pretty straightforward: such research does not tell conservation, pest control and fish and game advocates what they currently want to believe, so no one will fund their investigation.
Which scientists are we to believe?
To return to the question posed by this article, which scientists are we to believe? We think the answer is that all are telling a subset of the truth about introduced wildlife, but it is not a balanced or objective subset. Because scientists, like everyone, are guided by their values and worldview (and even more so by those of their funders and employers) they tend to focus on questions that do not challenge their own underlying beliefs.
As a result, the small subset of the truth that they tell us is conditioned by a kind of ecological xenophobia – the idea that, in our wild places (though not our farms and towns) natives are good and exotics are, by definition, bad. This idea forms their null hypothesis, which is assumed to be true unless strong contrary evidence is found. It stands to reason that if no one is looking for contrary evidence, it is a null hypothesis that will never be rejected.
To get a more balanced picture and make a more accurate assessment of the role of wild introduced species, scientists need to be more open about their values and acknowledge how those values influence the questions they choose to ask, and where they work and the questions they will be allowed to ask. And, of course, scientists need more support from the many other fields – most notably in the arts – where values are dealt with more openly and not submerged beneath a veneer of objectivity.
How we choose to see introduced species is a matter for the whole of society to debate and explore. Let’s not rely on the current enthusiasms of some of our biologists.
Dr Jamie Steer has worked in a range of different roles in the environmental services industry, including as an ecologist for an environmental design consultancy. He is particularly interested in challenging current attitudes toward introduced wildlife.
Rowan Taylor has had a long-standing interest in global environmental issues from co-founding Project Jonah and instigating the Marine Mammals Protection Act in the 1970s to producing New Zealand’s first State of the Environment report and representing NZ at the OECD’s Group on Environmental Performance in the 1990s. His current interests focus on the environmental costs of livestock production and the impacts of dietary choice on climate change and water degradation.
Featured image: A taxidermied stoat, Museum of New Zealand, Wellington.