As climate change progresses, more non-native species will be visiting our shores, our woodlands and fields – our rivers and trees. How people react when they encounter these new arrivals may determine our success in managing them. Without that management, our local flora and fauna, our food supplies and our health may be at risk. When an alien species can do that sort of damage, it gets labelled as an invasive species. In other words, it’s an arrival that really isn’t welcome.
Generally, the human brain is good at spotting new things. When something in the landscape looks unfamiliar, our attention is automatically drawn to it. The brain processes novelty in similar ways to how it processes reward, motivating us to approach and find out more. It’s thought we evolved this response partly to encourage us to explore and learn about the world. Generally, then, we love the different, the exotic. Indeed, it was the Victorians’ fascination with foreign plants that brought so many non-native species to our gardens. So, if a beautiful long-tailed blue butterfly flutters in from the Mediterranean, our response can be predictably positive. But, sometimes, we have past associations or information that suggests we should feel threatened by a new arrival. That, of course, motivates us to avoid rather than approach. Asian Hornets, for example, look like a larger version of insects we already know can sting. That makes us immediately more wary of them. But, importantly, the knowledge that these hornets feed on our native honey bees may prompt us to report the sighting. That can be a crucial step, because then the government can arrange for any nest to be destroyed. Sightings in the UK are rising, with 71 reported last year.
So our initial reaction may be based on past associations, but having accurate knowledge and understanding is important. First impressions can, after all, be deceptive. Take that beautiful long-tailed blue butterfly, for example. It’s currently not a UK threat because, since it started to arrive, it hasn’t been able to survive our winters. But the UK has been experiencing fewer and fewer frosts. And, in other, warmer countries, it’s labelled an invasive species that attacks pea and bean crops.
When we’re alerted to the danger, our dominant emotion can become something other than curiosity and wonder. We feel more negative emotions to an invasive species – not just avoidance, we even may want to act against the threat.
So maybe it’s all about knowledge – making sure people know which species are non-native threats and what they look like. One place to get that knowledge is your local conservation group. So, recently, I joined “The Friends of Brislington Brook”. These volunteers are trying to tackle Himalayan Balsam (Impatiens glandulifera), an invasive species threatening the banks of a local waterway.
There I met Andy, who explained how he’d initially had a very different attitude to Himalyan Balsam. “To me it was just a novel little plant. And it was only once I’d joined this group that I started to find out that it was the menace that it actually is. Nothing eats it, nothing predates on it. There’s no diseases. And so until we find some balance, then it is just going to increase and increase and increase. So the only thing that’s controlling it is groups like ours that pull the thing up.”
Himalayan Balsam tends to shade out other plants, growing and spreading quickly until it dominates. Its shallow root system means that riverbanks overcome by Balsam more easily succumb to erosion. That makes it not just a threat to local species but also to the basic structure of the adjacent land. I followed Leah, the lead volunteer, to a place where little else but Himalayan Balsam appeared to be growing. “You can see how it has completely shaded out any significant plant life in this little glade here. So we’re just giving the things that live underneath it a fighting chance. Because if they can grow bigger than the Balsam, then they’ll help us do our job.” It seemed a pretty daunting task to me but the volunteers also seemed very determined. “It’s a war of attrition,” Leah laughed. “We’re giving it a concerted effort at this time of year when it’s knee high before the seeds form. And, you know, both sides of the river would look like this if groups like us didn’t pull it up.”
Leah explained that her views towards this species had also changed as she learnt more about it. “It’s a pretty plant and I’m a gardener and I like pretty plants and I love nature. And at first, you know, I thought it was a bit of nativism. It would be like ‘oh, you know, those invaders coming to our island’. But once you read about the damage that it can do very, very quickly – it all of a sudden becomes extremely satisfying to pull it out.”
Leah’s idea that less rational things than ecology might influence attitudes seemed interesting, so I asked her more about this. “I was speaking to this one woman,” she told me, “who sort of thought that we were doing this in order to just eradicate any plant immigrants coming into the country. And it has sort of nationalistic overtones that we’re trying to do this – but it’s not that at all. There’s plenty of plants and species and animals that have come to the UK that live more or less in balance with the ecosystem. But the problem is this plant is not one of them. This will completely take over and, therefore, change the character of our woodlands so that there’s nothing left besides this plant.”
Leah’s remark about “nationalistic overtones” made me wonder our response to non-native species was just about what facts we possess. Was it possible that emotional and cultural biases get involved – like how nationalist or xenophobic we are? To find out more, I spoke to Dr Tanja Straka, guest professor in Urban Ecology at the Freie Universität Berlin.
The first thing I learnt from Tanja was that cities are actually a very likely place to find alien species. Partly, this is because they are warmer than the surrounding countryside. Plus they have features, such as impervious surfaces, that can make it more difficult for local species to maintain dominance. But there is also the human element. “They enter cities,” Tanja explained, “through trade and through the travel of people from Place A to Place B. Maybe accidentally or intentionally, they take non-native species with them.”
Tanja explained that people sometimes perceive non-native species as more colourful or cute. “And here,” she told me, “the experts are very worried that if people respond in favour of these species, without knowing the consequences, then it’s difficult to implement management decisions.”
I could understand someone might think a non-native species was more fluffy and cute just because it was different. To find out more, Tanja’s team asked 600 people in Berlin how acceptable different management strategies were for various species. They saw species they were reminded were non-native (like racoons and manadarin ducks) and some that were native (like foxes and mallard ducks). Tanja’s team was careful to select animals that kept basic features balanced between native and non-native. In the scenarios described to members of the public, the distance to the person’s home was also varied. That helped see if there was a “Not In My BackYard” or NIMBY effect. To discover what human traits were getting involved, she asked about peoples’ values, feelings and knowledge about different species.
Overall, Tanja found people weren’t that keen on destroying the wildlife around them. That was mostly true whether species were native or non-native, but she did detect some bias. “People were generally against lethal control of animals. They were also against eradication of plants. But once they learned that it was a non-native species, they were more open to control or eradication.”
Interestingly, gardeners seemed particularly to have a laissez-fair approach to non-native species. Tanja and myself found ourselves wondering why this might be. “When you think about gardens, like we also have a lot of non-native plants in our gardens, very ornamental plants. When we discussed it, we just came across also other studies showing gardeners especially have certain bonds with their plants.”
So, perhaps because many gardens already have so many non-native plants, gardeners are just more accepting of non-native plants. Compared with non-gardeners, perhaps a few more non-native species at their front door is not such a big issue.
But what about those values – is your attitude to non-native species influenced by xenophobia (i.e. how much you fear foreigners)? Well, based on Tanja’s data, apparently not. But she did see an effect of conservativeness (with a small “c”). “So if people really valued that things have to stay as they are, like these strong traditional values, they were strictly against not doing anything. It was not that they were suddenly (favouring) lethal control or eradication in general. They just said like, no, we have to do something.”
The effect of proximity wasn’t quite as expected. “We thought that we would find a much stronger effect of the NIMBY effect….but we only found a tendency for the NIMBY effect when it came to plants……a feeling ‘I need to have control about this non-native plant if it’s in my backyard.’”
“But not if it’s a raccoon, not if it’s an animal?” I asked, a little surprised.
“Exactly. Not if it’s an animal and not if the plant would be somewhere else in Berlin.”
I asked Tanja whether she hoped her research would lead to more psychological approaches to changing public perceptions about non-native species, but she was keen to emphasise that, really, her data just reinforced the need for those attempting to manage invasive species to better understand their public. “People are very different and have very different views, emotions, understanding and ideas about how we should live and manage native and native species in an urban environment. If you are an urban planner or a manager and you really want to have the support of a certain district or a certain park or a certain pond where people live close by, then I would think we also need to understand what do people value in this environment or how do they feel about certain wildlife or certain species. And then also include this in management strategies because we need the support of people in the urban environment, especially in the urban environment where we live so close together with plants and animals. There are some discussions around kind of how we can change people’s attitudes or how we can influence people’s emotions. But I would think it’s more about understanding how people think and feel about certain plants and animals and then integrating it and considering it. And that’s probably a big challenge that urban planners and managers have.”
One thing I’ve learned from exploring this issue is that our human response to non-native species is complex. As more invasive species arrive, simply making information available to the public may not be enough to prompt appropriate action. This is because so many factors influence how our brains respond, including things I would never have thought of! I think Tanja is correct in suggesting we don’t just need to be thinking about the non-native species themselves. We also need to be understanding more about the minds of the people who are encountering them.
Do you think you may have spotted an invasive species in the UK? You can check a potentially invasive species (and report it) via the Great Britain Non-native Species Secretariat.
To discover more, listen to the associated podcast.