What costs come with reintroducing species?

While reintroduction can solve problems for some, it can cause issues for others
09 August 2022

Interview with 

Chris Sandom, University of Sussex


Reintroductions can be deemed "sucessful" when a species is self-sustaining, like the red kite in the UK. But is everyone delighted by this project? And are there certain populations who might have to bear some consequences when new or once-lost species are brought into the environment. Chris Sandom, lecturer in Evolution, Behaviour and the Environment at the University of Sussex explains to Chris Smith...

Chris Smith - Still with us is Chris Sandom, he's a lecturer in evolution behavior and the environment at the university of Sussex. Chris, we have heard that the red kite is being hailed as a huge success story in reintroduction. Is everyone delighted though? You do occasionally hear dissenting voices where people say, 'look, there are consequences of doing this. There are knock on effects. These animals may take livestock and so on.' Is everyone in agreement? Is it a success story or are you hearing a bit of negativity?

Chris Sandom - So in general it really has been a remarkable success. I mean, this species that's now doing better globally, but in particular, in the Chiltons and potentially a victim of his own success. So the sheer numbers that are now occurring there, you start to hear people talking about they're being great, but maybe being too many of them. One of the particular areas of conflict is around feeding them. So a lot of people want to get out, get close and connected to these fantastic birds. So they leave out meat and the animals come down and you can see dozens are circling above an area and dive bombing down and collecting these resources. But that puts them in close contact with people and there's fear around what that might mean and what it might mean in terms of stealing food. They're primarily a scavenging bird as well, but they will occasionally take live prey and there's some concern that that might have impacts on things like game birds. So they might be coming into conflict with other people's livelihoods and that often is a key area of conflict around reintroduction, especially when you get anything larger and predatory.

Chris Smith - We've heard a lot about beavers being reintroduced into various places. I think on this program we talked about that wonderful invention, the 'beaver deceiver', because the beavers were flooding the farmland that they'd been reintroduced to, which wasn't going down too well. But they were protecting cities and other things downstream from flood risks. So there were winners and losers in that respect. How is that sort of thing, monitored, gauged, and then mitigated?

Chris Sandom - When you're looking at the winners and losers of any reintroduction, you're going to have to go through your risk assessment and that applies to species and other wildlife. You can't have a situation where you always have winners, essentially because there's competition for space, competition for resources, and that's true within ecosystems and for people. The issue then comes down to when you're looking at people and the example you used, there's often a lot of focus on the mitigation of flooding downstream and actually, this year in particular, the conversation of mitigating low flows as well. So you're reducing the extremes at both ends. But that does come through the flooding of farmland or places upstream to mitigate impacts downstream. Now, how do you go about compromising there? Well, you're going to need to find solutions, which essentially even out those costs and benefits. So I know there's people out there in areas where beavers have been reintroduced, dismantling dams that are causing particular and specific key problems, particularly if they're flooding buildings and having particularly negative impacts like that. So you can put in some mitigation methods that essentially mean the people are getting the benefits, maybe some conservation societies, ecotourism opportunities, even insurance companies are getting interested in nature-based solutions to these problems. It Means you share some of those benefits out and particularly targeting those that are suffering the costs of that wider benefit to society.

Chris Smith - Something like a beaver dam is pretty easy to spot. And if you get a flood in the wake of that, it's obvious what the cause is. Are there any sorts of ways of auditing other impacts? If you've got a predatory species, a red kite or something, and it is perhaps depriving other animals in the food chain of their dinner and having a knock-on consequence, is that being looked into and checked to make sure that the best intention reintroduction is not having unforeseen consequences?

Chris Sandom - There are lots of concerns around this and the species I've worked with is wild boar. And they have a really mixed reputation. There are these fantastic wild species that cause rooting and create opportunities for more species to grow. But they're also a conservation threat and places like the Forest of Dean, where there has been a thriving wild boar population after they largely escaped, so are kind of an unofficial reintroduction. There is concern that they're having a negative impact on species of conservation concern. But monitoring nature is incredibly time consuming and can be really expensive and quite difficult to work out what is actually causing the decline. So it's, as far as I'm aware, done on quite a case-by-case basis. So you might have a particular group or interested party concerned about a specific species or group of species and focus their monitoring in response to a threat that they might see as a species or introduction. So ecosystems are dynamic, they are competitive, but we can't monitor absolutely everything or, that's going to be very difficult and we don't really have the techniques in place yet. And that's just on the ecology, that probably applies to the economics and socially as well. So other projects elsewhere look at the negative impacts of large predators on livestock and there are schemes to compensate, but how do you work out whether a sheep has been killed by a war or is being scavenged by a war for the livestock's not being looked after properly or whether it's just bad luck? You know, for all of these things it's difficult to do. But it's the challenge that we have to grapple with.


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