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Make Space For Nature
Make Space For Nature
Helping our native wildlife thrive with the Scottish Invasive Species Initiative
Hear about the Scottish Invasive Species Initiative (SISI) from Project Manager Callum Sinclair of NatureScot. Learn how non-native invasive species like Japanese knotweed and American mink are not just persistent nuisances but significant threats to Scotland's ecosystems and economy. Callum delves into the challenges these species cause and explains the crucial ways we can all prevent and manage their spread.
He explains the effective and varied control strategies, from chemical treatments and manual removal, to community-driven efforts. We discuss the impact of these species on native wildlife such as ground-nesting birds, water voles and plants. Callum also emphasises the importance of public awareness and biosecurity measures, demonstrating how community engagement is vital in both reporting sightings and preventing the spread.
We hear about the invaluable contributions of volunteers and partners who dedicate their time and resources to this cause, showcasing how teamwork and passion can lead to substantial environmental conservation achievements.
More information:
Scottish Invasive Species Initiative
NatureScot: Invasive non-native species information
GB Non-native Species Secretariat
Report a non-native species
Hi and welcome to Make Space for Nature from NatureScot, the podcast that celebrates Scotland's nature, landscapes and species. I'm Kirsten Guthrie and in each episode I'll be joined by inspiring guests who share their expertise and passion for the natural world. In this episode, the first of two focusing on the Scottish Invasive Species Initiative, I chat to project manager Callum Sinclair from NatureScot. He explains the importance of this partnership project working to tackle invasive non-native species along rivers and water courses in northern Scotland. We discuss the target species we can all look out for and the invaluable role of volunteers dedicated to the project. So I'm standing in the Perthshire countryside and I've been joined by NatureScotts Callum Sinclair. So hi, callum, welcome to the podcast. Thanks for joining us today. So we're here to find out about the Scottish Invasive Species Initiative project that you manage. But first things first, can you explain what we mean by an invasive non-native species?
Speaker 2:Hi Kirsten. Yeah, it's really, really good to be here. An invasive non-native species is basically any non-native animal or plant that's got the ability to spread and cause damage to the environment, the economy or the health and the way we live. Not all non-native species cause problems. In fact, only a minority do, and can go on to have some serious negative impacts on our native species, on our health or economy, and these are the ones we call invasive non-native species.
Speaker 2:Invasive non-native species are actually a big threat to native wildlife in Scotland and globally, and there's been some international assessments that maybe are helpful. Just to think about, one just in 2023 found that invasive non-native species are involved in 60% of global plant and animal extinctions, and the annual costs of managing these problems now exceed $423 billion, and these costs have quadrupled every decade since 1970. A little earlier, a 2019 assessment identified invasive non-native species as one of the top five drivers of global biodiversity loss. So these species are big and expensive trouble, and our project is trying to help to get a grip of those in the Scottish catchments that we work on. There's around 2,000 non-native species established in Britain, and about 10 to 15 percent of these are invasive.
Speaker 2:More non-native species reach Britain every year, and so it's a constant battle to try and prevent the new ones arriving and reaching us in the first place, and then to tackle those that have the potential to become problems, and we try and do that by means of different sort of tactics and different sort of approaches. First one hierarchy of options here is to stop them arriving in the first place, preventing the problem arriving. Secondly is, if the problem does arrive on our doorstep, find it quickly and respond quickly before the problem becomes established and becomes expensive. And the project I run is about the management of the problem, and that's really where we've previously failed to either prevent the plants or animals arriving or we've failed to remove the problem quickly, and this control phase is often expensive and long term, if indeed it's possible at all.
Speaker 1:Okay, great thanks for explaining that. And what damage do these species actually do to the Scottish environment and economy?
Speaker 2:Yeah, they can cause lots of different problems depending on what plant or animal we're talking about and maybe just give some examples that might just give a flavour. So often they're very effective competitors and an invasive species can be better adapted to their new environment and growing quicker out, competing native plants or animals for space and for food and for nutrients. And, for example, japanese knotweed, one of the plants that we tackle, forms dense stands along riverbanks and outcombeats native flowers. We've also got a number of invasive animals in Britain and, again, one of the target species that we work with is American mink and the major impact it causes is due to its being a fantastic predator. And the major impact it causes is due to it's been a fantastic predator. It is the main problem, the main factor in the near demise of the water vole in Britain, where 94% of that population was lost, and a lot of that was attributed to the impact of the American mink. Alongside habitat loss etc.
Speaker 2:We've got other things that are a little bit more subtle, perhaps Hybridisation, where the invasive animal can actually interbreed with native species and you'll lose the genetic purity, if you like, at the genetic of the, the gene pool. So we have non-native seeker deer that can interbreed with native red deer in Britain. They can alter habitats. Invasive plants can actually take over in riverbanks and other areas where previously we had native plants thriving and doing really well, and by taking over the habitat they change the ecosystem there. They maybe allow soil to be bare and vulnerable to flooding and erosion and cause flooding problems. So they can cause lots of different issues.
Speaker 2:And then the other ones that might be more familiar about spreading of disease, where, infamously, the grey squirrel in Britain spreads a squirrel pox to the very cute and cuddly and iconic red squirrel. So there's lots of different ways that they can cause problems. And that's before you get to things like impacts on health and well-being, where species like giant hogweed are actually a damage and a health risk to us. They've got a really toxic sap which, if gets in contact with your skin, causes a burn, a burn which returns because it's triggered by sunlight. So you can have a scar on your arm from a hogweed burn that lasts many years and comes back to remind you of it every time the sun comes out. And also these plants get in the way and prevent us accessing the environment where we use these rivers and parks and outdoors to enjoy recreation and get fit and well and healthy. So they can affect our health in much more subtle ways, as well as the direct impact from burns.
Speaker 1:Wow, that is a huge amount of different ways that these species can affect us. So what is it the Scottish Invasive Species Initiative project? What does it aim to do? Can you tell us what it's all about?
Speaker 2:Yeah, we're a partnership project. By the time the current funding stream lasts, we'll have been running for eight years and we're targeting invasive non-native species, a lot of which live along rivers and watercourses in northern Scotland. So from Perth northwards across a third of mainland Scotland. We're funded by Scottish Government's Nature Restoration Fund to 2023, which is overseen by colleagues in NatureScot, and prior to that from 2017 to 23,. We're funded by the National Lottery Heritage Fund and the value of all that support, as well as the in-kind from the project partners and volunteers, gives a total value of in excess of £6 million. So quite a substantial project over a substantial area. We mentioned that we cover a big area of northern Scotland, half of mainland, 29,500km2, roughly almost 1.5 times the size of Wales because everyone measures projects and how many Waleses? We have but 1.5 and that covers areas like Perthshire, angus, aberdeenshire, moray, highland and it makes the project the largest invasive control project in the British Isles.
Speaker 2:Naturescot leads the project I'm lucky enough to be the project manager and we lead that partnership on behalf and with 10 rivers and fishery trusts and boards and with the University of Aberdeen, who provide important academic support. We support, train and equip volunteers with the University of Aberdeen who provide sort of important academic support. We support training equipped volunteers with the skills and equipment they need to help us to work alongside us to deliver control locally within communities and we hope that by building these community capacities that invasive non-native species will continue there with those people and with those communities long after the project ends. So we're trying to find a long-term solution to control. We also use contractors in the very worst of areas.
Speaker 2:We actually want to knock the problem back a little bit to give us a little chance to get in there with our project team and with volunteers and increasingly and crucially, we're signing up individual landowners and land managers to the partnership so that overall we can coordinate a programme of work which is delivered by our staff, our partners, our volunteers and community groups and the land managers and landowners. And that's essentially how we're tackling the plant aspect to this. And we also tackle one animal, the invasive American mink, which poses a different set of challenges to us and I guess the main thing really is the tactics of it all. We've got such a big area that we need to be systematic and organised. So we're working on a catchment-by-catchment basis with all the partners to reduce and try and eliminate these animals and to certainly depress the numbers of American mink.
Speaker 1:I'm just going to go back to the point you made about the Scottish Government Nature Restoration Fund You're funded. Is that up to 2026 then? Yes, it is. Yeah, yeah, no, that's fine, that's great. And are there any specific species that the project focuses on? What problems do these species cause in the local area?
Speaker 2:Yeah, I mean there's, as we mentioned earlier on, there's a lot of invasive non-native species around. So we've had to make some choices and make some prioritisations about the species that we can identify as particularly problematic and also the ones where we think we have a chance of making a difference to the problem. So we've got five target species in total. The American mink is the only mammal and animal that we're involved in. The American mink is the only mammal and animal that we're involved in, but we're also looking at giant hogweed, japanese knotweed, himalayan balsam and American skunk cabbage. So thinking maybe firstly about how we deal with the plants. Plants grow along watercourses as well as in the wider countryside, but rivers are fantastic highways for dispersal of plant materials, so seeds and fragments of plants can flow downstream and establish populations elsewhere, and so what we're really doing is working on a catchment-to-catchment basis, starting at the top and working our way down, so that we can make a difference to this problem and actually prevent the problem reoccurring continually. From above. Most of these plants that we're targeting establish really quickly and they form really dense stands which out-compete native plants and in turn, change the habitat for insects and other small creatures. We also mentioned that we were tackling American mink.
Speaker 2:American mink spread into Britain through fur farming in the later part of the 20th century and a number of animals escaped or indeed were released from those fur farms and these animals were very effective at establishing and distributing themselves across the countryside. These animals are a key factor alongside habitat loss etc. In the demise of the water vole population at the time. Thankfully that's now recovering. But the minx are a really fantastic predator, a fantastic hunter, a fantastic coloniser. It eats birds and their eggs, small mammals, fish, amphibians, shellfish, crustaceans and some birds, particularly ground nesting birds that live in colonies, for example terns, are particularly vulnerable to predation.
Speaker 2:Mink have an impact on native diversity across Scotland but often NatureScot has targeted areas where there's been a particular issue and colleagues have been running the Hebridean Mink Project in the Western Isles to try and protect ground-nesting birds there and internationally important migrant populations of seabirds as well as other mammals such as the water vole that we've mentioned. They can also take fish and other things as well, so they can be in the frame when people are thinking about freshwater fisheries, but they probably less have a direct impact on those populations. But we also get regular reports of predation of domestic fowl where people being very upset that they've lost whole chicken huts and ducks and etc. So they cause lots of problems to crofting, to sports and angling, gaming, game tourism and recreation. So really a problematic animal which is very difficult to deal with.
Speaker 1:Okay and that obviously can be really devastating for a lot of people and there's a real variety of problematic species here and I've seen the work firsthand just on a local walk that I go on and you've tackled the giant hogweed there and what a difference it's made. It's huge. Can you explain what methods are actually used to to try and control these type species?
Speaker 2:yeah, I mean thinking about plants first thing, kirsten. I mean plant control needs to work at a catchment scale, as we mentioned earlier on, to be effective. So that really is, you know, all parts of the river and essentially starting at the top and working our way down so that we remove plants and populations systematically from the top so that they can't continue to repopulate and reinvest from above. And that requires us to work with multiple organisations and landowners, particularly to clear the plants along their length, and working with the local fishery trusts, their partners, the volunteers and the population locally the plants along their length and working with the local fishery trusts, our partners, the volunteers and the population locally, we can coordinate that action to make a difference so that we actually move continually downstream as we, as we progressively clear. In terms of the practical methods of control, you know they're somewhat limited, to be honest, and particularly when you're working at the scale that we are, where we've got many hundreds of kilometres of riverbank under management. So for species like giant hogweed, japanese knotweed and American skunk cabbage, we use chemical application to allow us to manage these large areas in River Lane. So that's glyphosate. All our staff are qualified in the application of that chemical and we use techniques such as stem injection to be very plant specific and limit the chemical use. We're very, very aware of the need to constantly manage and limit the amount of chemical that we use, but the reality, the practical reality of this is to tackle this problem.
Speaker 2:We actually got to use these sort of approaches to have us any chance. Himalayan balsam is the other one that we talk about and that is a much more straightforward approach where they're very shallow rooted and we can simply pull those plants up. And that's a very common task that we do with volunteer groups, where we simply just pull the plants up, pile them up and compost them on site. And we're also looking at other approaches when we need to. So giant hogweed, which people may have seen, a very striking, tall, massive plant with very big flower heads, and when we get to the point of the season that we can no longer safely control those plants by chemical, we simply cut the flower heads off to stop the seeds dispersing. And you may also be aware that we've got a flock of sheep that are busy chomping their way through giant hogweed in a catchment in the north of Scotland on the river Devran. So we've we do have a range of different approaches, but the reality of it is that chemical applications is essential element in that, that sort of set of approaches that we use and helpfully those plants though.
Speaker 2:We have a growing season of April to September roughly. We have seasons within seasons. So we tackle hogweed first from April, may and into June, and then we move to balsam in July or so and then we move to knotweed and skunk cabbage a little bit later from August, september and July as well. So we allow ourselves to split the target plants even within the six month growing season, which gives us half a chance to make a difference and be organised.
Speaker 2:When it comes to mink control, we have an extensive network of volunteers, hundreds of people actually helping us to run mink rafts, which are floating bits of kit which essentially challenge the inquisitive nature of the mink to come and have a nosey around in the little tunnel and they can leave their footprints on a little clay pad that tell us they're in the neighbourhood. We then set a trap or, increasingly, we are just going straight to setting traps, where volunteers and technology allow us to keep an eye on that trap on a daily basis and the technology tells us when the trap's triggered and we can then go and humanely dispatch any animals that are captured. But we certainly couldn't run any of those programs without the help and support of the volunteer network that we train and engage with us directly.
Speaker 1:That's great and such a such varied work for the different species. I'm loving this flock of sheep. I wonder if we could repeat that in different places. But I mean, how do you encourage volunteers and communities to actually get involved with the project?
Speaker 2:Yeah well, I guess the trick to any of these volunteer-based activities you can't help if you don't know. So we're really conscious of the need to continually tell people what we're doing and to try and make people aware of the opportunities that we can provide. So platforms like this podcasts are fantastic opportunities for us to make the opportunity known, and we're always always looking for people to get involved in either the plant or the mink control work, or even both. We have some people that do both and there's no experience needed. We just need people to bring their enthusiasm and keenness to make a difference and to get involved, bring their enthusiasm and keenness to make a difference and to get involved. So we put out regular appeals on the usual suspects websites, social media platforms. We invite people to come forward locally to the local partners. That's part of the reason that we have this sort of network of local fishery trusts that give us a local connection to people within the places they operate, a local connection to people within the places they operate, and we continually promote the volunteering opportunities wherever and whenever we can, whether we're giving talks, attending meetings or just being out and about actually doing the work.
Speaker 2:We also try and make sure that the volunteering experiences that we provide are positive and rewarding for people.
Speaker 2:We're acutely aware that people giving of their time for free don't have to do that and there's many other things they could be doing with that time. So to give it to us is a gift and we appreciate that. So we try and make sure that they are supported and trained and our staff have the appropriate biscuits in the biscuit tin and the kettle is there and available. And we take great pride in the fact that, having run annual volunteer responses, the responses to those surveys are unanimously positive. Always room for improvement, of course, but we really want to make sure that people come here and enjoy what they do and feel they're making a difference. And we also have additional bait where, for plant volunteers in particular, we can support them to gain formal qualifications so that they become qualified and equipped to deliver chemical control using sprayers themselves. So we have budget to support people to do that and indeed we've paid for more than 250 volunteers to gain former qualifications already and you know we we've got that funding available for the next few years too.
Speaker 1:That's great to hear and you know we've done a few podcasts about the kind of benefits of volunteering and you know there's so many hidden benefits that perhaps we don't go on about as much. Maybe you know, but, um, your physical, mental health, making friends, just getting out and about and and all these kind of positive uh things people can experience from volunteering. So we can just encourage people to keep keep going with uh, with volunteering, and you know what can our listeners do to help beyond volunteering, whatever you know, wherever they're based in the country yeah, well, invasive non-native species are clearly a problem in the area of the project, but they're also a problem in areas outside the project.
Speaker 2:So there's a couple of things that maybe come to mind straight away. One, to make yourself aware of the invasive species issues and we've got lots of information about them on our own website and indeed you can actually report sightings from anywhere in Scotland to the Invasive Species Project website, wwwinvasivespeciesscot. And if you see a mink or an invasive plant that's within the project area, we receive each of those reports direct from the website and we respond to those. So if it's a mink, then we would be looking as to whether we have coverage there to try and catch that animal or to get volunteers to do that with us or for us. And if it's a mink, then we'd be looking as to whether we have coverage there to try and catch that animal or to get volunteers to do that with us or for us. And if it's a plant in the project area, then we can build that into our understanding of the catchments. That help us understand where we are, but always reminding ourselves that we need to be systematic and organised. So often there are big invasive plant problems at the bottom of catchments and we've simply not got to the bottom of some of those catchments so we do have to sort of. You know, we've got a little word of caution that we're not going to put the flashing blue lights on for a plant report at the bottom of a catchment necessarily.
Speaker 2:But perhaps as important as any of that stuff about reporting invasive nonnative species is just to be aware of them and to be aware of the actions that you can take yourself. And it goes back to this prioritisation of management. One is to prevent the problem arriving. So knowing about biosecurity measures. So if you're a water user, particularly an angler or a canoeist perhaps, or a sailor who may be active in different catchments or indeed different countries, you need to be practicing good biosecurity to make sure your equipment is not bringing hitchhikers with you back from your holiday in Russia if you're an angler or from one water course to the other. So cleaning your equipment and making sure it's safe and clean before you go to the next activity.
Speaker 2:If you find a problem, let someone know about it. We're more than happy to field those responses to colleagues outside the project area and to respond to those that are within the project area and, of course, you can volunteer with the project, as you've mentioned already, kirsten, but there are other initiatives elsewhere in Scotland where, even outside our area, there may be opportunities to get involved. So it is a big issue. It is a big problem, but it's always more people involved in understanding it, and helping to combat it gives us a better chance of tackling the problem.
Speaker 1:And how do you go about measuring the impact of the work? I mean, can you tell us about any success stories that have made the kind of biggest impact to the local area?
Speaker 2:Yeah, I mean, we've got hundreds of individual control sites for our plant work and each site has got a defined top and bottom and we do some very basic things to help us monitor progress and report success. What we do we undertake an annual survey of abundance of the target plant. So every year, before we have treated those plants, we make an assessment as to how abundant that plant is at that site, using, I think, the DAFOR scale, which is basically just an estimate of plant abundance by species, and we also take photographs of the plants at fixed points within our survey network and our management network. And what that lets us do is, over time, track change and we can therefore show and demonstrate on a site-by-site basis the reduction and abundance of these target plants, which is really important to show that this is not just a folly, this is not just a sort of pouring more money after bad, good money after bad. There's an opportunity here to remove. And the other thing that we measure is equally important is the time it takes us to deliver the control and the chemical that we use per site. We mentioned earlier how important it is to be super careful about the chemicals that we put in the environment, and we are really aware of that. So for all those control points where we are measuring the abundance of the plant, we're also tracking how long the control has taken us in that year and the volume of chemical that we've used. And we can show and we do show.
Speaker 2:We've got a number of case studies up on the website where we have been able to write up the story of these management sites to show this plant used to be very abundant and now it's not. This plant used to take us 100 hours to control and 5 litres of chemical and now it takes us 5 hours to control and a quarter of a litre of chemical. So we can track the change and track the reduction in effort and our chemical and also abundance of the plant. And those metrics together give us a chance to really hopefully be really clearly demonstrating that with a bit of focus and organisation and organisation these problems are not unbeatable but it does take a bit of discipline to make that happen. But there's a number of case studies on the website which we will be continuing to update but they can give a flavour as to what we've been doing.
Speaker 2:And for American mink a little bit more difficult because there's no population estimates of mink, but we're currently engaged with a PhD student from the University of Aberdeen who's looking at other species that may be responding to our management. So by reducing mink numbers are we seeing water vole numbers respond and improve? And the early findings for that are that in a number of cases we're seeing exactly that. So we're optimistic and positive that by depressing the numbers of mink we can see responses both in that particular species of water vole.
Speaker 1:Brilliant. Thank you so much. You've explained that so well and hopefully our listeners will now have a better understanding of why tackling invasive non-native species is so important and it's such a crucial part to fighting nature loss and climate change. So thank you for joining us, callum.
Speaker 2:Very welcome. It's been great to talk to Kirsten and I think maybe just to finish, for me, from my perspective, is the key element of this project is sometimes people think about the money. It's been great to talk to Kirsten and I think maybe just to finish, for me, from my perspective, is the key element of this project is sometimes people think about the money. It's not really the money, it's the people. And you know, the partnership is important because it gives us the geographic coverage. The staff are important. It gives us a way to reach out from those bases, but actually the key element of this project is the volunteers hundreds of them who've given hundreds and thousands of hours to this project since we've started and actually the time they've given far eclipses the time that the staff have actually given to the project. So it's a really important combination of staff and partners and volunteers now working alongside a number of landowners, and it's bringing that mix together gives us a chance to tackle a widespread and difficult problem.
Speaker 1:So much teamwork going on there. So thank you again. So I hope you enjoyed the first of our two podcasts about the Scottish Invasive Species Initiative. Make sure to catch the next episode where I get to meet some of the vital volunteers dedicated to this project. Subscribe via your preferred podcast app or listen to all episodes on our website at naturescot.