Zapping invasive plants – a trial on Exmoor

Holly Moser, Exmoor Non-Native Invasive Species Project Officer
September 2021

As many of you may be aware invasive non-native species (INNS) control can take many years and here at Exmoor National Park Authority we have been going at it for the last sixteen! A major part of our work, our knotweed control programme, has been running since 2005 and has resulted in a large reduction of the knotweed species, particularly Japanese and Himalayan knotweed across the National Park.

Each year we seek permission from landowners to treat knotweed using the conventional method of spraying glyphosate. Currently, thanks to the funding, we can offer this service free of charge. Our contractor completes the treatments between September and November when the herbicide is most effectively drawn down into the rhizome system.

Spraying Himalayan knotweed

This autumn we will be visiting 95% of the 850 plus knotweed sites we can treat using glyphosate, probably the highest percentage ever achieved on the programme! This may sound a lot but many of these sites are being monitored and may no longer need treatment because there is no visible growth showing. It is vital that we continue to monitor these sites because knotweed rhizomes can stay dormant underground for something like up to ten years, which means shoots can sneakily reappear!

On Exmoor there are several knotweed sites we cannot treat with herbicide because they fall on organically certified land and we have not found a suitable “organic” alternative to glyphosate treatment. This land provides a serious reservoir for invasive species to flourish, particularly where a plant is situated close to a watercourse allowing them to spread easily. There is also a lot of controversy surrounding the use of glyphosate as a herbicide and the future of its application is uncertain. So it is crucial that we expand our toolkit of methods to control INNS and find solutions for control on organic land.

In 2017, we began trialling Rootwave Pro which has proved to be very effective on annual weeds and was first trialled on Japanese knotweed in 2016 in Gloucester, by the Environment Agency. This technology forces an electric current of up to 5000 volts down through the plant, raising the temperature and boiling the plant cells. It’s very dramatic to watch – lots of steam and popping and banging! The plant is left to decompose, and you can see the effects of the treatment within a few weeks. I have to admit it is satisfying watching a plant which is causing so many problems and is so difficult to get rid of, turning yellow and wilting without the use of herbicides to treat it.

The Rootwave machine. You rub the electrode up each stem for approximately 30 seconds. It is a very dramatic treatment with lots of steam, popping and banging!

How are the trials going so far?

In 2017 and 2018 the National Park commissioned Ubiqutek, the manufacturers of Rootwave Pro, to carry out one treatment a year on five knotweed sites. It soon became clear that one treatment a year might not be enough because the knotweed continued to throw up lots of little shoots.

Left: 2017 – Japanese knotweed before any Rootwave treatments took place.
Right: 2018 – after a single treatment in 2017.

Luckily the project was able to use our new funding to purchase our own Rootwave Pro so that we could continue these trials and increase the frequency of treatments. We were also able to train up several local contractors to operate the machine. So we can now carry out up to three treatments a year on 28 different sites including other INNS: American skunk cabbage, giant hogweed and montbretia.

Although we have made great progress carrying out multiple treatments a year it has not been smooth sailing…

There are several factors to consider when using Rootwave Pro:

  • First the location. The machine needs to be transported to site on the back of a 4×4 or ATV due to its size and weight and you are also limited to a 27 metre long treatment cable from the vehicle. Although we would not expect to find knotweed on some of the most remote parts of Exmoor this has been a limiting factor for us. The technology is however adapting quickly and who knows how long it will be until Rootwave can be carried on your back…
  • Secondly, it cannot be operated if it is raining. On Exmoor this is a challenge, especially with the wetter summers we are now experiencing. However wetter ground is better for conducting electricity so if your operator is able to drop everything and fit in a couple of hours when the rain has stopped then rainy days don’t have to be a write off.  Having the flexibility to change plans and carry out a treatment when the time is right is definitely a bonus!

Of course, we have also had to deal with the elephant in the room which is affecting everyone. Busy schedules and short time windows impacted by the pandemic and combined with the British weather have not made it easy for our contractors. The result is that we have struggled to complete three treatments a year at all of our sites as we had first planned.

What results have you seen since you started the multiple treatments?

It’s important to point out that we are only in our second year of multiple treatments and the very early stages of this trial, but despite all the challenges things are looking quite promising.

It’s clear that every site has reacted differently to each treatment as you would expect when there are so many factors like competition from other species, ground substrate and moisture content in play. In our first year of multiple treatments, some of our knotweed sites continued to show vigorous growth. This is to be expected – invasive species, by their very nature, are tough to control.

Left: May 2020 – young Japanese knotweed appearing before Rootwave treatments took place.
Right: September 2020 – two months after the second treatment of the year.

Other sites looked more positive with less regrowth appearing. At this site (image below) our contractors reported only a handful of stems after its first ever treatment.

Left: August 2019 – before any Rootwave treatments.
Right: August 2020 – two months after its first ever treatment.

We have also seen similar results over the years at the sites that were first treated in 2017. Below you can see a comparison of two sites that received a single treatment in 2017, 2018 and 2019 and two treatments in 2020. These photos were taken in September. Both sites are yet to receive a treatment this year which makes a good comparison to September 2017 when the sites hadn’t been treated at all. Again, some sites have continued to show quite vigorous regrowth (top two images); while at others the difference is more obvious (bottom two images).

Two Japanese knotweed sites treated using Rootwave – single treatment in 2017, 2018 and 2019 and two treatments in 2020.
Top left: Site 1 before (Sept 2017), Top right – Site 1 after treatments (Sept 2021)
Bottom left – Site 2 before (Sept 2017), Bottom right – Site 2 after treatments (Sept 2021)

For our other species it is a similar story that multiple treatments for several years looks like it could be the way forward. We were however delighted to see that one of our skunk cabbage sites, where there was a single plant, does seem to have disappeared for the time being after its first year of multiple treatments.

Left: June 2020 – a single skunk cabbage plant before any Rootwave treatments.
Right: June 2021 – after two treatments in 2020.

So we are seeing some interesting results in the early stages and these trials are playing an important role in broadening our options for INNS control. Like any trial, there are always lessons learnt to be passed on and we have definitely had our fair share. Check our website for updates as our trials progress and please do get in touch if you have any questions.

Tel: 01398 322259

Email: ennis@exmoor-nationalpark.gov.uk

The Exmoor Non-Native Invasive Species (ENNIS) project is trialling innovative approaches to invasive species management and working with the local community to map and control invasive non-native species such as Himalayan balsam, American skunk cabbage and American signal crayfish. If you would like to find out more about the project please follow this link to our ENNIS website.

The ENNIS Project is funded by the European Agricultural Fund for Rural Development and Defra.

Flying, Flinging and Floating – Seed dispersal by Giant hogweed and Himalayan balsam

Vicky Hilton, Volunteer & Communications Officer, Scottish Invasive Species Initiative
September 2021

Here at the Scottish Invasive Species Initiative our invasive plant control seasons for giant hogweed and Himalayan balsam have now drawn to a close and thousands of plants have been sprayed, cut or pulled – removing these pesky plants for another year and critically preventing seeding and spread.  However, that’s not the end of the story.  In the soil lie dormant seeds: snoozing silently but waiting their chance to germinate.  And beyond our control areas are plants which are now about to do what they do best – scatter their seeds for future germination.

When it comes to invasive plants seed production and dispersal is usually significant and impressive – the ability to reproduce quickly, and in numbers, is one trait that makes these invaders spread successfully and be worthy of the status of ‘invasive’.

Plants have limited mobility and rely upon a variety of dispersal methods to transport their seeds, and so reproduce, away from the parent plant.  Seeds are more likely to survive away from the parent plant – they can reach habitats favourable to survival and with less competition and larger distance seed dispersal can allow plants to colonize altogether new geographical areas.

Giant hogweed and Himalayan balsam are both highly mobile species – they are good at seed dispersal and spread readily to new areas.  While this makes good evolutionary sense for the plant in ensuring its survival and success as a species – for those of us working to stop the spread of these species it certainly brings challenges.   

Understanding how these species disperse their seeds and how long these seeds persist in the soil helps enormously with the planning of control work.  For example, both these species use flowing water as a dispersal mechanism – meaning that control work needs to start with the most upstream plants in a river catchment. Treating plants downstream first would be futile as seeds from those upstream plants will wash down and re-infect cleared areas. 

Giant hogweed

Giant hogweed plants flower only once after growing for 2-5 years (longer if conditions aren’t ideal).  After seeding the plant dies.  Although that might give hope of successful control, in reality if the plant sets and spreads seed then the damage has already been done. A single flowering plant will produce between 10,000 – 50,000 seeds, with 20,000 seeds per plant being typical – and each seed can remain viable for many years. 

The dry flattened oval seeds are produced at the end of August.  Each is approximately 1cm in length with brown lines extending about three quarters of the length.

As the seeds are shed from the towering 2m high seed heads their winglike membrane allows them to be caught by the wind and dispersed over short distances (2-10m).  As they drift away from the parent plant they often fall into a river or burn where the water can carry them long distances to new areas.  Studies have shown that giant hogweed seeds can float for up to three days – in that time seeds could be moved huge distances in normal flows and even further in flood events.

Humans can also give a helping hand and be responsible for spreading giant hogweed seeds.  This can be accidental e.g. when seeds are caught and transported on vehicles or in shoe treads – or via transportation of seed contaminated soil.  

If seeds land on a suitable area of ground (there is usually plenty along a riverbank) they will settle into the soil and overwinter to allow maturation and breaking of dormancy.  Germination occurs from January to March with approximately 90% of seeds successfully germinating. Those seeds that don’t grow in the first year can lay dormant in the soil – the seed bank – for many years.

The consequence of this seedbank means that control works will need to be repeated on the same site for several years until the seedbank is depleted and the site truly clear of hogweed. Viable hogweed seeds have been recorded up to seven years after seeding occurs.  This reflects what we witness in the field – we have sites new to the Scottish Invasive Species Initiative where after control for four consecutive years, we still see significant regrowth of seedlings each year.   However, at sites where control has taken place for six or seven years (by previous and the current project) we see significant decreases in annual seedling reoccurrence giving hope that we are closer to achieving hogweed eradication in some locations.

Himalayan balsam

Himalayan balsam is an annual plant with a cycle of growing, flowering, seeding and dying all in one year. As such its survival from one year to the next depends entirely on successful seed production – so prevent the seed production and you remove the plant. 

Balsam seeds are produced in a seed pod, or capsule, which hangs on a long stalk alongside the flowers. The kite-shaped green pod is 2-3cm long and 8mm wide and contains on average 6 seeds per pod (between 4-16 seeds can be present).  The small round seeds are initially white, turning black as they dry.  On average 700-800 seeds per plant are produced.

When it comes to seed dispersal – balsam is the master.  It uses ballistic seed dispersal – exploding seeds pods – to forcefully fire the seeds up to 7m from the plant.  The seed pods are dehiscent – meaning that when mature they will spontaneously explode at the slightest disturbance. The capsule splits along the longitudinal edges – which are built in lines of weakness in the pod – firing out the seeds as the sections curl back.

These expelled seeds are often carried by humans – unintentionally caught on clothes and picked up in shoe treads – and there have also been observations of seeds being transported locally (up to 10m) by small rodents.  But mostly the spread of balsam seeds is aided by flowing water – fresh seeds can be transported within the sediment of riverbeds – particularly during the high flows present during flooding.  The dry seeds are buoyant and can float over large distances in the water currents – before being dropped into new areas to successfully colonise and continue their spread.

Himalayan balsam seeds also have a high germination rate – approx. 80% – but the good news is that balsam does not have a persistent seed bank.  Seeds only survive in the soil for around 18 months.  This means two to three years of control work at a site can be all that is required for successful balsam removal – as long as new seeds are not being brought into the site to replenish stocks!

A note on Japanese knotweed

Japanese knotweed (one of our target species in the project) is not of concern when it comes to seeding – it spreads solely by root and stem fragments.  While it does produce tiny white flowers each year it doesn’t set seed.  In Britain Japanese knotweed plants are all female with male sterile flowers. Its vigorous powers of vegetative reproduction mean that it has been able to spread to all parts of the British Isles without the aid of sexual reproduction – therefore it is classed as a single, exceptionally widespread clone.

Stopping the Spread

Everyone can help in stopping the spread of giant hogweed and Himalayan balsam seeds by practising good biosecurity – checking boots, equipment and vehicles for seeds and carrying out regular cleaning of these items between visits to different countryside sites.  You can find more information on good biosecurity practice on our website.

Autumn is the season

Of course, although we’ve covered giant hogweed and Himalayan balsam specifically here as problem and target species of the Scottish Invasive Species Initiative, do remember that not all plants are invasive.  Autumn is the main season for the setting and dispersal of seed of the majority of plants in Britain so now is a great time to see plant reproduction in action. 

As you’re out and about in the coming weeks take a second to appreciate the evolutionary genius of our plants as they spread seeds by wind, water, explosion, adhesion, using hooks to attach to passing animal traffic and as part of enticing fruits and berries for animal helpers to enjoy and transport.  You’ll be amazed at how many different tactics and methods there are – tell us how many you see.  

For more information about the work of the Scottish Invasive Species Initiative please visit our website – www.invasivespecies.scot

A day in the life of a SISI Project Officer

James Symonds, Project Officer, Scottish Invasive Species Initiative
November 2020

James

We asked our very own James Symonds, what a typical day of a Scottish Invasive Species Initiative (SISI) Project Officer looks like.

As a Project Officer, I am responsible for the management and co-ordination of invasive species control across four rivers in Moray and Speyside; the Rivers Spey, Findhorn, Nairn and Lossie.  Our main species of concern are; American mink, Giant hogweed, Japanese knotweed and Himalayan balsam – although we also have an interest in White butterbur and American skunk cabbage.

But what does a day in the ‘office’ look like for a SISI Project Officer?

Well that changed significantly this year with the coronavirus pandemic, but following lockdown we managed to get back out in the field to continue our work – albeit with changes to our work practices to keep everyone safe and whilst balancing home working and home schooling challenges.

My typical workday starts the same as any other for a father of 2 small humans – unsocially early! After making my way to the coffee pot and feeding the rabble I can check my work phone. I am checking my “Mink Police” app for any mink traps activated overnight and to see if any volunteers have been in touch about their mink monitoring rafts or traps.  All clear!

The Mink Police units are great innovations. Live capture traps, by law, have to be checked at least once in a 24hr period to meet animal welfare protection requirements.  The Mink Police units, using a combination of technology and magic, send multiple daily updates for specific trap locations which negates the need to physically check each trap in person each day. They allow me to remotely check the traps wherever I have access to Wi-Fi or mobile signal and, most importantly, notify me instantly if an animal has been caught.  This means that traps can be deployed to areas where, for example, mink have been sighted in physically difficult access locations or where we don’t have an elusive local ‘trapping volunteer’ to do these daily checks.  Using Mink Police units I can monitor multiple traps across a wide geographical area myself.

Mink Police unit mounted on top of a live capture trap

After finally managing to get a shower and get breakfast, I double check the weather for todays planned activity – Giant hogweed spraying. The weather looks good so I drop a text to all of the volunteers who have offered their help to reconfirm the meeting time and place.

I visit the stores and pick up all equipment required for the day and make sure I stock up on the ever-essential tea and biscuits on the way to site.

After a quick meet and greet with today’s volunteers, I go through the essential risk assessment and tools talk.  Much of the time we work on uneven terrain alongside rivers and today we are working with Giant hogweed – a dangerous plant with photo-toxic sap.  We also have in place additional COVID-19 working adaptations which need to be explained.  Safety and volunteer welfare is our number one priority.

Volunteer spraying Giant hogweed

We kit ourselves out with protective clothing, fill our knapsacks and set to work.  Today we are spraying in about six acres of riparian woodland with frequent sizeable Giant hogweed stands.  One of my volunteers is new, so I work alongside them offering support and supervision.  Pre-coronavirus there would be a team of volunteers working with me – battle hardened and dedicated hogweed assassins who gained their pesticide application qualifications with us – but today it’s just three people to keep numbers low and allow for social distancing.  We work in a rough line moving in a zig-zag upstream hoping to catch all of the hogweed we see on the way.

We started at 10.00 am it’s now 12.30 pm – definitely time for a proper break.  We put our knapsacks down and set up camp on the riverbank.  On a normal volunteering day I would  pull out the Kelly kettle, tea and biscuits – chocolate hobnobs if they are lucky – offer a demonstration on how to light the kettle using a fire steel and natural tinder and the volunteers would have a go at fire lighting themselves.  This year we’ve had to ask volunteers to bring their own flasks which is a shame as we like to offer additional activities alongside the hard work of plant spraying.  We appreciate the time our volunteers give to us and want to keep each day varied and fun for them – that way they might come back again!  

Putting the kettle on!

I check my phone and whilst we were working a trapping volunteer has called – she has a mink in a trap on another river. I phone back and she confirms the trap was empty last night but a mink has been caught this morning.  I’ll visit as soon as I am finished on site.

We spray for another 70 minutes and manage to cover the whole woodland.  My volunteers (and myself) have worked hard today but it’s been good fun.  As a reward I let them all go home early, 2.45pm instead of 3pm!  I’m nothing if not generous….

After the plant control equipment is cleaned down and packed in the car I can make my way to the mink in the trap. It’s a large mink and I have the unhappy task of humanely dispatching the animal.  This is done quickly, quietly and discretely with a high-powered air pistol. I take some basic measurements and sex the animal – a male.  You can tell this by feeling for a small bone between the hind legs – the baculum – present only in males. You can work out what this identifying feature is I’m sure!

Non-native American mink caught in trap

Dispatching mink is not something I or the project enjoy – but it is essential.  The mink is a voracious predator and their presence has a devastating impact on native wildlife.  For example, since the introduction of mink, Water vole numbers have declined by over 94% across the UK – largely due to predation.  They also have a negative impact on populations of native ground nesting birds, amphibians and fish species as well as taking domestic fowl.

I get home, change a nappy, check my emails and follow up with volunteers planning on coming out tomorrow.  The weather is looking wet so instead of spraying Giant hogweed we will decapitate the flower heads using pole saws – always fun!  I am just about to email a few volunteers about later in the week when my 4-year old runs in and rugby tackles me – it’s time to finish work for today.

Using a pole say to remove flower heads from Giant hogweed

Invasive species control work is seasonal so once we are done with Giant hogweed, we move on to pulling or slashing Himalayan balsam – great for all the family to get involved in and then, as autumn looms on the horizon, we move on to spraying or stem injecting Japanese knotweed.

The specific threats these plants pose vary in one way or another but what they all share is the fact that they are so successful in our climate and our native flora cannot compete. If left unchecked we face a massive loss to biodiversity, destabilisation of our riverbanks and very different ecosystems to the native ones that should be present. 

Injecting herbicide directly into Japanese knotweed stems (L) and slashing Himalayan balsam (R)

It’s been a productive day and there is a tremendous sense of achievement seeing what a huge difference can be made in such a short space of time with so few people.  I have missed the larger volunteering groups this year, it’s always good to get a big crowd out, but we soldier on for now and hope to get everyone back together next season.  The volunteering opportunities we have been able to offer this year have never felt so important – as well as helping nature they provide valuable time outdoors and social opportunities just when we’ve all needed these the most.

Volunteer groups 2019

If you’d like to find out more about getting involved and volunteering with James and the Scottish Invasive Species Initiative read more on our website.

The ins and sprouts of Giant hogweed control

Karen Muller, SISI Project Officer
June 2020

If you have ever come face to stem with a Giant hogweed plant or witnessed a dense infestation, you know it to be a truly impressive plant.  Not purely because of its size – but because it makes the very most of itself in everything it does to ensure success.  Huge leaves on a tall stem shading out other vegetation, an average of 20-50,000 seeds per plant which are viable for about 3 years (some studies say up to 7 years!), a taproot that stores energy and seeds that can float in water for up to 3 days on their voyage downstream to new realms.  Easy come, easy grow.

Giant hogweed in flower

It can be overwhelming to think about how best to tackle this towering hazard, but plant yourself here for a while and let’s talk about Giant hogweed control: methods, tried and tested by us, and the (mostly) weird and wonderful approaches that the internet spat out.

Before we dive in, safety first!  Giant hogweed sap contains furanocoumarins, which enhance the sensitivity of skin to Ultra Violet (UV) light. Simply put, when the sap comes in contact with skin it reacts with direct sunlight causing photodermatitis (skin burns) and you’re often left with long-term sunlight sensitivity in that area.  So, the first step is to get suited and booted and gloved to protect yourself.  A face shield or safety glasses are also advised where there is risk of getting splattered with sap e.g. when digging or cutting the plant.

The second basic rule when tackling Giant hogweed is that you need to have a plan.  Always start from the uppermost hogweed infestation along a water course, so that when you clear an area you don’t have to worry about any more seeds floating down and re-infesting your treated area.

Safety first; get suited, booted and gloved

Green and gone

At any point, while the plant is green and actively growing, a systemic herbicide with aquatic approval e.g. Glyphosate is perhaps the most straight forward answer for dealing with hogweed near water.  Note that you require the relevant training and qualifications before you can use pesticides, particularly near water.

Using a knapsack sprayer to apply the herbicide is the most efficient option for dense infestations and extensive populations.  For less dense areas or sites with occasional plants, you could consider wiping neat herbicide on the leaves with a weed wiper or directly injecting it into the hollow stem.  However, these methods do involve getting closer to the plant – something you should generally look to avoid.

Hogweed can be resilient and so a second ‘mop up’ visit a couple of weeks later can be warranted in the worst infected areas to catch any plants missed and to make your control effective.

Herbicide application by knapsack spraying, weed wiping and stem injecting

The taproot of the matter

Young Giant hogweed plants with their turnip-like taproot lend themselves well to digging up.  This is more labour intensive but it reduces the use of herbicide, requires only basic training and can be done by anyone.  Stick your spade through the root, cutting it approximately 15 cm below ground, then dig up the taproot and leave it above ground to dry out.

A sharpened spade is about as specialised as it gets with this method – but we have dug out plenty without sharpening, too.  It just very much depends on the ground you are working on.

Small hogweed plants can be dug out

Bud intentions

If you find that time has grown legs and the hogweed plants are forming flower buds or are already fully flowering, it is best to slash their ambitions with a long handled pruning saw.  It should be an absolute priority to treat flowering plants – every time a plant sets seed you can add another three years to your treatment plan.  Seed ‘em and weep!

Giant hogweed flowers only once after growing for 2-5 years and then only if the conditions and its energy reserves allow for it.  So, if you are only seeing hogweed leaves for several years at your site, there will be flowers coming soon.  Although the hogweed plant will die after flowering a lot of later treatment work can be avoided by removing the flowering head before it sets and disperses seed.

Giant hogweed bud and flower

Long handled cutting equipment is advised – this allows you to keep a safe distance from the plant and any sap splatters as you cut it.  If cutting is the only form of control you are doing be ready to revisit the site regularly during the growing season to cut any new emerging flower spikes on the lower stem or regrowth at the crown.  Cut under the flower head first – removing it intact – then cut the stem in sections until you’re as close to the ground as possible.  If you can combine this with chemical control – treating the cut stem with herbicide – you’ll get better results.  Chemical application needs to occur relatively quickly after cutting to ensure the plant will take up the pesticide and transport it into the taproot before drying out.

Catch them early enough – while there is only a bud or white flower – and it appears safe to leave the flower head on site to degrade.  However, if the flower head has turned green the seeds might still ripen on the cut head and be viable when they drop off.  If the flower head is green, and if you can reach, carefully put a cotton bag or similar over the flower head and tie it off before cutting – then collect and burn.

Cutting flowering heads followed by herbicide application directly into cut stem

All dressed up and nowhere to grow

Suppressing new Giant hogweed growth by covering with mulch or membrane is an interesting method that does come up frequently when looking for hogweed control solutions – but we haven’t used in in the project due to the often large areas we work in.  It is most suitable for smaller areas, like a garden, and is likely to work best on areas where there are only seedlings coming through.  The idea is to cover the area with sturdy black plastic and or a generous layer of mulch and suppress seedling growth by blocking out light – a reasonably standard approach to weed suppression in gardening.  You do need to check back regularly to make sure nothing pokes through the covering.  Let us know how you get on if you give this a try.

Giant hogweed seedlings and field ploughing (image – Stanze)

In suitable locations, particularly in fields, ploughing can be a good solution.  It is most effective if combined with chemical or mechanical control – cutting the plant low to the ground first, or treating it with herbicide and waiting for it to take effect, followed by deep ploughing the area.  After that most seeds, or seedlings, will be far enough underground to not see the light of day again.  If, after initial treatment, more mature plants are being ploughed the large taproots should be removed as much as possible to prevent regrowth.  Like the covering, we haven’t tried this approach ourselves, but in the right location this could be well worth a whack.

Rooting for native species

Where possible, and particularly in areas of previous heavy infestation and a built-up seed bank, reseeding with native plants and trees can make control efforts more effective.  The aim is for native vegetation to outcompete new hogweed seedlings which emerge from treated areas – this sort of planting can also help stabilise bare riverbanks following treatment or winter die back.  Timing is everything here – long-established, dense hogweed infestations cannot be defeated by reseeding alone.  Manual or chemical control is necessary until mostly just new hogweed seedlings are appearing and their density is reduced to a degree that they will not easily overpower the native species you have seeded.

Flocking to the rescue

Situation permitting, grazing can be an effective approach in Giant hogweed control.  Sheep, goats and cattle will readily eat hogweed and pigs even go one step further by uprooting and feeding on the taproot as well.  However, there are a few things to consider before sending the four-legged cavalry into the field.

Woolly warriors brought in to battle Giant hogweed

Hogweed infestations in fields, woodlands, or at the very least a few meters removed from the riverbank, can be suitable locations for grazing control.  However, stock still need to be managed and so the costs of additional fencing, gates etc should be considered.

Hairy breeds of animals, with dark skin, are the best choice to prevent the sap having negative effects on them.  Black face sheep, for example, have successfully and without injury been used to graze hogweed. Since 2014, such a trial has been taking place in the Deveron catchment, with a second grazing trial site set up in 2019 by the Scottish Invasive Species Initiative (read about it here).

Livestock prefer to graze younger or smaller plants, so grazing should start early in the growing year as hogweed emerges.  The grazing of seedlings can be very effective due to the lack of energy stored in the taproot at that point in the plants multi-year life cycle.  On the other hand, grazing of more mature plants might not be to every animal’s taste – although we have witnessed sheep taking down flowering plants during our trials – and while it prevents plants from growing larger, grazing doesn’t kill mature hogweed as the already stored energy in the tap root allows the plant to make a come-back that same year or the following year.  In this instance, the grazers merely work from season to season to prevent regrowth and progressively deplete the energy store – preventing flowering and spread.

Like chemical or mechanical control grazing is required at a site for a number of years before you can call it a job well done and consider the plant eradicated.  Ongoing review and assessment of livestock density and grazing days is also important to prevent overgrazing of other vegetation – otherwise you might just be replacing hogweed and grasses with native recolonising species such as nettles and dock.

The sheep in the trial developed a taste for Giant hogweed and made short work of these plants

A word of caution

Household ammonia, salt, liquid nitrogen and heating oil, amongst other things, are at times suggested on the internet for use as alternative approaches to Giant hogweed control.  We haven’t tried any of these methods ourselves and neither have we found any robust evidence to suggest that any of these would be effective.  The potential negative impacts on soils, waterways and wildlife when other proven methods are available means we won’t be exploring these methods further.

Summing up

Tackling Giant hogweed isn’t for the faint-hearted and isn’t for everyone.  Wearing protective gear is essential and specialised training is required to use pesticides safely.  But, hopefully, there are control methods, such as cutting flower heads, digging of roots, mulching or use of barriers in your garden or grazing with animals in larger spaces that might work for you in your own hogweed situation and circumstances.  So, don’t be afraid to try this at home – but do be careful and do some thinking beforehand.   If you do decide to take hogweed on use a method that is suitable for you and your site, only proceed after proper planning and, if needed, training and absolutely always with the correct protective clothing!

Just remember, always check and clean yourself and your equipment before leaving a site to avoid further accidental spread, prioritise control strategically in a downstream direction and focus on plants about to flower.

If you are in the Scottish Invasive Species Initiative area and want to help our control work then get in touch (E: sisi@nature.scot) and we will see what opportunities are available in your patch. Read more on our website.

Assessing the damage of the Tay Reedbeds blaze

Mark Purrmann-Charles, SISI Project Officer
May 2020

The fire takes hold at the Tay Reedbeds. (Image- Vicky Turnbull / RSPB Scotland)

On 27th April the Tay Reedbeds burned.  Following a rain-free month, the tinder-dry reedbeds spectacularly caught alight and fire ran along 3km of the River Tay’s north bank.  When it was over, an estimated 120 hectares of reedbed habitat – around 30% of the total area – had been destroyed in a matter of hours.

A Helicopter dropped water on the fire which destroyed the dry reeds. (Images – Vicky Turnbull / RSPB)

Mainly lying along the north bank of the Inner Tay Estuary, the Tay Reedbeds are the UK’s largest continuous reedbed and home to a vast range of wildlife – notably important breeding bird populations, many of which are endangered or rare species.

For example, the reedbed is thought to support up to 50% of Britain’s bearded tit population and last year at least five marsh harrier pairs nested there – incredible considering there are fewer than 20 breeding pairs in Scotland.  A range of notable bird species including water rail, redshank, reed bunting and reed warbler also call the place home.  Needless to say the area has a collection of designations – The Firth of Tay and Eden Estuary Special Protection Area and Special Area of Conservation and The Inner Tay SSSI to name but three.  The Tay Reedbeds are undoubtedly a special place.

Aerial view of Tay Reedbeds (Image P&A Macdonald/SNH). Bearded tit (Image Gus Guthrie)

We have been working at the reedbeds since 2019 – specifically to protect bird species from the non-native American mink.  Mink, well established in the wild having been brought to the UK in the 1930s for fur farming, can cause huge damage to ground/near ground nesting bird species by predating young and eggs.  With the support of local volunteers, landowners and RSPB Scotland, which has a reserve there, we have established mink monitoring and control across the reedbeds.

It is hard to know exactly how many mink operate in the reedbeds – in 2019, we caught eight in the five traps and monitoring rafts we operate there.  We also recorded mink tracks at all five sites, suggesting so far we’ve removed only a proportion of the total present.  The wider area provides excellent mink habitat and the reedbeds a happy hunting ground – together providing a prime breeding location for mink.  Therefore, the mink control we carry out is important not only in protecting the breeding birds on site but also in preventing the area acting as a breeding ground from which mink disperse into surrounding areas.

American mink in trap at Tay Reedbeds in August 2019 (Image – SISI)

With a large portion of prime nesting habitat now destroyed or degraded for this season, bird breeding will undoubtedly be affected – next year hopefully regrowth will support nesting in these areas again.  Species that have yet to nest or are able to attempt nesting again in 2020 will use remaining good habitat areas or be forced to sub-optimal locations.  This could leave them exposed and vulnerable to predation from mink.

Destroyed reedbed (Image – Alison Thornton / SISI). This dead chick was a casualty of the blaze (Valerie Stewart / SISI)

With the current COVID-19 movement restrictions we can take only limited action right now.  Where they can, local volunteers on their daily exercise outings are assessing damage and identifying surviving areas of reedbed – when complete we will relocate rafts and traps to protect these locations. Amazingly all our mink monitoring rafts survived the blaze – although some are a little singed around the edges! 

Mink do not live in the reedbeds, instead they access the area to hunt before returning to home territories in the surrounding countryside.  We know many of the access routes mink use and have caught them on these highways – since the fire some of our surviving rafts on these routes have already recorded tracks confirming mink remain at large.

Remarkably these mink monitoring rafts survived – although they were a little charred!
(Image – Alison Thornton / SISI)

We won’t catch all the mink, but if we can continue to reduce the population hunting the reedbeds, as well as the wider population in the area this will help native species make the best of what is clearly a bad situation and prevent the fire causing lasting impact.

The Scottish Invasive Species Initiative could not be successful without the hard work and commitment of volunteers. Those working on the Tay Reedbeds are among our most dedicated volunteers and care deeply about the nature and wellbeing of the area. We will work with them, landowners and RSPB Scotland to support site recovery for wildlife and everyone to enjoy.

One of several Scottish Invasive Species Initiative (SISI) volunteers on the Tay Reedbeds, Valerie Stewart.
(Image – Alison Thornton / SISI)

Perhaps you’d like to get involved with the Scottish Invasive Species Initiative at the Tay Reedbeds or where you live?  Visit our website and get in touch (sisi@nature.scot) and we can make plans for when COVID-19 restrictions are eased.

Buttery Business

James Symonds, Project Officer, Scottish Invasive Species Initiative
March 2020

White butterbur (Petasites albus) is a rather lovely plant in many ways. Its white, Hyacinth like flowers are, along with the Snowdrop, some of the first to be seen in the new year and can brighten up those winter walks along our rivers. In summer its plate-sized leaves create an overlapping mat of terrestrial lily pads that catch the breeze and flutter to and fro in a shimmer of white and green, very striking indeed.

White butterbur in flower in late February

However, its delicate appearance belies an insidious nature.

Native to the mountainous areas of Central Europe and the Caucuses it was, along with most invasive non-native plants species, introduced to Britain as an ornamental plant. Its introduction was earlier than most of the headline grabbing exotics like Japanese knotweed, 1683 to be precise, perhaps due to its natural range being so much closer to home. It was recorded in the wild by 1843 and is now firmly established and naturalised across much of Britain, with the North East of Scotland seeing the highest concentrations of plants.

White butterbur is a rhizomatous plant, meaning the plant has a network of roots (the rhizome) underground that are interlinked and plants grow from this root system. When the leaves die back in the late summer the plant puts energy back in to the rhizome where it is stored over winter ready for its early flowering and rapid growth in the new year. This is where its insidious nature starts to become evident.

Exposed rhizomes on the edge of a river bank

Because of the substantial energy stores in the plants rhizome it can grow rapidly as soon as conditions allow. By mid-April early May, just when our native woodland plants are really wanting to get going, it already has a dense mat of foliage covering the woodland floor. This mat completely shades the ground meaning no other plants can access the sunlight so essential for their growth. With little or no competition, the rhizome has enough energy to spread laterally potentially, or eventually, taking over entire woodlands.

Dense carpet of White butterbur leaves on the River Fiddich

As White butterbur prefers deciduous wet woodland, it is very common along the river networks of the North East of Scotland. When the rivers flood and erode their banks, fragments of this rhizome are broken off and washed down stream where they settle and create a new stand of White butterbur and so the plant spreads, eventually taking over entire woodlands along water courses to the detriment of our native flora.

Nowhere have I seen this more evident than on the River Fiddich, a sizeable tributary of the River Spey. From its confluence with the Dullan Water in Dufftown to where it meets the Spey at Craigellechie, White butterbur has become the dominant species along its course. Anywhere that is prone to flooding is a mass of White butterbur and very little else, hectares upon hectares of ecological desert.

White butterbur dominating the river banks

In these areas even young trees struggle to break through the darkness of the butterburs low lying canopy. Trees younger than perhaps 20 years are hard to find raising the question of the woodlands very existence. So what can be done?

There is, in fact, very little research out there on the control of White butterbur so here at the Scottish Invasive Species Initiative we have set up some trial sites to see what works and what doesn’t, you can read more about the details of our trial and findings here.

Early indications suggest, perhaps unsurprisingly, that application of a systemic herbicide is the most effective way of treating the plant. The most effective time to spray it seems to be once the plant is in full leaf, June onwards. At this point the biomechanics of the plant shift and instead of directing energy in to growth, energy is being transferred back in to the rhizome for over wintering, this greatly improves translocation of herbicide from the leaf that is sprayed to the rhizome which is where it is needed! That being said I have treated White Butterbur effectively in late April but these were small poorly established patches.

If your daily exercise is currently taking you for a walk along a river bank keep an eye out for this pretty little invasive (below left) and its cousins, the purple flowered native Common Butterbur, Petasites hybridus (below centre) and the formidable Giant Butterbur, Petasites japonicus (below right) with its more elaborate flower spikes and creamy flowers, the leaves of this one can get to 90cm across!!

Finally – how do you think the Butterburs got their name? Answers on the back of a postcard…

Deploying a natural enemy for one of the UK’s most invasive weeds

Wayne Coles, CABI
Jan 2020

For 180 years Britain’s waterways have gradually become clogged and choked with what the Victorian gardeners thought in 1839 was a pretty addition to the nation’s landscape.

But Himalayan balsam (Impatiens glandulifera), also known as Touch-me-not Balsam and Policeman’s Helmet, is no longer regarded as a visual delight but rather a blight upon Britain’s riverbanks, streams, ponds, lakes, damp woodlands, roadways and railways.

Himalayan balsam was brought to the UK by the Victorians as an ornamental plant but it has since become the scourge of the nation’s waterways – Photo: CABI

In fact, the plant – whose native range is the foothills of the Indian and Pakistani Himalayas – is considered one of the UK’s most widespread invasive weed species competing with native plant species for space, light, nutrients and pollinators, thereby reducing local biodiversity.

Though it dies back in winter, Himalayan balsam is – amongst other places – causing a nuisance on the River Tweed in Scotland as part of a nationwide invasion which in 2003 the Environment Agency (EA) has estimated would cost £300 million to eradicate. The plant has since continued to invade new areas.

Nevertheless, science is trying to fight back against the Himalayan balsam ‘menace’ with a biological weapon in its arsenal – the fungal agent Puccinia komarovii var. glanduliferae– that will be released into Scotland in 2020.

Dead plant material from Himalayan balsam can also enter rivers and increase the risk of flooding.

It was back in 2006 when CABI was asked by the EA, the Department for Environment, Food and Rural Affairs (Defra) and the Scottish Government to find a reliable. effective and safe natural enemy to help control Himalayan balsam – a journey which has seen scientists adopt a ‘classic approach’ and return to the foothills of the Himalayas for a natural solution.

After sourcing a rust fungus from the Puccinia species and bringing it back to CABI’s quarantine facilities in Egham, Surrey, for further analysis and rigorous testing scientist now believe they have a tangible biological solution for the invasive weed which will be released with funding from Scottish Natural Heritage’s Biodiversity Challenge Fund in partnership with the Tweed Forum.

Kate Pollard, a Research Scientist at CABI, said, “The highly damaging fungus was identified by CABI in the foothills of the Himalayas, where it infects leaves and kills seedlings of the plant, helping to maintain population levels.

Extensive laboratory testing was undertaken under quarantine conditions to confirm that the fungus was highly host-specific, infecting only Himalayan balsam, and safe for release.

“Approval to release the rust into England and Wales was granted in 2014 and since then, the rust has been released at 47 sites across 19 counties. Field results are promising with high levels of infection, spread and overwintering recorded at a number of sites.”

The rust fungus Puccinia komarovii var. glanduliferae could go a long way to helping to solve the River Tweed’s Himalayan balsam invasion – photo: CABI

Prior to the ‘appliance of this natural solution, Himalayan balsam on the River Tweed has been tackled using a combination of hand-pulling the weed, thanks to an army of volunteers, and spraying.

The fungus has previously been released at a site along the River Tweed on the English side of the border. It is hoped that the release later this year will help step up the fight against Himalayan balsam on the waterway further as part of a concentrated longer-term solution.

Reference
Environment Agency. (2003). Guidance for the control of invasive weeds in or near fresh water. Environment Agency, London, UK

Find out more about CABI’s work to release biological controls to fight Himalayan balsam from the dedicated website.
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Did you know?

Himalayan balsam is Britain’s tallest annual plant with each plant tending to be around 1-2 metres high, although they can reach a height of 2.5 metres in some cases!

According to Section 14 of the Wildlife and Countryside Act 1981, it is an offense in England and Wales to allow Himalayan Balsam to spread into the wild. Therefore, it is highly recommended that you remove Himalayan Balsam from your grounds or garden.

It is important to make sure that when disposing of Himalayan balsam, the waste disposal site has a permit to accept and dispose of invasive species. As GOV.UK explains, you can be fined up to £5,000 or be sent to prison for 2 years if you do not properly dispose of Himalayan balsam and other non-native invasive plants.

The Good, the Bad and the Balsam

Karen Müller, Project Officer, Scottish Invasive Species Initiative
September 2019

Himalayan balsam season has drawn to a close. On our river banks, our staff and volunteers have downed tools for another season. The time has come for the last of the pink-petaled invaders still left standing to be pinging their seeds from ripe pods in an endless effort to increase their range. But with thousands of plants degrading in piles on the banks and tens of thousands of seeds prevented from ever reaching nurturing soil we are happy to call this a job well done, for now.

It’s time to reflect on the last few months – our highs and lows, ayes and nays, lessons learned and casting our eyes to the future.

Getting to grips with balsam

This year’s waves of heat and rain appear to have been particularly favourable for balsam, with many areas dazzling with shades of pink. To counter this, a continuous thwacking of weed whackers, scythes and strimmers against balsam stems, the sound of soil releasing roots and the popping of hollow stems under the weight of more balsam being added to piles has filled the air over the last few months. There has been a flurry of volunteer activity across the project area, making it possible that river banks from Tayside to Sutherland have decidedly less of a pink hue to them.

Volunteers come in all shapes and sizes and the one lovely thing about balsam is that its control is suitable for a wide range of ages – from primary school children to people living out their best life in retirement – and can be done in larger groups. It’s the perfect way to meet new people, partake in a hands-on activity with your kids or spend some relaxing time in nature while trying something new and helping the environment. Whether it is anglers, dog walkers, bird watchers pulling a few plants when they are out and about or individual people, schools or organisations that specifically join us project officers for a balsam bash – many a mickle makes a muckle in the battle against balsam.

Compared to other invasive plant control, balsam provides instant gratification when you look back on the area you are working on – nothing makes your chest swell with pride like knowing you have just built the highest balsam pile yet of the season. And let’s not stop there, optical illusions, balsam snowmen, a spot of friendly competition who can build the biggest pile or who can scale the finished pile the fastest and stand victoriously at its summit – the pile is your oyster.

Unquestionably, balsam control is not always all sweetness and light –the plant is willing to make use of many kinds of growing spaces and so we found ourselves thigh deep in ‘bogs of eternal stench’ or crawling around in gorse on more than one occasion. Did it stop us having fun? Of gorse not!

Through the good times and the tough, plenty of opportunities to whip out the Kelly kettle, freshly brewed tea and coffee (not the instant kind, mind!) and, most vital, chocolate biscuits, support us in keeping our volunteers in top motivation.

Time to reflect and perfect

So, what have we learned over the past two seasons through trial and error? For one, we have stocked our armoury well with strimmers, scythes, weed whackers and gloves since last year – something to counter anything the balsam might throw at us.

Selectively pulling balsam from amongst other vegetation seems to have the least impact on non-target species, if compared to mowing down stretches of bankside vegetation at more badly infested sites. But, if you’re working on borrowed time, you sometimes have to face the hard hitting questions. Mowing is effective in terms of time and effort and, thus, usually prevents a much larger proportion of seeds from dropping. So, do we mow in the hope that after a couple of seasons we have adequately reduced the density and can move on to pulling the balsam up? Or shall we pull regardless of the fact that much less can be achieved in the same amount of time? It is important to ponder these quandaries and often we have to make decisions on a case by case basis, depending on the existing vegetation, how dense the balsam has become and its potential to spread from there.

As it gets later in the season the balsam is really out to impress, growing up to two meters in height. At times the stems are growing horizontally along the ground before reaching its flowers towards the sky and roots start to form on higher leaf nodes, digging into the soil where the stem touches the ground. The trouble with this is the increasing likelihood of snapping the stalk during pulling, followed by the balsam stubbornly re-growing from the left over stem. A weed whacker can be really handy here to slash the stalk below the first node closest to the ground and curbing the balsam’s ambitions once and for all.

Casting our eyes on the future, there are always things to improve. For one, we still need to understand the distribution of balsam throughout our catchments better, so that we can control it strategically from the most upper extent moving down the river. We really appreciate reports of sightings to help us with that. The species is widespread and we know that long-term, sustainable solutions require landowners who actively take responsibility and more volunteers to support the effective removal of the plants annually. While many landowners, local communities, environmental groups and countless more are already getting involved we need to increase these efforts catchment wide moving forward.

Last but certainly not least, both this year and last year it is a must to acknowledge that every single one of our enthusiastic volunteers is absolutely wonderful and invaluable! You make it a joy to get to grips with balsam and you make the improbable possible. Not all heroes wear capes – some wear waders and gloves!

If this has inspired you to get involved with the Scottish Invasive Species Initiative or you’d like to find out more, visit our website www.invasivespecies.scot or email sisi@nature.scot

Filling my wellies with water

Cally Day, SISI Volunteer, June 2019

Cally has been volunteering with the Scottish Invasive Species Initiative (SISI) for a year and shares her experiences with us of her time volunteering so far.

I was studying applied science when Karen from Scottish Invasive Species Initiative (SISI) came along to the college to give us a presentation explaining her role as project officer, which included, conservation work and reaching out to the community to help identify and tackle the problems we are facing with invasive species along our water courses. As Karen went on to explain in more detail about the activities her role involves the entire room turned to focus on me. Everyone who knows me understands how I love to be outside investigating and seeking out anything out of the ordinary. Hearing about her talk about her work and the benefits to the native wildlife and biodiversity, really had me interested. That was what I wanted to do. I got in touch via email immediately with Karen who works within the Deveron, Bogie and Isla rivers catchment area, and with James who works within the Lossie, Nairn and Findhorn rivers catchment. They both put me to work straight away…

Cally (right) with SISI project officer Karen (left)

My first volunteering expedition, and I call it an expedition because it was exactly that. Karen took me to a stretch of the river Ugie in Aberdeenshire which to say the least was varied terrain. We were surveying the presence and amount of the invasive non-native Himalayan Balsam plant. Along our route we encountered some overgrown bramble, nettles and some boggy areas which I almost lost a wellie in. I fell to the ground many times, which was mostly due to my lack of balance and finesse. However, it was a superb experience and we had some serious fun along the way. There was an area of intense overgrowth so we decided to it would be easier to cross the river onto the other side. No-one fell in, which was a real achievement, although we made sure that we were perfectly safe by choosing a relatively low and slow running area to cross, but the wellies did fill up. Fortunately, it was a scorcher of a day and during our lunch break I was able to dry my socks out. I think we must’ve walked about two and a half miles that day, and did what we set out to do, survey complete. I wasn’t sure if Karen would take me back out with her again or if she went away thinking I was a bit of a liability, but thankfully we have tackled the rivers many times since, mostly controlling Giant hogweed.

Finding Giant hogweed

James also got in touch and offered me my very own Mink Monitoring Raft, which I was delighted about. He came and explained how it all works and gave me information about what I could look out for and left me to it. It’s always very exciting to go and check a raft for any signs of wildlife. I have had several prints but none of them mink, which can be a positive sign. I have seen otters down by the river while I have been down checking my raft, which is always nice to see. Since James gave me my first raft, he offered me a second raft along a different stretch of river which again I was happy to agree to. When I go to the river to check on my rafts, I usually spend a few hours there just taking in the surroundings and taking that time to relax. I noticed other signs of wildlife presence, including footprints and padded down plants, holes in the embankments and feathers, so I bought myself a trail camera. Since I have set it up, I have had footage of roe deer, badgers, mice, pheasants and lots of various native birds.

Mink monitoring raft

I have been learning as I have been going along from the project staff, I have attended events including Wild about Aden, which is a family event within a country setting for all ages. We set up an information stall for SISI which was a public engagement role. Spending a couple of days engaging with the public, educating them about the invasive non-native species and their effects improved my confidence and I was surprised at how much I had learned in the short time I had been working with them. SISI has also given me the opportunity to attend courses, including the pesticide spraying course where I gained my certification which now enables me to use pesticides to treat invasive plants.

Treating Giant hogweed with pesticide

There have been so many opportunities in my first year working as a volunteer with SISI that I would never have expected, which I am very grateful for. It has been very rewarding seeing the impact we are making on embankments of the rivers and streams, and successfully handing over the opportunity and support to landowners to take the reins and continue.

I have been out many times now with Karen, James and Al on long days of Giant Hogweed control and my fitness levels have improved remarkably. I have noticed that my breathing has improved and my balance too. I can carry weights of 15 litres on my back and walk for many miles. But most of all, my mood is always on top form when I am out and about with them. They are a super team to work with.

Helping SISI project officer James light the Kelly kettle to make a brew

I have a lot of exciting times ahead with SISI and a lot more conservation work to do which I am looking forward to. Thanks SISI.

And thanks to you Cally 🙂

Back to basics: grey squirrels in Scotland

Guest BlogGill Hatcher, Saving Scotland’s Red Squirrel Project, May 2019

It’s ‘Invasive Species Week’: an opportunity to talk about the threats non-native species can pose to our special wild places, our natural heritage, and global biodiversity; as well as what people can do to help. But often the first challenge in raising awareness is simply explaining what ‘invasive’ means. It’s not a household term, and it can be a complex – and sometimes controversial – subject to discuss.

Perhaps none more so than the grey squirrel. The grey squirrel is equally one of the most familiar examples of an invasive species in Scotland, and the most clouded in confusion, misinformation and emotion.

Grey squirrel

The eastern grey squirrel is a North American species that was first brought to Britain to decorate the gardens of Victorian stately homes. With an abundance of food and fewer competitors to contend with, they quickly settled in their new surroundings and began to spread across the country.

As the only squirrel species native to the UK, red squirrels struggle to compete with grey squirrels for food and living space. Some grey squirrels also carry squirrelpox, a virus that doesn’t harm them but is deadly to reds. As grey squirrels have moved into an area, reds have gradually disappeared; and today greys have completely replaced reds throughout most of England and Wales, as well as Scotland’s Central Belt and the city of Aberdeen.

In many of these places grey squirrels have been present for well over a hundred years, with the native red squirrels barely a distant memory. So for many people in the UK today, grey squirrels are the norm. In cities and towns, they are often one of the few wild mammals people come into regular contact with, providing a rare connection with nature. It’s not surprising that many don’t realise that grey squirrels are not native, that red squirrels were once widespread or even that the two are different species of squirrel. Before we can even begin to explain the term ‘invasive species’, we often have to start with the basics if we want widespread understanding and support for red squirrel conservation action in Scotland.

Red squirrel

While raising awareness of the threat from invasive grey squirrels, it’s also important to emphasise that there are still many places in Scotland where red squirrels are thriving. Home to 75% of the remaining UK population, there are healthy populations in the Highlands, the Central Lowlands and parts of South Scotland. Red squirrels are under threat, but they are still very much worth saving.

Saving Scotland’s Red Squirrels is a partnership project led by the Scottish Wildlife Trust. Established in 2009, its aim is to protect Scotland’s red squirrels by combating the spread of grey squirrels. With the help of landowners and volunteers, grey squirrels are being controlled through live trapping and humane dispatch in the areas where this action will have a positive impact on core red squirrel populations.

In 2017 the project was awarded a £2.46 million National Lottery Heritage Fund grant to begin a new phase called ‘Developing Community Action’. Recognising that landscape-scale community involvement will be the key to the long-term protection of Scotland’s red squirrels, the project is now focussing on building a strong network of local volunteers, providing them with the skills and resources they need to carry out red squirrel conservation work in priority areas. The first step is community engagement: building a basic understanding of why red squirrels need our help and why, at this time, control of grey squirrels is the only way to ensure red squirrels will continue to have a home here.  

Community involvement in red squirrel conservation

One way to start this conversation, and one of the simplest ways people can help the project is by reporting red and grey squirrel sightings. The sightings map contributes to our understanding of squirrel distribution across Scotland, and it could act as a stepping stone to getting more involved. There are lots of ways to take action for your local red squirrels, from survey work, to grey squirrel control, to helping spread awareness by volunteering at an event.

You can report a sighting and find out more about volunteering with Saving Scotland’s Red Squirrels at scottishsquirrels.org.uk

Photograph credits; Grey squirrel -Bob Coyle, Red squirrel & community action – Jo Foo