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

Coronavirus, community conservation and the green recovery

Can a community and volunteer based approach to conservation projects lead the green recovery after coronavirus?

Callum Sinclair, Project Manager, Scottish Invasive Species Initiative
May 2021

As we emerge from the 2021 lockdown, we reflect on the impact the coronavirus pandemic has had on the Scottish Invasive Species Initiative.   As a project we weathered the Covid storm surprisingly well.  Although activities were constrained, we kept invasive plant species in check and maintained our mink monitoring and trapping network.  We credit this to taking a community-based approach to invasive species management – and so we pondered what we have learnt and whether other projects could take a similar approach to help deliver a ‘green recovery’ after the pandemic.

Community volunteers in Nairn.

Community control vs Covid

At the heart of the Scottish Invasive Species Initiative are the local people who care for their local environment.  An initial and ongoing programme of awareness raising and education activities raised the profile of invasive species and their impacts. This generated significant buy in and enthusiasm to get involved from land managers, local groups and organisations, businesses, and individual volunteers.  Having recruited and enthused, we support and enable people to actively volunteer by providing training and helping them gain qualifications and experience.  This network of committed people is gaining the skills needed to make a difference to their local places – in this instance controlling invasive non-native species – both now and in the future.

When the spring 2020 lockdown occurred we weren’t, like everyone else, able to carry on as usual. It was unclear if we were about to lose a year and give up the gains made by the project since 2018.  Rather than regress, however, what we witnessed instead were the investments in embedding skills and training with local communities paying back. Farmers and land managers used their staff (trained by us) to carry on giant hogweed treatment when we couldn’t, and local people headed out to pull Himalayan balsam at sites we’d worked on together previously.  Mink raft monitoring volunteers used their daily exercise to visit and check their rafts – telling us that this small activity gave them a purpose and made them feel they were making a difference during an immensely difficult time.  The project didn’t grind to a halt – far from it – in fact we perhaps were able to snatch a glimpse of what might happen when the Scottish Invasive Species Initiative is no more.

We believe that this approach – investing in communities, training volunteers and engaging people locally can provide effective and sustainable benefits – as endorsed by the enthusiasm of our volunteers and partners to carry on invasive species control when we weren’t around. 

To date volunteers have contributed a total of 2,181 days to control invasive plants and 119 volunteers have been put through their pesticide application course.

Building community resilience

Taking a community and volunteer-based approach – rather than just employing contractors on an ongoing basis – also provides benefits to the people involved.  Volunteering, pretty much any volunteering, is much more than just the activity itself.  In our case people are making a real contribution to their local environment. But the benefits are much wider than that. Being involved within their community, meeting other people and socialising, being physically active and engaging with nature – these all contribute to improved physical and mental wellbeing.  We believe these benefits have helped give people greater personal resilience to the individual and collective stresses we have all felt during the coronavirus pandemic.

Our engagement work in communities is wide and varied.  It ranges from providing education resources for remote use and our direct education work in schools, to partnerships with farmers and universities to find alternative and innovative techniques for invasive species control.  Engaging and enabling land managers to be a central part in the  development of potentially more sustainable and affordable invasive control methods – such as sheep grazing to control giant hogweed – helps these businesses to see alternative control strategies and be more resilient to future change.

Our Macduff sheep grazing trial in partnership with a local farmer is investigating if and how managed sheep grazing can be used as a form of chemical-free, low intensity giant hogweed control.

Environmental benefits

This community-based approach, as well as empowering people, also has environmental benefits. 

Invasive non-native species require long term management and commitment.  They often produce large numbers of seeds or have persistent rhizomes and require treatment year on year. The American mink needs ongoing control to continue to depress population numbers and counter inward migration. These animals travel great distances to secure new breeding territories and can quickly repopulate previously managed areas. Having an upskilled, enthusiastic and committed local community group willing to, for example, ‘adopt’ a section of river to deliver annual plant control and/or mink control can be effective through their collective efforts – both  providing sustainable and economically effective approaches to management.

Thanks to the monitoring and trapping work of 360 volunteers maintaining 670 rafts and traps, 388 mink have been removed. This provides benefits to the local native wildlife populations, particularly water voles and ground nesting birds.

Reaping the rewards

Restored river habitats and, in turn, landscapes that are free from invasive species give so much back to us.  Our rivers are important for recreation and provide brilliant opportunities to exercise and have fun or places for quiet reflection to boost mental wellbeing.  The connection between people and nature – widely recognised as providing significant health benefits – is further enhanced when people have directly contributed to the care and conservation of the environment.

The importance of connecting with nature has been widely recognised throughout the pandemic.  Many of us discovered, or rediscovered, our local green spaces and enjoyed, and needed, the serenity these places and being outdoors brought.  

As we carefully step into what, we hope, will be our recovery from the pandemic, we have the opportunity as a society to reshape and rethink the way we do things.   We can find new and sustainable ways to work which provide long-term benefits both to people and the environment – the “green recovery”.  For us at the Scottish Invasive Species Initiative we’re not sure that is actually such a new thing – it’s the ethos by which we’ve worked since we started.

Our rivers are important places for recreation and reflection.

Is the model sustainable?

The approach we take – working locally with partners, communities and individuals – undoubtedly benefits both people and the environment and fosters strong connections between the two. 

Volunteer input to the project – 9,794 volunteer days contributed, equal to 46 full time equivalent staff from March 2018 to March 2021 – is incredible and encouraging.  The work completed through these contributions, given by 650 people, would simply not be affordable to the project otherwise.  Each and every contribution – large or small – is important to us but, perhaps more significantly, important to the person donating their time.

The Scottish Invasive Species Initiative continues to build this community network so the work we have started can be a self-sustaining after we have gone.  The work continued by our volunteers and community network during the 2020 coronavirus lockdown suggests this can be the case. But we recognise that to sustain, connect and coordinate a volunteer network to a common and shared purpose will need support and resources.  Maintaining enthusiasm, preventing ‘volunteer fatigue’, continually recruiting and supporting volunteers, training and providing local co-ordination are all essential to the success of this approach. However, the scale of return we find would suggest these investments are both extremely cost effective and environmentally beneficial.

The scale of achievement in 2020, despite working restrictions due to the pandemic.

So, while the coronavirus pandemic has reached every part of our society and touched so many of us personally, we believe there are lessons from the period that can help us in the future.  Investing in people and communities is always worth it to build support, capacity and commitment.  When investments are maintained the benefits continue.  If those investments cease, then the goodwill and benefits generated from all that has gone before are lost. 

As a project we have emerged relatively unscathed from the coronavirus lockdown – we know many have not been so fortunate. We believe the community-based approach we have adopted and the hard work and dedication of our many, many volunteers have been central to this.  We simply can’t thank these people enough.

To find out more about our work and how to get involved visit our website, follow us on social media or contact us on sisi@nature.scot

Stopping mink in their tracks – tips and tricks of the trade

Karen Muller, Project Officer, Scottish Invasive Species Initiative.
May 2021

Sleek, dark brown fur, flashes of white under the chin and a bounding gate or streamlined-shape cutting through water – the invasive non-native American mink. In the last 50 years they have become a more common sight along our Scottish watercourses and coastlines than we – and our native wildlife – would like. 

The devastating impacts of this adaptable and ferocious predator are clearly apparent – mink predation contributing to significant declines of native wildlife species, particularly water voles and ground nesting birds.

Over the last 15 years much mink control has taken place in Scotland.  However as these are wily creatures who think nothing of travelling 80km to find new breeding territories and craftily avoid entering traps their removal is not straightforward.  So, here are some tips and hints from the Scottish Invasive Species Initiative for successful mink trapping and how to out-trick these irreverent tricksters.

Please note – this article is not a guide to trapping.  Trapping should only be undertaken by trained people who understand their responsibilities regarding animal welfare, humane dispatch and relevant legislation.

American mink (photo credit – Liam Skinner)

Understand your foe

Mink are very adept semi-aquatic predators, active during the day and night and feeding opportunistically on a wide range of prey, such as fish, amphibians, birds (and their eggs), rabbits and other small mammals.

They are solitary and territorial animals – a female territory will cover around 1-3kms while male territories are usually larger (5kms) and can span across several female territories.  It’s worth noting that territories in good quality habitats will be quickly recolonised if the original occupant has died or been removed.

A good territory will be close to freshwater and often along a river in low altitude farmland, marshland or woodland edge with a plentiful supply of food e.g. rabbits.  Coastal areas are also popular – but mink still need a freshwater source nearby to clean their coats regularly.

To trap or not to trap – that is the question

As traps must be checked every 24hrs trapping can be time consuming, so it is worth monitoring for mink presence first and only starting trapping when you know mink are in the neighbourhood.

Mink monitoring is done by using a floating raft with a clay pad – to record footprints.  The raft is easily switched to trapping mode by adding a live capture trap when you know mink are present.  Read more about mink monitoring rafts on our website.

The mink monitoring raft – the clay pad sits inside the tunnel.

It’s also worth remembering to keep in touch with neighbouring monitoring rafts – our mink control is part of a large scale effort and so if you find mink signs let your neighbours know so trapping effort can be co-ordinated. The chances are that, due to their transient nature the mink you detected might have already carried on upstream and already be in your neighbour’s patch!

Alternatively, you can use a trail camera, or look for field signs if you don’t have a monitoring raft.   Check muddy or sandy banks for tell-tale footprints, bridge arches or prominent rocks for scat and look for flattened trails on riverbanks. 

Key trapping times

The best times for catching mink are pre- and post- breeding periods when mink are mobile and so there is a greater likelihood of catching them. Trapping success at these times will have a greater impact on the overall mink population.

Between January and March, many mink are transient and travel widely outside of their territories – males searching for a mate and young females searching for a breeding territory. Catching mink at this time will avoid successful breeding and prevent new mink being added into the population mix.

In summer family groups emerge from the den and by early autumn young mink are starting to leave their natal home territory but still congregate quite locally. These juvenile mink are extremely inquisitive and naïve making them easier to catch – so from July – October is the second critical trapping time.

Young female mink caught in trap.

The ‘how’

There are many native and domestic animals which can frequent the same habitats as mink – so we use live-capture traps and release non-target species unharmed.  Placing the trap on a floating raft on water further reduces the likelihood of catching non-target species as many of these are less likely to make the swim to the raft and trap.

Always cover your trap with a wooden tunnel for shelter and securely tie both the trap and tunnel to the raft.  This prevents the trap being dislodged by an angry mink or another animal and avoids the risk of accidental drowning.  Raft and traps units should be disabled or removed if the river is going to be in flood.

Live capture trap set on a mink raft, under the tunnel.

Location, location, location

Finding the right spot in the river for your mink raft and trap is the number one deciding factor in capture success – so here’s some handy hints to help you site your kit effectively on the water:

  • Look for confluences, where two water bodies join – you are doubling your chances that a mink will come across the trap by following either of the rivers or burns.
  • Find freshwater sources along coastlines – sooner or later mink are bound to search them out and use them.
  • Use pinch points – where mink are naturally forced through smaller gaps – as mink traffic can be funnelled towards your trap.  These can be:
    • under/near bridges or on bridge foundations/arches
    • culverts
    • weirs
    • in-stream islands
    • inflows and outflows on lochs
  • Select a sheltered spot out of the main flow – mink are good swimmers but they are not daft and will use the most efficient route to pass through their territories. Slow glides and slack water which make for easier swimming are ideal.

Remember – the location is no good if you can’t safely reach it in both high and low flow conditions – double check this first.  Also ensure if placed near a structure like a bridge or culvert that your raft will not cause a blockage in a flood.

A perfect spot at the confluence of two water courses.

A raft set up won’t be suitable for all locations – sometimes you can set a ground trap.

In these cases, you need to think like a mink!  Consider the likely routes mink use to move around.  In coastal areas, on beaches, this could be along the bottom of cliffs or harbour walls or between rock outcrops or prominent rocks.  Inland look for trails through vegetation along the bank, along hedges or fence lines, or fallen logs and wood and rock piles – even better if you find a well-situated log or rock pile and can fit the trap amongst them.  A mink might go for a rummage there for their next meal.

Note – If using a ground trap ensure the location is not at risk of flooding or within the tidal area. If in doubt put your trap on a raft, tied with enough slack that the raft can move in the case of water levels rising unexpectedly.

Please keep in mind that, any spot, even if it ticks all the boxes above is likely to be of little use if it is in too public a place.  We have had equipment vandalised or removed in the past and, given that if you catch a mink it will need to be despatched this task is not one which should have an audience and you certainly do not want a member of the public approaching a trapped animal.  If in doubt – find another place.

Ground traps; under a rock (L) and in a well camouflaged tunnel (R)

So, you’ve found your spot; you’ve set up your trap – time to open the box of tricks! Read on.

Trapping Hacks

Mink are curious, and you may never need to reach deep into your bag of tricks.  But if after a few weeks you are not having success then it may be time to try something a little different.

Location and set up:

  • Move your raft slightly -Try swapping to the opposite bank or a move upstream or downstream by 200 metres. Mink are fickle and these moves can often make a difference!
  • Change the direction of the trap opening – Footprints on your clay pad may give a clue to the general direction of mink travel so switch things around to see if that helps.
  • Try a double ended trap – Set two rafts with two traps opening in opposite directions. Or if on land set two traps up back to back.
  • Use camouflage – Your mink might be shy, so blend the unit into the environment. Pile some vegetation on top of a floating raft and tunnel and weigh it down with rocks.  If on land, cover it with small logs, branches, or rocks.
  • Make it obvious – This is a bid of a reverse to the camouflage suggestion above but, in non-public areas, you could also play to the mink’s curiosity and have the raft/trap in plain sight.  Sometimes the animal can’t resist the urge to explore the new addition to its habitat.
  • Make the tunnel appealing – Stuff some dry grass or other vegetation between the trap and tunnel – it creates an appealing tunnel to explore and a trapped animal to make a cosy nest from material pulled through the cage.  Make sure vegetation won’t be a hindrance when it comes to animal dispatch.  There is an added bonus here – if you catch a mink this vegetation will be saturated with scent and might entice the next one to the trap too!
  • Make sure it’s stable – If trapping on land, make sure your trap is stable – use stones or wood if needed. A wobbly trap can dissuade a mink from entering it or worse, set the trap off when knocked from the outside.

Go mad with camouflage (L) or line the tunnel with dried grass (R)

Baiting is usually unnecessary but if you do feel you need a little bit of extra help, you can try baiting with food, visual attractants or scent:

  • Food – Stab a cat food pouch a few times and hang it in the back of the trap or season your raft with a bit of oil from a tin of sardines or something else debatably “delicious” smelling. Don’t use actual food – you’ll attract every animal in the neighbourhood!
  • Visual attractants – Hang a bit of tin foil or a budgie mirror in your trap to grab the mink’s attention – get creative!
  • Scent – A scent lure holds the biggest potential, because mustelids use scent marking to communicate with each other. So, use of scent can be effective in enticing territorial animals to investigate a trap more closely – even the wily ones that turn their noses up at anything else.  There are options of how to do this but whatever you do – wear gloves!

You can collect your own scent – though this often isn’t for the faint hearted.  You can –

  • Relocate scent doused vegetation, tunnels, or traps after a mink dispatch to a different raft – though that may be impractical on a day to day basis.
  • Harvest your own scent – This is perhaps not for the squeamish or faint nosed – but I have experimented with scent harvesting from dispatched mink. A biodegradable cigarette filter, held in forceps, is saturated with “Eau de mink” from their anal scent gland. This can be done by just bringing the filter contact with their anus or, if we take it a step further to harvest even more scent, can be brought into contact with a scent gland after it has been extracted from the mink.  Not for everyone this!

Wire is threaded through the filter which is then hung from the cage grid above the trap treadle to entice the mink to enter as it takes a closer sniff.  These “scent bombs” can be stored in sealed plastic bags and added to traps as needed. This method has been used in other mink eradication programmes in preference to baiting with food.  An advantage of scent is it is more likely to specifically attract mink compared to food aromas which may also attract non-target species such as rats, otters or the odd adventurous cat.

Finally, a tip that makes your life easier – especially if your trap is located on a small island, or in a difficult to reach areas.   Attach a flag to your trap door as a visual aid to check on the status of your trap – some trap designs are better suited to this than others, and some are not suited at all but it can be really helpful. When the trap door is open the flag is up, when the trap door closes the flag goes down and is no longer visible – time to check on the trap!  You may even be able to check on your flag with binoculars from a distance. Watch a video of Karen demonstrating the signal flag.

All of the above should give a good starting point.   But of course, sometimes you may still catch nothing – remember you are pursuing a wild animal which won’t always behave as we hope or expect it to.  Be flexible and try something new now and again.

A bit of patience and luck results in a capture.

Sometimes, of course, it’s not you or the trap itself.  Perhaps the mink was transient (just moving through) and won’t come back, maybe it found itself in a different trap in the area or met its demise in a natural way, or possibly there is too much disturbance at your location and the mink doesn’t take time to investigate.  Or maybe you have a wily and cautious animal which simply won’t enter the trap pretty much whatever you do!

Despite our best efforts, there is always a little bit of luck and patience involved in mink trapping. Remember no signs of mink is a good sign – but please remain vigilant so we are ready when an animal heads your way, don’t get disheartened and don’t give up.  And while you’re there,  remember to take a moment to enjoy the native plants and animals living and thriving around you, breathe some fresh air, listen to the birds and relish the opportunity to get to know parts of your local river better you’ve never explored before.  Nature is good for you!

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Read more about the Scottish Invasive Species Initiative Mink Control Project on our website (www.invasivespecies.scot). Most of our rafts and traps are looked after by volunteers, if you’d like to find out more about getting involved read more about volunteering or contact us on sisi@nature.scot

Please note – our mink project only operates in Northern Scotland – specifically Highland/Eastern Perthshire, Angus, Aberdeenshire, Moray, Inverness-shire, Ross-shire and West Sutherland.

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.

Restoring Ratty – Bringing the water vole back to Kielder

Graham Holyoak – Restoring Ratty Project Officer, Northumberland Wildlife Trust
July 2020

I am writing this having just completed our 7th release of water voles, with over 1700 animals released in total so far.  The eighth release is just a couple of weeks away so we are preparing for this now.  It seems a long time ago when I sat down to start the first phase of the project back in 2013!

Graham with a water vole

The idea for reintroductions actually started long before this with Forestry Commission (now Forestry England) surveying the rivers in Kielder Forest back in 2008, and the then Forest Management Director Graham Gill suggesting that a reintroduction would be a good fit in an operational Forest.  On the back of this idea , a lottery bid was submitted in 2009 which unfortunately failed, and it wasn’t until 2013 that a partnership of Tyne Rivers Trust, Forestry Commission and Northumberland Wildlife Trust received funding from the National Lottery Heritage Fund for a two year Water Vole Heritage Project.  This aim of this project was to show that there was a suitable mink free habitat for water voles and that the local community was supportive.

On the successful completion of this project with no confirmed mink found we applied for further funding from the National Lottery Heritage Fund to begin bringing water voles back… and so the Restoring Ratty project was born! 

Water vole

Kielder Forest is the largest man-made forest in England and lies in Northumberland on the Scottish border.  It produces 20% of all the timber in England.  Over the last 30 years, changes in forest management practices have changed the dark stream sides with conifers down to the edges, to an area of excellent riparian habitat for water voles as planting of new trees is now done further back from the banks..  This process is ongoing so the amount of habitat for voles carries on increasing.  Forestry England’s Wildlife rangers had been controlling mink since the 1990s meaning that there was very few left in the forest.

Restoring Ratty is unusual in water vole reintroductions, as the donor animals for our captive breeding programme come  from wild populations rather than the usual method of removing water voles from building development sites.  Voles were captured from sites in the North Pennines, North Yorkshire Moors and the Trossachs in order to create a wide genetic pool to breed from – with genetics similar to the water voles that would originally have been in Kielder.   In order to not harm the donor population we only captured voles in later summer that were smaller than 160g and would be unlikely to survive the winter.  The voles were transported down to Derek Gow Consultancy (DGC) in Devon for breeding.

Water voles ready for release

The first 317 voles were ready in June of 2017 for our big first release!  Along with a team from DGC it was the chance for our amazing volunteers to see voles back in Kielder after close to 4 years of monitoring for mink!  This was followed by a further release in August 2017 and then every June and August to the present day!

We employ a soft release method where voles are put into a straw filled pen on the edge of a stream at the release site.  They are then fed with apple and carrot for several days to allow them to acclimatise to their new surroundings, and in the case of paired voles – hopefully breed.  A wooden plate with two holes is then placed over one end of the pen and this allows the voles to come and go as they please, but prevents most predators getting in.  Some voles are eager to go and head off into the wilds as soon as the plate is put on whilst others are more tentative.  By the time we remove the pens a few days later a handful of times have we had to evict a water vole!

Water vole release pen on site – nearly free!

The criteria we use to choose our water vole reintroduction sites have changed over time as well.  Prior to the project, a feasibility study was conducted looking at habitat suitability from the water vole handbook.  Well it is safe to say that some of our water voles haven’t read the handbook!  We initially put them in streams with lovely earth banks and widths of between 1-3 metres with a mix of grass and herb vegetation.  Where they seem to thrive in Kielder are very small ditches often around 30cm width.  As per best practice, we have also often conducted surveys along burns looking at the banks and the 2m zone on each side and found little. Feeling despondent on the walk back, further away from the burn we have stumbled across some feeding signs or a latrine tucked away in some rushes or a burrow under a tussock or the scampering of a water vole through the vegetation over 10m away from the streams.  These small streams and ditches are now our release sites of choice – you have to listen to the voles!

Local school helping with water vole release

We have continued the mink monitoring from the first phase throughout the project mainly using mink rafts. We have around 60 rafts that are checked on fortnightly basis by volunteers, land owners and project staff.  Mink rafts are essentially a floating platform containing a tunnel with a clay and sand tracking pad inside with floral foam to keep the clay moist.  We have been trying to make the rafts more environmentally friendly and reduce plastic loss to the environment.  We use recycled plastic rafts and wrap the polystyrene that provides the buoyancy to ensure that this does not wash away.  We have also been trialling substitutes to the floral foam using coir (coconut husk) and that has worked well in some situations.  We have also increased our use of camera traps and have tried baiting them further away from water vole locations.  It seems that mice are very fond of tinned sardines as surprisingly are red squirrels!  We have found that mink numbers are low although we have had a couple of incursions that we have had to deal with so vigilance and continued mink monitoring is paramount.

Volunteers checking mink monitoring raft

We only have a year left of Restoring Ratty – but this cannot be the end.  We have a commitment to carry on the mink monitoring to ensure that this reintroduced population is safe.  That is not the extent of our ambitions though.  Our ultimate aim is to link up the new population with the nearest donor population some 40 miles away in the North Pennines.  We are looking at a phase 3 of the project to continue this progress with further releases to boost the natural recolonisation of the water voles as well working to improve habitat and remove mink.  We have recently had some good news on this front with a partnership of Durham Wildlife Trust, Tees Valley Wildlife Trust and Northumberland Wildlife Trust receiving funding from National Lottery Heritage Fund for a three year mink control project in the Tyne, Wear and Tees catchments.

A final note on the 2020 releases – they have been very strange as we haven’t been able to have our volunteers with us due to COVID19 restrictions.  The volunteers have been integral to every part of the project from helping with events, mink monitoring, water vole monitoring and the releases.  It is not an exaggeration to say that we could not have done this project without them and so although the water voles may be the stars our volunteers are not far behind!

L to R; The pringles tube, perfect for vole handling. Ratty Ale, innovative fundraising! One of the first water voles released.

Follow the work of the Restoring Ratty project on their Facebook page.