Keep your boots clean

The week after I attended the YWT INNS Volunteer Discovery Day at Slaithwaite, I found myself in Scotland by the River Teviot using my newly trained eye to look for Invasive Non-Native Species. The usual suspects were absent. No Himalayan Balsam. No Japanese Knotweed. No Giant Hogweed. No Floating Pennywort. I couldn’t believe it, and I was actively looking. Once back home I totally changed the start of this half-written blog.

There are still places in the UK that are not overwhelmed with Invasive Non-Native Species (INNS) and it is up to us to keep them that way, so whatever you do, make sure you clean your boots after any countryside pursuit. After a day in the Colne valley and a day tackling Balsam at Barlow, I could have transported all sorts to the Teviot. Even if you can’t see anything, it doesn't mean there’s nothing there. Just as there are different birds and plants in Scotland, there may also be unfamiliar invasives. The key message is - CHECK CLEAN DRY.

Invasive Non-Native Species (INNS)

“Invasive Non-Native Species” as a title says it all. Many species in the UK have been introduced over time and most of them fit in quite well. The Sycamore tree was introduced around 500 years ago and is now part of the scenery. It supports ecosystems, it doesn't outcompete other trees or cause any harm. So it is a NNS - it misses the “I”. An INNS species has to be both Invasive and non-native.

The INNS Volunteer Discovery Day

I am sure the YWT INNS team won’t object at all to me getting the key message in before reporting on the Discovery Day. The team were out in force to enlighten us, with Simeon Gurr, Hollie Warman and Elliot Baxendale leading the discussions and the guided tour down the Huddersfield Narrow Canal to the bank of the River Colne. Also joining us were Marie Fooks and Jen Squires from the Volunteering Support Team. Simeon opened up the proceedings by wishing us all “Happy INNS Week” and letting us know that we have 193 INNS species in Yorkshire alone. So it’s like one of those episodes of Dr. Who where he has to fight all his enemies at once - Daleks, Cybermen and all the rest - only we have to do it all the time. INNS is a big deal, not only in Yorkshire. The annual cost of managing INNS in the UK is measured at around £4 billion, but is likely to be considerably higher. Worldwide, INNS is the second biggest cause of habitat loss, after habitat destruction for development.

The presentations were a mix of jaw-dropping information and group tests to see if we could ID the different species, and crucially tell them apart from similar, more friendly species. Here, our table got 100% right! Note the coffee, kindly supplied by our hosts for the day, Dark Woods Coffee. It was so good, I took some home.

It’s not just Himalayan Balsam, but we need to talk about it..

Himalayan Balsam comes from the Himalayas, where it has developed a suite of morphological traits that allow it to quickly outcompete our native species (shallow roots, fast growth, high water retention, no need for specialist pollinators, and pods that send seeds flying up to 8 Metres). It has advantages at every stage of its life cycle, yet it is hard to find if you look for it in its native habitat. It has competitors and parasites. Over here, all the things that allow it to fill a niche in the Himalayas make it dominant, and invasive in our environment. Not only that, but the Seed pods are fun for children to “pop”.

The main problem with Himalayan Balsam is its devastating dominance. It grows quicker and taller than most native species. It can grow in bramble patches and spread seeds from there. It out-competes native species of plant, which in turn impacts specialist pollinators and their predators. It loves wet conditions and grows on watercourse banks. Of course, when it dies back in the autumn, it leaves a soggy mess that further inhibits other plants and partly, but not only, due to its shallow rooting, it contributes to bankside erosion, especially after flooding.

No wonder most of us spend much of our early summer volunteering time “Balsam Bashing”.

Elliot explained that there is hope, in the form of a rust fungus (from the Himalayas) that inhibits Balsam growth. Of course, this is a long term project as the fungus needs to be tested against native species before it can be released. The good news is that it is being trialled in the Colne catchment area with an upstream release that should allow it to gradually find its way downstream. There is more work to be done, especially to monitor if the fungus overwinters well in the UK and inhibits our potentially hybridised balsam. That’s right, there is more than one type of Balsam in the UK, for instance there is Orange Balsam (from North America). Orange Balsam is a Non Native species that may be spreading and could become invasive, but needs monitoring. Small changes to the climate make it possible that such species could become invasive.

The Other species…

Simeon took us through 6 main species that we manage - Balsam, I’ve already mentioned. Here’s some frightening facts about some of the others

Japanese Knotweed

• All Japanese Knotweed plants in the UK are clones of a single male plant. If it was able to breed, it would spread even further.
• It propagates from small stem or root fragments - The rhizome can be buried 6 metres deep.
• It damages buildings and other infrastructure and can be very expensive to get rid of.
• If you bring it home on your boots and it comes to life in your garden, it is your responsibility to make sure it doesn’t spread. Whilst you don’t have to remove it from your own property, it can have a massive impact on your house value and the ability to sell it.

Giant Hogweed

• Contact with this vicious looking plant can leave you with long term skin damage, so do not touch it. The sap reacts with UV light to cause massive blisters. It can take years for your skin to recover.
• A single plant can produce 50,000 seeds which are viable for up to 20 years.

Australian Swamp Stonecrop

• An aquatic plant, once sold in the UK for aquariums, that totally envelops any pond it gets into.
• One of the ponds at Potteric Carr is effectively dead because of it - there is no way to fully remove it as bio-controls for it die back over the winter. The only thing we can do is contain it. Not only CHECK CLEAN DRY but keep away from it unless managing it.

Floating Pennywort

• Grows at up to 20cm per day and loves slow moving water, for instance canals
• In recent summers, Selby canal (Between the Ouse and Aire) was largely impassable by narrowboat due to almost total coverage. Keeping it down requires active management.
• Like Japanese knotweed, it grows from fragments. Removing it from aquatic environments is almost impossible without systematic ‘fine -toothed comb’ management.
• It is the common enemy of all canal users and wildlife in the canal as it blocks oxygen.

Signal Crayfish

• Introduced in the 1970’s as a commercial crop, they carry a fungus, known as crayfish plague, to which they are immune. This is deadly to our indigenous white claw crayfish.
• This in addition to the fact that they outcompete the white claw crayfish
• Since their introduction, 95% of White claws have been wiped out
• The white claw crayfish is now extinct south of Birmingham
• Ark sites are for white claws being identified and protected in the hope of re-introduction if we can find a solution. Don’t forget to CHECK CLEAN DRY before visiting any watercourse
• The signal crayfish is cannibalistic, so removing the more easily visible big ones just means we have more smaller ones to deal with
• They burrow into watercourse banks and destabilise them. The same banks that are already destabilised by Himalayan Balsam.

What Can we do? Introducing the INNS Mapper

Hollie, who as part of her role with YWT also chairs the Yorkshire Invasive Species Forum, is responsible for looking after the INNS mapper recording website and APP.

We can, and should, download INNS Mapper on our phones and record any of the 62 species listed there whenever we spot an INNS. All you have to do is take a close-up picture (or two) and share the location and estimated quantity. I recorded 50 Himalayan Balsam at Barlow Common, then bashed at least 100 in the same spot - so you don’t need to be 100% accurate. You can even start the tracker if you go for a walk and record at points, or areas along the walk. This gives useful negative recordings to add to the positives. The app currently has 1,400 users and is also available in Welsh.

By using the maps, we can see which species are where and form plans of action. The maps are available for all to see.

Horizon species are not included in INNS Mapper, but some Alert species are. Alert species are the more worrying of the horizon species, for instance the Asian Hornet, which preys on honey bees, and has its own website and app “Asian Hornet Watch” for reporting. Other non established species such as the racoon dog and Monk Parakeet can be reported via the Irecord site.

I think this blog is long enough already, so I’m going to stop here and just say that I will be returning to this subject from different angles in the future. I’ll be telling you more about INNS Mapper and the Yorkshire Invasive Species Forum and giving updates on the Balsam bio-controls.

To find out more and join the fight against INNS, the links below lead to some great resources:

Link to the Innsmapper App - https://innsmapper.org/home

Irecord for reporting Horizon and Alert species - https://irecord.org.uk/enter-non-native-records

Yorkshire Invasive Species Forum - https://yisf.org.uk/

NNSS, the GB non-native species secretariat - Home » NNSS (nonnativespecies.org)

Article in the Independent about the cost of INNS nationally - Invasive non-native species costing UK economy £4bn a year, research suggests | The Independent