How a strategy and community are taking on invasive non-native species in Cumbria

Izzie Mullin, Invasive Non-Native Species (INNS) Project Officer, WCRT

When people ask what I do at West Cumbria Rivers Trust, I tell them I’m on a mission to outsmart invasive species while spreading the Check, Clean, Dry message.

What this means is that I manage invasive non-native species (INNS) in the Derwent Catchment and have responsibilities for raising awareness to stop new ones. This usually leads to a long chat about all the Himalayan balsam they’ve spotted—coordinates included—followed by musings on how impossible my job must feel!

But I’m not over faced by the task. I believe that a strategic and consistent approach can make a huge difference. I’m not going to lie though, it is a huge and challenging task, and we certainly do have some prolific invasive species in our region.  

Himalayan balsam is probably the most well-known invasive species and one of the most time consuming. It’s a master spreader; but it’s also very easy to pull.  Each plant you remove stops around 800 seeds from spreading, so every pull counts and does make a difference. We always start upstream to cut off the spread at its source and stop it in its tracks before seeds can reinfest the catchment. With multiple sources to manage, we prioritize by position and funding, as grants often dictate where we can work.  This can make it a complex puzzle to strategically manage sometimes, but that’s part of the fun.

It’s not just us though! Community groups and passionate Guerrilla balsam bashers are the real heroes, tackling far more than we ever could alone.  We’ve got lots of resources on how to identify balsam, when to pull it and how to set up your own Balsam Bashing group on our website.  My long term goal is to have the balsam problem in the Derwent catchment firmly under control, but if that ever happens, it will be through a collective, community effort. In all seriousness though, reports of INNS are always useful, and every report added to INNS Mapper is useful to build up a picture.

Himalayan balsam however, is not the only INNS on my radar.  Species such as Japanese knotweed, American skunk cabbage (head to our handy wildlife pages to find out more about these species) and American mink all require slightly specific skills to tackle. All our INNS are tackled strategically, following our INNS catchment plan, to ensure that we’re tackling them as sustainably and cost effectively as possible, using what little funding we have.

We’re unfortunately at risk of new INNS being introduced to the region with every hiker, swimmer, paddler or boater who travels to our region to enjoy our wonderful lakes and rivers. With some simple knowledge however, that risk can be easily mitigated.  Whether it’s muddy boots, a kayak, swimming paraphernalia or a paddleboard, I’m here to remind everyone to give those sneaky hitchhiking species the boot. This awareness raising is another key part of my role. There are some incredibly efficient lake weed spreaders that can wreak havoc on our waterways, killing native plants and wildlife.

Not all lakes, like Buttermere, have INNS yet, and it’s my mission to keep them out. To do that, we need everyone to follow the simple rule: Check, Clean, Dry.

Before moving to a new waterbody, remember:

• Check your gear for mud, plants, or animals (leave them at the site)

• Clean it thoroughly, especially damp spots (use hot water if possible)

• Dry it as long as possible—some species survive over two weeks in damp conditions.

My work depends on when people like to come and visit and when the plants grow, which both fall into the summer months, making it one hell of a busy period for me!

We can’t tackle invasive species alone, so we’ve teamed up with key partners to form the Derwent Invasives Partnership. With the National Trust, Lake District National Park Authority, Natural England, Environment Agency, and Cumberland County Council on board, we’re all spreading the same message across the Derwent Catchment to locals and visitors alike.

Thanks to this teamwork, we’ve earned Bronze AQUA Accreditation for Derwent Water—and we're not wanting to stop there – we’re aiming for more for all the lakes in our catchment! If you want to get involved and help us, check out our DIP project page!

To wrap up, yes, it can feel like I’m battling Himalayan balsam one plant at a time, but I’m not daunted. I love what I do, and with a solid strategy and awesome community support, we’re making real progress—and aiming for even more shiny badges across the catchment!

Izzie Mullin is Invasive Species Officer for West Cumbria Rivers Trust