WISP – Wye Invasive Species Project

Introducing WISP

WISP is our Wye Invasive Species Project. The aim of WISP is to support the local communities of the lower Wye Valley (downstream of Monmouth currently) in tackling 3 key target species across our project area – Himalyan balsam, Japanese knotweed and American Skunk Cabbage. These are the worst offenders, causing significant problems and they are found throughout the lower Wye Valley. Together we will work to control these species to help our biodiversity recover and our natural habitats to be better able to cope with the changing climate.

These target invasive species produce large numbers of seeds every year, which are spread by humans, by wind and by water, or they have stubborn rhizomes (roots).  Seeds, plant and root fragments are readily spread by water and new populations of plants are often found downstream of original sites.

So, to be effective, plant control needs to work at a catchment scale (encompassing all the small streams that feed into the main river) so all the plants are removed and there is nothing left to re-infest rivers downstream. However, this is challenging as there are many landowners and communities within these catchments. By working with landowners, residents, local councils, local fisheries, community volunteers and land managers we are co-ordinating action and undertaking control work to get these invasive plant populations into a maintenance state.

Click on the photos below to find out about the 3 species, what we’re doing to tackle them and how you can support this project.

Himalayan Balsam

Large leaves of the American Skunk Cabbage

American Skunk Cabbage

Japanese Knotweed

Introducing our Target Species

Some species have been introduced into the UK deliberately for use in forestry or agriculture, and others have arrived as a result of human activity via the transport of goods or brought in by botanists and explorers. It’s currently estimated that Britain has more than 3,000 non-native species (plants and animals). Many are harmless, but occasionally a species will be introduced that can pose a threat to native biodiversity – these are Invasive Non-Native Species (INNS).

On our current ‘Hit List’ are the 3 most prevalent INNS in the lower Wye Valley, Japanese knotweed, American skunk cabbage and Himalayan balsam. It’s believed these were introduced as exotic garden plants and, finding our climate favourable, they spread out into the countryside via watercourses and other means. Sale of Himalayan Balsam and Japanese Knotweed is banned and both are listed under Section 9, Wildlife & Countryside Act and categorised as a ‘Controlled Waste’. American Skunk Cabbage is found along watercourses, bog gardens and ornamental ponds across the UK, but still in fairly localised areas.

Are they really a problem?

INNS are the second greatest threat to biodiversity after habitat loss and fragmentation of habitats. Common to our 3 species is that they spread very successfully along watercourses, growing fast and outcompeting less vigorous native plants. In the winter they die back completely, leaving bare earth with no stabilising vegetation. This heightens the risk of erosion during floods and high rainfall, which can lead to habitat loss, soils washing into watercourses, reduced water quality and smothering of aquatic habitats. The one benefit of Himalayan Balsam is its nectar-rich flowers attract an abundance of pollinators. However, this can leave native plants at a heightened risk of being unpollinated. With our biodiversity in catastrophic decline and flood events increasing in frequency and severity, you can understand why we’re taking this so seriously. 

And of course, these INNS don’t solely impact our ecology, they negatively impact us too. INNS have been estimated to cost the UK economy at least £1.8 billion pounds annually, they mainly affect farming and horticultural sectors but can affect transport, construction, recreation, aquaculture and utilities. There are hidden costs too. For example, the increased sedimentation of rivers increases water companies’ costs of treating the water to make it safe for public consumption, and that translates into higher water bills. Growing so tall and densely along riverbanks – Himalayan Balsam is the largest annual plant in Britain –  they can impede visibility and access and alter the appearance of our landscapes and riverscapes, something that’s very difficult to put a price on. 

You can help us to tackle INNS and stop the spread:

Be Plant Wise – get familiar with these species and keep a look out when you’re out and about in the lower Wye valley – have a look at the web pages below and the ID sheets.

Raise Awareness – help to spread the word within your local community about INNS and WISP.

Manage INNS where appropriate – Himalayan Balsam can be pulled up gently with its roots intact. Do this before the flowers set seed as those seedpods are explosive, firing hundreds of seeds up to 7 metres away!. Pile up the pulled plants, ideally making sure no roots are in contact with the soil and, if you can, stomp on the stalk to reduce the chance of them re-rooting.

With American Skunk Cabbage we advise landowners 1) to cut the flowers off (live-heading) in the spring before they go to seed to help reduce the spread of seeds and 2) to get in touch with us to discuss the best control method. Japanese knotweed is a different ball-game altogether. Please do not attempt to cut, strim or mow Japanese knotweed as it increases the risk of spreading the plant and could constitute an offence. Repeatedly cutting can encourage the plant to spread underground and it’s well documented that the cutting method can take over 10 years to weaken the plant enough to kill it. Attempts at digging the plant out must be avoided as the roots go incredibly deep. Before you try any knotweed control method please do contact us to find out if we can add it to our schedule of chemical treatment. 

Report It – if you spot any INNS in the lower Wye Valley do email us your sightings at projects@wyevalleyaonb.org.uk. If you see Japanese knotweed along a road or in a park please report it to us and to your local council (via the Monmouthshire App (under ‘Grasses, Trees & Hedges’), or the Forest of Dean DC or Gloucestershire CC website reporting pages. If you see it on Forestry England, Woodland Trust or Natural Resources Wales (NRW) estate do report it directly to them.

Get Active and Involved – if you’ve been inspired by The Narth & District Footpath Group’s initiative and you have some spare time to get active outside, there are a few things you can look into. The Wye Valley AONB has its own Volunteer Group, which, when Covid-19 restrictions allow, is out and about in the local area and you’re very welcome to join us. Your local community might also have a relevant volunteer group you could join or, if you don’t have one, how about setting one up yourself? There’s support and resources available – do get in touch. 

Support the Wye Valley AONB – You can donate or fundraise for the AONB Fund and that money goes towards worthwhile local projects.

Useful information sources:

GB Invasive Species Secretariat: ‘Be Plant Wise’ http://www.nonnativespecies.org/beplantwise/

Japanese Knotweed: https://www.plantlife.org.uk/uk/discover-wild-plants-nature/plant-fungi-species/japanese-knotweed

Himalayan Balsam: https://www.plantlife.org.uk/uk/discover-wild-plants-nature/plant-fungi-species/himalayan-balsam

American Skunk Cabbage: https://www.plantlife.org.uk/uk/discover-wild-plants-nature/plant-fungi-species/american-skunk-cabbage

If you would like to be involved or find out more about WISP please contact Nickie Moore at projects@wyevalleyaonb.org.uk or call 07539 902 681 (currently home working)