Nottinghamshire Invasive Non-native Species Initiative

In 2009, the NottsBAG partnership agreed to take action to monitor and control invasive non-native species within the county. Building upon previous work undertaken by individual organisations, the initiative sought to improve partnership working to create a more comprehensive approach towards tackling invasive species across Nottinghamshire.

Invasive non-native species are defined as "species which have been introduced, usually by human actions, to an area that is outside the range where they exist naturally". Some native species can be invasive in their nature, such as bracken or bramble, but are a part of the native ecosystem and are utilised by a variety of species. Britain supports thousands of non-native species, many of which have naturalised and live in harmony with the native flora and fauna. This initiative focuses on plants and animals that are both invasive and non-native in their characteristics, and importantly, that cause harm to our biodiversity as well as our environment.

The spread of invasive non-native species is the second largest threat to biodiversity across the globe, behind only habitat loss. These introductions are harmful to our native species in a variety of ways, such as causing an increase in competition and predation, or carrying fatal diseases, which increases the likelihood of extinctions. Prevention and education is vital in stopping the spread of invasive non-native species, but there are already multiple species that have been introduced into Nottinghamshire that are negatively affecting our wildlife. The Nottinghamshire Biodiversity Action Group is committed to protecting our county's biodiversity, and are working together to monitor and control some of Nottinghamshire's most invasive species.

Below is information about some of the invasive non-native species that have been identified as priorities in Nottinghamshire.

Species the partnership are actively controlling

Giant Hogweed (Heracleum mantegazzianum)

The introduction of Giant Hogweed to the UK can be traced back to the early 19th century when the plant was grown in botanical gardens, impressing visitors with its extreme height. Not long after its introduction, a population managed to escape and naturalise into the wild. They are biennial plants, forming a rosette of leaves in the first year, and send up a large flower spike in year 2.  The plant prefers damp conditions and is often found on riverbanks where its seeds can be transported by the water.  It negatively effects biodiversity due to the vast height it can grow to, up to 5 metres, which then shades out other plants.  It also has the potential to cause lasting harm to people who come into contact with it due to the production of a phytotoxic sap which when exposed to UV light, can cause burns and blisters on human skin. These can have a long-lasting effect. This creates complications with the eradication process, as anyone attempting to remove the plant will need to use the correct PPE and training. Please seek guidance from a knowledgeable source before attempting to interact with this plant.

Case study: Giant Hogweed Control, Nottingham City Council

Giant hogweed in flower at Broxtowe Country Park

Giant hogweed stem at Broxtowe Country Park

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Himalayan Balsam (Impatiens glandulifera)

This plant is extremely fast growing and spreads rapidly due to its specially designed seed, which can remain in the seedbank for at least 2 years. As the seedpods burst, hundreds of seeds are flung up to 7m from the original plant and have the ability to float along streams and rivers. The plant itself can grow taller than 2m, which shades and outcompetes our native species.  Himalayan Balsam is mainly found in wetlands and damp woodlands, and can be commonly seen along waterways, railway lines, and roadside verges.  It is widespread across Nottinghamshire, with extensive populations along the River Erewash, River Idle, River Leen, River Maun, River Meden, and on certain sections of the River Trent. Notts BAG have had great success in managing the plants spread within a number of river catchments using various techniques. At some sites Himalayan Balsam has been eradicated in as little as 5 years. For example, Broxtowe Country Park had over 100,000 plants in 2015, but due to the work of the partnership only a single plant was found at the site five years later, in 2020. After the plant has been eradicated from a site, regular visits will need to be undertaken to ensure that Himalayan balsam does not re-establish itself.  Check out this video to tell you more about the project, or click here for more information about Nottinghamshire's Himalayan Balsam Control Project.

Himalayan balsam flower

Patch of Himalayan balsam

 

 

Japanese Knotweed (Fallopia japonica)

Japanese Knotweed was introduced to the UK in the Victorian era and became a staple in many botanical gardens. Since then, it has spread across the country and is now considered an invasive non-native species.  It is a herbaceous perennial that can grow up to 2 metres tall with heart shaped leaves, multiple green, red flecked hollow stems and in the summer, produces white pendulous flowers.  The plant dies back over winter, leaving stands of tall dry canes.  As all Japanese Knotweed plants in the UK are male, the plants in our country cannot reproduce by seed, instead they reproduce through pushing out rhizomes underground. These rhizomes are known to cause problems with housing developments, as they will push themselves up through the floorboards of buildings and are known to be extremely difficult and costly to remove. Japanese Knotweed is commonly found in urban areas, by water courses, and at brownfield sites where it favours disturbed ground. It can establish itself from a small fragment of vegetation and is often spread through fly tipping, poor waste disposal or washed downstream in rivers and canals.  The plant outcompetes native flora, narrows river and drainage channels and dead stems block culverts, causing issues with flooding. As stated in the Wildlife and Countryside Act 1981, it is an offence to plant, allow the spread or grow Japanese Knotweed in the wild and it must be disposed of as controlled waste as instructed in the Environmental Protection Act 1990.  We work with homeowners who may have Japanese Knotweed in their gardens and provide information on how to best remove the plant. In 2009, a county-wide citizen science project was undertaken, encouraging members of the public to send in any records of where they have seen the plant. As a result of this project, we were able to create a database with over 1000 records of Japanese knotweed in the county. Education on how to identify the plant and dispose of it correctly is also very important to prevent its spread.

Case Study: Nottinghamshire County Council

Patch of Japanese Knotweed

Japanese Knotweed in flower

Rhododendron (Rhododendron ponticum)

Rhododendron was introduced to the UK by the Victorians. It remains a popular species among gardeners, who enjoy the plants bright purple/pink blooms and hardy nature. When it is allowed to spread into the wild, it can have a negative impact on biodiversity. It thrives in acidic soils and can be found spreading across multiple habitats, such as woodland, moorland and heathland. Rhododendron's sprawling growth can quickly overwhelm an area and shade out the existing vegetation. Research has shown that areas invaded with Rhododendron have reduced populations of certain animal species, like birds and earthworms. Another advantage Rhododendron has over native species is its ability to produce toxins, which make it unpalatable to animals who may otherwise graze on it. When the toxic leaves fall to the ground, the decomposing leaf litter changes the soil chemistry which negatively affects the existing biodiversity. Eradicating Rhododendron from a site can be hard work depending on the size of each patch, but NottsBAG partners have had success in removing this invasive species across their nature reserves and green spaces.

Case Study: Rhododendron Control, Forestry England

Rhododendron flower

Patch of Rhododendron

Signal Crayfish (Pacifastacus leniusculus)

Eradication of the crayfish plague carried by American Signal Crayfish has become such a large priority for the BAG, that the Nottinghamshire Crayfish Group was set up in 2009 to take a lead on Signal Crayfish removal. Click here for more information about the effect Signal Crayfish have on our native White-clawed Crayfish.

American signal crayfish

American signal crayfish caught using traps

Water Fern (Azolla filiculoides)

Water fern was introduced from North America into the UK in the late 19th century as an ornamental pond plant from which it was dispersed into the wild.  As their name suggests, they are found in freshwater bodies including ponds, lakes, canals ditches and slow flowing rivers.  The free-floating perennial fern produces rosettes which form thick, dense mats that can completely cover the water’s surface.  Light is prevented from penetrating the surface which as well as de-oxygenating the water, can also impede the movement of amphibious and invertebrate species.  As well as the environmental impacts, it can also have negative health and social impacts including disruption of water based recreational activities.  The dense mats have also been mistaken by both humans and dogs as being solid surfaces, resulting in both falling into the water.  The plant can block sluices, adversely affecting flow and cause potential flood issues.

The plant is easily dispersed by machinery, boats, humans and potentially wildfowl and has the ability to reproduce from small fragments of vegetation and therefore, eradication is very difficult. There are no native organisms in the UK that are known to control the plant and as a result, a north American weevil that feeds on Azolla species was introduced into the UK and has been established since 1921.

Case Study: Water Fern Control, Canal & River Trust

Water fern © GBNNS

Water fern © GBNNS

Water fern winter form © GBNNS

Alert Species

We have a few records of these species, but they are not yet considered a threat in Nottinghamshire. If you spot any the species listed below within the county, please contact us with details of where you found it so we can keep tabs on their spread.

  • Asian Hornet
  • Chinese Mitten Crab
  • Water Primrose
  • American Skunk Cabbage

If you are interested in getting involved to support this work, you can either join in at one of our volunteer work-parties or alternatively send your records of invasive non-native species to us at biodiversity@nottscc.gov.uk. Please see our page on Biological Recording to ensure you include the 4 key bits of information that make a good record.

 

If you would like to find out more about invasive non-native species, then please visit the 'Great Britain Non-native Species Secretariat' website at GB Non-native Species Secretariat