Source to Sea: non-native invasive plants

May 10, 2012 - PRLog -- Wiltshire Wildlife Trust has joined forces with Hampshire & Isle of Wight Wildlife Trust and Dorset Wildlife Trust to get rid of plants such as Himalayan balsam, Japanese knotweed and giant hogweed among others that threaten to overwhelm native wildlife in the waters and on the banks of this internationally important river catchment.

Called Source to Sea, the project has received substantial backing from the Environment Agency.  Richard Cresswell, Regional Director for the Environment Agency in the south-west is fully supportive of the project, as are Natural England.

The river Avon rises in the Vale of Pewsey in Wiltshire and passes through Hampshire at the edge of the New Forest before flowing into the sea at Christchurch in Dorset, which is why an integrated approach across county boundaries is so crucial to its success.

Sam Bull, Source to Sea project manager at Wiltshire Wildlife Trust says: “The Salisbury Avon and tributaries such as the Nadder and Wylye are magical waterways recognised for their magnificent wildlife by being designated as Sites of Special Scientific Interest and Special Area of Conservation.

“Non-native invasive plants could threaten the survival of water voles and otters, Atlantic salmon, brown trout and lamprey.  If we stand by and do nothing these plants will steadily suffocate the banks.”

“For the project to succeed we will need lots of volunteers to help us pull up the balsam, and we will need the help and support of riverside landowners to either remove the plants or allow access for our volunteers to remove them.” says Sam.

Joanne Gore, Field Officer for the Hampshire & Isle of Wight Wildlife Trust says: “I am very happy to be working with my colleagues in Wiltshire and Dorset to tackle non native plants on this internationally important river catchment. Tackling the problem from source to sea will ensure that the project can look to effectively control the devastation caused by non native species. Nothing on this scale has been tried before.”

Joanne has already begun working in the Hampshire Avon valley, supporting landowners who have non-native plants on their land. “I have been delighted by the response of landowners on the river catchment. They have been very willing for me to survey their sections of the river catchment and have allowed me to organise contractors and volunteers to help remove non native plants, like balsam, where they have been found.”

Amanda Broom Conservation Officer at Dorset Wildlife Trust, says: “Invasive alien plants are threatening our streams, rivers and their wildlife. We have been working to remove this threat in Dorset and we welcome this opportunity to take the fight to the very east of the county and one of its most iconic rivers.”

Himalayan balsam is an annual plant that grows into bankside thickets, crowding out all native wildlife. Then when the stalks die back in winter it leaves bare river banks that are vulnerable to soil erosion.

The key to its control is to pull the plants up while it is flowering and before it releases it seeds, because if these get into a water system they very quickly spread and can colonise areas downstream.

Japanese knotweed and giant hogweed cannot be hand pulled by the public.  

Source to Sea follows on from previous work funded by the Environment Agency, DEFRA, the Forestry Commission, New Forest National Park and Natural England targeting non-native plants on the Avon and other rivers, but never has a collaborative whole catchment programme been attempted before.

If you are a land owner on the River Avon catchment and would like further advice on non-native invasive plants or would like to volunteer for the project to help carry out surveys or practical work this summer then please contact: Sam Bull on (01380) 736066, email samb@wiltshirewildlife.org for Wiltshire.
Joanne Gore on (02380) 424205 joanneg@hwt.org.uk for Hampshire and Dorset.
www.hwt.org.uk