Wednesday, 21 August 2013

Invasive Species I

We are out cruising on our boat, enjoying the experience even if the weather is being very changeable. There is however one very disturbing aspect that I have noticed. One that seems to have taken off big style since last year. It is the amount of Japanese Knotweed, it seems to be everywhere you look. The rivers and canals are known to be providing a superhighway for the spread of this particular problem species. It is listed by the World Conservation Union as one of the world's 100 worst invasive species. The invasive root system and strong growth can damage concrete foundations and flood defences. It can also reduce the capacity of channels within flood defences to carry water.

Then the more I started to take interest and look around, the more Himalayan Balsam and Orange Balsam I came across. Seemingly the balsam is almost if not more prolific than the Knotweed. Himalayan Balsam is now widely established in British Isles and is able to outcompete our native plants. Adding to the mix is Buddleia that seemingly can root in the tiniest cracks and spaces along the banks of the inland waterways. This time out I have seen several plots of Giant Hogweed. The sap of giant hogweed causes phytophotodermatitis in humans, resulting in chemical burns and blisters, with long lasting scars and if it comes in contact with eyes blindness. Giant Hogweed is highly invasive and has spread throughout the whole of Great Britain, primarily favouring canal and river banks. 

The Wildlife and Countryside Act 1981 states that it is an offence to "plant or otherwise cause to grow in the wild" any plant listed in Schedule nine, Part II of the Act. This lists over 30 plants including Japanese Knotweed and Giant Hogweed.

Call me old and cynical, but maybe the latest of CaRT's ideas the 'Great Nature Watch' is a bit of lip service to placate the prospective punters. Now, you might think with CaRT getting all 'touchy feely' over ecological and environmental issues. The invasive stuff would be high on the agenda. For protecting hundreds of miles of waterways habitat. You might think that getting rid of the invasive species was much more important. Much more important than concentrating on voles and shrews. But then the cute furry little critters will help with the dash for the punters cash, (fleece a friend) much more than an appeal for money to combat Knotweed.

There is one huge problem looming on the horizon. Getting rid of Knotweed is an expensive operation. Land owners are now more than ever beginning to realise that an infestation of Knotweed can dramatically  reduce land values and significantly raise development costs. The longer it is let unremedied the more expensive it becomes.

A couple have been told their new build home must be demolished to rid it of an invasion of Japanese knotweed. Matthew Jones and fiance Sue Banks have seen the value of their four-bedroom house in Broxbourne, Hertfordshire, almost wiped out – dropping from £305,000 to £50,000 as direct result of the damage. There was no sign of the plant when the couple bought the house two years ago, believing it to be the ideal location to bring up a young family. But it was growing unnoticed on wasteland next to the property. Slowly it crept over the garden fence and took over the lawn before forcing its way into the house.

The couple fear being sued for damages, leaving them with an even greater bill, if the weed spreads to neighbouring homes in the quiet cul-de-sac. Mr Jones learnt about the superweed when he called in an expert from Broxbourne Council. 'He took one look and knew what it was straight away. He told us to get a solicitor involved,' said Mr Jones. The owner of the wasteland it spread from is legally responsible to clear the area of the plant. But officials failed to track down the person responsible. The couple then called in experts who advised them that demolition was the only option.

However, as stated in the Environment Agency Knotweed Code of Practice “It is not an offence to have Knotweed on your land”. It is generally thought that house gardens do not come within the definition of wild. Under the Environmental Protection Act 1990 all Knotweed material (and soil containing Knotweed) is classed as controlled waste and must be disposed of at a licensed landfill site under codes of practice.

There are also powers under the Town and Country Planning Act which empower local authorities to require landowners to treat the land if it detracts from local amenities and that could include situations where Knotweed is present on the land. The Town and Country Planning Act is often used by local planning authorities by way of planning conditions to force developers to treat sites infested with Knotweed. These and other statutory material give rise to potential criminal prosecutions.

Given the underground complexity of Knotweed rhizome it is almost certainly going to be the case that a landowner will need to require his neighbour to effectively treat Knotweed on the neighbour’s land in order to abate the nuisance and solve the problem. In the event of a neighbour failing to cooperate a legal action may be commenced seeking various remedies including damages equating to the cost of treatment and possibly diminution in value of his land and injunctions enforcing the neighbour to carry out specific methods of treatment. Indeed, the granting of injunctions (which is a discretionary remedy) is generally the appropriate remedy. In encroachment cases no actual damage needs to be proved in order to bring a claim.

Where Knotweed spreads from land A to land B and then to land C, although the owner of land B may be liable to the owner of land C he may be able to claim an indemnity from the owner of land A. A landowner can be liable for allowing nuisance to continue even if he did not create it he will be responsible for continuing damage and given the likely claim against him for an injunction, the cost of its treatment.

As is always the case, prevention is better than cure. Any landowner should therefore seek immediate advice from specialists as soon as they are aware or made aware of the presence of Knotweed to avoid what could turn into an extremely costly and complicated piece of litigation.

Solid structures such as concrete and tarmac are no barrier to its growth and the weed also creates a risk of flooding if leaves clog waterways. As the Knotweed takes a more significant hold along many watercourses and the adjoining land much of which is now owned by CaRT. People with adjoining properties that have been or are at risk of being infested by knotweed. Will be taking CaRT to court if the infestations remain unremedied and begins to spread onto their property. As one solicitor said, Japanese Knotweed is going to be a good replacement for whiplash injuries in no win no fee litigation.

Japanese knotweed is still spreading rapidly despite our best efforts. Since its introduction the species has spread throughout the British Isles, only the Orkney Islands are currently exempt. See the distribution map Click Here. 
The use of smartphone apps such as 'Plant Tracker' is already adding photographic sightings and GPS locations of existing infestations into the Plant Tracker database. This could be used to provide evidence of the locations of pre-existing infestations for landowners. I have been recording and reporting for some time now the waterways locations of Giant Hogweed and Knotweed infestations while cruising the waterways. (

There are no definitive industry wide figures for just how much the Japanese Knotweed plant costs to eradicate. But even on relatively small building sites the cost of control can run into hundreds of thousands of pounds. Developers are also often required to tackle the plant in order to maintain their legal obligations under the Wildlife and Countryside Act 1981. The annual cost across Britain is likely to be many tens of millions. The cost to eradicate Japanese Knotweed in Britain using conventional methods was estimated to be £1.56 billion.

Knotweed leaf litter provides less good nutrients to streams than the native vegetation it displaces and this has the potential to alter food chains. Japanese knotweeds impact on water quality may threaten fisheries and it can also leave riverbanks vulnerable to erosion as well as increasing the flood risk by blocking channels.

Continued in Invasive Species II

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