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UK: MPs want to tackle invasive species threat

A ‘Citizens’ army’ is needed to tackle any biosecurity risk from invasive non-native species in the UK according to MPs on the Environmental Audit Committee. Recommendations have also been passed to Government to triple its funding to tackle the national threat as non-native invasive species are estimated to cost Britain’s economy £1.8 billion a year.

The plan would see trained volunteers help identify and respond to biosecurity outbreaks, modelled on a system developed in New Zealand. The report found that urgent action is needed to slow the rate of arrival of invasive species and prevent them from becoming established. It estimates that around 40 non-native species will become invasive within 20 years.

MPs concluded that the Government has missed its legal targets on tackling invasive species and has failed to give it the same priority and funding as animal and plant health regimes. Current funding for biosecurity in Great Britain is estimated at £220 million a year, however invasive species receive less than one per cent of that sum (£0.9m).

The term invasive non-native species (INNS) describes those species that have been directly moved as a result of human activity.

Chair of the Environmental Audit Committee Mary Creagh MP said: "INNS is one of the UK’s top five threats to the natural environment. If we’re to beat this, we need people power with an army of volunteers trained to spot and stop an invasive species before it becomes established. We’re witnessing changes, from climate change, that put the future of our natural landscape at risk. Oak Processionary Moth caterpillars can strip an oak tree bare as well as posing a hazard to our own health. We face losing half of the UK’s native ash trees to ash dieback within a century costing £15 billion. New regulations to halt their progress are welcome but they are too little, too late. Government funding to tackle invasive species is tiny and fails to match the scale of the threat."

The report calls on the Government to:

  • Train a ‘biosecurity citizens’ army’ of 1.3 million volunteers to identify and respond to outbreaks of invasive species
  • Establish a dedicated border force by 2020 to improve biosecurity at UK borders
  • Ban imports of problem species before they present a risk to the UK
  • Set up a rapid response emergency fund to enable agencies to tackle a threat before it becomes out of control
  • Increase funding to Non-Native Species Secretariat to £3 million a year
  • Include invasive pathogens in next Invasive Non-Native Species Strategy

Risks to human health
A small proportion of non-native species established in the UK are harmful to human health, including the spread of Lyme disease by non-native deer, giant hogweed causing skin rashes and blistering, and the Oak Processionary Moth caterpillars which can cause skin irritation and breathing difficulties. INNS that pose the greatest threat to human health are mosquitoes and ticks, with the UK starting to see the arrival of the Asian Hornet which can cause anaphylactic shock. Future threats are predicted to come from the Asian Tiger Mosquito which carries chikungunya and dengue fever.

MPs found the example of the Oak Processionary Moth (OPM) invasion highlighted the importance of swift biosecurity and trade restrictions. Government policy on tackling the OPM changed from eradication to containment, with legislation to restrict the import of larger trees introduced in 2018. However, despite further import restrictions in 2019, outbreaks of OPM continue. While new regulations were welcomed, they were too little too late. The Committee urged the Government to legislate for other risks as soon as they are identified.

Future trade
Changing trade routes in the event of Brexit could allow more invasive species to arrive from South America and Asia with online trade considered a new and significant risk for introducing invasive species. The report finds that despite having regulations in place, and enforcement and penalty gap remains. It supports DEFRA's consideration of establishing a dedicated INNS inspectorate.

  • A dedicated invasive species border force should be established by the end of 2020 with similar resourcing to other inspectorates to improve biosecurity at the UK’s borders and tackle the risks from increased online trade and new trade routes
  • Should the Government engage in new bilateral trade deals, invasive species must be factored into risk assessments and enhanced biosecurity measures introduced at points of entry, where risks are identified

Epidemics and invasions
A significant increase in the numbers of invasive species across the globe is put down to a threefold increase in travel, and a rise in air and sea transport of goods. MPs echo concerns flagged by biosecurity minister Lord Gardiner that invasive species were arriving in the UK on ships at an alarming rate.

Arrivals include species that attach to the hulls of ships, ‘hitchhikers’ within the ballast water of ships, horticulture escapes, contaminants of ornamental plants, or ‘stowaways’ on fishing equipment.

Major invaders that have established in the UK over the past decade include the killer shrimp in Grafham Water, Cambridgeshire, and the quagga mussel in Rosebery Reservoir, London, threatening local wildlife. The spread of these species to other reservoirs, sometimes separated by long distances, is attributed to water sports events or angling.

The report finds the need for swift biosecurity and trade restrictions highlighted by:

  • An epidemic of ash dieback, caused by a non-native fungus, predicted to kill half of the UK's native ash trees with a cost of £15 billion over the next 100 years
  • Signal crayfish that have been the main cause of the rapid decline in native crayfish through the transmission of crayfish plague
  • Xylella on olive imports that can infect more than 350 different plant species and causes symptoms including leaf scorch, wilt, dieback and plant death

Biosecurity: legislation 'too little, too late'
Biosecurity and closing pathways are identified as the first lines of defence to prevent the introduction of INNS. Prevention is viewed as the only real mechanism of reducing their impact on the marine environment due to the cost and difficulty of removal. Ensuring vessels arriving or leaving UK waters have stringent hull cleaning and all ships having a ballast water management plan would offer increased protection. However, despite EAC’s predecessor Committee recommending in 2014 that the Government ratify the Ballast Water Management Convention and 80 other countries implementing it, ministers have delayed the UK’s implementation to 2020.

Given the significant pathway for the introduction of invasive species and invasive plant pathogens offered by the import of trees and plants, MPs were disappointed at the lack of engagement from the horticultural trade sector during the inquiry, with limited evidence given on what measures the industry is putting in place to prevent outbreaks.

The UK Overseas Territories are home to 90 per cent of the UK’s biodiversity and the introduction of invasive species has been recognised as the biggest threat to island biodiversity and caused numerous extinctions. The report calls for the Government to support each Overseas Territory to have up to date biosecurity legislation and adequate powers of enforcement by the end of 2020.


  • Government must urgently accede to the Ballast Water Management Convention at the earliest possible opportunity
  • DEFRA's monthly biosecurity meetings must result in problem species being identified and banned from import before they present a risk to the UK
  • Government should work to support the UK horticulture industry to ensure that it relies less on imports.
  • Government should produce guidance for the public sector in its procurement of trees and mandate a biosecurity assurance scheme, given the Government's intention to plant more trees such as the northern forest

In response to the published report, a Defra spokesman said: "Invasive non-native species not only challenge the survival of some of our rarest species but damage our natural ecosystems as well as costing the economy more than £1.7 billion per year. We are committed to being leaders in tackling invasive species, and our 25 Year Environment Plan commits us to enhancing the biosecurity of the country even further.

"We welcome the EAC's report and will now carefully consider its findings and recommendations."

For further information on some of the invasive species referred to in this article, visit BALI's help and advice section.

Source: British Association of Landscape Industries

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