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The Rapid Risk Assessment screening process

How do you differentiate between a potential problem plant and one that's likely to be of low risk?

The current method involves a time-consuming detailed risk assessment process. This makes it inappropriate to apply to large numbers of plants. So Plantlife has devised a ‘Rapid Risk Assessment’ screening process for quickly assigning a broad level of invasive threat to a non-native plant. We applied the process to almost 600 plants that are grown or sold here or are already present but not yet widespread in the wild and of these:

  • 92 were ranked as 5-starcritical risk’ – we believes a more detailed risk assessment should be carried out as a matter of priority;
  • 55 were ranked as 4-starurgent risk’ – a more detailed risk assessment is highly recommended;
  • 72 were ranked as 3-starmoderate risk’ – a more detailed risk assessment is recommended;
  • 380 were ranked as ‘low risk’ - a more detailed risk assessment is not considered necessary at present.

By recommending a shortlist of plants for which the more detailed risk assessment is considered imperative and/or prudent and a list of plants for which such assessment is deemed currently unnecessary, the Rapid Risk Assessment screening process can help policy-makers to prioritise limited resources and focus on identifying plants most likely to prove problematic in future.

Plantlife’s new report Here today, here tomorrow? (download here) summarises the development of the Rapid Risk Assessment screening process and also illustrates some of the key botanical sites Plantlife considers to be under threat from invasive non-native plants.

Further development of the Rapid Risk Assessment scheme is required, particularly in relation to uncertainty and question weighting. We would be pleased to share our knowledge and experience with anyone who wishes to develop the screening process. We are aware that many people will have made observations of non-native plant behaviour in the wild or a landscape/horticultural context, either relating to the plants screened so far or other non-native plants sold or used in Britain. We would be grateful to receive any comments and observations in this respect both to add to the evidence base relating to specific taxa and to help evaluate the scheme by highlighting likely false positive and false negative results.

Please email: invasives@plantlife.org.uk with any such information or comments.

The development of the new rapid risk assessment is described in detail in a Natural England Commissioned Report NECR053 Horizon scanning for invasive non-native plants in Great Britain, available to download from Natural England.

All opinions expressed in the summary and detailed reports are those of Plantlife and do not necessarily reflect those of our funders.