Risk Assessment Scheme for Non-native Species in Great Britain

Specific scope
This program provides the template for Risk Assessors commissioned by the Non-native Species Secretariat (NNSS) for Great Britain. It is developed from a scheme used by the European and Mediterranean Plant Protection Organisation (EPPO) and is a further development of the UK Non-Native Risk Assessment Scheme template from 2005. It provides detailed instructions for the following stages of risk assessment for non-native species: initiation, entry, establishment, and impact. It provides a consistent scheme based on a sequence of questions to assess and document the risk. Both expert judgement and objective information can be used, but all responses should be documented.

The Scheme has been developed by the NNSS in cooperation with EPPO. Continued technical support from EPPO is acknowledged.


The NNSS Risk Assessment Scheme for non-native species is intended to be used to assess the potential importance of a particular species within a clearly defined area (the Risk Assessment area). The Risk Assessment area may be the whole of Great Britain or a region or part of a region within the several countries.

The Scheme concentrates on the assessment of individual species.

The Scheme provides detailed instructions for the following stages of risk analysis: initiation, organism risk assessment, pathways of introduction, assessment of environmental and economic impacts, and a section to list all references used in the assessment.

The Risk Assessment is divided into two major sections. The assessment in Section A establishes if there is a need for a more detailed assessment in the second section. If the Scheme leads to the conclusion that an organism has the necessary characteristics of a quarantine pest, the pest is then evaluated in greater detail, in Section B. Responses within the template consist of a menu choice or short typed entry, and a larger block in which explanatory text, justifications, references, etc can be either typed or cut and pasted from other documents. The program saves itself continuously, and can be re-entered or redone in any order.

Information requirements
Before beginning the Risk Assessment, information should be collected on the various characteristics of the species that will be evaluated in the procedure. This may include specific information related to each major pathway by which the species may enter. It is preferable to prioritize the pathway listing, based on expert judgement on species distribution and types of pathways.

A preliminary evaluation may be done and then the Risk Assessor can pass through the Scheme again to update entries once an overview has been obtained. In particular, for template questions where there is a low level of confidence in the response, more information may need to be addded later. It may be obvious in section A that a particular species does not pose a significant risk, so that there is no purpose in continuing with a full assessment.

In going through the Scheme, the assessor may find that certain questions cannot be answered. This may be because the question is not relevant in the particular case (N/A), in which case the question can be ignored and the absence of a reply will not affect the value of the Risk Assessment. Alternatively, it may prove impossible to obtain the information, in which case its absence will to a certain degree reduce the value of the assessment depending on the importance of the question. A meaningful Risk Assessment cannot be performed without adequate information, and at the end of this Scheme the Risk Assessor is asked to indicate a subjective opinion of the broad risk components for the species and the degree of confidence in the assessment, given the quantity and quality of the information was satisfactory.

In cases where particular information is lacking about a pest, useful information may sometimes be obtained by reference to closely related organisms. Where such indirect information is used, this should be recorded during the assessment and taken into account in the final evaluation