A decision support scheme for mapping endangered areas in pest risk analysis

International standards for pest risk analysis (PRA) require assessors to define the endangered area: “the part of the PRA area where the presence of the pest will result in economically important loss.” In some cases it may be appropriate to use a simple geographical description but maps generally provide a much better method for defining this area. However, mapping the endangered area is very challenging because it needs to be defined by combining maps of the area of potential establishment (based on climatic suitability and the distribution of hosts, habitats, soils, etc) with maps of factors that indicate where economically important loss is likely to occur. This presentation will describe progress made by the EU-funded PRATIQUE project in developing a decision support scheme (DSS) to guide risk assessors when mapping endangered areas highlighting the importance of clearly defining the map combination rules. The DSS shows how MCAS-S (The Multi-Criteria Analysis Shell for Spatial Decision Support) can be used to display, manipulate, and combine map layers. This software does not require GIS skills, and allows risk assessors to combine maps derived from either continuous or categorical variables using simple mathematical equations and risk matrices. The DSS is linked to the computerised EPPO PRA scheme and modules for mapping climatic suitability, quantifying economic impacts and modelling spread. The DSS is illustrated with a case study of the western corn rootworm (Diabrotica virgifera virgifera) in Europe