Prediction of the geographic distribution of an exotic species in a new environment is an important element of risk assessment as it provides an assessment of the spatial scale of potential impacts and the range of ecosystems affected by the establishment of an exotic species. For a more complete risk assessment, however, information on how abundant the species is likely to become at specific locations within the predicted geographic distribution would allow a more detailed analysis of potential environmental and economic impacts. In this study an improved species distribution model for Epiphyas postvittana, an Australian leafroller, is developed and used to test for an abundance–suitability relationship based on survey data on its relative abundance in coastal California where it has become established as an exotic species. To better assess the current status of this exotic leafroller as a quarantine pest in California, the potential geographic distribution and its relative abundance are predicted for the conterminous United States. These analyses predict that E. postvittana would primarily be limited to the Pacific coastline with small pockets of less suitable environment supporting lower relative abundance on the east coast and in the southwest. This study also highlights the potential value of the core distribution from the CLIMEX species distribution model as a more informative metric of environmental suitability with respect to relative abundance, based on surveys of larval populations of E. postvittana at 30 different locations in coastal California.

预测新环境中外来物种的地理分布是风险评估的重要元素，因为它提供了对潜在影响的空间规模和受外来物种建立影响的生态系统范围的评估。但是，为了进行更完整的风险评估，有关物种可能在预测的地理分布内的特定位置变得有多少丰富的信息，将允许对潜在的环境和经济影响进行更详细的分析。在这项研究中，一种改良的附生附生植物物种分布模型，是澳大利亚的一种卷叶草，是根据加利福尼亚沿海地区相对丰度的调查数据开发的，用于测试其丰度与适宜性之间的关系，在加利福尼亚沿海已将其确定为外来物种。为了更好地评估这种外来卷叶植物在加利福尼亚作为检疫性有害生物的当前状况，预测了美国本土的潜在地理分布及其相对丰度。这些分析预测，E。postvittana主要限于太平洋海岸线，环境不适合的小区域支持东海岸和西南地区相对较低的相对丰度。这项研究还根据对加利福尼亚沿海30个不同地点的虾肠夜蛾幼虫种群的调查，着重说明了CLIMEX物种分布模型中核心分布的潜在价值，这是相对于相对丰度的环境适宜性的更丰富的度量标准。