Ameixa, O.M.C.C., Šipoš, J., Burda, M., Soares, A.M.V.M. & Soares, A.O. (2019) Factors influencing the introduction and spread of Harmonia axyridis in the Iberian Peninsula.Biological Invasions, 22(1), 323-331. DOI:10.1007/s10530-018-1841-x (IF2017 3,054; Q1 Biodiversity Conservation)
Harmonia axyridis is a global invasive alien species and its ecological effects are well documented. However, in some regions where it was deliberately introduced, it never became fully established. Until recently, Southern Europe was one such region, although, recently several overwintering populations were found in northeast Spain, which may indicate that the species can potentially spread to the rest of the Iberian Peninsula. Besides the negative impacts for native coccinellid species, the establishment of H. axyridis in the Iberian Peninsula could have an important impact on the wine industry, which is very significant in this region. To predict if H. axyridis will be able to spread across western southern Europe, with an emphasis on vine-growing regions, we used the Mahalanobis distance presence-only species distribution model, which was constructed based on 16 bioclimatic and environmental variables to characterize the occupied niche and predict the distribution of this invasive alien species. Our model revealed that H. axyridis can find suitable conditions mostly in northern regions of the Iberian Peninsula, as well as in punctual locations, in coastal regions of this territory, including important vine-growing regions, which will constitute a challenge to producers. Until recently, the spread of H. axyridis was constrained by climatic factors such as high summer temperatures, however, the overwintering individuals found in Spain seem to be able to deal with such limitations, which apparently indicate the ability to adapt to these conditions. To prevent future negative impacts of H. axyridis in the Iberian Peninsula, we recommend the implementation of an active monitoring programme, together with local stakeholders (farmers and advisers) and citizens, to record and track the dispersion of seminal propagules, which could be more easily contained, with fewer resources.