Making smart use of woody alien plants

It is unquestionable that some alien woody plant species are a major issue for biodiversity conservation. However, being alien species generally adapted to warmer conditions than natives, they could be particularly suited to cope with the new environmental and climatic conditions that are also forecasted in the coming decades in Sicily. This poses an issue that is not easy to deal with, whether trying to use these species for the advantages they could bring, for instance in the new reforestation activities, while avoiding them becoming a serious problem for biodiversity conservation in natural and seminatural areas. Here, we present some study cases of non-native tree species which represent emblematic examples in that regard: Acacia saligna and A. cyclops, Eucalyptus spp., Leucaena leucocephala, Opuntia ficus-indica and Ailanthus altissima. These tree species are very invasive in some ecological contexts, while being useful to meet ecological services in others. A sound planning activity could help distinguish where planting these species could be not only possible but also desirable, from areas where their presence should be totally avoided.