A project for a Eucalyptus sentinel garden in the Mediterranean island of Sardinia (Italy)

Sentinel plants and sentinel gardens are commonly located close to high risk areas in order to timely detect signs and symptoms of novel pest attacks. They are an important part of the post-border surveillance toolbox and can be carried out for early detection of recently-introduced, non-native species, therefore increasing chances of eradication and control. Occasionally, sentinel plants and sentinel gardens may also help in identifying new associations between pests and planted trees. Many non-native trees used in planted forest are successful because they have been separated from their natural enemies. However, when plantation trees are reunited with their coevolved pests, which might be introduced accidentally, or when they face novel pests to which they have no resistance, substantial damages can be observed. Among non-native trees, eucalypts play a very important role in the economies of many countries, including the Mediterranean and Europe, but there might be also environmental, economic and social concerns associated with their widespread use, namely on biodiversity, water and soil resources. Plantations of eucalypts have increased during the last 50-70 years and have experienced a steady increase of pest problems as well. Fairly large numbers of native pests and pathogens have also adapted to feed on or infect eucalypts in the non-native range. Considering the importance of this group of species for the southern Italian region, the Sardinian Regional Authority, Environmental Directorate supported the establishment of a Eucalyptus sentinel garden in the Mediterranean island of Sardinia (Italy). We here describe its preliminary planning and establishment phases.