The vascular flora of conservation interest in Sicily: a multistep procedure aimed at identifying the priority targets for risk assessment and plant conservation

Without prioritisation of risk assessment targets based on objective and explicit criteria, we risk to protect “too much” on paper, yet too little in practice. To create a more effective priority list, besides of the standard criteria related to distribution, rarity, and degree of threat, we considered the following four ones: (1) biogeographic interest (e.g., narrow endemics, highly disjunct taxa, populations at the edge of the species range), (2) conservation interest (e.g., taxa found only in Sicily within the Italian territory), (3) legally protected and (4) subject to IUCN assessments, whilst we suggest to rule out the endemic taxa shared with neighbouring regions, those belonging to poorly studied genera or resulting from apomixis, and the archaeophytes. IUCN criteria can hardly be applied to all rare plants: for example, annual plants typical to ephemeral swards, as well as pioneer and wandering plants related to disturbed habitats, can be easily overlooked. Moreover, the high amount of “data deficient” taxa underlines the need to intensify field activities. Although a more rigorous assessment procedure has allowed to downscale the risk level for many taxa, yet the number of regionally extinct plants is higher than previously reported, emphasizing the need to reduce human impact especially on the most threatened habitats linked to wetlands and dune ecosystems.