Abstract
Plants are the basis of life on earth and provide multiple ecosystem services. However, scientific research on the underlying biology of extinction risks is developing piecemeal, and has mostly focused on vertebrates. To date, the IUCN Red List provides the most widely used and well-known system for assessing extinction risks (1). Initially, it was not intended to set conservation priorities, but in practice it often feeds directly into this process. Recent research by the PI of this proposal showed that the processes of extinction and speciation are linked in the Cape flora of South Africa - seemingly the most vulnerable species are often the youngest (2). This research revived debates about how best to employ IUCN Red Lists: indeed, young species may appear at high risk of extinction simply because their populations have not yet had time to grow and spread (2, 3). However, it is also possible that some plant species might be doomed to extinction from their very inception. Critically, Savolainen and co-workers found that the most vulnerable plant species are nonetheless marching towards extinction at a more rapid pace, but surprisingly, independently from human impact (2). Encroachment by invasive alien plants is another major source of threat to ecosystems. Indeed, up to half a million species are classified as invasive aliens worldwide, causing costs of over 1 trillion euros per year (4). So far, it has not been possible to predict whether an introduced species will become invasive, and it is unclear whether certain traits promote invasiveness. Recent research by the PI in a subtropical archipelago (Azores) showed that introduced plant species are likely to become invasive when there are no closely related species in the area (5). Using phylogenetic information, some measures of evolutionary relatedness turned out to a reliable predictor of invasiveness. Also, using analyses at different geographic scales, Savolainen and co-workers argued that enemy release plays an important role in biological invasions in the Azores (5). Although British plants are by far some of the best-known anywhere in the world in terms of taxonomy, geography and ecology - astoundingly, the causes of their extinction risks as well as threats by alien taxa (currently outnumbering native species in the UK) are understudied. Following methodologies developed by the PI in subtropical areas, and building on preliminary phylogenetic data available at the host, we will fill this knowledge gap - aiming to identify correlates of extinctions and predictors of invasions in the British flora. Undoubtedly comparisons between the UK and the subtropics will also prove pertinent.
United Kingdom