Extinction risks and invasiveness in the British flora

植物是地球上生命的基础，提供多种生态系统服务。然而，关于灭绝风险的潜在生物学的科学研究正在零星地发展，主要集中在脊椎动物上。迄今为止，国际自然保护联盟红色名录提供了最广泛使用和最广为人知的评估灭绝风险的系统(1)。最初，它的目的不是设定保护优先事项，但实际上，它经常直接进入这一过程。这一提议的国际和平研究所最近的研究表明，在南非的开普敦植物群中，物种灭绝和物种形成的过程是相关的--似乎最脆弱的物种往往是最年轻的物种(2)。这项研究再次引发了关于如何最好地利用IUCN红色名单的辩论：事实上，年轻物种可能出现灭绝的高风险，仅仅是因为它们的种群还没有时间增长和传播(2，3)。然而，也有可能一些植物物种从一开始就注定要灭绝。关键的是，萨沃莱宁和他的同事发现，最脆弱的植物物种仍然在以更快的速度走向灭绝，但令人惊讶的是，它们不受人类影响(2)。外来入侵植物的入侵是威胁生态系统的另一个主要来源。事实上，全世界多达50万物种被归类为“入侵外星人”，每年造成的损失超过1万亿欧元(4)。到目前为止，还不可能预测引进的物种是否会成为入侵性物种，也不清楚某些特征是否会促进入侵性。亚热带群岛(亚速尔群岛)的PI最近的研究表明，当该地区没有密切相关的物种时，引进的植物物种很可能成为入侵物种(5)。利用系统发育信息，一些进化关联性的衡量标准被证明是入侵的可靠预测指标。此外，利用不同地理尺度的分析，萨沃莱宁和同事认为，敌人的释放在亚速尔群岛的生物入侵中起着重要作用(5)。尽管英国植物在分类学、地理学和生态学方面是世界上最知名的植物之一，但令人惊讶的是，它们面临灭绝风险的原因以及“外来分类群”(目前在英国数量超过本土物种)的威胁还没有得到充分研究。遵循亚热带地区国际生物多样性研究所开发的方法，并以宿主可用的初步系统发育数据为基础，我们将填补这一知识空白-旨在确定灭绝的相关性和英国植物区系入侵的预测因素。毫无疑问，将英国与亚热带地区进行比较也将被证明是中肯的。

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.