Evolutionary winners are ecological losers among oceanic island plants

Aim: Adaptive radiation, in which successful lineages proliferate by exploiting untapped niche space, provides a popular but potentially misleading characterization of evolution on oceanic islands. Here we analyse the respective roles of members of in situ diversified vs. non-diversified lineages in shaping the main ecosystems of an archipelago to explore the relationship between evolutionary and ecological 'success'. Location: Canary Islands. Taxon: Vascular plants. Methods: We quantified the abundance/rarity of the native flora according to the geographical range (number of islands where present and geographical extent of the range), habitat breadth (climatic niche) and local abundance (cover) using species distribution data based on 500 × 500 m grid cells and 2000 vegetation inventories located all over the archipelago. Results: Species of diversified lineages have significantly smaller geographic ranges, narrower climatic niches and lower local abundances than those of non-diversified lineages. Species rarity increased with the degree of diversification. The diversified Canarian flora is mainly comprised by shrubs. At both archipelagic and island level, the four core ecosystems (Euphorbia scrub, thermophilous woodlands, laurel forest and pine forest) were dominated by non-diversified lineages species, with diversified lineages species providing <25% cover. Species of diversified lineages, although constituting 54% of the archipelagic native flora, were only abundant in two rare ecosystems: high mountain scrub and rock communities. Main conclusions: Radiated species, endemic products of in situ speciation, are mostly rare in all three rarity axes and typically do not play an important role in structuring plant communities on the Canaries. The vegetation of the major ecosystem types is dominated by plants representing non-diversified lineages (species that derive from immigration and accumulation), while species of evolutionarily successful lineages.适应性辐射（Adaptive radiation）指成功演化类群通过开拓未被利用的生态位空间实现增殖，该理论是对大洋岛屿上演化过程的一种常见但可能存在误导性的刻画。本研究旨在分析原位分化类群与非分化类群成员在塑造群岛主要生态系统中的各自作用，以此探讨演化与生态“成功性”之间的关联。 研究区域：加那利群岛（Canary Islands）。 研究类群：维管植物（Vascular plants）。 方法：本研究依托遍布全群岛的500×500米网格单元物种分布数据与2000份植被调查样地数据，从地理分布范围（现存岛屿数量与分布区地理尺度）、生境广度（气候生态位）以及本地多度（盖度）三个维度，量化了本土植物区系的丰度与稀有程度。 结果：相较于非分化类群物种，分化类群物种的地理分布范围显著更小、气候生态位更窄，且本地多度更低。物种的稀有程度随分化程度升高而加剧。加那利群岛的分化类群植物区系主要由灌木类物种构成。在群岛及单个岛屿尺度下，四大核心生态系统（大戟灌丛、嗜热林地、月桂林与松林）均以非分化类群物种为主导，分化类群物种的盖度占比不足25%。尽管分化类群物种占群岛本土植物区系的54%，但它们仅在两种稀有生态系统中占据优势：高海拔山地灌丛与岩生群落。 主要结论：作为原位物种形成的特有产物，辐射类群物种在三个稀有性维度上大多表现为稀有类群，且通常未在加那利群岛的植物群落构建中发挥重要作用。主要生态系统类型的植被以非分化类群植物（源自外来定植与类群积累的物种）为主，而演化成功类群的物种。