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.

To obtain information about species contributions to ecosystem assembly and structure, we collated 2001 vegetation plots covering all major habitats and islands, extracted from the online database SIVIM (Information System of the Iberian and Macaronesian Vegetation: http://www.sivim.info/sivi/). This database includes most of the published phytosociological surveys on the Canary Islands in the last 50 years. Some additional plot data from other published sources have been used (Cabrera, 2020; Gaisberg, 2005; Méndez, 2010; Santos-Guerra, 1983; Stierstorfer, 2005).

In compiling our data, we used the most recent checklist of the vascular flora of the Canary Islands (Acebés Ginovés et al., 2010). Species of doubtful native origin were excluded following Price et al. (2018). Based on the most recent phylogenetic studies, each species of the entire native Canary flora was assigned to a putative colonist lineage following the approach used by Domínguez-Lozano, Price, Otto & Fernández-Palacios et al. (2010) and Price et al. (2018).

Spatial rarity was assessed by three different indices: the number of islands occupied, the geographic extent and the spatial occupancy across the Canaries, although in most analyses only the latter two were used. From the Canary Islands checklist of vascular plants (Acebes Ginovés et al., 2010), we extracted the number of islands a species is present on. Geographical extent and spatial occupancy were based on occupancy data across a grid of 500 x 500 m cells from the Canarian Government Atlantis 3 Biodiversity bank (Martín et al. 2005).