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Aim: We explore the idea that most pre-glacial non-endemic Canarian flora became endemic to the archipelago by the extinction of its mainland populations during the late Pleistocene glaciations, implying that the extant non-endemic flora is mostly post-glacial: the ‘late Pleistocene endemicity increase hypothesis’. Taxon: The native flora of the Canarian archipelago. Methods: We statistically compare the distributions of 2087 Canarian endemic and native non-endemic plants across islands. We also carry out connectivity analyses using their dispersal paths, obtained by connecting all the islands of occurrence for each taxon. Results: While the distribution of the endemic flora is strongly L-shaped (with a much higher proportion of Single-Island Endemics than Multiple-Island Endemics), that of the native non-endemics is U-shaped (i.e. similar prevalence of single-island taxa and taxa distributed on all islands). The native non-endemics have a significantly lower proportion of single-island taxa and a higher proportion of widespread taxa than the endemics. Most dispersal paths in the endemics connect the central and western islands, whereas they are extended across all islands in the native non-endemics. Main conclusions: The contrasting distributional patterns of the endemics and the native non-endemics support an outstanding role of species diversification in the endemic flora, but a still negligible influence of the insular selective and stochastic pressures (including extinction) in the native non-endemic flora, arguably due to its recent origin. Our results suggest that the high endemicity levels of the extant Canarian flora can be explained by two complementary processes: (i) high diversification rates throughout the ontogeny of the archipelago, often from colonisers that attained a widespread distribution prior to speciation, and (ii) an ‘endemicity increase’ during the late Pleistocene glaciations, whereby most of the pre-glacial non-endemic Canarian flora became endemic due to the extinction of its mainland conspecific populations, thus emphasising the role of the Canaries as climatic refugia.

AIM: Habitat diversity has been linked to the diversity and structure of island communities, however, little is known about patterns and processes within habitats. Here we aim to determine the contributions of habitat type and inferred dispersal frequency to the differences in taxonomic structure between assemblages in the same island habitat. LOCATION: The Macaronesian archipelagos (Azores, Madeira, the Canary Islands and Cabo Verde). TAXON: Spiders (Araneae). METHODS: We established forest and dry habitat sites (each with five plots) on two islands per archipelago. We collected spiders using standardised sampling protocols. We tested the differences in beta diversity separately for each habitat and for each inferred category of ballooning (an aerial dispersal strategy) frequency across geographic scales through nested non-parametric permutational multivariate analyses of variance. We then tested whether ballooning and habitat influenced heterogeneity in species composition (dispersion in beta diversity) in the two habitat types. We analysed the effects of habitat and ballooning on species abundance distribution (SAD) and rarity by fitting Gambin models and evaluating the contribution of ballooning categories to SAD. RESULTS: Communities of the same archipelago and habitat were taxonomically more similar, and beta diversity increased with geographic scale, being greater in dry habitats. There was greater species replacement among assemblages in dry habitats than in forests, with greater differences for rare ballooners. There were no differences in SAD between habitats although dry habitat sites seemed to harbour more species with low abundances (rare species) than forests. MAIN CONCLUSIONS: Habitat type does not only condition the differences between spider assemblages of the same habitat but also the scale at which they occur. These differences may be determined by the heterogeneity in the physical structure of each habitat as well as how much this structure facilitates aerial dispersal (ballooning), and should be considered in theories/hypotheses on island community assembly as well as in conservation strategies. The Government of the Canary Islands, Grant/Award Number: SE-12/02, SE-12/03 and SE-12/04; Fundação para a Ciência e a Tecnologia, Grant/Award Number: FCT-PTDC/BIABIC/0054/2014, DL57/2016/CP1375/CT0003 and UIDB/00329/2020-2024; FEDER, Grant/Award Number: 0003/2011 info:eu-repo/semantics/publishedVersion

Euphorbia tuckeyana is a dendroid spurge endemic to Cabo Verde. It belongs to E. subgenus Esula section Aphyllis subsection Macaronesicae, a monophyletic group of eleven species restricted to the Canaries, Madeira archipelago, the Selvagens islands, Cabo Verde, a small area of Atlantic Morocco, and Portugal, that have high horticultural potential for xeric gardens. Among them E. tuckeyana grows well in tropical environments with a summer rainy season. History of early collections and records is reviewed. The species has been previously depicted on one postage stamp and in papers focusing on the Cabo Verde flora. Three other phylogenetically distant groups of dendroid spurges, also with leaves spirally arranged in clusters located on stem tips, occur in the West Indies, Africa, and Asia. They also show high potential for tropical gardens. We present a previously unpublished ink‐drawing of E. tuckeyana that was made by the great Spanish plant illustrator Eugeni Sierra Rafols (1919–1999). The name is lectotypified with a specimen housed in the Museum National d'Histoire Naturelle (Paris) that was collected by the Portuguese naturalist Joao da Silva Feijo in the late 18th century.

Original Research Macaronesia has long been recognized as a natural model for studying evolutionary processes in plant diversification. Several studies have attempted to focus on single lineages, and few have covered the diversification of a family across all the archipelagos. We used a comprehensive sample to clarify the phylogenetic relationships and the biogeographic history of the Macaronesian Campanulaceae. Hypotheses related to the colonization of these archipelagos will be used to examine the diversification patterns of different lineages. We sequenced the ITS region and six cpDNA markers (atpB, matK, petD, rbcL, trnL-F, and psbA-trnH) from 10 Campanulaceae species, including seven endemic species in Macaronesia. The phylogeny of these taxa was reconstructed using maximum parsimony, maximum likelihood, and Bayesian inference. To study the relationships within each lineage, haplotype networks were calculated using NeighborNet and TCS algorithms. Moreover, data were combined with fossil information to construct time-calibrated trees for the Macaronesian Campanulaceae species. The phylogenetic analyses are largely congruent with current taxon circumscriptions, and all the endemic genera formed monophyletic clades, namely Azorina in Azores; Musschia in Madeira; and Campanula in Cape Verde. The Azorina clade and the Cape Verde endemic Campanula may share a common ancestor in North Africa, and the divergence was dated ca. 12.3 million years ago (Mya). The divergence of the Musschia clade began in the Pliocene ca. 3.4 Mya. Moreover, several examples of intraspecific variation were revealed among the native species with a clear geographic structured patterns, suggesting that cryptic diversity might exist within the native Macaronesian Campanulaceae when compared to the close mainland taxa (e.g., Campanula erinus, Trachelium caeruleum), but additional studies are needed to support the molecular data. This study highlights the power of combining data (e.g., phylogeny and divergence times, with species distribution data) for testing diversification hypotheses within the unique Macaronesian flora, providing useful information for future conservation efforts. info:eu-repo/semantics/publishedVersion

Additional co-authors: Jose Maria Fernandez-Palacios, Rosalina Gabriel, Roy E. Gereau, Rosemary G. Gillespie, Josef Greimler, David E.V. Harter, Tsurng-Juhn Huang, Severin D.H. Irl , Daniel Jeanmonod, Anke Jentsch, Christoph Kueffer, Sandra Nogue, Rudiger Otto, Jonathan Price, Maria M. Romeiras, Dominique Strasberg, Tod Stuessy, Jens-Christian Svenning, Ole R. Vetaas, Carl Beierkuhnlein

The application of IUCN Red List criteria to oceanic islands often produces uniform species assignments to high-threat categories, but in some cases this may result from uncertainties in the data and overly precautionary attitudes to risk. We illustrate this problem using the endemic vascular flora of the Cape Verde archipelago, and show that changing risk tolerance along the precautionary-evidentiary gradient greatly affects conservation assessments. Most taxa qualified for threat categories due to small areas of occupancy, but while precautionary assessments classified 88.9% of 81 evaluated taxa as Critically Endangered, evidentiary assessments assigned taxa to a wider range of categories. Taxa with very small ranges and restricted to one–three islands were consistently considered Critically Endangered. Our results suggest that conservation assessments under uncertainty may benefit from a more evidentiary attitude, which seem to provide higher discrimination ability among taxa, thereby enhancing the contribution of Red List assessments to prioritize conservation action.