RESUMEN

Estimates of the number of vascular plant species currently under threat of extinction are shockingly high, with the highest extinction rates reported for narrow-range, woody plants, especially in biodiversity hotspots with Mediterranean and tropical climates. The large genus Erica is a prime example, as a large proportion of its 851 species, all shrubs or small trees, are endemic to the Cape Floristic Region (CFR) of South Africa. Almost two hundred are known to be threatened and a further hundred are 'Data Deficient'. We need to target conservation efforts and research to fill the most problematic knowledge gaps. This can be especially challenging in large genera, such as Erica, with numerous threatened species that are closely related. One approach involves combining knowledge of phylogenetic diversity with that of IUCN threat status to identify the most Evolutionarily Distinct and Globally Endangered (EDGE) species. We present an expanded and improved phylogenetic hypothesis for Erica (representing 65% of described species diversity) and combine this with available threat and distribution data to identify species and geographic areas that could be targeted for conservation effort to maximise preservation of phylogenetic diversity (PD). The resulting 39 EDGE taxa include 35 from the CFR. A further 32 high PD, data deficient taxa are mostly from outside the CFR, reflecting the low proportion of assessed taxa outside South Africa. The most taxon-rich areas are found in the south-western CFR. They are not the most phylogenetically diverse, but do include the most threatened PD. These results can be cross-referenced to existing living and seed-banked ex situ collections and used to target new and updated threat assessments and conservation action.

RESUMEN

Species identification is fundamental to all aspects of biology and conservation. The process can be challenging, particularly in groups including many closely related or similar species. The problem is confounded by the absence of an up-to-date taxonomic revision, but even with such a resource all but professional botanists may struggle to recognise key species, presenting a substantial barrier to vital work such as surveys, threat assessments, and seed collection for ex situ conservation. Genus Erica: An Identification Aid is a tool to help both amateurs and professionals identify (using a limited number of accessible characteristics) and find information about the 851 species and many subspecific taxa of the genus Erica. We present an updated version 4.00, with new features including integrating distribution data from GBIF and iNaturalist, links to taxonomic resources through World Flora Online, and a probability function for identifications, that is freely available for PCs. It remains a work in progress: We discuss routes forward for collaboratively improving this resource.

RESUMEN

In support of ongoing taxonomic work on the large and complex flowering plant genus Erica (Ericaceae), we document nineteen pairs of homonyms representing currently used illegitimate names. We provide replacements for thirteen names and new typifications for five. We relegate five names to synonymy: Ericaaemula Guthrie & Bolus under Ericadistorta Bartl.; Ericaarmata Klotzsch ex Benth. under Ericaumbrosa H. A. Baker; Ericacapensis T.M. Salter under Ericaturbiniflora Salisb.; Ericalanata Andrews under Ericaflaccida Link; and Ericatomentosa Salisb. under Ericavelutina Bartl. Finally, we suggest conservation of Ericaaristata Andrews. The new names are: Ericaadelopetala E.C. Nelson & E.G.H. Oliv. replacing Ericainsignis E.G.H. Oliv.; Ericabombycina E.C. Nelson & Pirie replacing Ericaniveniana E.G.H. Oliv.; Ericaconcordia E.C. Nelson & E.G.H. Oliv. replacing Ericaconstantia Nois. ex Benth.; Ericadidymocarpa E.C. Nelson & E.G.H. Oliv. replacing Ericarugata E.G.H. Oliv.; Ericagalantha E.C. Nelson & E.G.H. Oliv. replacing Ericaperlata Benth.; Ericamallotocalyx E.C. Nelson & E.G.H. Oliv. replacing Ericaflocciflora Benth.; Ericanotoporina E.C. Nelson & E.G.H. Oliv. replacing E.autumnalis L.Bolus; Ericaoliveranthus E.C. Nelson & Pirie replacing Ericatenuis Salisb.; Ericaoraria E.C. Nelson & E.G.H. Oliv. replacing Ericaspectabilis Klotzsch ex Benth.; Ericaoresbia E.C. Nelson & E.G.H. Oliv. replacing Ericademissa Klotzsch ex Benth.; Ericapoculiflora E.C. Nelson & E.G.H. Oliv. replacing Ericastenantha Klotzsch ex Benth.; Ericarhodella E.C. Nelson & E.G.H. Oliv. replacing Ericarhodantha Guthrie & Bolus; Ericasupranubia E.C. Nelson & Pirie replacing Ericapraecox Klotzsch.

RESUMEN

BACKGROUND: The disproportionate species richness of the world's biodiversity hotspots could be explained by low extinction (the evolutionary "museum") and/or high speciation (the "hot-bed") models. We test these models using the largest of the species rich plant groups that characterise the botanically diverse Cape Floristic Region (CFR): the genus Erica L. We generate a novel phylogenetic hypothesis informed by nuclear and plastid DNA sequences of c. 60 % of the c. 800 Erica species (of which 690 are endemic to the CFR), and use this to estimate clade ages (using RELTIME; BEAST), net diversification rates (GEIGER), and shifts in rates of diversification in different areas (BAMM; MuSSE). RESULTS: The diversity of Erica species in the CFR is the result of a single radiation within the last c. 15 million years. Compared to ancestral lineages in the Palearctic, the rate of speciation accelerated across Africa and Madagascar, with a further burst of speciation within the CFR that also exceeds the net diversification rates of other Cape clades. CONCLUSIONS: Erica exemplifies the "hotbed" model of assemblage through recent speciation, implying that with the advent of the modern Cape a multitude of new niches opened and were successively occupied through local species diversification.

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RESUMEN

Whilst most of the immense species richness of heathers (Calluna, Daboecia and Erica: Ericeae; Ericaceae) is endemic to Africa, particularly the Cape Floristic Region, the oldest lineages are found in the Northern Hemisphere. We present phylogenetic hypotheses for the major clades of Ericeae represented by multiple accessions of all northern Erica species and placeholder taxa for the large nested African/Madagascan clade. We identified consistent, strongly supported conflict between gene trees inferred from ITS and chloroplast DNA sequences with regard to the position of Erica lusitanica. We used coalescent simulations to test whether this conflict could be explained by coalescent stochasticity, as opposed to reticulation (e.g. hybridisation), given estimates of clade ages, generation time and effective population sizes (Ne). A standard approach, comparing overall differences between real and simulated trees, could not clearly reject coalescence. However, additional simulations showed that at the (higher) Ne necessary to explain conflict in E. lusitanica, further topological conflict would also be expected. Ancient hybridisation between ancestors of northern species is therefore a plausible scenario to explain the origin of E. lusitanica, and its morphological similarities to E. arborea. Assuming either process influences the results of species tree and further evolutionary inference. The coalescence scenario is equivocal with regard the standing hypothesis of stepping stone dispersal of Erica from Europe into Africa; whereas reticulate evolution in E. lusitanica would imply that the colonisation of Tropical East Africa by E. arborea instead occurred independently of dispersals within the rest of the African/Madagascan clade.

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RESUMEN

Erica L. is the largest of the 'Cape' clades that together comprise around half of the disproportionately high species richness of the Cape Floristic Region (CFR) of South Africa. Around 840 species of Erica are currently recognised, C.680 of which are found in the CFR, the rest distributed across the rest of Southern Africa, the highlands of Tropical Africa and Madagascar, and Europe. Erica is taxonomically well documented, but very little is known about species-level relationships. We present the first densely sampled phylogenetic analysis of Erica, using nuclear ribosomal DNA sequences (internal transcribed spacers; ITS) of c. 45% of the species from across the full geographic range of the genus, both Calluna and Daboecia (Ericeae; monotypic genera and putative sister groups of Erica), and further Ericoideae outgroups. Our results show both morphological and geographic coherence of some clades, but numerous shifts in floral macro-morphology as represented by variation in individual morphological characters and pollination syndromes. European Ericeae is a paraphyletic grade subtending a monophyletic African/Malagasy Erica. Given the limited resolution of this single gene tree, more data are needed for further conclusions. Clades are identified that will serve as an effective guide for targeted sampling from multiple linkage groups.

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