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.

Centre for Functional Biodiversity School of Life Sciences University of KwaZulu Natal Scottsville Pietermaritzburg 3209 South Africa

Department of Biochemistry University of Stellenbosch Private Bag X1 Matieland 7602 South Africa

Department of Biological Sciences University of Cape Town Private Bag Rondebosch 7701 South Africa

Department of Botany and Zoology University of Stellenbosch Private Bag X1 Matieland 7602 South Africa

Department of Botany Faculty of Science Charles University 128 00 Prague Czech Republic

Department of Genetics University of Stellenbosch Private Bag X1 Matieland 7602 South Africa

Department of Plant Systematics Bayreuth Centre of Ecology and Environmental Research University of Bayreuth Universitätsstraße 30 95447 Bayreuth Germany

Hortus botanicus Leiden Leiden University P O Box 9500 2300 RA Leiden Netherlands

Institute of Biology Leiden Leiden University PO Box 9505 2300 RA Leiden Netherlands

Naturalis Biodiversity Center P O Box 9517 2300 RA Leiden Netherlands

Senckenberg Biodiversity and Climate Research Centre Senckenberg Gesellschaft für Naturforschung 60325 Frankfurt am Main Germany

Universidade da Coruña BIOCOST research group Centro Interdisciplinar de Química e Bioloxía Rúa As Carballeiras 15071 A Coruña Spain

Universidade da Coruña Departamento de Bioloxía Facultade de Ciencias 15071 A Coruña Spain

University Museum University of Bergen Postboks 7800 N 5020 Bergen Norway

Zobrazit více v PubMed

Akinlabi FM, Pirie MD, Oskolski AA. (2023) Fire, frost, and drought constrain the structural diversity of wood within southern African Erica (Ericaceae). Botanical Journal of the Linnean Society 203: 370–389. 10.1093/botlinnean/boad033 DOI

Bachman SP, Brown MJM, Leão TCC, Lughadha EN, Walker BE. (2023) Extinction risk predictions for the world"s flowering plants to support their conservation. bioRxiv. 10.1101/2023.08.29.555324 PubMed DOI

Bellstedt DU, Pirie MD, Visser JC, de Villiers MJ, Gehrke B. (2010) A rapid and inexpensive method for the direct PCR amplification of DNA from plants. American Journal of Botany 97: e65–68. 10.3732/ajb.1000181 PubMed DOI

Brown MJM, Bachman SP, Nic Lughadha E. (2023) Three in four undescribed plant species are threatened with extinction. New Phytologist 240: 1340–1344. 10.1111/nph.19214 PubMed DOI

Colville JF, Beale CM, Forest F, Altwegg R, Huntley B, Cowling RM. (2020) Plant richness, turnover, and evolutionary diversity track gradients of stability and ecological opportunity in a megadiversity center. Proceedings of the National Academy of Sciences of the United States of America 117: 20027–20037. 10.1073/PNAS.1915646117 PubMed DOI PMC

Cowling RM, Bradshaw PL, Colville JF, Forest F. (2017) Levyns’ Law: explaining the evolution of a remarkable longitudinal gradient in Cape plant diversity. Transactions of the Royal Society of South Africa 72: 184–201. 10.1080/0035919X.2016.1274277 DOI

Cowling RM, Gallien L, Richardson DM, Ojeda F. (2018) What predicts the richness of seeder and resprouter species in fire-prone Cape fynbos: Rainfall reliability or vegetation density? Austral Ecology 43: 614–622. 10.1111/aec.12606 DOI

Elliott A, Bester SP, Klopper RR, Nelson EC, Pirie M. (2024) Curating an online checklist for Erica L. (Ericaceae): contributing to and supporting global conservation through the World Flora Online. ARPHA Preprints 5: e121772. 10.3897/arphapreprints.e121772 PubMed DOI PMC

Faith DP. (1992) Conservation evaluation and phylogenetic diversity. Biological Conservation 61: 1–10. 10.1016/0006-3207(92)91201-3 DOI

Faith DP. (2008) Threatened species and the potential loss of phylogenetic diversity: Conservation scenarios based on estimated extinction probabilities and phylogenetic risk analysis. Conservation Biology 22: 1461–1470. 10.1111/j.1523-1739.2008.01068.x PubMed DOI

Forest F, Grenyer R, Rouget M, Davies TJ, Cowling RM, Faith DP, Balmford A, Manning JC, Procheş Ş, van der Bank M, Reeves G, Hedderson TAJ, Savolainen V. (2007) Preserving the evolutionary potential of floras in biodiversity hotspots. Nature 445: 757–760. 10.1038/nature05587 PubMed DOI

Forest F, Moat J, Baloch E, Brummitt NA, Bachman SP, Ickert-Bond S, Hollingsworth PM, Liston A, Little DP, Mathews S, Rai H, Rydin C, Stevenson DW, Thomas P, Buerki S. (2018) Gymnosperms on the EDGE. Scientific Reports 8: 6053. 10.1038/s41598-018-24365-4 PubMed DOI PMC

Gallagher RV, Allen SP, Govaerts R, Rivers MC, Allen AP, Keith DA, Merow C, Maitner B, Butt N, Auld TD, Enquist BJ, Eiserhardt WL, Wright IJ, Mifsud JCO, Espinosa-Ruiz S, Possingham H, Adams VM. (2023) Global shortfalls in threat assessments for endemic flora by country. PLANTS, PEOPLE, PLANET 5: 885–898. 10.1002/ppp3.10369 DOI

GBIF.org (2023) Occurrence Download [Data set]. The Global Biodiversity Information Facility. 10.15468/DL.KG7QKF DOI

Gizaw A, Kebede M, Nemomissa S, Ehrich D, Bekele B, Mirré V, Popp M, Brochmann C. (2013) Phylogeography of the heathers Ericaarborea and E.trimera in the afro-alpine "sky islands" inferred from AFLPs and plastid DNA sequences. Flora - Morphology, Distribution, Functional Ecology of Plants 208: 453–463. 10.1016/j.flora.2013.07.007 DOI

Goldblatt P. (1978) An Analysis of the Flora of Southern Africa: Its Characteristics, Relationships, and Orgins. Annals of the Missouri Botanical Garden 65: 369. 10.2307/2398858 DOI

Gumbs R, Gray CL, Böhm M, Burfield IJ, Couchman OR, Faith DP, Forest F, Hoffmann M, Isaac NJB, Jetz W, Mace GM, Mooers AO, Safi K, Scott O, Steel M, Tucker CM, Pearse WD, Owen NR, Rosindell J. (2023) The EDGE2 protocol: Advancing the prioritisation of Evolutionarily Distinct and Globally Endangered species for practical conservation action. PLOS Biology 21: e3001991. 10.1371/journal.pbio.3001991 PubMed DOI PMC

Hamel T, de BÉLAIR G, Slimani A, Meddad-Hamza A. (2021) De nouvelles données sur l"état critique d"Ericanumidica (MAIRE)ROMO et BORAT. en Numidie (Algérie occidentale)). Lejeunia, Revue de Botanique 205: 1–16. 10.25518/0457-4184.2416 DOI

Hitchcock A, Rebelo AG. (2017) The restoration of Ericaverticillata: a case study in species and habitat restoration and implications for the Cape Flora. Sibbaldia: The International Journal of Botanic Garden Horticulture 15: 39–63. 10.24823/Sibbaldia.2017.222 DOI

Humphreys AM, Govaerts R, Ficinski SZ, Nic Lughadha E, Vorontsova MS. (2019) Global dataset shows geography and life form predict modern plant extinction and rediscovery. Nature Ecology & Evolution 3: 1043–1047. 10.1038/s41559-019-0906-2 PubMed DOI

Isaac NJB, Turvey ST, Collen B, Waterman C, Baillie JEM. (2007) Mammals on the EDGE: Conservation priorities based on threat and phylogeny. PLoS ONE 2(3): e296. 10.1371/journal.pone.0000296 PubMed DOI PMC

IPBES (2019) Global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. Zenodo, 1144 pp. 10.5281/zenodo.5657041 DOI

IUCN (2023) The IUCN Red List of Threatened Species. Version 2023-1. https://www.iucnredlist.org

Kadlec M, Bellstedt DU, Le Maitre NC, Pirie MD. (2017) Targeted NGS for species level phylogenomics: “made to measure” or “one size fits all”? PeerJ 5: e3569. 10.7717/peerj.3569 PubMed DOI PMC

Levyns MR. (1964) Migrations and origin of the Cape flora. Transactions of the Royal Society of South Africa 37: 85–107. 10.1080/00359196409519059 DOI

Linder HP. (2003) The radiation of the Cape flora, southern Africa. Biological Reviews 78: 597–638. 10.1017/S1464793103006171 PubMed DOI

Liu U, Cossu TA, Davies RM, Forest F, Dickie JB, Breman E. (2020) 29 Conserving orthodox seeds of globally threatened plants ex situ in the Millennium Seed Bank, Royal Botanic Gardens, Kew, UK: the status of seed collections, 2901 pp. 10.1007/s10531-020-02005-6 DOI

Lötter D, Le Maitre D. (2014) Modelling the distribution of Aspalathus linearis (Rooibos tea): implications of climate change for livelihoods dependent on both cultivation and harvesting from the wild. Ecology and Evolution 4: 1209–1221. 10.1002/ece3.985 PubMed DOI PMC

Lughadha EN, Bachman SP, Leão TCC, Forest F, Halley JM, Moat J, Acedo C, Bacon KL, Brewer RFA, Gâteblé G, Gonçalves SC, Govaerts R, Hollingsworth PM, Krisai-Greilhuber I, Lirio EJ de, Moore PGP, Negrão R, Onana JM, Rajaovelona LR, Razanajatovo H, Reich PB, Richards SL, Rivers MC, Cooper A, Iganci J, Lewis GP, Smidt EC, Antonelli A, Mueller GM, Walker BE. (2020) Extinction risk and threats to plants and fungi. PLANTS, PEOPLE, PLANET 2: 389–408. 10.1002/ppp3.10146 DOI

Maddison WP, Maddison DR. (2021) Mesquite: a modular system for evolutionary analysis. Version 3.70. http://mesquiteproject.org

Mast AR, Olde PM, Makinson RO, Jones E, Kubes A, Miller ET, Weston PH. (2015) Paraphyly changes understanding of timing and tempo of diversification in subtribe Hakeinae (Proteaceae), a giant Australian plant radiation. American Journal of Botany 102: 1634–1646. 10.3732/ajb.1500195 PubMed DOI

McGuire AF, Kron KA. (2005) Phylogenetic relationships of European and African ericas. International Journal of Plant Sciences 166: 311–318. 10.1086/427478 DOI

Mugrabi de Kuppler AL, Fagúndez J, Bellstedt DU, Oliver EGH, Léon J, Pirie MD. (2015) Testing reticulate versus coalescent origins of Ericalusitanica using a species phylogeny of the northern heathers (Ericeae, Ericaceae). Molecular Phylogenetics and Evolution 88: 121–131. 10.1016/j.ympev.2015.04.005 PubMed DOI

Musker SD, Pirie MD, Nürk NM. (2023) The dynamics of species divergence in South Africa"s megadiverse Cape region. bioRxiv, 1–25. 10.1101/2023.07.19.549682 DOI

Myers N, Mittermeier RA, Mittermeier CG, da Fonseca GA, Kent J. (2000) Biodiversity hotspots for conservation priorities. Nature 403: 853–858. 10.1038/35002501 PubMed DOI

Nelson EC. (2011) Hardy heathers from the northern hemisphere: Calluna, Daboecia, Erica. Royal botanic gardens Kew, Richmond.

Ojeda F. (1998) Biogeography of seeder and resprouter Erica species in the Cape Floristic Region–Where are the resprouters? Biological Journal of the Linnean Society 63: 331–347. 10.1111/j.1095-8312.1998.tb01521.x DOI

Oliver EGH, Forshaw N, Oliver IM, Volk F, Schumann AWS, Dorr LJ, Hoekstra RD, Musker SD, Nürk NM, Pirie MD, Rebelo AG. (2024) Genus Erica: An identification aid version 4.00. PhytoKeys 241: 143–154. 10.3897/phytokeys.241.117604 PubMed DOI PMC

Oliver EGH, Linder HP, Rourke JP. (1983) Geographical distribution of present-day Cape taxa and their phytogeographical significance. Bothalia 14: 427–440. 10.4102/abc.v14i3/4.1189 DOI

Ondo I, Dhanjal-Adams KL, Pironon S, Silvestro D, Colli-Silva M, Deklerck V, Grace OM, Monro AK, Nicolson N, Walker B, Antonelli A. (2023) Plant diversity darkspots for global collection priorities. bioRxiv, 1–33. 10.1101/2023.09.12.557387 DOI

Paradis E, Schliep K. (2019) ape 5.0: an environment for modern phylogenetics and evolutionary analyses in R. Bioinformatics 35: 526–528. 10.1093/bioinformatics/bty633 PubMed DOI

Pasta S, El-Zein H, Şentürk O, Gücel S, De Simone L, Makhlouf MH, Abu-Hadra M, Al-Zein MS, Bou Dagher Karrat M, Montmollin de B. (2024) Wide-ranged, highly disjunct, locally rare and severely endangered: the challenging risk assessment and a global conservation strategy of Ericasicula Guss. sensu lato (Ericaceae). In: 4th Mediterranean Plant Conservation Week. Valencia. ARPHA Preprints, e124671. 10.3897/arphapreprints.e124671 DOI

Pirie MD, Humphreys AM, Barker NP, Linder HP. (2009) Reticulation, data combination, and inferring evolutionary history: an example from Danthonioideae (Poaceae). Systematic Biology 58: 612–628. 10.1093/sysbio/syp068 PubMed DOI

Pirie MD, Oliver EGH, Bellstedt DU. (2011) A densely sampled ITS phylogeny of the Cape flagship genus Erica L. suggests numerous shifts in floral macro-morphology. Molecular Phylogenetics and Evolution 61: 593–601. 10.1016/j.ympev.2011.06.007 PubMed DOI

Pirie MD, Oliver EGH, Mugrabi de Kuppler A, Gehrke B, Le Maitre NC, Kandziora M, Bellstedt DU. (2016) The biodiversity hotspot as evolutionary hot-bed: spectacular radiation of Erica in the Cape Floristic Region. BMC Evolutionary Biology 16: 190. 10.1186/s12862-016-0764-3 PubMed DOI PMC

Pirie MD, Oliver EGH, Gehrke B, Heringer L, Mugrabi de Kuppler A, Le Maitre NC, Bellstedt DU. (2017) Underestimated regional species diversity in the Cape Floristic Region revealed by phylogenetic analysis of the Ericaabietina/E.viscaria clade (Ericaceae). Botanical Journal of the Linnean Society 184: 185–203. 10.1093/botlinnean/box021 DOI

Pirie MD, Kandziora M, Nürk NM, Le Maitre NC, Mugrabi de Kuppler A, Gehrke B, Oliver EGH, Bellstedt DU. (2019) Leaps and bounds: geographical and ecological distance constrained the colonisation of the Afrotemperate by Erica. BMC Evolutionary Biology 19: 222. 10.1186/s12862-019-1545-6 PubMed DOI PMC

Pirie MD, Blackhall-Miles R, Bourke G, Crowley D, Ebrahim I, Forest F, Knaack M, Koopman R, Lansdowne A, Nürk NM, Osborne J, Pearce TR, Rohrauer D, Smit M, Wilman V. (2022) Preventing species extinctions: A global conservation consortium for Erica. PLANTS, PEOPLE, PLANET 4: 335–344. 10.1002/ppp3.10266 DOI

Pollock LJ, O’Connor LMJ, Mokany K, Rosauer DF, Talluto MV, Thuiller W. (2020) Protecting Biodiversity (in All Its Complexity): New Models and Methods. Trends in Ecology and Evolution 35: 1119–1128. 10.1016/j.tree.2020.08.015 PubMed DOI

R Core Team (2022) R: A language and environment for statistical computing. https://www.r-project.org/ [July 6, 2023]

Raimondo D, Van Staden L, Foden W, Victor JE, Helme NA, Turner RC, Kamundi DA, Manyama PA. (2009) Strelitzia No. 25 Red list of South African plants 2009. South African National Biodiversity Institute, Pretoria, ix + 668 pp. http://hdl.handle.net/20.500.12143/260

Rodríguez-Buján I, Díaz-Tapia P, Fagúndez J. (2024) Genetic and morphological evidence support the specific status of the endemic Ericaandevalensis (Ericales, Ericaceae). PhytoKeys 244: 57–76. 10.3897/phytokeys.244.120914 PubMed DOI PMC

Romo AM, Boratynski A. (2010) A new combination in Erica (Ericaceae). Collectanea Botanica 29: 95–98. 10.3989/collectbot.2010.v29.009 DOI

Segarra-Moragues JG, Ojeda F. (2010) Postfire response and genetic diversity in Ericacoccinea: connecting population dynamics and diversification in a biodiversity hotspot. Evolution 64: 3511–3524. 10.1111/j.1558-5646.2010.01064.x PubMed DOI

Stamatakis A. (2014) RAxML version 8: a tool for phylogenetic analysis and post-analysis of large phylogenies. Bioinformatics 30: 1312–1313. 10.1093/bioinformatics/btu033 PubMed DOI PMC

Steel M, Mimoto A, Mooers A. (2007) Hedging our bets: The expected contribution of species to future phylogenetic diversity. Evolutionary Bioinformatics 3: 237–244. 10.1177/117693430700300024 PubMed DOI PMC

Tietje M, Antonelli A, Forest F, Govaerts R, Smith SA, Sun M, Baker WJ, Eiserhardt WL. (2023) Global hotspots of plant phylogenetic diversity. New Phytologist 240: 1636–1646. 10.1111/nph.19151 PubMed DOI

Vaidya G, Lohman DJ, Meier R. (2011) SequenceMatrix: Concatenation software for the fast assembly of multi-gene datasets with character set and codon information. Cladistics 27: 171–180. 10.1111/j.1096-0031.2010.00329.x PubMed DOI

Van Der Niet T, Pirie MD, Shuttleworth A, Johnson SD, Midgley JJ. (2014) Do pollinator distributions underlie the evolution of pollination ecotypes in the Cape shrub Ericaplukenetii? Annals of Botany 113: 301–316. 10.1093/aob/mct193 PubMed DOI PMC

Westwood M, Cavender N, Meyer A, Smith P. (2021) Botanic garden solutions to the plant extinction crisis. PLANTS, PEOPLE, PLANET 3: 22–32. 10.1002/ppp3.10134 DOI

Zhigila DA, Muasya AM, Verboom GA. (2023) Extinction risk patterns in a biodiversity hotspot–The case of Thesium (Santalaceae) in the Greater Cape Floristic Region. Conservation Science and Practice n/a, e12932. 10.1111/csp2.12932 DOI