Conservation gap analysis identifies gaps in protecting threatened Erica species

A conservation gap analysis found that 89 of 189 threatened Erica species, or 47%, are represented in at least one ex situ collection, while taxonomic knowledge, threat assessments and ecological data remain uneven across the genus. The study synthesised existing information on the 830 accepted non-hybrid species in Erica and assessed gaps in their in situ and ex situ conservation.

The analysis was conducted under the Global Conservation Consortia framework by the GCCErica working group, which drew on taxonomic records, occurrence data, protected-area coverage, conservation assessments and PlantSearch records. Researchers consolidated names through World Flora Online, filtered Global Biodiversity Information Facility occurrences to produce three increasingly precise datasets, compared South African distributions with protected areas, and assessed representation in seed banks and botanic gardens. Working groups also discussed obstacles, required actions and measures of success in March 2025.

World Flora Online documented 830 accepted non-hybrid species in June 2025, alongside 20 accepted non-horticultural hybrid names. The genus contains 1,214 taxa when species, subspecies and varieties represented in the identification aid are counted. All accepted subspecific taxa are included in the Erica Identification Aid, but 220, all from South Africa, are not character coded.

Of 572,990 occurrence records retained initially, the most precise filtering stage retained 388,411 records representing 782 species and 1,026 taxa. This represented reductions of 32% in records, 7% in species and 13% in taxa compared with the first filter. Among non-hybrid taxa represented in GBIF, seven species, comprising 61 taxa, had no records; 656 species had been recorded within the previous 10 years.

Threat coverage was broad but uneven. About 90% of species had been assessed, but 53 species were Data Deficient and 518 had not been assessed within the preceding 10 years. The source combined South African Red List and IUCN assessments, noting that many South African assessments relied on the 2009 assessment and later updates, while most species outside South Africa, including nearly all Malagasy species, lacked assessments.

Ex situ representation was concentrated among common European and northern species. Of 830 species, 209 were held by the Millennium Seed Bank, 230 occurred in two or more collections, 187 were represented in one collection and 413 were not known to be held in any collection. Among threatened species, 32 of 48 Endangered and 44 of 95 Vulnerable species were absent from ex situ collections. Critically Endangered and Endangered accessions were concentrated mainly in SANBI gardens and the Millennium Seed Bank, which together held 88 of 109 such accessions.

The analysis also identified major ecological and research gaps. Pollinators had been identified for only 1.8% of Erica species, and seed longevity, dispersal and germination requirements remained poorly studied. Around one-third of species lacked DNA sequence data, limiting reliable inclusion in phylogenetic analyses, while undescribed diversity and unclear species or subspecies boundaries persisted.

The authors concluded that threatened-species coverage remains below the Convention on Biological Diversity target of 75%, although the available collection data provide a minimum estimate rather than a complete accession-level assessment. The Erica Identification Aid can support prioritisation, but further collection-level data, updated threat assessments, targeted fieldwork and improved ecological knowledge are required to guide in situ protection, cultivation and the development of distributed metacollections.

Subject of Research: Conservation status and collection gaps for the flowering plant genus Erica

Article Title: Conservation gap analysis for Erica ( Ericaceae )

Article References: Pirie, M. D., Bester, S. P., Blackhall-Miles, R., Coetzee, A., Crowley, D., Ebrahim, I., Elliott, A. C., Fagúndez, J., Forest, F., Forshaw, N., Hoekstra, R. D., Kandziora, M., Klopper, R. R., Koopman, R., Musker, S. D., Nürk, N. M., Osborne, J., Pasta, S., Pipins, S., … Wilman, V. (2026). Conservation gap analysis for Erica (Ericaceae). Nature Conservation, 63, 199-236. https://doi.org/10.3897/natureconservation.63.175466

Image Credits: AI Generated

DOI: 10.3897/natureconservation.63.175466

Keywords: Erica, Ericaceae, conservation gap analysis, ex situ conservation, botanic gardens, seed banks, threat assessment, biodiversity data, plant taxonomy, South Africa, Conservation, analysis