Checklist of the vascular plants of Río Muni (Equatorial Guinea): floristic analysis, diversity, endemicity, and threatened status

Abstract

An updated checklist of the vascular plants from the continental region of Equatorial Guinea (Río Muni) is presented. The catalogue (Appendix 1) is the result of the compilation of herbarium specimens (6850), species records (7985) from the botanical literature and online databases (10109 GBIF records and 8897 RAINBIO records). A database of 23517 georeferenced records was prepared by updating the nomenclatural and standardizing the locality names from all these sources. The catalogue comprises 2707 taxa (2598 species, 81 subspecies, and 28 varieties) included in 1020 genera and 178 families. About 90.6% of the taxa are considered native, 1.17% introduced and 5.96% naturalized. The 10 most diverse families are Rubiaceae (294 species), Fabaceae (290), Orchidaceae (168), Poaceae (105), Euphorbiaceae (87), Apocynaceae (85), Cyperaceae (79), Annonaceae (68), Acanthaceae (65) and Melastomataceae (61), which comprise 49.22% of the species in Río Muni. Only 11 species can be considered endemic to Río Muni; this low number reflects the absence of natural barriers in the territory. The number of threatened taxa (VU, EN and CR) is 134 (5.02% of the total evaluated), of which 43 are at risk of extinction, being within the categories of Endangered or Critically Endangered. Five species restricted to the Gulf of Guinea are considered threatened: three Endangered (Grossera angustifolia, Polyscias aequatoguineensis and Rhipidoglossum montealenense), and two Critically Endangered (Asplenium carvalhoanum and Macropodiella uoroensis), thus they should be considered as priority in management plans development and conservation strategies.