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Walters G.,Institute Of Pharmacopee Et Medecines Traditionnelles | Walters G.,University College London | Walters G.,British Petroleum | Dauby G.,Roosevelt University | And 5 more authors.
Edinburgh Journal of Botany | Year: 2011

Since the publication of the Gabon Checklist in 2006, intensive fieldwork activity has led to the discovery of many novelties. We document here 61 new records for the flora of Gabon, including nine new generic records. Five taxa are also removed from the Gabon flora. © 2011 Trustees of the Royal Botanic Garden Edinburgh.

Walters G.,University College London | Walters G.,Institute Of Pharmacopee Et Medecines Traditionnelles | Parmentier I.,Roosevelt University | Stevart T.,Missouri Botanical Garden | Stevart T.,Roosevelt University
Plant Ecology and Evolution | Year: 2012

Background and aims Eighty per cent of Gabon's territory is covered by forest with most species inventory work focused on these areas. However, herbaceous open vegetation types are abundant in this country and can be found in savannas on the coast, in the centre and in the south, and on inselbergs. The species diversity patterns of these habitats remain largely unexplored yet are targeted for both conservation and development. Here, we evaluate the floristic diversity of savannas in Gabon, their affinities with the inselberg open vegetation, and their contribution to the national park system in Gabon, which is currently undergoing a gap analysis. We then use a case study from the Batéké Plateaux to demonstrate species rarity in a single savanna. Materials and methods Species presence in the grassy formations of the savannas in Loango, Lopé, Pongara, and Plateaux Batéké national parks and in Kum inselberg is compared using ordination and clustering based on a similarity matrix (Sørensen index). For the Batéké Plateaux savannas, the species rarity and distributions are assessed using Star ratings. Key results The species in the open herbaceous vegetation in Gabon account for at least 11% of the total flora of the country (508 species out of 4,710). Except for the coastal savannas, all sites are highly dissimilar in floristic composition (Sørensen index 0.065-0.26) and no dominant savanna type occurs within the dataset. The inselberg site is the most dissimilar and constitutes a separate vegetation unit. Most savanna species of the Batéké Plateaux area are widely distributed, but not weedy. A few are extremely rare and are linked with moist habitats, substrate, and fire occurrence. Our results show the diversity and the conservation value of open, herbaceous habitats. Currently, the Gabonese National Park network is partly protecting the savanna and inselberg vegetation. However, several areas remain un-assessed and merit further exploration. © 2012 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.

Lachenaud O.,Roosevelt University | Stevart T.,National Botanic Garden of Belgium | Stevart T.,Institute Of Pharmacopee Et Medecines Traditionnelles | Stevart T.,Missouri Botanical Garden | And 8 more authors.
Plant Ecology and Evolution | Year: 2013

Background - A new species of Rubiaceae, Psychotria wieringae O.Lachenaud, is described and illustrated. Methods-Normal practises of herbarium taxonomy have been applied. Key results - P. wieringae is endemic to the Libreville peninsula (Gabon), where it is locally abundant in the undergrowth of littoral forests on sandy soils. It is related to P. gabonica Hiern but differs in its pale bark, glabrous inflorescences, flower colour, and leaves with a prominent midrib on the upper surface. IUCN assessment - The species is considered as Endangered EN B2ab(i,ii,iii,iv,v) according to IUCN criteria. Its survival in situ will likely depend on the maintenance of the subpopulation at the "Ferme des crocodiles", situated in the Raponda-Walker Arboretum. The occurence of several other endemic species in the area, and their conservation, are also discussed. © 2013 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.

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