Diversity and in situ Conservation Value of the Flora of the Marahoue Ranch in the Sub-sudanese Forest-savanna Contact Zone in Côte d'Ivoire

Abstract

Background: Plant formations such as ranches play a major role in the conservation of woody biodiversity. However, there is little data on the floristic composition and biodiversity conservation value of these ecosystems in Côte d'Ivoire. Aim: The aim of this study is to assess the plant diversity of the Marahoué ranch in the context of biodiversity conservation. Methodology: Floristic inventories carried out in 2,500 m² (50 m x 50 m) surface units set up in three types of biotopes and using the itinerant method over a 12-month period made it possible to characterize the floristic diversity of the Marahoué ranch. Results: A total of 308 species (riparian forest: 97 species; open forest: 137 species; savannah: 153 species) were inventoried in 231 genera and 82 families. Fabaceae, Rubiaceae and Euphorbiaceae are the most abundant families. Floristic compositions show an abundance of microphanerophytes and transitional species from the Sudanese sector. Most species have sarcochore-type diaspores spread by animals or zoochory (46.93%). The flora of these classified forests is also characterised by the presence of 109 species of special status, including one that is almost threatened (Milicia excelsa). The biotopes are moderately diverse, with Shannon diversity indices ranging from 2.80 bits (savannah) to 3.13 bits (riparian forest). Conclusion: This study highlighted the floristic particularities of the Marahoué ranch and its role as a refuge for special-status species, which constitute a sufficient indicator to justify the protection and sustainable management of the ranch with a view to conserving biodiversity in west-central Côte d'Ivoire.