Update on the Diversity of Gallery Forests in the Sub-Sudanese Zone of Côte D'ivoire

Abstract

Various forms of anthropogenic pressure have significantly altered the structure and floristic composition of gallery forests, leading to a departure from their previously described floristic profile. In this context, the present study aims to update knowledge on the floristic composition of gallery forests in the sub-Sudanese region of Côte d’Ivoire. The methodology combined surface surveys and itinerant inventories. For each inventoried species, the family, genus, morphological type, and phytogeographic distribution were determined according to the APG IV classification. Species distribution across these characteristics was analyzed using bar charts and pie charts. Endemism was assessed by identifying species endemic to the West African forest block, with particular attention to those restricted to Côte d’Ivoire. The resulting floristic list was compared with the UICN Red List and the reference list in. The results show that the gallery forest flora comprises 153 species distributed among 122 genera and 51 families. The most represented families are Fabaceae, Moraceae, Rubiaceae, Euphorbiaceae, and Sapindaceae. A diachronic comparison between 1971 and 2025 highlights the persistence of a resilient floristic core dominated by Fabaceae, Rubiaceae, Moraceae, and Annonaceae. In contrast, formerly abundant families such as Euphorbiaceae, Sterculiaceae, and Meliaceae exhibit a marked decline, while Apocynaceae, Sapindaceae, and Combretaceae emerge as increasingly important families. Species from the Guineo-Congolese region and the transition zone are the most numerous. Structurally, shrubs predominate, followed by trees and lianas. The characteristic species currently observed include Berlinia grandiflora, Carapa procera, Cola gigantea, Cola laurifolia, Dialium guineense, Lecaniodiscus cupanioides, Ochna membranacea, Olax subscorpioidea, Synsepalum brevipes, and Phoenix reclinata. Overall, floristic diversity has declined since the 1971 inventories, with several hygrophilous species disappearing and being replaced by disturbance-tolerant taxa. Nevertheless, these gallery forests remain important refuges for threatened and endemic species, some of which are classified as rare or vulnerable by the IUCN and Aké-Assi.