Impact of Climate Change on the Carbon Sequestration Capacity and Distribution Area of Afzelia Africana Sm. Ex Pers and Pterocarpus Erinaceus Poir in Cote D'ivoire: Case of the Lamto Scientific Reserve and the Badenou Classified Forest

Abstract

Forests are important for carbon sequestration and biodiversity preservation, but they remain vulnerable to climate change. This study aims to analyse the impact of climate on the carbon sequestration capacity and spatial distribution of two ecologically and economically important species, Afzelia africana and Pterocarpus erinaceus, in the Lamto Scientific Reserve and the Badenou Classified Forest in Côte d'Ivoire. The study began with an analysis of the influence of climatic variables on land use dynamics between 1990 and 2022, using Landsat images, as well as an evaluation of the correlations between these variables and the areas of the different land use classes. A botanical inventory was then conducted on 1000 m² plots to catalogue the species and monitor regeneration. Stem discs were collected and analysed to measure the rings, then converted into carbon stocks using allometric equations, allowing for the evaluation of the spatiotemporal evolution of sequestration. Finally, the Maximum Entropy (MAXENT) algorithm was used to model the future distribution of the two species. The results revealed a gradual densification of the vegetation, marked by a transition from savannas to forest formations, more pronounced at Lamto. Temperatures and drought indices appear as the main factors of these changes. Lamto exhibits a richer biodiversity than Badenou, with 292 species (179 genera, 66 families) compared to 242 species (137 genera, 55 families). Afzelia africana is associated with 46 species with special status, compared to 12 for Pterocarpus erinaceus. Afzelia africana stores more carbon and shows greater resistance to climatic variations, particularly at Lamto, while Pterocarpus erinaceus is more vulnerable to drought, especially at Badenou. The modelling indicates that under moderate warming (+2°C), Afzelia africana could expand its range, while Pterocarpus erinaceus would remain stable. On the other hand, under an extreme scenario (+4.4°C), Afzelia africana would maintain its habitat, but Pterocarpus erinaceus would lose its favourable habitats, threatening its regeneration and survival.