Konaté Alassane1, Bongoua-Devisme Affi Jeanne2, Dibi N’Da Hyppolite3, and Akotto Odi Faustin4
1 Laboratoire de Pédologie et Agriculture Durable, UFR Sciences de la Terre et des Ressources Minières, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
2 Laboratoire de Pédologie et Agriculture Durable, UFR Sciences de la Terre et des Ressources Minières, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
3 Centre Universitaire de Recherche et d’Application en Télédétection (CURAT), Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
4 Département des Sciences du sol, Université Félix Houphouët-Boigny, UFR STRM, Abidjan, Côte d’Ivoire
Original language: English
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Abstract
Soil quality is a key determinant of vegetation cover dynamics in tropical protected areas, yet its quantitative relationship with vegetation degradation under anthropogenic pressure remains poorly documented at the profile scale in West African savannas. This study, carried out in Comoé National Park (CNP, north-eastern Côte d’Ivoire), tested the hypothesis that the forest-savanna vegetation gradient along an approximately 800 m transect of the corresponds to a measurable decline in soil quality driven by increasing anthropogenic pressure at the park periphery. Five pedological profiles were excavated in March 2023, morphologically described and analysed following ISRIC protocols, and classified using WRB 2022. Clay cation exchange capacity (clay-CEC) and available phosphorus (P) were used as primary soil quality indicators. Results revealed a systematic soil quality gradient from gallery forest to degraded tree savanna: clay-CEC in the argillic horizon decreased from 27.4 cmol (c) kg⁻1 (Ferric Lixisol, gallery forest) to 9.5 cmol (c) kg⁻1 (Ferric Acrisol, degraded savanna), while available P declined from 16.3 to 0.1–1.4 mg kg⁻1. Three mid-slope profiles classified as Stagnic Ferric Acrisols showed temporary waterlogging from 10–11 cm depth and near-complete P immobilisation, directly constraining rooting depth and woody species regeneration. Two pedological anomalies were documented: MnO2-mediated pH buffering (pH 7.0) and smectite neoformation (CEC = 148 mmol⁺ kg⁻1) under pseudo-gley conditions. These findings establish a quantitative edaphic basis for vegetation cover decline in the CNP periphery and support differentiated conservation management strategies.
Author Keywords: Lixisol, Acrisol, soil-vegetation relationship, clay-CEC, Comoé National Park, Côte d’Ivoire.
