Effects of Ecological Factors on Population Status and Morphological Traits of <i>Faidherbia albida</i> (Del.) A. Chev. in Burkina Faso

Abstract

<i>Faidherbia albida</i> (Del.) A. Chev. is a key agroforestry parklands species providing provisioning and regulating ecosystem services to people. Therefore, sustainable management and conservation of the species populations are great challenges on its distribution area. However, the species response to spatial variability of ecological conditions is poorly addressed, limiting its management and conservation. The objectives of this study were to: (i) assess the population status of <i>F. albida</i> along climate gradient in Burkina Faso and (ii) determine the effects of biotic and abiotic variables on population status and morphological traits of the species. Data were collected in 99 plots equally distributed in three climatic zones by focusing on biotic data in the plots (tree diversity and density, morphological traits of <i>F. albida</i> and all adult trees) and abiotic data (climate variables and elevation). The results showed that tree density and morphological traits of <i>F. albida</i> are significantly influenced (P<0.05) by climate zone. Tree density of the species increased from Sahelian to Sudanian zone while specific zone effects were observed for its morphological traits (tree diameter and height). Irrespective to climate zone, linear regressions based on diameter class distribution indicated that populations of <i>F. albida</i> are in degraded status exhibited by the dominance of largest trees. Tree diversity using Shannon index was negatively and significantly correlated to tree density of <i>F. albida</i> while opposite correlation was observed with tree height of the species. Specific and significant correlations were observed between abiotic variables considered in the study and morphological traits of <i>F. albida</i>. This study highlighted the instability of the population structure of <i>F. albida</i> and specific effects of biotic and abiotic variables on the species density and morphological traits. The results of this study could direct the management and conservation policies to ensure its sustainable use.