Variation of Loranthaceae impact onVitellaria paradoxaC. F. Gaertn. fruit yield in contrasting habitats and implications for its conservation

Abstract

Introduction . Shea tree (V. paradoxa C.F. Gaertn.), a species endemic to the Sudanian savanna woodlands, is dominant in the parklands of West Africa where it is of great socioeconomic importance. However, shea tree has been reported in recent decades to be threatened by plant parasites, Loranthaceae. Our study aimed to assess possible variation of the impact of these parasites on shea tree fruit yield in two contrasting habitats. Materials and methods . We selected 41 weakly and 41 heavily infected shea tree individuals, of similar size, in a protected area as well as in its adjacent parklands. Shea tree traits such as diameter at breast height, canopy diameter, tree height, canopy height, number of fruit yielded, number of parasite stumps per tree and an impact index ratio were assessed on each shea tree individual. Two-way ANOVA was performed to compare parasite impact on shea tree fruit yield in relation to habitat. Hierarchical cluster, canonical discriminant and one-way ANOVA analyses were used to show quantitative traits that characterize shea tree groups from habitats. Results . Loranthaceae did not reduce fruit yield significantly either in the parklands or in the protected area. Quantitative traits tended to discriminate all pooled shea trees in relation to habitats. Shea tree individuals in parklands were characterized mostly by the highest value of number of infected stumps per tree and of the impact index ratio, suggesting that many shea tree individuals in parklands were sensitive to Loranthaceae impact on their fruit yield. Conclusion . These findings were helpful for implementing some shea tree conservation plans.