Abundance and effects of climate change on geographical distribution of Mondia whitei (Hook.f.) Skeels (Apocynaceae) in the Dahomey Gap (West Africa)

Abstract

African healthcare system depends upon indigenous medicinal plants, harvested wild and traded for significant income generation. Mondia whitei, one of these plants, is threatened by over-exploitation, climate change and unsustainable land use management. Detailed knowledge is lacking regarding the species' conservation-driving forces and preservation of its ecological niche within fragile ecological regions. This study assessed the influence of the land use types on the abundance of M. whitei and the spatio-temporal evolution of its ecological niche in the Dahomey Gap. The abundance of the species was evaluated in different land use systems. Available bioclimatic and soil layers were used for the distribution modelling. Results showed that M. whitei was mainly found in three land use systems: cropland, fallow and forests. Density of adults averaged 281.5 ± 99.1, 323.2 ± 93.9 and 305.9 ± 154 individuals/ha in fallow, forest and cropland, respectively. For juveniles, density was on average of 222.2 ± 205.7 individuals/ha in cropland vs 59.3 ± 71.8 and 57.4 ± 94.1 individuals/ha in forest and fallow, respectively. The majority of the species distribution will possibly remain stable with some expansion under future climates. Persistence of the species' niche in the Dahomey Gap under climate change indicates its potential as a contributor to future livelihood improvement, via local health care and the strengthening of local economy.