Impact of climate on ecology and suitable habitat of Garcinia kola heckel in Nigeria

Garcinia kola is an indigenous multipurpose tree species, with significant cultural value and medical benefits, commonly found in the tropical rain forest zone of West and Central Africa. The species has been reported to be over-used and are now classified as vulnerable species close to commercial extinction. Hence, requires immediate conservation action. This study assessed the impact of climate on habitat for cultivation of G. kola in Nigeria. Ecological niche modelling approach was used to estimate the current geographical range and predicts the future distribution of G. kola in Nigeria, using the nineteen (19) bioclimatic environment layers at a 30 'secs resolution. Two climate models were used (HadGEM2-ES and CNRM-CM5) with two Representative Concentration Pathways (RCP), RCP 4.5 and RCP 8.5 scenarios as predictor variables for projections of the potential geographical range of this species for 2050 horizon. Results revealed that about 397,094 km(2) area, corresponding to 43.6% of Nigeria land surface, are currently suitable for cultivating G. kola. The future projections showed a significant decrease in area suitable for propagating G. kola under the RCP scenarios used in the two climate models. HadGEM2-ES predicts 27.2 and 26.1% loss of suitable habitats under RCP 4.5 and 8.5, respectively, by 2050 while CNRM-CM5 projects 26.7 and 35.8% decrease for the corresponding RCPs. Furthermore, the HadGEM2-ES predicts that 149,365 and 159,384 km(2) corresponding to 16.4% and 17.5% of total land area will be suitable for cultivation of G. kola in Nigeria under RCP 4.5 and 8.5, respectively. The model results showed that climate change would have significant influence on the future suitable habitat of G. kola in Nigeria and the species is more subservient in moist, humid area and some part of derived savanna zone in Nigeria. The results underscore the significant influences of climate change on the ecology of G. kola. Based on these results, immediate action should be initiated to conserve this valued species and secure their inherent agro-ecosystems services