Regional dynamics in distribution of Prosopis juliflora under predicted climate change in Africa

Abstract

Climate change is considered to be one of a principle reason for spread of invasive alien species. Thus, it is essential to examine potential invasion dynamics of Prosopis juliflora at continental scale under climate change scenario to better guide management of the invasive species. A consensus model derived from five models were used to examine the current and future (2050 and 2070) climatic suitability for P. juliflora under two climate scenarios (RCP4.5 and RCP8.5) in Africa. The mean area under the receiver operating characteristic curve (AUC) and the threshold-dependent true skill statistic (TSS) value of the models were 0.85 and 0.94, respectively, this put the models in the “very good” category. Results showed that temperature related variables were the main determinant factor accounting for 65.7% of the distribution of P. juliflora. Under current climatic scenario, 75.6% of the continent was unsuitable for P. juliflora establishment and invasion while 5.6% was highly suitable. The total suitable areas for P. juliflora under RCP4.5 and RCP8.5 would increase by 2050 and 2070 compared to the current conditions. Meanwhile, a decrease in total unsuitable areas would be expected by 2050 and 2070 under both RCP4.5 and RCP8.5. This study has revealed that; the rates of P. juliflora invasion will expand further inland across Africa as climatic conditions become favourable. Negative environmental and economic impacts caused by P. juliflora will be high if management measures are not earnestly taken. We recommend for a cross-border continental wide effort towards combating P. juliflora expansion to new areas, especially in countries predicted as frontiers of potential expansion.