Impacts of Climate Change on the Distribution of African Wild Olive Tree in the Arid Environments of Northern Ethiopia

Abstract

Climate change is impacting the sustainability of indigenous tree species. However, the impacts of climate change on African olive tree (Olea europaea subspecies Cuspidata) are less-explored. Tis study, conducted in Tigray, northern Ethiopia, aims to determine the impacts of climate change on the current and future distributions of the species. A total of 225 presence points and abundance of O. europaea within 20 m × 20 m plots at each location were collected. Additional input variables, such as the 19 bioclimatic variables, 3 topographic variables, and Pedologic data, were used. Maxent software was employed to predict the distribution of the species under current and future climate scenarios. Te correlation between the tree’s abundance and environmental factors was ascertained using Spearman’s correlation. Te fndings indicated that the most crucial factors afecting the distribution of the tree were temperature seasonality, altitude, and precipitations during the driest month. Te current range of the species covered 1979 km2 (3.01%) of Tigray. Tis coverage is expected to increase by 13.64% under 2070_RCP4.5 scenario. However, under 2070_RCP8.5, a total loss of suitable habitats is anticipated. Rainfall, slope, altitude, soil organic carbon, and silt contents had a positive correlation with the species abundance, whereas sand, clay, bulk density, and soil pH had a negative correlation (p < 0.05). In conclusion, the species may locally disappear due to the adverse effects of future climate change under the RCP8.5. Hence, the study recommends immediate in situ and ex situ conservation eforts to sustain the populations and important values of the tree