Geospatial modelling of Agro-climatic suitability for Coffea arabica under CMIP6 scenarios in the Western Highlands of Ethiopia

Coffea arabica holds utmost economic and cultural significance for Ethiopians, being one of the major sources of national income and rural livelihoods. However, slight warming or changes in rainfall have catastrophic effects on the land suitability for cultivation and threaten the species. This study aimed to assess climate change impacts on a species’ land suitability across tropic agro-ecological zones (Wwarm/Hubhumid, Warm/Humid, Cool/Sub-humid, and Cool/Sub-humid) of western Ethiopia, using baseline conditions (1981-2010) and future climate scenarios (2041-2070) under the Shared Socioeconomic Pathways (SSP1-2.6, SSP3-7.0, and SSP5-8.5). Climate data were obtained from CHELSA, species occurrence data were collected through field surveys for the present, and data from the Global Biodiversity Information Facility were used for the last 30 years. A digital elevation model was also sourced from the USGS Website. Data quality control (multicollinearity) was tested to ensure variable independence. First, the MaxEnt model was used to predict the potential distribution and habitat suitability of Coffea arabica , and its outcomes were further refined by the ANN model, which evaluated the species' response to current and projected climate scenarios. The maximum entropy (MaxEnt) model was used for projecting species distribution, while the Artificial Neural Network (ANN) model was used for species response modelling. Results show that C. arabica suitability exhibits varied changes by agro-ecological zones, increasing under SSP1-2.6 (+18.9%) and SSP3-7.0 (+9.0%) but marginally decreasing under SSP5-8.5 (-2.0%). Future coffee suitability shows gains in tropical-warm/humid zones and major losses in tropical-warm/sub-humid areas. Suitability increases with altitude but decreases with higher precipitation seasonality across all scenarios. Farmers should integrate shade trees, adopt drought-tolerant varieties, and conserve soil moisture while gradually shifting coffee to higher altitudes.