Opuntia ficus-indica under climatic pressure: evapotranspiration dynamics and adaptive resilience in semi-arid Tunisia

Land degradation and increasing aridity threaten the sustainability of Mediterranean dryland agro-ecosystems, where water scarcity and climate variability are expected to intensify. This study examines the potential of Opuntia ficus-indica (OFI) as a climate-resilient crop in Central Tunisia, analyzing its response to historical and projected hydroclimatic changes and assessing its resilience and water requirements under future climate scenarios. Methods – Observed climate records (19822005) and projections from six bias-corrected CORDEX Regional Climate Models were used to analyze air temperature (Tair) and precipitation variability in the semi-arid regions of Kasserine and Thala. To assess implications for crop water demand, historical and projected crop evapotranspiration (ETc) fluxes of OFI were also analyzed. Results and discussion – Historical hydroclimatic trends reveal significant precipitation declines (up to 55%) accompanied by increasing Tair, indicating ongoing aridification. Future projections (2052–2100) suggest further intensification, with precipitation decreasing by 45–60% and mean annual Tair rising by 0.3–0.7 °C under RCP4.5 and RCP8.5 scenarios. A marked seasonal pattern was observed in ETc, with minimum winter values (0.41–0.50 mm d−1) and summer peaks reaching 4.49 mm day−1 in Kasserine and 4.18 mm d−1 in Thala regions. Future projections indicate moderate increases in ETc of 1–14% under RCP4.5 and up to 18% under RCP8.5 compared with historical conditions. This will lead to summer peaks of 4.69 mm d−1 (RCP4.5) and 4.89 mm d−1 (RCP8.5) in Kasserine, and 4.47 and 4.74 mm d−1 under RCP4.5 and RCP8.5, respectively, in Thala. Under these scenarios, OFI is expected to maintain its ecological tolerance due to its high water-use efficiency, highlighting its potential for climate-resilient agriculture and land restoration in Mediterranean semi-arid environments.