<![CDATA[Abstract. Wulandari AA, Agustina AT, Aulia AD, Safaraz BR, Mukarromah AN, Dzihni A, Azzam AK, Hafiffah AS, Sulton MN, Setyawan AD. 2026. Climate-associated shifts in potential habitat of the vulnerable tree Eusideroxylon zwageri in Southeast Asia using an exploratory MaxEnt assessment. Nusantara Bioscience 18 (1): n180107. https://doi.org/10.13057/nusbiosci/n180107. Eusideroxylon zwageri (Bornean ironwood) is a slow-regenerating, high-value rainforest tree threatened by timber extraction, habitat conversion, and climate change. We examined its current and future potential habitat in Southeast Asia using an archived MaxEnt workflow based on 57 GBIF occurrence records and 18 climatic, topographic, edaphic, vegetation, radiation, and anthropogenic predictors. Baseline climate was represented by WorldClim variables, whereas projections used HadGEM2-ES conditions for 2030, 2050, and 2080 under RCP 2.6, 4.5, 6.0, and 8.5. The baseline model had an AUC of 0.91. Precipitation of the driest quarter contributed 57.40%, followed by human population density (9.85%), minimum temperature of the coldest month (9.43%), and annual temperature range (7.78%). Under baseline conditions, high-suitability habitat occupied 0.22×106 km2 (5.16% of the modeled region), principally in Borneo, Sumatra, Brunei Darussalam, and Peninsular Malaysia. Across future scenarios, total modeled area remained approximately constant (4.25-4.28×106 km2), but the distribution among suitability classes changed; high suitability ranged from 4.94% to 6.82%. Within Borneo, high suitability ranged from 22.35% to 38.06%, and the 2080 suitability centroid shifted 7.81-66.54 km depending on the RCP. These outputs indicate redistribution of modeled environmental suitability, not demonstrated adaptation, occupancy, or population persistence. The maps are therefore appropriate for regional screening but require confirmation through bias-corrected occurrence data, spatially independent validation, multiple climate models, model-tuning and extrapolation diagnostics, dynamic land-cover scenarios, and field assessment before site-level conservation decisions.]]>
