Modeling habitat suitability for Calligonum species using remote sensing and environmental data to support desert reclamation in central Iran

Species Distribution Models (SDMs) are key tools in conservation science, relating species occurrence records to environmental variables to predict potential habitat distribution. This study aimed to identify suitable habitats for three species— Calligonum comosum, C. persicum , and C. bungei — that are valued for desert reclamation and sand stabilization by integrating remote sensing indices with SDMs and assessing the environmental factors influencing their distribution in the Gavkhouni sub-basin of Central Iran. The dataset comprised 33 environmental variables, including 14 remote sensing indices from Landsat 8 OLI–TIRS imagery, 15 soil physical and chemical characteristics, three topographic parameters, and one variable representing distance to sandy hills, along with 92 species occurrence points. Ten SDMs and an ensemble model were applied. The ensemble model outperformed all individual SDMs, achieving Area Under the Curve (AUC) values of 0.98–0.99 and True Skill Statistic (TSS) values of 0.97–0.99 for all three species. This study offers a novel contribution by simultaneously modeling multiple Calligonum species in an arid region using a comprehensive set of predictors, revealing the underexplored importance of soil variables in shaping their distribution. Sensitivity analyses indicated that distance to sandy hills, pOH, sulfate (SO₄²⁻), and pH were key predictors for C. comosum ; Tasseled Cap Brightness Index, elevation, and soil calcium sulfate (CaSO₄) were most influential for C. persicum ; and sodium, calcium carbonate (CaCO₃), and bicarbonate (HCO₃⁻) were primary determinants for C. bungei . Habitat suitability maps showed that 11% of the study area was suitable for Calligonum species, with high-suitability areas for C. comosum, C. persicum , and C. bungei covering approximately 375, 27, and 14 km², respectively. By identifying the key soil variables shaping the distribution of multiple Calligonum species, this study provides targeted guidance for managing soil health and monitoring critical properties, thereby supporting effective conservation planning and enhancing desert reclamation and sand stabilization in arid regions.