Abstract The presence of plant species in a certain habitat can be predicted if the ecological range of the species is known and its habitat conditions are determined. This research explored the habitat suitability of the endangered species Hedysarum criniferum in eight natural habitats in Iran using fuzzy logic. We eva‎luated the potential and efficiency of the fuzzy method in predicting H. criniferum habitat suitability by eva‎luating the success of field-sowing of the seeds in habitats with different habitat suitability classes. In this regard, 24 environmental variables (soil, climate and topography) of the eight natural habitats and the plant species cover percentage were measured. The response of the species to these environmental variables was also explored by the eHOF model. The environmental parameters were examined and grouped using the equal distance method and were valued by the fuzzy logic. The most important environmental factors influencing species distribution and the species response curves were determined by principal component analysis (PCA) and the generalized linear model, respectively. Then, the optimal growth conditions and the tolerance ranges of the studied species for the environmental factors were specified, and each range was divided into 11 classes with fuzzy values, and the fuzzy function of the environmental factors was developed. To test and validate the fuzzy model, three regions where the studied species did not exist were selected, their soil, climatic, and topographical factors were studied, their fuzzy suitability was determined, and the germination viability and seedling growth length in these habitats were used as the criteria to validate the suitability. The PCA results showed that the distribution of H. criniferum was most effectively influenced by Mg, K, Ca, and pH among soil factors, wind speed and minimum temperature among climatic factors, and slope and elevation among the topographical factors. According to the results of the eHOF model, the likelihood of H. criniferum presence exhibited an ascending behavior toward the variables of precipitation and elevation and a descending behavior toward the variables of mean annual temperature, minimum annual temperature, gravels, whereas its behavior towards pH was sine-shaped. The fuzzy validation results revealed that the seedling length and germination percentage significantly differed between the habitat with fuzzy suitability of 0.6 and the habitats with fuzzy suitability of 0.5 and 0.3 (p < 0.05). Also, seedling length had a strong significant correlation with the predicted suitability (R2 = 82%). The method used in this research to predict suitable habitats can be applied to other endangered species in different ecosystems. The results of the species cultivation showed that the irrigation period had a significant effect on the length of the germinated seedlings and the percentage of germination of H. criniferum (α = 5%), so that the highest percentage of germination and the height of the sprouted seedlings was observed during the 7-day irrigation period. During this irrigation period, the average height of seedlings was 4.93 cm and seed germination was estimated at 77.77%. The method used in this study can be employed in predicting optimal habitats for other endangered species in different ecosystems.

حميد متين خواه , حسين بشري

مصطفي تركش اصفهاني , حميدرضا كريم زاده

محمد رضا وهابي , رضا جعفري , شمس اله ايوبي