Maximum Entropy modeling for habitat suitability assessment of Red-crowned crane

Habitat suitability assessment is an important approach for conserving and restoring biodiversity and waterfowl's habitats. Previous habitat suitability index (HSI) models define the weights of each habitat feature subjectively in their approach. To address this problem, we utilized a data-driven Maximum Entropy (MaxEnt) model to assess the fine-scaled habitat suitability of Red-crowned crane (Grus japonensis) in the breeding period based on the occurrence locations of Red-crowned crane and the habitat features derived from optical, radar imagery and topographical ancillary data. Results of this research show that the developed MaxEnt model improves the performances of previous HSI models. The MaxEnt model could identify the influences of the selected habitat features on the habitat suitability of the species and quantify the optimal habitat conditions for the Red-crowned cranes automatically. We found that habitat composition, water depth, and distance to roads and ditches were most important habitat features for Red-crowned cranes in the breeding period. The optimal conditions for each selected habitat features were recognized according to the response curves of environmental variables to occurrence probability of the species. For the breeding Red-crowned cranes, the desirable land cover type of breeding habitat is reed swamp; the suitable depth of water under the canopy is between 15 and 30 cm approximately; the selected vegetation cover is about 47.5%-74.5%; and the suitable distance from human disturbances is above 2500 m. This study demonstrated the practicability of the developed species distribution model (MaxEnt) on habitat suitability assessment for Red-crowned cranes, and provided a quantitative and automatic habitat suitability evaluation method for endangered waterfowl's protection.