[Suitable summer habitat of the khulan in the Mt. Kalamaili Ungulate Nature Reserve and estimation of its population].

The khulan (Equus hemionus hemionus) is a representative species in desert, semi-desert and desert steppe in Asia. The estimation of suitable habitat and population density of khulan can provide scientific decision-making basis for the conservation management. We investigated the distribution and population density of khulan in the Mt. Kalamaili Ungulate Nature Reserve in Xinjiang during May-August in 2018 and 2019, using the line transect method. The khulan population density, number and the encounter rate were estimated by the Distance 7.0 software, and through the MaxEnt model analysis and combining environmental variables, we assessed the most suitable habitats and main influencing factors. In total, we recorded 4782 individuals from 718 groups and 363 effective occurrences. Our results showed that the suitable summer habitat covered an area of 6737.5 km2, accounting for 45.4% of the total reserve area and located mainly in the central and eas-tern parts of the reserve. We estimated that the density of the summer khulan population was (0.5±0.1) individuals·km-2 and the total khulan population were (3246±575) individuals in the Mt. Kalamaili Ungulate Nature Reserve. The prediction accuracy of MaxEnt model was relatively high, with an average AUC of 0.890. The results of the Jackknife test showed that the distance to water sources, vegetation type, distance to human interference, distance to national highway G216, altitude, and precipitation of driest areas were the most important factors affecting the habitat suitability for khulan. For improving the protection of the khulan population in this reserve, we suggested strengthen the protection of water sources, adjust the core areas, monitor wildlife passages, and enhance traffic construction.