唐家河国家级自然保护区川金丝猴生境适宜性评价

生境适宜性评价是濒危物种保护的重要基础。川金丝猴（Rhinopithecus roxellana）是栖息于温带森林的、中国特有的珍稀灵长类动物。位于岷山山系的四川唐家河国家级自然保护区是川金丝猴的重要分布地之一，但涉及该地区川金丝猴的生境信息却较缺乏。运用最大熵（Maximum entropy，MaxEnt）模型对四川唐家河国家级自然保护区川金丝猴不同季节的生境适宜性进行了研究，发现四个季节的训练集和验证集的受试者工作特征曲线下面积（Area under the receiver operator characteristic curve，AUC）值均超过0.8，说明模型预测结果较好。结果显示：（1）影响不同季节川金丝猴分布的主要因子是海拔、河流和道路。（2）川金丝猴的适宜生境面积存在季节性变化。其中，春季的适宜生境面积最大，为233.94 km²，占全区面积的58.48%；夏季的次之，为192.75 km²，占48.19%；秋冬季的适宜生境面积相对较低，分别为145.54 km²（占36.39%）和142.63 km²（占35.66%）。（3）川金丝猴的适宜生境分布具有明显的季节性垂直变化。研究揭示保护好完整的森林植被带对川金丝猴的生存具有重要意义，尤其要重视对人为干扰较强的低海拔生境的保护。

Habitat suitability assessment of Rhinopithecus roxellana in Tangjiahe National Nature Reserve

Information on the spatial temporal dynamics of wildlife habitat suitability is critical for conservation. Sichuan snub-nosed monkey (Rhinopithecus roxellana) is a rare and precious primate endemic to China, living in temperate forests on mountains in Sichuan, Gansu, Shanxi and Hubei Province. Sichuan Tangjiahe National Nature Reserve is located in Minshan Mountains, which is one of the important distribution areas for Sichuan snub-nosed monkey. However, little is known about the spatial distribution of the habitat of Sichuan snub-nosed monkeys and its changes across different seasons in this area. Here, we generated seasonal distribution maps of habitat suitability of Sichuan snub-nosed monkeys in Sichuan Tangjiahe National Nature Reserve by integrating field data, remote sensing imagery, and the maximum entropy (MaxEnt) model. Between 2017 and 2018, occurrence sites global position system(GPS)coordinates of Sichuan snub-nosed monkey were collected by line transect surveys and patrol data from Sichuan Tangjiahe National Nature Reserve, China. A total of 536 occurrence sites of Sichuan snub-nosed monkey were used in the habitat modeling, including 149 records in spring, 94 records in summer, 115 records in autumn and 178 records in winter. The environmental variables used in the modeling can be divided into three categories, including terrain factors (slope, aspect and elevation) extracted from the Digital Elevation Model (DEM), vegetation factor extracted from the Thematic Mapper, and other factors (road and water source) extracted from the 1: 50000 vector maps of Sichuan Tangjiahe National Nature Reserve. The assessment results of receiver operating characteristic curve (ROC) show that the area under the curve (AUC) values of training data and test data in four seasons are more than 0.8, which indicates the habitat modeling results are good. We identified three main factors affecting the habitat distribution of Sichuan snub-nosed monkeys in different seasons, including altitude (accounting for 41.1% in spring, 34.4% in summer, 38.7% in autumn and 13.6% in winter), distance from the river (accounting for 33.3% in spring, 18.8% in summer, 12.9% in autumn and 40.2% in winter), and proximity to road (accounting for 5.9% in spring, 17% in summer, 32% in autumn and 30.9% in winter). There are seasonal variations in the suitable habitat area of Sichuan snub-nosed monkeys. In spring, the potential habitat area reaches its maximum of 233.94 km², accounting for 58.48% of the nature reserve. It decreases to 192.75 km² (48.19% of the reserves) in summer, 145.54 km² (36.39%) in autumn, and reaches its minimum of 142.63 km² (35.66%) in winter. The habitat distribution of Sichuan snub-nosed monkeys in the reserve exhibits obvious seasonal shift across different altitude ranges. In summer, the altitude of suitable habitat is within 1900 m to 2800m, but in the winter it is below 2400 m. The results highlight that it is important to protect the complete forest vegetation belts for the survival of Sichuan snub-nosed monkeys, and special attention should also be paid to the protection of the habitat of Sichuan snub-nosed monkeys at lower altitudes, where human disturbance is stronger in Sichuan Tangjiahe National Nature Reserve.