基于MaxEnt模型的甘肃安西极旱荒漠国家级自然保护区北山羊生境评估

明晰甘肃安西极旱荒漠国家级自然保护区珍稀濒危物种北山羊的分布格局，并阐释气候变化和人类活动对北山羊的影响，对今后北山羊生境管理和物种保护具有重要意义。基于北山羊实测分布点记录和环境变量数据，结合MaxEnt模型和ArcGIS空间分析功能，利用CMIP6的8个气候模式均值预测中度发展路径（SSP2-4.5）下，基准期（1970-2000年）和未来气候（2041-2060年、2081-2100年）变化情景下，甘肃安西极旱荒漠国家级自然保护区北山羊的潜在适生区分布范围及变化，并综合贡献率和置换重要性值对北山羊生境选择关键环境因子进行了分析。研究结果表明：（1） MaxEnt模型的预测精度较高，三种气候条件下ROC曲线下面积（AUC，Area Under Curve）>0.97，且真实技巧统计（TSS，True Skill Statistic）>0.90，模拟结果可靠。（2）影响北山羊生境选择的主要环境因子为气候条件（降水量季节性变异系数和等温性）、海拔和人为干扰（距泉和居名点距离）。水是保护区北山羊生存的最基本要素，气候条件共同控制北山羊生境条件。此外，北山羊习性决定其生境宜选择高海拔和远离人类活动影响地区。（3）基准期保护区北山羊主要分布在北片和南片高海拔山区，面积365.77 km²（占整个保护区的4.31%），北山羊适生区面积北片>南片、中高等适生区主要位于保护区北片。（4） CMIP6未来气候变化情景下，随着保护区生态环境改善和濒危物种保护措施的实施，北山羊潜在适生区面积呈增加趋势，但是受北山羊近亲繁殖的影响，整体上北山羊数量和适生区面积增加并不显著且有向南部及高海拔地区转移趋势。

Assessment of habitat suitability of Asiatic ibex (Capra sibirica) in the Gansu Anxi Extreme-Arid Desert National Nature Reserve based on MaxEnt model

To clarify the distribution pattern for the rare and endangered wild animals of Asiatic ibex (Capra sibirica) and determin the influence of climate change and human activities to this specises in the Anxi Extreme-Arid Desert National Nature Reserve (AEDNNR) of Gansu Province, have great importance for the future habitat management and species protection. In this paper, based on the field survey points and enviromental variables, the maximum entropy (MaxEnt) model and ArcGIS spatial analysis tools were used to predict the potential distribution and dynamic of Asiatic ibex in AEDNNR. For the nineteen bioclimatic variables, we selected an average of eight global climate models under the intermediate greenhouse gas emissions (SSP2-4.5) for the base period (the years of 1970-2000) and future climate periods (the years of 2041-2060 and 2081-2100). Additionally, the key enviromental factors for the habitat selection of Asiatic ibex were examined by combing the percentage contribution and permutation importance. The results showed that:(1) The prediction accuracy of MaxEnt model was high. The value of AUC (Area Under Curve) > 0.97, and TSS (True Skill Statistic) >0.90, which indicated that the modeling results was reliable. (2) Niche suitability of the Asiatic ibex was dominated by climate conditions (including precipitation seasonalit and Isothermaality), altitude and hunman activities (distance to springs and residential areas). As the basic element for the survival of Asiatic ibex, it control the habitat ecology and enviroment together with climate conditions. Moreover, influenced by the behaviors of Asiatic ibex, it always distributed in the regions with relatively higher altitude and aways from human activities. (3) In the baseline period, Asiatic ibex mainly distributed in the northern and southern regions with higher elevations, which occupied apprimixily 365.77 pa (accounting for 4.31% of the total area of AEDNNR). Saptially, the suitable area for Asiatic ibex in the north is larger than that in the south. The high and middle suitable habitats mian located in the northern AEDNNR. (4) In the future climate scenarios, the suitable areas appeared increasing trends by the eco-enviromental improvement and the implementation of endangered animanls protection measures. However, influenced by inbreeding of Asiatic ibex, the long-term growth of the numbers and suitable areas were not significant. The occupied area increased towards the relatively higher elevation southern regions.