气候变化和人类活动干扰下骆驼刺潜在分布格局变化特征

气候变化和人类活动是影响物种分布的最重要因素。骆驼刺是我国荒漠区的重要建群种，建群种的丧失将对荒漠生态系统产生严重损伤。因此预测气候变化和人类活动影响下骆驼刺适宜生境的变化特点对保护我国荒漠生态系统具有重要的意义。本研究采用61个骆驼分布点数据，和21个环境因子数据，运用最大熵模型（MaxEnt）预测骆驼刺当前在有、无人类活动干扰下的适宜生境分布，对影响其分布的环境因素进行了评估。并预测未来（2021-2040，2041-2060，2061-2080，2081-2100）四条共享社会经济路径（SSP126，SSP245，SSP370，SSP585）情景下，骆驼刺潜在分布区的变化特点。研究结果表明，在无人类活动干扰的情况下，骆驼刺适生区面积达132.29万km²，覆盖我国西北干旱区的大部分面积。年均降水量、最冷季度平均温、平均气温日较差、年均温、温度季节性、降水的季节性和高程被确定为影响骆驼刺潜在分布区的最重要因素。而在加入人类活动强度因素之后，骆驼刺适生区面积显著下降至71.31万km²，且呈现出破碎化状态。此时，年降水量、人类活动强度和高程是影响骆驼刺分布的最重要原因。在未来气候情景下，骆驼刺的适生区将产生一定的扩张。尤其在中高强迫（SSP370）和高强迫（SSP585）情景下，骆驼刺的适生面积将随时间推移产生显著的增加，且这种扩张主要向高纬度和高海拔地区发展。骆驼刺能保留大部分原有生境，仅在内蒙古中西部地区发生少量收缩。在气候变化条件下，骆驼刺能够在西北干旱区生存并扩张，故可将其作为防沙治沙的优良物种进行保护与开发。

Variation characteristics of potential distribution patterns of Alhagi sparsifolia Shap. under climate change and human disturbance

Climate change and human disturbance are important factors affecting species distribution. Alhagi sparsifolia Shap. is an important construction species in desert areas of China. The loss of the construction species will cause serious disruption to the balance of desert ecosystems. Therefore, predicting the changes of suitable habitat under climate change and human disturbance is of great significance for the conservation and development of the species. In this study, 61 geographical distribution data and 21 environmental variables were used to predict the appropriate distribution of A. sparsifolia with or without human disturbance. In addition, the change characteristics of distribution areas of A. sparsifolia under four shared socio-economic paths (SSP126, SSP245, SSP370, SSP585) were predicted in the future (2021-2040, 2041-2060, 2061-2080, and 2081-2100). The results showed that without the human disturbance, the suitable area of A. sparsifolia was 1.32 million km², covering most of the arid area of northwestern China. The annual precipitation, mean temperature of the coldest quarter, mean diurnal range, annual mean temperature, temperature seasonality, precipitation seasonality and elevation were the most important environmental variables affecting the distribution of A. sparsifolia. Considering the influence of human disturbance, the distribution area of A. sparsifolia reduced to 0.71 million km², showing a state of fragmentation. In this case, the annual precipitation, human activity intensity and elevation were the most important factors affecting the distribution of A. sparsifolia. The projected suitable areas of A. sparsifolia under different SSPs scenarios may be enlarged. Especially under SSP370 and SSP585 scenarios, the projected suitable area of A. sparsifolia would increase significantly with time, and the expansion area mainly developed to high latitudes and altitudes areas. The habitat of A. sparsifolia shrank a little in the middle and western part of Inner Mongolia. A. sparsifolia can survive in the arid area of northwestern China under climate change, so it is an excellent species for desertification protection and development.