基于MaxEnt模拟人类活动与环境因子对青藏高原特有植物祁连獐牙菜潜在分布的影响

以青藏高原特有植物祁连獐牙菜(Swertia przewalskii Pissjauk.)为材料,基于该物种18个种群分布点及8个生物气候变量、海拔变量以及人类活动强度变量,运用最大熵模型(Max Ent)和ArcGIS技术分别构建当前气候情景下及人类活动影响下祁连獐牙菜的适宜生境预测模型,研究人类活动及自然环境变量对祁连獐牙菜空间分布的影响。结果显示,人类活动影响下的训练集和测试集的AUC值均小于无人类活动干扰的AUC值,人类活动与祁连獐牙菜分布呈负相关。限制祁连獐牙菜分布的主要变量为海拔、等温性、人类活动足迹指数及平均温度日较差。当前气候情景下祁连獐牙菜的最适宜生境占祁连山国家公园青海片区总面积的36.6%,有利于该物种的保护和恢复,而位于门源县和祁连县保护区内一般控制区的潜在生境受到人为干扰的可能性较大,应加强关注和保护。

Impacts of human activities and environmental factors on potential distribution of Swertia przewalskii Pissjauk., an endemic plant in Qing-Tibetan Plateau,using MaxEnt

In this paper, the distribution of potentially suitable habitat of Swertia przewalskii Pissjauk., an endemic and endangered plant in the Qing-Tibetan Plateau, was studied to provide a scientific basis for effective conservation. This study was based on 18 occurrence records and eight environmental variables, including human activity, bioclimate, and altitude. We used the maximum entropy model and ArcGIS spatial analysis to construct a suitable habitat prediction model for S. przewalskii under the influence of modern climate scenarios and human activities and analyzed the influences of human activities and natural environmental factors, respectively. Results showed that the AUC of the test set under human activity interference was lower than that under no human activity interference. Human activities exerted negative impact on the potential distribution of S. przewalskii. Altitude, isothermality, human footprint index, and mean diurnal range were the main environmental factors influencing the distribution of S. przewalskii. At present, the most suitable habitat included 36.6% of the Qilianshan National Park area (Qinghai), which should benefit species conservation. However, the potential habitat in the utilization zones of the Qilian and Menyuan counties may be disturbed by human activities. We suggest policy makers focus greater attention on these utilization zones and increase conservation efforts.