不同放牧强度对荒漠草原草地微斑块特征的影响

Effects of Different Grazing Intensities on the Characteristics of Micro-patch of Desert Grassland Meadows

草地植被的斑块化分布是其对自然条件与利用方式长期适应的外在表现。在草地放牧生态系统中,采食、践踏和排泄物沉积等作用都可以引起草地植被变化,导致草地植被异质性。为探究放牧强度对内蒙古荒漠草原斑块特征的影响,本文以四子王旗荒漠草原为研究对象,利用无人机遥感结合野外调查的方法对该草原不同放牧强度下微斑块的特征进行分析,主要结论如下:(1)随放牧强度的增加,草地斑块多趋于细小破碎、空间分布分散的状态,中度放牧区蔓延度指数值最小,为57.41,且景观分离指数和分散指数均为最大,分别是0.74和42.1。(2)随放牧强度的增加,短花针茅(Stipa breviflora)和冷蒿(Artemisia frigida)斑块聚集度提高,空间分布均匀;而无芒隐子草(Cleistogenes songorica)、刺藜(Chenopodium aristatum)斑块的空间分布和形状分散杂乱,抗干扰的能力较差。综上可知,荒漠草原植物群落稳定性的维持可在不同干扰强度或干扰条件变化之间相互转化,来保证其生态系统维持生态功能。

The patchy distribution of grassland vegetation is the external manifestation of its long-term adaptation to natural conditions and utilization methods.In the grassland grazing ecosystem,feeding,trampling and excrement deposition can cause vegetation change and lead to vegetation heterogeneity.In order to explore the influence of grazing intensity on the patch characteristics of desert steppe in Inner Mongolia,this paper took desert steppe of Siziwang Banner as the research object,and analyzed the characteristics of micro-patches under different grazing intensity by using UAV remote sensing combined with field investigation.The main conclusions are as follows:(1)With the increase of grazing intensity,grassland patches tended to be small and fragmented and dispersed in space.The spread index value of moderate grazing area was the smallest(57.41)and the landscape separation index and dispersion index were the largest(0.74 and 42.1,respectively).(2)With the increase of grazing intensity,the patches of Stipa breviflora and Artemisia frigida increased and their spatial distribution was uniform;The spatial distribution and shape of Cleistogenes songorica and Chenopodium aristatum were scattered and disorderly,and the ability of anti-interference was poor.In conclusion,the stability of desert steppe plant communities can be transformed between different disturbance intensities or disturbance conditions to ensure that the ecosystem can maintain ecological functions.