荒漠草原优势种群油蒿空间分布格局对封育恢复的响应  

Responses of spatial distribution pattern of the dominant population Artemisia ordosica to enclosure restoration in desert steppe

作　　者：刘建康 冯湘 张克斌[2] 刘淑琴 刘新月 LIU Jian-kang;FENG Xiang;ZHANG Ke-bin;LIU Shu-qin;LIU Xin-yue(Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Key Laborato-ry for Restoration and Reconstruction of Degraded Ecosystem in Northwest China of Ministry of Education,Ningxia University,Yinchuan 750021,China;Key Laboratory of State Forestry Administration on Soil and Water Conservation/Ministry of Education Engineering Research Center of Forestry Ecological Engineering,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]宁夏大学,西北土地退化与生态恢复国家重点实验室培育基地/西北退化生态系统恢复与重建教育部重点实验室,银川750021 [2]北京林业大学,水土保持国家林业局重点实验室/林业生态工程教育部工程研究中心,北京100083

出　　处：《应用生态学报》2022年第3期720-726,共7页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(32001117);宁夏自然科学基金项目(2020AAC03085);宁夏高等学校一流学科建设项目(NXYLXK2017B06)资助。

摘　　要：灌木对维持草原生物多样性、稳定性及生态服务功能等具有重要作用,探究封育措施对优势灌木种群的影响,可为草原恢复和抚育管理提供科学指导。本研究对荒漠草原4个封育时间(封育0、5、15、25年)的优势种群油蒿个体特征及种群空间分布格局进行研究。结果表明:油蒿种群密度随着封育时间延长先增加后降低,封育15年时最高,为未封育样地的3.7倍;冠幅和投影面积变化趋势与密度正好相反,封育15年后分别减少了31.7%和52.3%;封育5年后个体高度减小了25.3%,之后逐步增加;半方差函数分析表明,各样地油蒿种群分布均符合高斯模型,封育初期种群空间异质性逐渐降低,封育15年后又有所增加。各样地结构比均高于0.75,而块金值相对较小,表明油蒿种群空间自相关性较高,空间分布格局受结构性因素影响较大,受随机性因素影响较小。油蒿种群呈斑块状和条带状空间分布,封育可降低种群小尺度空间变异程度,但封育25年后随着斑块分离,种群空间异质性及尺度依赖性又有所增强。恢复时间是影响荒漠草原优势种群生长及分布的关键因子,长期封育导致优势种群空间异质性增强,建议在封育15年后对草地进行适度人为干预。Shrubs play an important role in maintaining biodiversity,stability and ecological service in grassland.Exploring the effects of enclosure on dominant shrub population can provide scientific guidance for grassland restoration and tending management.In this study,we investigated main growth characteristics and spatial distribution pattern of Artemisia ordosica population in four enclosed grasslands with duration of 0,5,15,and 25 years.The results showed that population density increased first and then decreased with time extension,and peaked after enclosed for 15 years,which was 3.7 times that of unenclosed plot.The crown and projected area showed opposite responses trend to that of density,which decreased by 31.7%and 52.3%after enclosed 15 years,respectively.The height decreased by 25.3%after 5 years of enclosure,and then increased gradually.Semi-variance function analysis showed that population distribution in all grasslands conformed to Gaussian model.The spatial variation decreased gradually in the early stage of enclosure,and then increased after enclosed for 15 years.Structure ratio in each plot was higher than 0.75,but nugget was relatively small,indicating that spatial autocorrelation of population was mainly affected by structural factors rather than random factors.Spatial distribution of A.ordosica population was patchy and striped.Enclosure reduced spatial variation of population at small scale.However,spatial heterogeneity and scale dependence of population enhanced after enclosed 25 years as plaque dissociating.Our findings suggest that enclosure duration is the key factor affecting plant growth and spatial distribution of dominant population in desert steppe.Long-term fencing enhances the spatial heterogeneity of dominant population.Appropriate human intervention should be carried out after 15 years of enclosure.

关 键 词：空间分布格局 封育 荒漠草原 油蒿 种群特征 

分 类 号：S812[农业科学—草业科学]