PDF HTML阅读 XML下载 导出引用 引用提醒 巴丹吉林沙漠东缘天然梭梭种群空间分布异质性 DOI: 10.5846/stxb201411142250 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院西部之光项目(内蒙古中西部荒漠草原地表粗粒化过程研究);内蒙古自然基金资助项目(2013MS0613);内蒙古农业大学优秀青年科学基金资助项目(2014XYQ-8) Spatial heterogeneity of natural Haloxylon ammodendron Populations at Ta-Mu-Su, Badain Jaran Desert, China Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:梭梭(Haloxylon ammodendron (C. A. Mey.) Bunge)是生长于沙漠地区的一种特有灌木,在维持荒漠生态系统平衡和地区经济发展中发挥着不可替代的作用。为掌握天然梭梭种群空间分布规律,以巴丹吉林沙漠东缘塔木素地区的“野生肉苁蓉及梭梭产籽基地”为试验区,采用样线法测定梭梭株高、冠幅直径,统计梭梭分布密度,分析梭梭种群数量特征空间分布特征及其与生境之间的关系。结果表明:梭梭林密度、株高、冠幅直径均符合正态分布,表现为强度变异;株高、密度、冠幅直径的半方差函数理论模型均为高斯理论模型,其相应的变程为1249、909、1035 m;空间自相关比例均超过70%,受随机因素影响较小,保持着较好的天然分布和生长状态。梭梭种群数量特征的分形维数均大于1.5,空间依赖性强,空间结构性好。长期风蚀作用,小地形海拔高度体现为不同沙层厚度,梭梭株高、冠幅直径和密度在空间上的分布呈西高东低,北高南低的趋势,与海拔高度存在极显著相关;梭梭群落的空间异质性表现出一定的适度沙埋效应。 Abstract:The Badain Jaran Desert, located in a temperate arid region, is characterized by some of the tallest stationary dunes on Earth. Often, these dunes support the growth of unique vegetation species, such as Haloxylon ammodendron (C. A. Mey.) Bunge. Haloxylon ammodendron, a shrub indigenous to the area, is of high socio-ecological importance and has the following functions: desertification control, improving soil quality in degraded areas, and supporting local economic development. Although the socio-ecological importance of Haloxylon ammodendron is well-understood, very few studies have addressed the spatial heterogeneity in the soil and vegetation at different scales in this landscape and its role in desertification dynamics. We conducted extensive replicated field experiments in Ta-Mu-Su at the east edge of the Badain Jaran Desert in order to examine the spatial distribution of Haloxylon ammodendron and the relationship between quantitative plant characteristics and altitude. We hypothesized that the spatial heterogeneity in the soil and vegetation in this landscape could be used as an indicator for desertification. We designed experimental plots (area, 192 hm2) with natural Haloxylon ammodendron shrubs as the dominant vegetation type. We investigated the relationship between the spatial heterogeneity of shrub distribution and thickness of sand deposition. We measured plant growth indicators such as plant density, height, and crown diameter. We measured plant growth parameters during the growing season (months) by using the line transect method, recorded plant coordinates, and monitored plant growth parameters along the transect line. The collected data were integrated into a global positioning system simultaneously, and statistical methods were used to analyze the spatial distribution and heterogeneity of natural vegetation. Our results suggest a normal distribution in plant height, crown diameter, and density with corresponding coefficients of 43.8%, 36.4%, and 36.38%, respectively, indicating an intensive spatial variation in plant growth parameters. The semi-variance optimal function of population characteristics and altitude plots was Gaussian; the semi-variance functions of height, crown diameter, and density were 1249 m, 909 m, and 1035 m, respectively; and spatial variation in crown diameter was significant with the highest C0+C caused by random factors, where C0 is the nugget or variability not explained by distance and C is the spatial heterogeneity caused by autocorrelation factors. Spatial heterogeneity of the plant characteristics was autocorrelated with a structure ratio, C/(C0+C), of more than 70%. The large structure ratio suggests that Haloxylon ammodendron maintains a natural distribution with few disturbances. The fractal dimension was greater than 1.5, which suggests that the spatial structure of Haloxylon ammodendron was simple with strong spatial dependence. Significant positive correlation was observed between plant height and crown diameter (0.8771). Accelerated wind erosion resulted in decreased sand thickness along the prevailing wind direction (west-east and north-south) across the spatial domain. Plant height, crown diameter, and density also decreased along the direction of the prevailing winds. Overall, the spatial heterogeneity observed in our study suggests that sand deposition favors the growth and development of Haloxylon ammodendron. 参考文献 相似文献 引证文献