甘肃民勤不同演化阶段白刺灌丛沙堆分布格局及特征

通过对甘肃民勤不同演化阶段灌丛沙堆的调查,研究了其空间格局、形态和表层土壤水分特征及其差异,并对研究区的生态环境现状进行了分析。结果表明,研究区灌丛沙堆以稳定阶段为主,但这种稳定状态可能是暂时的,随着距离沙丘距离的变化,不同演化阶段灌丛沙堆呈现出有规律的分布,植被、表层土壤水分以及风力的相互作用是引起这种分布的主要原因。随着灌丛沙堆的演化,灌丛沙堆的形态参数呈现不同的变化趋势,雏形阶段灌丛沙堆的高度与水平尺度之间无明显相关性,发育阶段灌丛沙堆高度随水平尺度的增加呈现二次函数增长,稳定阶段灌丛沙堆高度随水平尺度的增加呈现对数函数增长,活化阶段灌丛沙堆高度与水平尺度的相关性较差。

Distribution patterns and characteristics of Nitraria tangutorun nebkha at its different evolvement stages in the Minqin County of Gansu Province

After a thorough investigation on the Nitraria tangutorun nebkhas at its different evolvement stages in the Minqin County of Gansu Province, this paper studied the spatial pattern and shape index of the nebkha, with the local environmental conditions analyzed. The results showed that the N. tangutorun nebkha in Minqin County was mainly at its stable stage, although this stage could not last too long. With the increase of the distance from dune, the nebkha at its different evolvement stages had a regular distribution, and the main reason for this was the interaction among vegetation, surface soil water, and wind. The shape index of the nebkha showed different variation trends with evolvement stage, i.e., no obvious correlation between height and horizontal component at rudimental stage, a second-order polynomial increase of height with increasing horizontal component at developing stage, a logarithmic increase of height with increasing horizontal component at stabilizing stage, and poor correlation between height and horizontal component at degrading stage.