基于微地形的毛乌素沙地飞播杨柴生长特征空间异质性研究

Study on Spatial Heterogeneity of Growth Characteristics of Hedysarum laeve by Aerial Seeding Based on the Microtopography in Mu Us Sandy Land

以毛乌素沙地2002年飞播杨柴灌木林为研究对象,选择一个典型的迎风坡——丘间低地——背风坡连续体,调查了杨柴的生长指标,分析了其基于微地形的空间异质性,结果表明:(1)杨柴株高、冠幅和地径均随着坡位的下降呈明显的减小趋势,并且杨柴个体大小的顺序为背风坡>迎风坡>丘间低地。(2)杨柴单位面积分株数有沿迎风坡——丘间低地——背风坡连续体呈下降的趋势。整体上,杨柴单位面积分株数背风坡最少,而盖度则是迎风坡>背风坡>丘间低地。(3)丘间低地拥有较低的枯枝数、最高的活枝数以及最低的枯枝率,种群活力最高;迎风坡拥有最高的枯枝数、较高的活枝数以及相比背风坡低的枯枝率,种群活力次之;背风坡拥有最低的枯枝数、最低的活枝数以及最高的枯枝率,种群活力最差。(4)单位面积生物量丘间低地>迎风坡>背风坡,并且坡中部杨柴的单位面积生物量在各自的坡向中均是最大。

Taking Hedysarum laeve shrubs by aerial seeding in 2002 in Mu Us Sandy Land as the study object, a typical continuum of windward slope - lowland between hills - leeward slope has been chosen to investigate the growth indexes of Hedysarum laeve and its spatial heterogeneity based on microtopography has been analyzed. The results show ： （ 1 ） Plant height, crown width and ground diameter of H. laeve have obviously decreased with the de- crease of slope, and the order of the individual size of H. laeve is leeward slope 〉 windward slope 〉 lowland be- tween hills. （2） The individual number of H. laeve in unit area presents a downtrend along the typical continuum of windward slope - lowland between hills - leeward slope. On the whole, the individual number of H. laeve in unit area in leeward slope is the least, while the order of coverage is windward slope 〉 leeward slope 〉 lowland between hills. （3） In lowland between hills, the number of dead branches is lower, the number of live branches is the highest, the rate of dead branches is the lowest and the population vitality is the highest. In windward slope, the number of dead branches is the highest, the number of live branches is higher, the rate of dead branches is lower than the one in leeward slope and the population vitality is lower than the one in windward slope. In leeward slope, the number of dead branches, the number of live branches and the population vitality are the lowest, and the rate of dead branches is the highest. （4） The order of biomass of H. laeve in unit area is lowland between hills 〉 windward slope 〉 leeward slope, and the biomass of H. laeve in unit area in middle part of three kinds of slope is the highest.