科尔沁沙地固定沙丘系统种子雨时空格局特征

Temporal and spatial patterns of seed rain for stabilized sand dune system in Horqin Sandland of Inner Mongolia,northern China.

该文研究了种子雨在科尔沁沙地西部的固定沙丘系统(包括固定沙丘、过渡带、丘间低地)的时空分布,及其与地上植被的关系。结果表明:固定沙丘系统种子雨密度达到(4 782±894)粒/m2;沿着主风向的方向(即从丘间低地到固定沙丘的方向),种子雨平均密度呈现偏正态的空间格局,而且种子雨密度与地上植物多度之间负相关,但不显著(P>0.05);种子雨密度在每年的10月底达到最大值(6 064±330)粒/m2,到翌年3、5、7月,种子雨密度逐渐递减,并在7月达到最小值(513±48)粒/m2;种子雨密度的年际变化为1.6倍。可见,固定沙丘系统种子雨密度大,季节变异大、波动性强,但是种子雨密度不是固定沙丘系统植被更新的限制因子。

Temporal and spatial patterns of seed rain in stabilized sand dune system （including stabilized dune, ecotone and interdune lowland）, and the relationship between seed rain and aboveground vegetation were explored in this study. The results showed that the density of seed rain in stabilized sand dune system was （4 782 ± 894） seeds /m^2. Along with the main wind direction （i. e. from interdune lowland to stabilized dune） ,the mean density of seed rain was represented with a partial normal distribution pattern, and there was an insignificantly negative relationship between seed rain density and plant abundance （P 〉 0.05 ）. Temporally, seed rain density reached the largest in late Oetober（ （6 064 ±330 ） seeds/m^2）, gradually decreased in March, May, July, and reached the smallest in July of the coming year （（513 ± 48） seeds/m^2）. Furthermore, there was a 1.6-fold between-year difference in seed rain density for the stabilized dune system. These findings suggest that the density of seed rain in stabilized sand dune system is large, and fluctuates strongly among seasons, however, is not a limiting faetor for the vegetation regeneration of stabilized dune system.