科尔沁沙地流动沙丘3种常见植物的空间分布格局与异速生长

Spatial distribution pattern and allometric growth of three common species on moving sand dunes in Horqin Sandy Land,China

研究流动沙丘上物种小尺度分布格局和植物异速分配特点有助于理解植物在流动沙丘生境上的适应策略.调查了科尔沁沙地28个1 m×1 m样方内沙蓬、烛台虫实和狗尾草3个物种的位置、多度、高度以及生物量信息.采用最近邻体法与O-ring O（r）函数方法进行空间格局分析.结果表明：在1 m×1 m样方内,群落水平上植物个体间以聚集分布为主,而在种群水平上物种大体以随机分布为主;个体间距离在0-50 cm范围内无论种内还是种间,它们以互助作用为主,在特定尺度上物种出现聚集分布并随1 m×1 m样方内植物多度增加而变化.在0-40 cm内,沙蓬和狗尾草聚集分布增加;在10-20 cm内,3个物种的种内和种间聚集均增加;在10-30 cm内,狗尾草与沙蓬、烛台虫实出现种间正相关的概率增加;在40-50 cm内,沙蓬与烛台虫实以及沙蓬与狗尾草出现正相关的概率增加.物种构件结果表明：3个物种地上部分生长速度显著大于地下部分,狗尾草根冠比最大且营养器官的生物量比例居中,烛台虫实分配给生殖器官和茎的生物量比重较大,沙蓬分配给营养器官的比重较大.结合小尺度上的格局分析与构件分配特点,可以推断3种植物是典型的r对策者.

Research on fine scale pattern and characteristics of allometric growth could contribute to better understanding plants＇ adaptation in moving sandy dunes. The abundance,height and biomass of 3 species Agriophllum aquarrosum,Corispermum candelabrum and Setaria viridis in twentyeight 1 m × 1 m quadrats of Horqin Sandy Land were identified,mapped and described. The nearest neighbor method and O-ring O（ r） function analysis were applied to analyze the spatial patterns. The results showed that the individual spatial pattern was mainly aggregated in 1 m × 1 m quadrat at community level but mainly random at population level. At 0- 50 cm individual distance scale,both intraspecific and interspecific relationship were facilitation and aggregated distribution occurred at some scales and varied with increasing plant abundance in 1 m × 1 m quadrat. In 0- 40 cm,the aggregated distribution of S. viridis and A. aquarrosum increased obviously; in 10- 20 cm,both intraspecific and interspecific aggregation increased; in 10- 30 cm,the occurrence possibility of positive correlations between S. viridis and A. aquarrosum,S. viridis and C. candelabrum all increased; in 40- 50 cm,the possibility of positive correlations between A. squarrosum and S.viridis,A. squarrosum and C. candelabrum all increased. Research on the three species components indicated that the growth rate of above-ground was faster than that of underground. S. viridis had the highest ratio of under-ground biomass to above-ground biomass but its nutritional organs＇ biomass ratio was medium. C. candelabrum allocated more biomass to propagative organs and stem,but A. squarrosum allocated more biomass to nutritional organs. Based on the spatial distribution and allometric characteristics,the three common species in moving sand dunes preferred r strategy in their life history.