内蒙古退化草原狼毒种子的种群分布格局与散布机制  

Spatial distribution patterns and dispersal mechanisms of the seed population of Stellera chamaejasme on degraded grasslands in Inner Mongolia, China

作　　者：邢福[1] 王艳红[1] 郭继勋[1] 

机构地区：[1]东北师范大学草地科学研究所,植被生态教育部重点实验室,长春130024

出　　处：《生态学报》2004年第1期143-148,共6页Acta Ecologica Sinica

基　　金：国家重点基础研究发展规划资助项目 (G2 0 0 0 0 1860 6) ;国家自然科学基金资助项目 (3 0 170 668)~~

摘　　要：狼毒 (Stellera chamaejasme)为瑞香科多年生草本植物 ,是主要的草地有毒植物种类之一。采用邻接格子样方法和分布指数 (DI)以及平均拥挤度 (m* )指标 ,研究了内蒙古西辽河平原北部典型草原区内的狼毒 (Stellera chamaejasme)种子种群分布格局强度、类型与规模 ;根据顺序远离母株的取样调查 ,定量地分析了狼毒种子在 8个方向上的散布格局。结果表明 ,狼毒种子在落种期之前为随机分布 ,而在落种期结束后为聚集分布 ,种子种群斑块大小平均为 0 .0 8m2 。狼毒种子在 8个方向上的散布表现为不同的散布格局模式。在不同方向随着累积面积增加狼毒种子散布数量变化符合 L ogistic曲线增长。各方向种子散布数量与顺风风向频率显著正相关。狼毒种群具有“近母株散布”的种子散布机制 ,基本散布半径为 0～ 5 0 cm。Stellera chamaejasme is a perennial herbaceous plant of Thymelaceae. It is poisonous to herbivores and widely distributes on grasslands in Northern and Northwestern China. S. chamaejasme population increases rapidly on degraded grasslands, which can negatively affect the health of livestock. The objective of this study was to determine the distribution and dispersal patterns of S. chamaejasme seed population, to determine its spatial dynamics and to provide baseline for its control.The research site was located at a typical steppe in Alukerqin County, Chifeng Prefecture, Inner Mongolia (120°25′E, 43°43′N). Vegetation is S. chamaejasme + Enneapogon borealis associationand with S. chamaejasme being the dominant species. The sampling of soil seed bank was conducted both before and after the onset of seed disprsal of S. chamaejasme (early May and late June, respectively) with the Contiguous Grid Quadrat (CGQ) design. Seeds were separated from soil samples using a sieve with apertures of 0.45 mm and then counted. Seed distribution pattern of S. chamaejasme was measured by the two parameters, dispersion index (DI) and mean crowding index (m~*), and tested for Poisson and Negative Binomial Distribution using χ~2 test. Data were analyzed with the Greig-Smith's method——Paired Quadrat Variance (PQV). Eight directions (E, S, W, N, NE, SE, SW and NW) were selected from the basal tiller of S. chamaejasme for seed dispersion. Soil samples were collected from the basal tiller along each direction at 5 cm intervals. Correlation analysis was conducted between total seed density at different sampling directions and tail wind frequency, and between seed density and mean wind speed.Results show that before the onset of seed dispersal, the distribution of seed population of S. chamaejasme was random, but the distribution was aggregated distribution after seeds had been dispersed. The dispersion indices were 1.16 and 1.70, respectively, for seeds before and after dispersal, and mean patch size for seed population was

关 键 词：狼毒 种子种群 分布格局 散布机制 

分 类 号：Q948.1[生物学—植物学]