北砸山沙冬青种群分布格局与群落特征

Distribution Pattern and Characteristics of Ammopiptanthus Mongolicus Population in Beiza Mountain

[目的]了解石质山不同坡向沙冬青的种群结构、分布格局,旨在揭示沙冬青种群与环境异质间的相互关系。[方法]在北砸山不同坡向上采用样线和样方相结合的方法调查沙冬青群落特征,运用平均拥挤度、丛生指数、聚块性指标、Cassie指标、扩散系数、负二项分布指标等方法对景泰北砸山不同坡向沙冬青种群结构和分布格局进行了研究。[结果](1)北砸山阳坡沙冬青种群密度最高,是半阳坡的2.5倍,半阴坡生长状况最好;(2)阳坡、半阳坡、山脊处沙冬青年龄结构为稳定型,半阴坡年龄结构为增长型;(3)阳坡、半阳坡、半阴坡扩散指数C均大于1,说明阳坡、半阳坡、半阴坡都服从集群分布,而山脊处扩散指数C小于1,说明山脊处沙冬青服从均匀分布;(4)北砸山沙冬青种群分布格局规模:阳坡为4m×8m,半阳坡为4m×4m,半阴坡为8m×8m,山脊部为4m×8m。[结论]北砸山沙冬青生长状况良好,年龄结构稳定,分布格局大多为集群分布,各区域分布的沙冬青种群格局规模存在差异。

[Objective] The population structure and distribution pattern of Aminopiptanthus mongolicus in different slope aspects of Beiza Mountain were demonstrated and the relations between A. mongolicus popula- tion and the surroundings were analyized. [Methods] Population structure and distribution pattern of A. mongolicus population in different slope aspects of Beiza Mountain were studied by using mean crowding, clumping index I, patchiness index, Cassie index, dispersal index（C） and parameter of negative binominal （K）. [Results] （1） The highest population density of A. mongolicus was at sunny slope, which was 2. 5 times of the half-sunny slope; and the population grew best at half-shaded slope. （2） The age structure at sunny slope, half-sunny slope and ridge were stable, the half-shaded slope was increasing; （3） The dispersal index at sunny slope, half-sunny slope and half-shaded was clump distribution, and the ridge was uniform distribution; （4） The pattern scales were as follows： sunny slope, 4 m×8 m; half-sunny slope, 4 m×4 m; half-shadedslope, 8 m×N8 m; ridge, 4 m×8 m. [ Conclusion] The growth status was well, the age strueture was stable, and the most distribution patterns were clump distribution, the pattern scale was different in imparity distribution.