塔里木河下游胡杨种群空间分布格局分析

在塔里木河下游胡杨分布集中的英苏、喀尔达依断面,设置了6条样带38块样地进行植被种类、高度、胸径、冠幅、株数等因子调查,研究了不同离河距离胡杨格局分布类型、聚集强度及其格局规模.结果表明:胡杨在不同离河距离大都表现为聚集分布,在离河最远的地方有扩散趋势,呈随机分布;不同离河距离的两断面均表现出随离河距离加大胡杨格局规模加大、聚集强度加强的趋势,同一离河距离喀尔达依断面比英苏断面胡杨格局规模小,这主要是地下水条件和当地地形不同所致.喀尔达依断面个别离河距离并未遵从随离河距离加大胡杨格局规模也随之加大的规律,则是胡杨种群对异质环境响应的表征.

Spatial Distribution Pattern of Populus euphratica Populations in the Lower Reaches of Tarim River

The species,heights,diameter breast heights,canopy widths and plant numbers in 38 quadrats of 6 belt transects,which were located in Yingsu Crosssection and Kaerdayi cross-section lying in the lower reaches of Tarim river where Populus euphratica concentrated,were investigated to study the distribution patterns,aggregation intensities and distribution pattern scales of P.euphratica populations at different distances away from the river.It was shown that in most cases P.euphratica appeared to have an aggregative distribution at different distances away from the river but it tended to be diffusive,appearing to have an random distribution;In the two cross-sections,P.euphratica tended to increase its distribution pattern scale and aggregation intensity as the distances increased and the distribution pattern scale of P.euphratica in Kaerdayi cross-section was lower than that in Yingsu cross-section at the same distances away from the river,which was because the cross-sections had different underground water conditions and topographical conditions.However,at several distances away from the river,P.euphratica did not followed the pattern in distribution pattern scale that the distribution scale increased as the distances away from the river increased,which was a responsive expression of P.euphratica populations to heterogeneous environments.