天山北坡不同区域及海拔对天然草地鸭茅群落物种种间关系影响

以天山北坡不同区域与海拔地段鸭茅群落主要物种为研究对象,采用邻接格子样方法测定鸭茅群落物种优势度,通过方差比率计算、χ2检验、联结指数即秩相关分析种间联结性,分析鸭茅群落主要优势物种在群落中的分布及优势物种鸭茅与其他物种之间的关系,探讨区域与海拔梯度变化对鸭茅群落物稳定性的影响。结果表明,1)东、西两段山地鸭茅群落主要物种种间联结性在海拔1800~2200m间呈现出由正关联逐渐向负关联过渡,群落稳定性有随海拔升高呈逐渐减弱趋势。2)联结系数及联结指数结果均说明不同区域与海拔梯度对的鸭茅群落物种间的联结程度有一定影响,但均表现不强,而处于弱联结的较多或无联结,群落中各物种间较松散。3)鸭茅种群与群落内其他种之间的相关性有时呈正联结,有时呈负联结,这与区域与海拔地段所处的环境因素存在异质性有关。研究结果为揭示影响鸭茅群落物稳定性因素,预测鸭茅种群动态和种间竞争与共存机制提供重要的理论依据。

Interspecific associations in Dactylis glomerata communities in different regions and altitudes on the northern slope of Tianshan Mountain

The aim of this research was to identify the interspecific associations of Dactylis glomerata and to identify changes in community stability related to altitude.D.glomerata communities in different regions and altitudes on the northern slope of Tianshan Mountain were analyzed using the adjacent lattice method to identify and compare the dominant species.The interspecific associations of D.glomerata and changes in community stability related to altitude were determined by calculating association indexes and spearman's RAML correlation coefficients,and by conducting variance tests and x2 tests.The results showed that:1) the overall association of the D.glomerata community changed from a positive implicative association to a negative association as the altitude increased from 1800 m to 2200 m.The stability of the D.glomerata communities gradually weakened with increasing altitude.2) The association coefficient and association index were weak for most pairs of species,and most of the species pairs showed weak or no interspecific associations.3) D.glomerata showed a positive implicative association with a species in some cases,and a negative association with the same species in other cases.The associations were related to the environmental factors in different regions and at different altitudes.