中卫山羊核心产地植物群落的数量分类与排序

应用数量分类(TWINSPAN)和DCA排序方法，对我国特有裘皮用山羊(中卫山羊)核心产地——宁夏香山地区植物群落进行多元分析，根据TWINSPAN分类结果，并结合生态特征将所调查的28个样地植被分为6组，代表了该山地在海拔、地形、土壤、山坡坡度等环境作用下植被空间的分布格局。TWINSPAN分类结果与DCA排序结果较一致，DCA排序第一轴结果主要体现出海拔和山坡坡度对植被分布的作用，第二轴结果主要体现了地形(坡向)和土壤基质(沙地、石质山坡、土质山坡)对植被分布的作用。影响该干旱山地植被分布的主要环境因子有海拔和山坡的坡度，另外长期过度放牧对植被的空间分布影响较大，导致了该山地系统植被空间结构紊乱，并干扰了群落数量分析结果的准确性。

Quantitative Classification and Ordination of the Florae in the Nuclear Production Region of Zhongwei goats,Ningxia

Two-way indicator species analysis and detrended correspondence analysis were adopted to conduct the multi-analysis of the florae in the region covered by the Xiangshan Mountains of Ningxia,the key production area of Zhongwei fur goats (Zhongwei goat).According to the results of the multi-analysis and in combination with the ecological characteristics of the region,the vegetation distributions depended on their latitudes,landforms,soil and slope gradients.The classifications by the two-way indictor species analysis were consistent with the rankings by the detrended correspondence analysis;the first axis of the rankings by the detrended correspondence analysis mainly expressed the influence of latitudes and slope gradients on the vegetation distribution and the second axis mainly showed the effects of landforms (slope directions),soil textures (sandy soil,lithoid slopeland soil,terrene slopeland soil) on the vegetation distribution.But the major ambient factors affecting the vegetation distribution were latitudes and slopeland gradients.In addition,overgrazing interferred with spatial vegetation distribution to a higher extent,thereby leading to a disordered spatial vegetation structures in mountainous regions and interfering with the quantitative analysis of the florae in the region.