贺兰山的灰榆林与灰榆疏林草原—以贺兰山东坡为例

The Woodland of Ulmus Glaucescens and the Ulmus Glaucescens Woodland-Steppe in Helan Mountain

本文从植物区系、群落的结构和动态、生境、在山地植被垂直带系列中的位序以及改造利用等方面论述了贺兰山灰榆疏林草原的主要特征,从而认为过去所称大面积的“灰榆疏林”除在个别地点分布的属于落叶阔叶林外,绝大部分应是一类由草原植物与散生小乔木结合形成的温带山地稀树草原,但它不同于热带稀树草原,故称为疏林草原。在贺兰山灰榆疏林草原是一类独特的原生植被类型,占据着一个独立的植被垂直带。

In this paper, by analysing the floristie composition, structure, dynamics. habitat and other characters of communities, the Ulmus glaucescens woodland-steppe has been distinguished. The result shows that although the vegetation forms discussed in the paper have been traditionally considered as the woodland of Ulmus glaucescens, only a small part of them truly belong to the deciduous broadleaved forest. Most of those vegetation forms are the special temperate mountainy parkland composed of isolated small trees(Ulmus glaucescens)and the species of steppe. In Helan Mountain, this vegetation form exists as one of vertical vegetative zones and is defind as the Ulmus glaucescens woodland-steppe.