锦鸡儿属植物在鄂尔多斯高原区系和植被中的作用

锦鸡儿属植物在鄂尔多斯高原分布有9种。是物种多样性相对丰富的一个地区。其中中间锦鸡儿Caragana korshinskii var. intermedia,在鄂尔多斯高原东部和毛乌素沙地被当作优选的、广泛栽培的、习见的固沙和水土保持灌木树种。从植物区系成分上分析,主要是中亚成分和东亚成分,中亚成分有蒙古高原分布,阿拉善分布,戈壁-蒙古分布,内蒙古草原-黄土高原分布;东亚成分有华北分布,华北-青藏高原分布,以及蒙古高原南部-青藏高原成分。这些成分充分反映出这一地区与相邻地区的联系和过渡性。形成明显替代现象是本区东部的C. korshinskii var. intermedia与西部的C. korshinskii之间的替代。灌木种类是鄂尔多斯高原的优势生活型植物。在鄂尔多斯高原分布的14个主要灌木群落中,其中有4个重要的锦鸡儿群落,即中间锦鸡儿群系Form. Caragana korshinskii var. intermedia,狭叶锦鸡儿群系Form. Caragana stenophylla,柠条锦鸡儿群系Form. Caragana korshinskii,藏锦鸡儿群系Form. Caragana tibetica。中间锦鸡儿群系为优良的固沙和水土保持灌木。藏锦鸡儿群系则主要分布在西鄂尔多斯,为自然分布。在硬地及覆沙梁地形成高达40~80 cm的小沙丘包,在灌丛中占绝对优势,是锦鸡儿属植物在鄂尔多斯高原最典型的景观之一。这些锦鸡儿属植物群落对于揭示植被从东到西典型草原-荒漠化草原-荒漠的地带性分布具有典型的表征意义。

FLORISTICS AND VEGETATION OF THE GENUS CARAGANA IN ORDOS PLATEAU

There are 9 species of the genus Caragana in the Ordos Plateau, which is a rich biodiversity region of the genus. Specially, Caragana korshinskii var. intermedia was treated as one of the most suitable species cultured to preserve soil and fix sand in the Maowusu sandland which located at eastern Ordos Plateau. There are two phytogeog raphical distribut ion elements, the Central Asia element and East Asia element of the genus in Ordos Plateau. The Central Asia element consists of Mongolia Plateau distribution, Alashan distribution, Gobi-Mongolia distribution, and Inner Mongolia Plateau-Loess Plateau distribution. The East Asia consists of North China distribution, North China-Qinghai-Xizang(Tibet) Plateau distribution and southern Mongolia Plateau-Qinghai-Xizang(Tibet) Plateau distribution. These elements showed the conjunction and transition between Ordos Plateau and the adjacent regions. The vicarism is illust rated by two typical species C. korshinskii and C. korshinskii var. intermedia. The former occurs in western Ordos Plateau and the latter in the east. The shrub communities are the dominant life form in the vegetation of Ordos Plateau. There are fourteen life forms, of four belong to Caragana community, i. e., Form. Caragana korshinskii var. intermedia, Form. Caragana stenophylla, Form. Caragana korshinskii, and Form. Caragana tibetica. Form. Caragana tibetica distributing in western Ordos Plateau and usually forming the small sand hill about 40~80 cm high, is one of the most typical natural landscapes in Ordos Plateau. These Caragana communities represent the characteristic of the vegetation zone, namely from eastern typical steppe and desert-steppe to western steppe-desert zones in Ordos Plateau.