Research On The Plant Communities Spatial Heterogeneity Of The Helan Mountain

Mountains with its complex topography features and habitats heterogeneity, become a complicated ecosystem complex, which are rich in species and vegetation types. The mountains have been the focus of research at home and abroad. This paper takes the Helan Mountain as research object. For 3556m above sea level and relative high in 1500-2000 m above, the mountain forms a relatively integrated vertical zonation.The Helan Mountain ,which is isolated from desert, is more similar to a mesophytic "islands" habitat. The drought will certainly have an impact on the Helan Mountain and the outcome is represented on the vegetation types. Through the actual field survey of geospatial elements of the Helan Mountain in 2006 and 2007, we discuss the vegetation spatial heterogeneity. The conclusion follows:1 .Despite the changes with altitude, there are clear vertical zonation changes in the mountain vegetation, but in the horizontal direction, that is, from shallow to deep distance, because of moisture gradient differences, in the vegetation vertical zonation, there is a lower threshold on the distribution of plant communities.2.This article first proposes "the mountain degree" concept, and accordingly, quantitatively describes the " remote-mountains effect" in arid zone, that is, from the edge to the mountainous hinterland, the environment gradually changes from the arid to the humid. On this basis, this paper assumes that the ideal distribution pattern of the Helan Mountain vegetation is the distribution of plants gradually changes along the combination of water and heat gradient, which excludes the impact factors of climate in the mountain (open valley status).3.In Helan Mountain, particularly in the shallow mountainous foothills, the ridges and slope tops because of the unique features of the terrain and long-term water deficit form a special type of plant community, that present the inverted vegetation vertical zonation.