Control of vegetation distribution: climate, geological substrate, and geomorphic factors. A case study of grassland in Ordos, Inner Mongolia, China

摘要

Many studies have dealt with the relationship between climate factors and vegetation, and some worksnconfirmed the underlying substrate as an important factor in vegetation complexity and diversity in semiarid regions ofnnorthern China. However, the leading factor in vegetation distribution may vary with spatial or temporal scales. Thenobjective of this study was to analyze the dominant factors in vegetation distribution and dynamics at large (regional)nscales of space or time and at small (local) spatial scales. The results showed that temperature and precipitation werenpositively correlated with normalized difference vegetation index (NDVI) during a 20 year period (1980u00022000) in thenOrdos region. Both NDVI and average annual precipitation had the same trends, i.e., decreasing from east and southeastnto west and northwest, which indicates the leading role of precipitation in vegetation distribution. At some locations,ngeologic faults with a well-developed clastic rock pervious layer are important effects on the distribution of vegetationncover in northern Ordos, near the border with the Kubuqi Desert. The lithology of bedrock greatly affects vegetationncover and distribution in the Mu Us Sandy Land area. There, a high percentage farmlands and grasslands with largenNDVI values are mainly on low-permeability strata, such as the Quaternary Lake and alluvial deposits.