Chin J Plan Ecolo ›› 1996, Vol. 20 ›› Issue (3): 193-206.

• Research Articles •     Next Articles

Ecological Vicariance of Steppe Species and Communities on Climate Gradient in Inner Mongolia and Its Indication to Steppe Dynamics under the Global Change

Li Yong-hong   

  • Online:1996-03-10 Published:1996-03-10
  • Contact: Yan Chang-rong

Abstract: Based on the investigation of the vegetation and environment in 119 sites along an itinerary from the desert-steppe transition zone to that of forest-steppe in Inner Mongolia steppe region, the vegetation environment relationships were quantitatively analyzed.The preponderance of the 30 factors in determination of vegetation composition were hierachized according to their sampling quality and their mutual information with the 50 most frequent species. The result showed that climate was the most preponderant; while the topographic and managerial factors were secondary or local. The community composition was well associated with the first dominant species, so the dominance community-type identified according to the first dominant species was the relatively stable unit of similar composition and structure.The ecological vicariance of a large amount of steppe species along climate gradient were revealed by an ordination of these species on a precipitation-temperature plane according to their preference to these 2 factors. This vicariance, especially the vicariance of the dominant species including a group of Stipa species, resulted in the vicariance of the Stipa communities.The traits of the main steppe communities were characterized by presentation of their preference and amplitude on the climate, soil and grazing gradient, and by synthesis of their vegetation features. The direct ordination of the species and communities along the gradients of climate and grazing intensities provided a dynamic scenario of the steppe vegetation under the climate and landuse changes.