The evaluation on interaction between structures and succession of vegetation/ecosystems and arid land environment in Western China: Desert vegetation/ecosystem of Fukang in Xinjiang as a study case

This article discusses the relationship between desert ecosystem structures, succession and environment factors which include soil moisture, salt content and pH values in Fukang of Xinjiang. Some preliminary conclusions have been drawn as following: (1) In the study area the niche breadth of typical species in desert vegetation/ecosystem is closely related to environment factors, such as soil moisture, soil pH and salinity. The biggest niche breadth species are Haloxylon ammodendron (1.412) and Reaumuria soongorrica (1.399), which are dominant species in climax communities of the region, and they have very strong adaptability to the arid desert environment. The niche breadths of Nitraria rovorowskii, Kalidium foliatum and Suaeda acuminate range from 0.8 to 1.2. The smallest niche breadth species are Tamarix spp. and Anabasis spp., ranging from 0.4 to 0.8, and both of them show sensitivity to drought and salinity. (2) Low species diversity in desert vegetation/ecosystem of Fukang was found. In general, the grade of community diversity from high to low is defined as: Tamarix soongorica community, Kalidium foliatum community, Suaeda physophora community, Halocnemum strobilaceum community, Haloxylon ammodendron community, Salsola passerina community, Reaumuria soongorica community, Bassia spp. community and Suaeda acuminate community. The most important factors that influence the species diversity of communities are soil salinity and pH values. Because of saline-sodic environment desert vegetation has developed a saline-sodic endurance ecological type. The main effects of salinity on vegetation are observed in the change of dominant and constructive species in communities, and halophyte becomes the dominant species gradually. (3) The limit factor on secondary succession in regional ecosystem is soil salinization. The trend and phase of community succession are in accordance with soil salinization development. There are three soil types: non-salinity, saline soil, and strong saline soil. Communities of Bassia spp., Suaeda acuminnata, Petrosimonia sibirica, Suaeda physophora, Anabasis spp., Kalidium foliatum, Haloxylon ammodendron. Haloxylon ammodendron distributed in non-saline soil and Reaumuria soongorica community is regarded as a climax community in this area and distributed in all kinds of saline soils. The appearance of Tamarix spp. is the result of succession development responding to salinity and increased water content. The plant communities are distributed, in turn, within the entire basin because groundwater table and soil salinity changes from the foothill of mouatain to desert, and this sequence is the same as the scondary succession serial of the vegetation / ecosystem of this era.