| The paper chiefly had a comparison study on the dynamic character of recovering of degenerative steppe plant community by different site preparing modes in southern Ningxia . The methods were the diversity analysis, distribution patterns of population analysis, and the analyses of interspecific association of species and stability. The bases of data were from the investigation of fixed sample plot and quadrat of community. And further study the road and the effects of artificial disturbance, offering a reference of scientific decision to the area. The results indicated:(1) The flora components of vegetation and plant community types are simple in investigated area.(2) In a long temporal scale, the heterogeneity of habitat affected the plant community structures in fish-scale pit site preparing mode greatly. Site preparing mode had a little effect on the character of plant community structures.(3 ) The difference of habitat affected diversity. Fish-scale pit site preparing mode had higher levels of heterogeneity of habitat. It can promote higher levels of diversity. The order of three sample plot diversity was: fish-scale pit site preparing>88542 level furrow site preparing>natural closed steppe.(4) With temporal changes, the difference of habitat affected the biomass of different plant community. Diversity and biomass were not obviously correlative.(5) The distribution patterns of prime forage population were different in different habitat, a partly forage population had a pattern of random distribution in fish-scale pit and natural closed steppe communities, but the most forage population had a pattern of aggregated distribution.(6) The overall interspecific association of prime forage species were not significantly associated in different site preparing modes. All plant communities were in the relatively unstable stages of succession.(7) The order of three sample plot relative stability was: fish-scale pit site preparing>88542 level furrow site preparing> natural closed steppe. And the situation of the tendency to stable point(20 divide 80) did not exist. The steppe plant community in the region was all in the relatively unstable stages of resuming.(8) The diversity of plant community in fish-scale pit site preparing was the highest, the relative stability was also the highest. The diversity of plant community in natural closed steppe was the lowest, the relative stability was also the lowest.(9) In the closed steppe of 4-5 years, fish-scale pit and level furrow site preparing modes had a little effect on the character of steppe plant community, natural ecological factors had a greater effect on the character of steppe plant community than the artificial site preparing mode. |
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