The Impact Of Community Characteristics On The Different Fencing Condition

The study was carried out in desert grassland of Seriphidium transiliense in Lucaogou Township of Midong District in Urumqi City.Based on theories and methodology of grassland ecology,field observation was combined with inddor analysis of samples taken from the field to determine the dynamics of S.transiliense grassland communities with different duration of closure,further to explore the impacts of duration of closure on the S.transiliense grassland community.The study would provide a scientific,objective and accurate basis for rational utilization,restoration and rehabilitation of S.transiliense grassland.The results of this study indicated that:1?After 11 years of closure,the total coverage,average height of the plants were significantly increased compared to those not with closure.There were significant(P<0.05)differences between the closure of3,8 and 11 years,and the control with no closure After enclosure,the community appeared to become higher,and the density of the dominant population in S.transiliense was significantly changed.2?The effect of fencing closure on aboveground biomass of sagebrush grass plant and edificators of S.transiliense were:W3>W2>W1>W0,aboveground biomass showed a gradual upward trend with the duration of fencing closure,mainly due to the increase of biomass of Seriphidium transiliense.The results from the analyses of biomass of S.transiliense and from the total biomass were basically the same.3?With the extension of fencing closure,species richness increased first and then decreased,the number of species decreased gradually after fencing closure.However,the species evenness showed a "up and down" pattern;species diversity displayed a concave curve;the grassland productivity decreased with increasing diversity,the number of species did not change significantly.4?With the increase of fencing duratin,the importance value of S.transiliense was increasing rapidly,making it at a position with absolute advantage in the community.The diversity and richness of the community at 3 years of closure were significantly higher than that of the other treatments,considering both the diversity and the biomass of community,rational utilization during 8 years of fencing closure would help to maintain community diversity and obtain a higher biomass.