The Impact Of Community Characteristics On The Degraded Grassland Of The Seriphidium Transiliense In The First Year Of Fencing

Aimming at solving the urgent need to address the scientific issues that spring and autumn pasture for ecological restoration of degraded grassland,this paper,analysis the the degradation for different stages of vegetation communities and individual characteristics,seed germination,soil seed bank,seedlings propagation characteristics of the quantity and pattern in Seriphidium transiliense desert grassland grazing in the elimination of interference,the research results show that:1,Seriphidium transiliense is the dominant species of grassland in moderate degradation stage in fence and out of fence,the important value of Seriphidium transiliense was significantly higher in fence than out of fence in May.The important value of Petrosimonia sibirica in fence and out of fence in the severe degradation stage is the largest,but the important value has little difference between in fence and out of fence.The important value of Petrosimonia sibirica and Ceratocarpus arenarius is larger in the extreme degradation stage is lager in fence and out of fence,the important value of Petrosimonia sibirica was higher than that out of fence.There are same conclusions on Seriphidium transiliense and other spices in fence.2,The germination time of Seriphidium transiliense seeds lasted for a long time,there is a peak paragraph in the pre-germination germination.The speed of Petrosimonia sibirica seeds germination is prompt,the germination rate of Trigonella arcuata seeds is extremely lower.There is a positive correlation between the Seriphidium transiliense seeds' weight and germination index,while there is a negative correlation between the Petrosimonia sibirica seeds' weight and the germination index.3,The amount of species of seed banks in fence is more than that in out of fence,Chenopodiaceae plants have a high proportion in fence and out of fence,the number of Gramineae plants and Leguminosae plants are higher in fence than out of fence.The amount of germination seeds in germination peak in fence is higher than in out of fence,in moderate and extreme stages.The seeds' number of seeds' bank is higher than the number of plants above ground,in fence and out of fence,it is obviously in moderate stage.4,The spatial distribution of population are gathered distribution in May and September.The gathered strength of the Seriphidium transiliense in the fence is higher than that out of fence.Heterogeneity of environmental conditions have strong impact to number of seedlings,in the same time,there are differences on gathering strength.Under the different habitats,the number of seedling survival is very low, environmental screening play a decisive role,no matter in any habitat conditions,which has emerged the characteristics of large-scale "explosive emergence" and "sudden death".