The Studies On Effects Of Artificial Fencing On Rehabilitation Of Vegetation In The Ecotone Of Agriculture-animal Husbandry

Yanchi county, Ningxia Hui Autonomous Region located in the Ecotone of Agriculture-animal Husbandry of China is one of the representative belt in the north of China. Yanchi county is also one of the severity desertification area in China. This paper based on the vegetation cover degree and vegetation biomass ,the biodiversity of grassland community in the artificial Closure Area, in Yanchi county, Ningxia Hui Autonomous Region was measured by using the methods of α-diversity index (including Shannon-Wiener index, Simpson index, Js which are community evenness indices) and β-diversity index (measured by similarity coefficients) and Vegetation fraction Remote sensing estimated manners based on depart two grid cell model design method using NDVI as parameter.The research discovered that, Seals after three years nurtures themultiple index and the uniformity index arrangement becomes edge >Core > The periphery (comparison), the pasture destroyed relativelyserious fringe area each multiple index to be higher than 2003 eachmultiple index, ecology superiority reduces 41%, the fringe areavegetation group fell tends to stably is even. The multiple indexchange indicated artificially seals nurtures is one effective economicrecovery vegetation's method, through artificially seals to adestruc tive -ness lighter land sector nurtures, may cause thedegenerated vegetation in to compare in the short-term the rapidrestoration. The ecology position overlaps the research to indicate AremisiacapillalisThunbthe unique biology, the ecology characteristic, cause itsrapidly in to seal nurtures after the short several years (in 2000 toseal nurtures) becomes seals nurtur -es the area domi -nant. AremisiacapillalisThunbthegroup falls the establishment changed will have sealed nurtures thearea group to fall the environment, and expanded for otherpo -pula tions' invasions has created the stable matrix foundation,hereafter the group will fallcontinues succession.Analyze the dynamic changes of every sandy dune land in Yanchi County in the last 40 year, found that the region desertification before 1989 in YanChi County appear enlarge trend, the sandy dune area in 1989 has increased to 2366.67km~2 from 1006.11km~2,each year enlarge 46.92km~2,the average annual increase ratio is 4.66%.Appear decrease trend after 1989,especially after 2000,until 2003, the desertification area has decreased to 455.75km~2,take 19% to 1989.The data analyzed result is consistent with located monitoring and NDVI result.Then this paper analyzed the causes of Steadiness of vegetation , the research show that the desertification area has negatively correlated with the precipitation in former year (α<0.05), has obvious linear positive correlation relationship with the total amount of goat (α<0.01) .According to the analyzed result, summarize that the main causes of better vegetation restoration speed were two points: firstly, first is the implementation of policy of reverting farming land to forest and grassland since 2001 and forbidding graze in the whole county since November 1st, 2002. Secondly, the distinct increase of rainfall especially in 2002 and 2003 contributed greatly to restoration of vegetation.