The Research Of Kobresia Tibetica Swamping Meadow’s Degeneration And Dynamic Monitoring Technology For The Yellow River Source Zone

On the basis of ground sampling survey, combined with the TM images, in order tostudy the distribution and community characteristics related data, remote sensingimage interpretation and other issues of kobresia tibetica swamping meadow in theYellow River source zone, selected a number of important indicators such as grasscover, plant height, aboveground biomass, species diversity to research degradationclassification. Use ArcGIS, Erdas software to superimpose different periods of thesame region TM remote sensing images, get the size and distribution of degraded,analysis of degradation situation, spatial patterns, characteristics and causes of thetime course,the purpose is to provide a scientific basis for the management andconservation of resources, the main results are as follows:1, The kobresia tibetica swamping meadow in the Yellow River source zone consistsof11families and32genera49kinds. Varying degrees of degradation of plantcommunity composition and important value has greatly changed, with the degree ofdegradation intensifies, kobresia tibetica average height of26.2cm reduced to7.3cm,cover from76%down to31%.With increasing degree of degradation, abovegroundbiomass decreased, sort of non-degraded grassland（1505.1g/m2）> lightly degraded（1222.1g/m2）> moderately degraded（840.8g/m2）> heavily degraded（576.4g/m2）> over degradation（466.4g/m2）. Species diversity index was positivelycorrelated with richness and evenness index,was negatively correlated withdominance index;The highest species richness index is in Moderate-degradationstage,and the highest diversity and evenness index in Heavy-degradation stage,evenness is largely affected the diversity of the communities. Proposed criteria for theclassification level of degradation that based on tibetica height and cover, grasslandsmain companion plants, habitat conditions，divided the kobresia tibetica swampingmeadow into non-degraded, lightly degraded, moderately degraded, heavily degraded,over degradation.2, Based on TM remote sensing image interpretation,1994and2013kobresia tibeticaswamping meadow area were269,000hectares and201,000hectares, mainly around lakes, riparian, seasonal water areas and low-lying land at altitude of4100m. The TMimages in1994and2013that are two different periods varying degrees of degradationare interpreted on the distribution,overlay analysis,came out Qumarleb County has alarge area of kobresia tibetica swamping meadow goes moderately degradedgrassland and other categories from non-degraded, the area also has a significantdegradation around Zaling and Eling lakes,distribution has become relativelyconcentrated with the Stars Sea region in Madoi County,change region has reached39%in19years.3, Establish the correct lawn interpretation signs and TM image band selection is thekey to interpret the accuracy results,using4,5,3band combination of TM image iseasy to interpret non-degraded, lightly degraded, moderately degraded kobresiatibetica swamping meadow.Experiments show that the method can better analyzethree kinds of big gap between different levels of degradation. Secondly,usingsoftware to overlay comparison,can come out distribution and area change of differentperiods kobresia tibetica swamping meadow’s degradation process.Experiments showthat the technology can analyze and extract kobresia tibetica swamping meadow’smacro changes, experiments have reached a certain target.