Desertification Evaluation Research on Artemisia ordosica Community in Mu Us Sandland Based on TWINSPAN Classification

With the quantitative community classification method TWINSPAN, the Artemisia ordosica communities in Mu Us Sandland were classified into five types, i.e., Artemisia ordosica+Agriophyllum pungens community, Artemisia ordosica+Agriophyllum pungens/Corispermum heptapotamicum community, Artemisia ordosica+herbaceous vegetation dominated by desert plants community, Artemisia ordosica+weeds/gramineous grasses community and Artemisia ordosica+herbage layer dominated by mesophyte community. Based on analyzing the field survey data, the principal factors influencing upon the community composition and characteristics were categorized into three factors, i.e., pedologic properties, species diversity information and biomass and coverage information of the communities. The desertification grade evaluation was discussed from the point of views for assessing the changes of community characteristics, so as to provide the smaller scale desertification grade evaluation on community level, and the utilization and management of degraded grassland with theoretical guidance for reference. Through statistical analysis and appropriate adjustment, it was proven by the results that the classification of Artemisia ordosica communities by TWINSPAN could well represent the degradation process of Mu Us Sandland and TWINSPAN methodology could be applied to evaluation of desertification development.