The Distribution of Ephemeral Vegetation on the Longitudinal Dune Surface and Its Stabilization Significance in the Gurbantunggut Desert
古尔班通古特沙漠短命植物分布 及其沙面稳定意义

Field surveys of vegetation were conducted in the southern area of the Gurbantunggut Desert from March to August 2002. Vegetation cover was measured using 6 quadrats at different geomorphic positions on the longitudinal dune. Species numbers, coverage and growth of plants were recorded. Distributions of ephemerals on the dune surface were obtained, and the stabilization significance of the distribution ephemerals on the longitudinal dune surface in Gurbantunggut Desert was discussed. Threshold wind data from the Cainan meteorological station covering 1994 to 1995 were also analysed. A total of 45 species were recorded at the study site, of which 29 species were ephemerals. They formed special spring synusiae communities, of which Alyssum linifolium and Erodium oxyrrhynehum were the dominant species. At the peak of the ephemeral growth cycle most of the above-mentioned ground biomass was measured between surface level and a height of 30 cm, and root density was the greatest, ranging between 0 and 30 cm. The temporal and spatial distributions of ephemerals are unique. Their germination period is from late March to early April. Most of the ephemerals end their life-cycle according to climatic conditions. This usually occurs sometime between the last 10 days of June and the first 10 days of July. The average coverage of ephemerals on the interdune corridor and the two plinths reached 13.9% in March, 40.2% in April and 14.1% in June. Ephemeral coverage also varied in different zones of the dune. Spring coverage was 40.2% on the interdune, 44.9% on the plinth and 4.4% on the crest.