Abstract: Spatial-temporal pattern of vegetation is determined by a variety of environmental factors on different scales. The influence of slope aspect and terrain on vegetation pattern has been increasingly reported in recent years. This study investigated the influence of slope location and terrain on vegetation distribution and their temporal structure on typical longitude sand dune in Gurbantunggut desert to provide scientific evidence for vegetation utilization and management, biodiversity conservation and ecosystem restoration and reconstruction. On each of three selected typical sand dunes, five parallel transects (west eastern direction) were established at 20 m intervals. Each transect covered six terrains: The base, lowslope, and upslope of the windward and leeward slopes of the sand dune. In midApril 2015, the aboveground vegetation was sampled in three 1 m × 1 m quadrats randomly placed along the transects. All plant species within each quadrat were identified and recorded. Among windward slope and leeward slope of sand dune, the main herbaceous species were from Compositae, and life form of ephemeral plants had the highest proportion; herbaceous density on windward slope was significantly lower than that on leeward slope, but showed a same trend of “V” pattern from April to September. On both slope aspects, the highest α diversity (richness index, Shannon index, Simpson index and Pielou index) was observed at up-slope and the lowest at base of slope; there was a decreasing trend or a “V” pattern in each terrain over investigation time. Cody index decreased but Sorenson index increased with the terrain rising on windward slope and leeward slope. The results suggested that habitat heterogeneity of sand dune terrain and slope should be considered to preserve and restore the desert plant diversity. Meanwhile, the temporal variation of plant diversity should be also considered to make scientific measures for desert management.

Key words: organic carbon., paddy soil, amino sugar, long-term fertilization