Effects Of Biological Soil Crusts In Gurbantunggut Desert On Soil Seed Bank Diversity And Distribution Characteristics

In this paper, by collecting three kinds of biological soil crust(cyanobacterial-algal crusts, lichen crusts and moss crusts) development of soil seed bank in Gurbantunggut Desert in different months(March, September, November), by comparing about composition, density, distribution, diverse to summary and analysis the difference of Soil seed bank of different surface types, and study about the seasonal dynamics of soil seed bank is how to change, moreover, this study provided a theoretical basis and scientific foundation for restoration and reconstruction of degraded ecosystems.The main results were concluded as follows:Through statistical analysis, three kinds of life style plant were found in soil seed bank, which were ephemeral plants, annual herbs and perennial herbs. Species composition of soil seed bank in different seasons are annual herbs number accounted for most of the total number of seed banks, the results showed loose sand, algal crust, crust lichen and moss crust on soil seed bank of annual herbs number accounted for 50%,71.43%, 96.54% and 81.48% of the total number of seed banks; In November, in addition to the number of annual herbs(40.91%) in loose sand seed bank is slightly lower than the number of ephemeral plant(50%), Three other seed banks of annual herbs are accounted for more than 50% of the total number of seed bank; overall analysis of the experimental results in September,frombare sand to moss respectively of annuals:46.15%,58.16%,57.58%,46.15%. According to the seed bank with seeds if appendage, The soil seed bank in different seasons and different surface types are all captured in seed number of smooth seed with seed appendages.Comprehensive analysis, the Pielou index all three are bare sand soil seed bank of the maximum value in every season of soil seed bank, respectively, 0.91 ± 0.05, 0.95 ± 0.02, 0.93 ± 0.03, In March and November, Shannon-wiener index and Margalef index were the highest in the soil seed bank of algal crust. And for these four types of index, the value of the soil seed bank of lichen crust was the lowest in November and March. Be somewhat different, in September, The highest value of Shannon-wiener diversity index and Margalef richness index both are the lichen crust, but not difference between algae crust.In the horizontal distribotion of the soil seed bank, different from the loose sand,soil seed bank density was significantly higher in biological soil crusts, and moreover, it also differed among three types of crusts, in March and November, soil seed bank density was highest in lichen crusts, reaching 5905 ± 778.65 individuals.m-3 and 6368.42 ± 2256.91 individuals.m-3, and in March, lichen crusts showed significant difference among the other three types of surface of soil seed bank. In November, Lichen crust only significantly higher than the loose sand.with With the change of seasons, soil seed bank in September is different, The maximum density of soil seed bank in algal crust, 7100.00 ± 515.99 individuals.m-3, And significantly higher than the bare sand, lichen crusts and moss crust.In the vertical distribution of soil seed bank, seed bank density showed that with the increase of soil depth, density decreased, seeds were primarily distributed on the shallow soil layer of 0~2cm in biologically crusted soil. soil seed bank showed the vertical distribution law in March, November and September. The number of seeds in 0~2 cm soil layer was significantly higher than that in 2~5 cm, 5~10 cm and 10~15 cm soil layer. the same, 0-2 cm soil layer in the largest number of seeds both are lichen crusts in March and November. The highest density of algal crust soil seed bank in 0~2cm soil layer in Sep.Contrast between the four soil seed bank features in diffenence season, The number of species of bare sand and moss crust soil seed bank were the most in November, the lowest in March, the maximum value was 8 and 12 respectively; There was no significant difference in the density of the soil seed bank between the bare sand and the lichen crust. The algal crust density of the soil seed bank in September and November was significantly higher than that in March, moss crust soil seed bank in November and March, there were significant differences, but there was no difference in September. In November, the seed bank density of loose sand, lichen crust and moss crust was higher than that of March and September, and the density of algal crust seed bank was the largest in September.