阿拉善干旱荒漠区不同植被类型土壤种子库研究

Soil seed banks of different grassland types of Alashan arid desert region, Inner Mongolia.

对阿拉善干旱荒漠区不同草地类型土壤种子库的研究表明,在海拔高度为1370～1750 m样地间,天然草地土壤种子密度从326粒·m^(-2)减少至76粒·m^(-2),呈随海拔高度增加而减少的趋势。海拔高度为1100m的典型荒漠区,土壤种子密度为56粒·m^(-2)沙漠区土壤种子密度仅为8粒·m^(-2),在沙漠区建立白沙蒿草地后,其土壤种子密度明显增加,为沙漠区的17～29倍。本研究共统计到31种植物种子,分属11科。其中,以一年生草本植物种子的比例最高,分别在天然草地、沙漠区和飞播白沙蒿样地种子库中占77％、100％和70％;多年生草本植物次之,分别占21％、0和16％;半灌木种子比例最低,分别占2%、0和14％,所有种子库中未发现灌木的种子,在海拔高度为1100～1750 m样地间,天然草地土壤种子库的丰富度指数从1.49增至2.77,多样性指数从0.697增至0.917,呈随海拔高度的升高而增加趋势。

Investigations on the soil seed banks of different grassland types of Alashan arid desert region in Inner Mongolia showed that when the altitudes of sampling plots increased from 1 370 m to 1 750 m, the soil seed densities of natural grasslands decreased from 326 grain.m 2-2 to 76 grain.m-2. At the altitude of 1 100 m, the soil seed density was 56 grain.m-2 in typical desert plot, but only 8 grain.m-2 in the sand dune plot. After the vegetation was restored with Artemisa sphaerocephala on sand dune, its soil seed density increased obviously, almost as 17 -29 times as sand dune's. In this study, 31 seeds m-2 were sampled, which belonged to 11 families. A-mong them, annual plants accounted for 77%, 100% and 70%, perennial plants accounted for 21%, 0 and 16%, and semi-shrubs accounted for 2%, 0 and 14%, respectively for natural grassland, sand dune and sown grassland. Shrub seeds were not found in all the soil seed bank plots. When the altitudes of sampling plots increased from 1 100 m to 1 750 m, the species richness (Margalet index) of soil seed banks of natural grasslands increased from 1. 49 to 2. 77, and the species diversity (Shannon-Winner index) increased from 0. 697 to 0.917.