新疆地区表土孢粉分布规律及其与植被关系研究

对中国新疆地区218个样点进行植被调查及表土孢粉分析的研究结果表明,新疆地区温带山地针叶林、高寒草甸及盐生草甸、温带草原、荒漠以及荒漠-沙漠过渡带均具有相对特殊的孢粉组合,新疆南北向样带的孢粉图式揭示出表土孢粉从北到南随地形、纬度和植被的改变而发生的空间变化。针叶林区表土孢粉浓度平均值为22 602粒/g、草原为3 834粒/g、荒漠为1 762粒/g、沙漠为0-10粒/g。但在同一植被类型中,特别是在草原和荒漠中,孢粉浓度与植被盖度之间并不呈现线性相关关系。根据大空间尺度样品的A/C(蒿Artemisia/藜Chenopodiaceae)值的中位数统计,草原为1.264、荒漠为0.565、沙漠为0.243。Ep/C(麻黄Ephedra/藜Chenopodiaceae)比值的中位数在荒漠为0.098、草原为0.063。

Distribution of surface soil spore-pollen and its relationship with vegetation in Xinjiang, China

The results of vegetation investigation and spore-pollen analyzing of 218 surface samples indicate that different spore-pollen taxa can reflect the vegetation of different vegetation types.There are a lot of vegetation types: needleleaf forests on mountains in temperate zone,high-cold meadows,halophytic meadows,temperate steppes,deserts,the transition plants between deserts and sandy deserts in Xinjiang,each has relatively special spore-pollen taxa.The spore-pollen diagram of northsouth transect in Xinjiang reflects the surface soil spore-pollen distribution change along with the landform,latitude and vegetation change from the north to the south of Xinjiang.The spore-pollen taxa in the south edge of the Altai Mountains are dominated by needleleaf forest pollen,in the Junggar Basin are leaded by Artemisia and Chenopodiaceae.The spore-pollen in the eastern Tianshan Mountains has vertical distribution characteristics.The spore-pollen taxa of deserts and sandy deserts in the Tarim Basin are mainly composed of Chenopodiaceae and Ephedra,in the western Kunlun Mountains are controlled by Chenopodiaceae and Artemisia.The average of spore-pollen concentration of needleleaf forests is 22 602 grains/g,the value of steppes is 3 834 grains/g,the value of deserts is 1 762 grains/g,the value of sandy deserts is 10 grains/g.But the spore-pollen concentration does not have linear correlativity with vegetation coverage of the same vegetation type,especially for steppes and deserts.Based on analyses of 151 samples,the median of A/C(Artemisia/Chenopodiaceae) ratio of steppes is 1.264,the ratio of deserts is 0.565,the ratio of sandy deserts is 0.243.It validates from large space scale A/C values that the environment is drier when A/C is lower.Ep/C(Ephedra/Chenopodiaceae) ratio is also the reference to recover the vegetation types.The median of Ep/C of deserts(0.098) is higher than that steppes(0.063).