川北若尔盖高原表土孢粉的特征及其与现代植被的关系

Relationship between the surface pollen and modern vegetation in Zoigê Plateau,northern Sichuan, China

通过对若尔盖高原不同植被带34个表土样的孢粉分析,研究了各植被带的表土孢粉组合与现代植被的关系。结果显示:表土孢粉组合基本上能够反映出现代植被的整体特征,与现代植被带在空间分布、建群种和优势种属方面基本相同,但不完全等于植被组成,影响其差异的原因可能是人类活动、孢粉保存、孢粉产量、外来孢粉和孢粉鉴定。表土花粉的代表性因种属的不同而各有差异。乔木花粉中,松属具有超代表性,云杉属代表性较好,而桦木属不具有超代表性;草本花粉中,菊科具较好的代表性,蒿属和藜科等具代表性,而禾本科和莎草科具低代表性;蕨类孢子具等代表性。

In order to investigate the relationship between the surface pollen and modern vegetation, surface soil samples collected from 34 sites in Zoigê Plateau were analyzed, and then the pollen assemblages of every zone were obtained. It is found that pollen assemblages of surface soil samples generally reflect the whole features of the modern vegetation, and they are basically similar in the spatial arrangement, types and the main and dominant genera. But pollen assemblages of surface soil samples aren＇t completely equal to the vegetation composition, maybe because of the influences of mankind＇s activities, pollen preservation, pollen production, foreign pollen and pollen identification. The representation of pollen in surface soil is different between families and genera. The tree pollens such as Pinus is over-represented, and Picea pollens are moderately represented, but Betula isn′t over-represented; the herb pollens such as Compositae is well represented; Artemisia and Chenopodiaceae are equal-represented, but Gramineae and Cyperaceae are under-represented; the fern spores are equal-represented.