中文摘要：

基于坝上草原地区30个采样点表土花粉分析和植被调查的研究结果显示,花粉组合以蒿属、藜科、禾本科、菊科和莎草科等草本植物为主,基本能够反映草原植被特征,但花粉百分比与其在植被中盖度差异明显.运用Extended R-Value（ERV）模型估算的坝上草原区相关花粉源范围大致为2100m,当风速大于3.5m/s时,基本稳定,受风速影响不大.估算的相对花粉产量结果显示,蒿属和藜科的相对花粉产量最高,为禾本科的20倍左右;其次为莎草科和菊科,为禾本科的7～9倍;百合科略高于禾本科;旋花科、豆科、唇形科及委陵菜属的相对花粉产量则明显低于禾本科.利用相对花粉产量对花粉与植被关系的校正结果表明：蒿属、藜科的校正效果明显,其相对花粉产量可以作为定量重建古植被的参考;莎草科、菊科、百合科和唇形科由于受植被和花粉数据梯度限制,其相对花粉产量能否用于植被与花粉关系的校正有待通过更多植被群落调查进一步证实;其他花粉类型由于在花粉组合中含量多低于5％,所以在校正花粉与植被关系时的作用不明显.

英文摘要：

Relative pollen productivity estimates （RPPEs） are indispensable prerequisites for quantitative vegetation reconstructions. RPPEs have now been calculated in many regions of Europe, while only few work has been done in China. In this paper, the relevant source area of pollen （RSAP） and the RPPEs of the common taxa of Bashang steppe （41°10＇- 42°50＇N, 114°10＇-116°10＇E） were done with 3 Extended R-Value （ERV） models using ERV-Analysis.vl.2.3 Program. Pollen Sampling was performed at 30 random sampling sites selected by random function. Vegetation survey followed the standard vegetation survey method promoted by ＂ Crackles Bequest Project＂. Top soils are used for the pollen samples. The pollen analysis results showed that Artemisia, Chenopodiaceae, Poaceae, Asteraceae and Cyperaceae etc. herbaceous taxa dominate pollen assemblages. That is basically consistent with composition of the steppe vegetation. However, the differences are obvious between the pollen percentage and vegetation cover. So we calculate the RASP and RPPEs to calibrate the relationship between pollen percentage and vegetation cover. The RSAP is about 2100m in Bashang steppe based on ERV submodel 3 with Prentice＇s distance-weighting method. The comparison of RASP in different wind speeds indicates that the RSAP changes very few with the increasing of wind speed from 3.5m/s . The results of RPPEs suggest that the values of Artemisia and Chenopodiaceae are 20 times higher than Poaceae; Cyperaceae and Asteraceae are 7 -- 9 times; Liliaceae is only slightly higher than Poaceae; Convolvulaceae, Fabaceae, Lamiaceae and Potentilla are much lower than Poaceae. Then the relationship between pollen and vegetation are calibrated with RPPEs. The results show that the relationship between pollen and vegetation will become much better after calibrated with RPPEs for Artemisia and Chenopodiaceae because their higher percentages appear both in vegetation and pollen assemblages, thus their RPPEs can be used as a reference of quantita