准噶尔盆地西部花粉对植被的指示性研究

基于准噶尔盆地西部46个样方的植被调查和表土花粉资料,估算了19种主要花粉类型的联合指数（A）、低代表性指数（U）、超代表性指数（O）、代表性系数（R）、区内无植被出现时某花粉类型百分比的平均值（Ma）、区内有植被出现时某花粉类型百分比的平均值（Mp）、样方花粉组合与植物群落间相似系数（CC）,定量描述花粉对植被的指示性。结果表明：第1组包括藜科,A值为1.0,O、U值均为0,R值为12.5,Mp远大于Ma,对植被指示意义明显;第2组包括蒿属和麻黄属,A值在0.1～0.4之间,O值在0.6～0.9之间,U值均为0,R值大于18.5,Mp与Ma相差3.6%～12.1%,对植被具较明显指示意义;第3组包括白刺属、百合科、唇形科、豆科、禾本科、菊科、蓼科、毛茛科、蔷薇科、伞形科、莎草科、十字花科、石竹科、旋花科、荨麻科和紫草科,A值小于0.6,U值在0.2～0.9之间,O值在0.1～1.0之间,R值小于4.0,Mp与Ma相差小于4.9%,对植被指示意义不明。研究结果可为利用化石花粉资料准确恢复古植被提供参考依据。     

洛阳盆地全新世炭屑记录及其古环境意义

黄土-古土壤剖面保存的炭屑记录了全新世古火与环境演变信息.文章以洛阳盆地五岔沟(WCG)剖面(厚度200 cm)为研究对象,利用该剖面的炭屑记录,并结合磁化率、有机碳等古环境指标,试图恢复和重建洛阳盆地中部全新世野火的演变历程,进而探讨洛阳盆地中部全新世以来野火与气候、人类活动之间的相互关系.研究表明:马兰黄土堆积时期...     

Relationship between pollen assemblages in surface soil and modern vegetation and climate in the western Tianshan Mountains,Xinjiang北大核心CSCD

Based on the pollen spectrum characteristics of 46 surface samples collected in the western Tianshan Mountains of Xinjiang and a plant community quadrat survey, we analyzed the relationship between pollen assemblages and modern climate and vegetation distribution in the region. The results showed the surface pollen assemblages were consistent with the distribution of modern vegetation. Based on the results of cluster analysis, the study area could be divided into three pollen assemblage zones（mountain steppe zone, desert vegetation zone and typical desert zone）. In general, pollen assemblage can roughly reflect the main characteristics of local vegetation, but there are significant differences in the percentage of some pollen types and the coverage of related plants. The pollen of Picea and Pinus in arbor plants, Ephedra in shrub plants, Chenopodiaceae and Artemisia in herb plants were high represented due to the influence of natural wind, water flow and their own pollen yield. While Rosaceae pollen in shrubs and Poaceae in herbs were less representative in a modern plant community with its own dominant species;The Artemisia and Chenopodiaceae（A/C）ratio can distinguish the desert zone from the mountain steppe zone, and could clearly reflect the aridity level. However, when using this indicator to reconstruct the climate environment, it is necessary to combine the characteristics of pollen assemblage and the influence of changes in vegetation composition and other factors to distinguish;Altitude, average annual precipitation, and average annual temperature all affect the distribution of surface pollen in the area. © 2022 The authors.