探索新近纪植被和环境的发展规律,是了解当今地球生物多样性和环境的形成过程、预测今后可能变化趋势的重要途径,已成为当今学术界研究的一个热点.鉴于中国新近纪植被和环境演化的错综复杂性,为使相关研究工作的开展真实有效,特提出下列几个问题进行讨论,以期引起大家的重视:1)资料的不均衡性.现有的有关中国新近纪古植物资料因研究时期、产地和化石类型的不同,存在着很大的不均衡性,如一些源于油田的孢粉资料,大多是以孢粉组合的形式陈述,孢粉组合所涵盖的地层往往很厚,其精度远比以样品为单元的资料为低.2)地质年代的精确对比.中国陆相地层年代的确定以往主要参照化石证据,其中孢粉为重要证据之一.鉴于新近纪植被分异的增大,大区域间的孢粉对比存在着较大的风险,工作中需要更多地运用其他证据,如古地磁等.3)大植物与孢粉资料运用的利弊.用综合化石证据来恢复古植被,需要根据不同化石的保存特性区别对待,如孢粉的产出层位一般比较连续,但更多地代表区域性植被面貌；而大植物的分布层位比较局限,主要反映本地植物的情况.此外,由于保存的缘故,草本植物的花粉比大植物更容易被保存.4)定量方法的运用.对原始资料需要建立一个严格的取舍标准,以去除因资料的不均衡所引起的误差.对孢粉和大植物资料要区别对待,因孢粉组分的百分含量对决定植被的类型至关重要.%Neogene is an important period for the evolution of vegetations. The distribution pattern of modern vegetation on the earth is largely affected and restricted by the Late Cenozoic environment changes to a great extent. Consequently, the relevant Neogene vegetation and its relationship with environment have got more and more attention in the academic circle. Some new approaches, such as various related quantitative and semi-quantitative methods, are increasingly applied in different studies, which greatly improve the resolution of the results obtained. As for the situation in China, the uplift of Qinghai-Tibet Plateau and the formation and afterward development of the East Asian monsoon, are indubitably the cause for the wide diversification of Neogene vegetation in China. Meanwhile, limited outcrops with discontiguous strata of the widespread terrestrial deposits in China, makes stratigraphic comparison in different regions difficult. In view of the above circumstances, this paper discusses some possible bias in the Neogene vegetation and environmental studies based on some related case studies.( 1 ) Unequilibrium of the data; the existing Chinese Neogene mega-plant and pollen data display a great imbalance among the different study periods, fossil sites and fossil types. For example, pollen data from some oilfields were generally compiled in the palynological assemblages that cover thick stratigraphic beds. Their precisions are much lower than those based on separate samples. ( 2 ) Precise chronological comparison; chronology for the terrestrial strata in China was formerly established mainly by fossil evidences. Among them, palynology was one of the major approaches, whereas increasing vegetation differentiation in the Neogene of China, implicates the underlying risk in the pollen comparison between regions. Therefore, other evidences, such as paleomagnetic study, etc. Are necessary as a supplement. (3) Advantages and disadvantages in using mega-plant and palynological data: while using comprehensive fossil evidences to restore the paleovegetation, it is required to make a different treatment of the respective fossil groups based on their characteristics of preservation. Pollen data are generally representative of continual beds for a series of time, but more regional, while mega-plants are often limited to certain definite beds, but more local. In addition, under the different preservation condition, herbaceous plants tend to be more often preserved with pollen rather than the mega-plants. (4) Application for quantitative method; a strict standard is necessary in dealing with the original data; so that we will be acquaint in advance to avoid the existing bias caused by the uneven development of the data. It is also definitely important to differentiate pollen data from the mega-plant data. As for a pollen assemblage, percentage of the representative elements is a primary factor in determining a vegetation type.
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