新疆西部博尔塔拉河流域相对花粉产量估算及其应用

Estimating relative pollen productivity (RPP) is a suitable method to understand quantitative relationships between modern pollen and vegetation, which is important to objectively interpret fossil pollen records. Earlier studies in China have demonstrated that there are significant differences of RPP for different plant taxa in the same region and for the same plant type in different regions. As a result, RPP estimates in one region are not able to be applied to another region, and it is therefore necessary to carry out RPPs studies in other regions of China with different vegetation types. The RPPs results are so far scarce in Xinjiang where vegetation is sensitive to climate change. The Bortala River Basin in western Xinjiang has several vertical vegetation zones, indicating that it is an ideal region for RPPs studies. In this study, we are aim to collect modern pollen samples and to conduct vegetation surveys in the Bortala River Basin. The Extended R-Value (ERV) model will be used to estimate RPP for common plant types. The Reveal model (Regional Estimates of Vegetation Abundance from Large Sites) will be applied to a fossil pollen record in the upper part of the basin for reconstructing the vegetation changes during the Holocene. We will compare our pollen record with other Holocene pollen records from the Bortala River Basin in order to investigate the Holocene vegetation patterns in different altitude regions of the basin.

相对花粉产量估算是正确地认识现代花粉与植被的数量关系，及客观地解释化石花粉组合的有效途径。已有研究表明，中国同区域不同植物类型之间的花粉产量存在显著差异，不同区域同种植物类型之间的花粉产量也存在显著差异。因此，一个地区的花粉产量不能应用到其他区域，有必要开展我国不同地区和植被带的花粉产量研究。目前新疆的花粉产量研究较少，其西部的博尔塔拉河流域分布有明显的植被类型垂直带，适合开展相对花粉产量研究，且对气候变化响应较为敏感，是研究不同海拔高度全新世植被演变模式的理想区域。本研究计划在博尔塔拉河流域采集现代花粉样品和进行植被调查，运用ERV模型估算常见植物类型的相对花粉产量。在流域上部的温泉县湿地，获取新的全新世花粉谱，将花粉产量结果和REVEALS模型应用于化石花粉记录，定量恢复全新世植被景观的变化过程。对比温泉与流域其他样点的化石花粉记录，探讨流域不同海拔高度全新世植被演变模式的异同。

研究花粉产量是准确认识花粉与植被的数量关系，及正确解释花粉组合的必要前提和基础，有助于客观地反映过去植被的动态演替过程。中国西北干旱区的花粉产量研究较少，急需开展相关工作。本项目选择新疆天山西部的博尔塔拉河流域及其周边地区为研究对象，通过46个表土样点的现代孢粉分析及植被数据调查，利用ERV模型估算了6个主要植物种类的相对花粉产量，并检验其可靠性。结果表明，研究区的相关花粉源范围为600m左右，相对花粉产量由高到低依次为藜科>麻黄>蒿属>莎草科>菊科>禾本科。依据新获得的相对花粉产量数据，定量重建了博尔塔拉河流域温泉湿地全新世植被组成的变化过程。研究结果为正确解释西北干旱区化石孢粉记录，定量重建全新世植被变化过程提供了关键参数和科学依据。