| 摘要: |
| 表土植硅体组合与其上覆植被类型之间的关系研究是利用植硅体进行古气候和古植被重建的基础。选取位于湿润亚热带地区的戴云山作为研究对象，沿海拔梯度以50—100 m为间隔共采集21个表土样品，以探讨该地区表土植硅体组合对山地植被的指示意义。结果表明：戴云山表土植硅体含量丰富，类型多样，主要以禾本科类植硅体占优势；此外，随着海拔的升高，表土植硅体组合中哑铃型和短鞍型百分含量快速增加，而扇型和长鞍型，特别是木本类植硅体的百分含量则逐渐减少，指示了山地植被从温性针叶林向常绿灌丛林的过渡，说明戴云山表土植硅体组合能够反映山地垂直植被带变化的主要特征；植硅体类型主成分分析（PCA）结果显示位于湿润亚热带地区的戴云山表土植硅体组合变化可能主要受温度的控制。本研究为今后在湿润亚热带山地地区开展古气候和古植被重建研究提供了重要的基础资料。 |
| 关键词: 湿润亚热带 植硅体 非地带性植被 古气候重建 |
| DOI：10.7515/JEE202017 |
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| 基金项目:国家自然科学基金项目（41771241，42077407）；福建师范大学创新团队项目（IRTL1705） |
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| Indication of soil phytoliths for the vertical vegetation change — a case study from Daiyun Mountain, Fujian Province, China |
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PEI Yaoyao, DAI Jinqi, CHEN Wenwei, LI Wenzhou, ZUO Xinxin
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1. State Key Laboratory of Subtropical Mountain Ecology (Funded by Ministry of Science and Technology and Fujian Province), Fujian Normal University, Fuzhou 350007, China
2. School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
3. Daiyun Mountain National Nature Reserve Administration Bureau, Quanzhou 362503, China
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| Abstract: |
| Background, aim, and scope Phytoliths are micro silica bodies (SiO2·H2O2) that precipitate in or among cells of living plant tissues. Their potential for long term preservation in sediments makes them a useful tool in reconstructing of ancient plant communities and plant/human interactions. Materials and methods In this study, 21 topsoil samples were collected from a 0—5 cm depth along the elevation gradient of Daiyun Mountain, from 871 m to 1856 m above sea level (a.s.l.). Phytoliths were extracted by a wet digestion method. In each sample, at least 500 phytoliths were counted. Results The results show that there were a large number of phytoliths with various morphotypes in the 21 topsoil samples from Daiyun Mountain. Topsoil phytolith assemblages included 24 diagnostic morphotypes. In the temperate coniferous forest zone, at 871—1601 m a.s.1., the percentages of bilobate, short-saddle, long-saddle, bulliform, and broadleaf-types were 36.7%, 19.4%, 11.3%, 8.7%, and 3.1%, respectively. In the evergreen broad-leaved shrub zone, at 1601—1856 m a.s.1., bilobate and short-saddle increased by 11.1% and 19.2%, respectively, but the percentages of bulliform and long-saddle decreased (9.2% and 6.5%, respectively) and broadleaf-types disappeared. Discussion The abundance of bilobate and short-saddle increased with the rising elevation, but the percentages of bulliform, long-saddle, and broadleaf-types decreased gradually. Principal component analysis performed on the eight selected topsoil phytolith morphotypes from the Daiyun Mountain shows that the first two axes account for 76.2% of the date variability, where axis 1 accounts for 63.9% of the variability, and axis 2 captures about 12.3%. Phytolith morphotypes with positive loadings in the first PC1 are bulliform, square, rectangular, and long-saddle and prevalent in warm-loving conditions. The wavy-trapezoid, bilobate, rondel, and short-saddle, prevalent in cold-loving conditions, dominate the negative loadings of the PC1. The PC1 may thus represent a low to high elevation and a temperature gradient across the Daiyun Mountain. Additionally, we tested the aridity index (Iph) and the climate index (Ic). Results show that the working potential of the phytolith indices was unsatisfactory. Conclusions Our study indicated that topsoil phytolith assemblages can reflect the change of vertical vegetation zones in Daiyun Mountain. The phytolith assemblages exhibit a high degree of sensitivity to temperature. Recommendations and perspectives Our research provides a reference for the correlation between phytolith assemblages and altitude and additional insights into the reconstruction of paleoclimate and paleovegetation in humid subtropical mountainous areas. |
| Key words: humid subtropical zone phytoliths azonal vegetation paleoclimate reconstructions |
