鄱阳湖地区过去2160年孢粉记录的植被变化及影响因素  

Vegetation change and its driving factors recorded by pollen assemblage from Lake Poyang over the past 2160 years

作　　者：庞有智[1] 杨明生[2] 张虎才 邓财 唐领余[4] PANG Youzhi;YANG Mingsheng;ZHANG Hucai;DENG Cai;TANG Lingyu(School of Geography and Resource Science,Neijiang Normal University,Neijiang 641100,Sichuan;School of Resources&Environment,Nanchang University,Nanchang 330000,Jiangxi;Institute for Ecological Research and Pollution Control of Plateau Lakes,Shool of Ecology and Environmental Science,Yunnan University,Kunming 650504,Yunnan;Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,Jiangsu)

机构地区：[1]内江师范学院地理与资源科学学院,四川内江641100 [2]南昌大学资源与环境学院,江西南昌330000 [3]云南大学生态学与环境学院,高原湖泊生态与污染治理研究院,云南昆明650504 [4]中国科学院南京地质古生物研究所,江苏南京210008

出　　处：《第四纪研究》2023年第5期1225-1240,共16页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:41561045);四川省自然科学基金项目(批准号:2022NSFSC1045);内江师范学院校级科研项目(批准号:17JC13)共同资助。

摘　　要：本研究在AMS14C测年的基础上,通过分析鄱阳湖430 cm沉积剖面44个样品的孢粉记录和有机碳(TOC)指标,同时结合江西人口密度指标及当地历史文献资料,重点探讨了该区过去2160年植被变化的影响因素及在人类活动影响下该区域植被变化的历史。研究结果显示,鄱阳湖流域过去2160年植被变迁及人类活动变化主要分为5个阶段:1)160 BC~400 A.D.,乔灌木花粉含量较低,草本植物花粉较高,指示鄱阳湖流域周围地势低平的地带已经被广泛垦殖,但周围仍分布着一定量的常绿阔叶类、落叶阔叶类以及针叶类植被。高含量的禾本科表明鄱阳湖流域的稻作农业已初具规模,但该期乔灌木花粉含量相对较高,蕨类孢子含量较低,人口密度较小,指示该时期森林覆盖度较高,人类活动相对较弱。2)400~800 A.D.,乔灌木植物花粉与草本植物含量变化不大,植被与前期基本一致。高含量的蕨类孢子指示人类活动进一步加强,但人口密度较低,指示该时期森林覆盖度仍然较高,人类活动相对较弱。3)800~1350 A.D.,乔灌木花粉含量显著下降,而与人类活动相关的草本植物花粉含量略有上升,表明鄱阳湖流域随着人类活动增强,地带性森林植被遭受到一定的破坏,森林覆盖度明显下降,该期人口密度迅速递增,农业垦殖强度进一步加强,农业生产规模继续扩大,指示该时期人类活动影响较强,森林植被覆盖度较低。4)1350~1650 A.D.,乔灌木花粉含量略有上升,草本植物花粉含量略有下降,指示该时期鄱阳湖流域常绿阔叶类、落叶阔叶类及针叶类植被较前期略有恢复,尤其是松属花粉含量增长明显,表明该区地带性植被破坏后逐渐演变为具有次生性质的松林。该时期由于气候变冷,自然灾害频发,加上战争频繁,人口密度显著下降,人类活动影响减弱,进而导致森林植被略有恢复。5)1650 A.D.至今,鄱阳湖流域植被与前期较为一致,�Lake Poyang Basin(28°22'~29°45'N,115°47'~116°45'E)is located in the middle reaches of the Yangtze River basin.It was always regarded as a famous grain base since ancient times due to superior natural conditions.The development of agricultural activities has exerted a huge impact on the vegetation evolution dynamics in this basin.And the basin has experienced frequent flood and drought disasters as a result of global warming in the region.Therefore,it is essential for natural disaster prevention and sustainable development of ecological environment to study the relationship between vegetation change and human activity in the past.In this study,a 4.3-m-depth section(29°02'52″N,116°18'37″E)was collected from the southwest of Poyang Lake.We combined down-profile analyses of pollen records,organic carbon(TOC)content with population density for a AMS 14C-based profile to track the vegetation history in Lake Poyang basin over the past 2160 years.The results showed that the vegetation variation and human activities in Lake Poyang basin during the past 2160 years were mainly divided into five periods.(1)160 BC~400 A.D.,the concentrations of trees and shrubs pollen were very lower,whereas the herbs pollen concentration were relatively higher,indicating that the low-lying area around Lake Poyang basin had been extensively reclaimed.These results also suggests that there were still small-scale of vegetation such as evergreen broad-leaved,deciduous broad-leaved and coniferous trees across this area.High concentration of Gramineae pollen indicates that farming practices in the basin had been extensively developed.The combination higher pollen concentration of trees and shrubs,low spore content of ferns,and low population density indicates that the forest cover was higher and human activities were relatively weak in this period.(2)400~800 A.D.,the pollen contents of the trees and shrubs and the herbs pollen were consistent with those of the earlier period,which indicated that the vegetation did not change.High levels

关 键 词：气候变化 孢粉 植被变化 鄱阳湖 退耕还湖 

分 类 号：Q944.571[生物学—植物学] P941.78[天文地球—自然地理学]