滇西北天才湖地区过去400年以来植被变化的孢粉记录  

POLLEN RECORD OF VEGETATION CHANGES IN TIANCAI LAKE AREA OF NORTHWESTERN YUNNAN OVER THE PAST 4OO YEARS

作　　者：钟海璐 张雨桐 王皓言 孔令阳 廖梦娜 李凯 ZHONG Hailu;ZHANG Yutong;WANG Haoyan;KONG Lingyang;LIAO Mengna;LI Kai(College of Life Sciences,Zhejiang Normal University,Jinhua 321000,Zhejiang;Department of Geography,Yunnan Normal University,Kunming 650050,Yunnan)

机构地区：[1]浙江师范大学生命科学学院,浙江金华321000 [2]云南师范大学地理学部,云南昆明650050

出　　处：《第四纪研究》2024年第3期715-726,共12页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:42177433)资助。

摘　　要：本研究以横断山区高山湖泊天才湖为对象,通过对43 cm沉积岩芯进行210Pb和137Cs测年以及孢粉分析,重建了老君山地区过去400年的植被组成、植物功能性状和功能多样性的变化。研究结果显示,老君山高海拔地区植被以针叶林为主,以松属植物为优势,在过去400年间区域植被类型稳定,但植被成分发生了一定改变。松属植物在1900 A.D.以前呈扩张趋势,表现为松属花粉百分含量的逐渐增加,而1900 A.D.以后则呈现减少趋势。在过去400年间,云杉属、铁杉属和冷杉属植被成分总体呈下降趋势,尤其是1850 A.D.以后最为明显;与针叶植物减少的趋势相反,阔叶木本植物则表现出长期增加的趋势,并于1960 A.D.以后达到剖面最大值。以现代植物性状为参考,在孢粉科属分类水平重建的植物功能性状结果显示,植物叶干物质含量(LDMC)和叶厚度(LT)在1900 A.D.之前处于高值,之后呈现波动下降趋势,与之相反的是,叶面积(LA)和比叶面积(SLA)在1900 A.D.以后明显增加。基于植物功能性状变化重建的植物功能离散度(FDis)在1900 A.D.前后也由波动降低转为增加趋势。冗余分析结果显示天才湖地区年均温度、太阳辐射和CO_(2)浓度可能是驱动过去400年区域植被变化的主要因素。从生态学角度来看,热量(温度)、光照和CO_(2)浓度是影响植物光合作用和生长的重要环境因子,过去400年年均温度和CO_(2)浓度的增加,以及光照条件的变化可能通过不断影响植物功能性状,进而导致了植物组分和功能多样性的改变。植物功能性状的改变可能是植物响应气候变化的重要机制,这对于理解滇西北高海拔地区长期气候变化对植被的影响具有重要意义。Modern global warming and intensified human activities have cast increasing pressure on vegetation change on alpine regions.Study palaeovegetation on change in alpine region and reveal their response to climate change gains priority on understanding the current vegetation statues and their likely variations under global warming.Tiancai Lake(26°38′N,99°43′E)on Laojun Mountain in Jianchuan County,Yunnan Province,is a typical alpine lake with continuous lake sediments and surrounded by dense forest,which makes it a suitable region to study the vegetation change and the mechanism responding to modern climate warming.Here,we collected a 43-cm sediment core from Tiancai Lake and conducted pollen analysis,based on which,detailed changes in vegetation composition,plant functional traits,and functional diversity in the Laojun Mountain area over the past 400 years were discussed.The age-depth model,established by using 137Cs and 210Pb,yielded that the deposition age of the bottom sediment was 1635 A.D.(1592~1635 A.D.).A total of 91 pollen taxa had been identified,including 32 families and 59 genera.There were 47 woody plant pollen taxa,27 terrestrial herbaceous taxa,3 wet herbaceous taxa,and 14 fern taxa,with an average pollen concentration of 70891 grains per gram.Pollen composition indicated that coniferous forests dominated the vegetation since 1600 A.D.Although the regional vegetation remained stable,notable shifts in vegetation composition has been uncovered.Specifically,Pinus exhibited an expanding trend before 1900 A.D,after which this trend reversed.The vegetation components of Tsuga and Abies have generally shown a downward trend after 1900 A.D.Conversely,broad-leaved woody plant taxa have demonstrated a long-term increasing trend,peaking after 1960s.Reconstructed plant functional traits based on pollen taxonomy suggest that leaf dry matter content and leaf thickness were elevated before 1900 A.D.,followed by fluctuating decreasing trends.Leaf area and specific leaf area increased significantly after 1900 A.

关 键 词：孢粉 植被变化 植物功能性状 过去400年 天才湖 

分 类 号：Q944.571[生物学—植物学] Q948.112