SURFACE POLLEN DISTRIBUTION AND ITS RELATIONSHIP WITH CLIMATE IN SUBTROPICAL CHINA
The subtropical zone of China(22°～34°N,98°～123° E)is located in the main influence area of East Asian summer monsoon(ESM)and Indian summer monsoon(ISM).Paleoclimate reconstruction in this region is crucial for understanding global climate change.Modern pollen processes play an important role in the quantitative reconstruction of paleoenvironment using fossil pollen data.Based on 1140 surface pollen samples,the distribution of surface pollen and its relationship with climate in subtropical China is analyzed with Redundancy Analysis(RDA).The results show that:(1)There were abundant pollen taxa in the subtropical zone,such as Pinus,Castanopsis,Cyclobalanopsis,Alnus and Quercus.Five vegetation zones are characterized with different pollen assemblages.(2)The distribution of pollen exhibited significant changes in longitude,latitude,and altitude,with the specific percentage of pollen indicating geographic variations.(3)The winter mean precipitation(MWP)is a crucial climatic factor influencing the distribution of surface pollen in subtropical China and should be prioritized in selecting quantitative reconstruction parameters.Additionally,mean temperature in January(Mtco),mean relative humidity in winter(MWH),mean temperature in July(Mtwa),and mean relative humidity in July(Mhwa)also significantly impact surface pollen distribution.(4)The main climatic factors controlling surface pollen distribution in the north subtropical,eastern mid-subtropical,southeastern subtropical,western mid-subtropical and southwestern subtropical regions are annual mean temperature(MAT),summer mean relative humidity(MSH),winter mean precipitation(MWP),mean temperature in January(Mtco),and July mean precipitation(Mpwa),respectively.However,the low λ1/λ2 ratio suggests that the relative explanatory power of climate variables is limited,and caution should be exercised when utilizing them in climate reconstruction.(5)Different pollen taxa are associated with distinct climatic conditions.For instance,pollen taxa such as Castanopsis,Euphorbiaceae,Mallotus,and Liquidambar are indicative of warm and humid climates.In contrast,the pollen taxa such as Alnus,Betula,Corylus,Quercus and Quercus-sclerophyllous type are associated with cold climates.
万方数据
维普
