This paper presents the pollen assemblages from 108 surface sediment samples from 4 lakes(the Lake Daihai,Lake Hongjiannao,Lake Hulunnao and Lake Duikounao) in the monsoon fringe area of China.The herb pollen taxa Artemisia,Chenopodiaceae,Poaceae and Compositae are the major components of pollen assemblages of the 4 lakes and Pinus,Betula,Quercus,Ulmus,Populus,Ostryopsis and Elaeagnaceae are frequently presented,which reflect regional and local vegetation well.The mean similarity coefficients for samples from the Lake Daihai,Lake Hongjiannao,Lake Hulunnao and Lake Duikounao are 0.66 ± 0.17,0.71 ± 0.11,0.73 ± 0.12 and 0.67 ± 0.12 respectively,so pollen assemblages are relatively consistent in each lake,which shows that focusing and mixing effects have occurred before and after pollen deposition.However,pollen assemblages do differ between sampling sites in each lake.The largest difference is seen in the Lake Daihai,followed by the Lake Duikounao,Lake Hulunnao and Lake Hongjiannao(The mean Euclidean distance is 20.09 ± 11.11,11.22 ± 3.64,10.67 ± 4.03 and 8.44 ± 4.51 respectively).These differences are possibly caused by the differences of focusing and mixing effects,pollen source areas,drainage areas and regional vegetation compositions.The Lake Daihai and Lake Hongjiannao have water deeper than 5 m and strong re-suspension,focusing and mixing effects occur in the lakeshore and shallow water areas,where pollen concentrations are lower than in deeper lake areas.In the Lake Hulunnao and Lake Duikounao,with depths less than 5 m,re-suspension and mixing effects are obvious across the whole lake area,so pollen assemblages and pollen concentra-tions are more consistent among sampling sites in each lake.Comparison between the lake samples and samples from the inflowing river reveals that wind is primary pollen transportation force in the Lake Hongjiannao,where the consistency of pollen assemblage is conspicuous,while there is greater variation in lakes where pollen input is dominated by waterborne sources.
TIAN Fang1,2,XU QingHai1,2,3,LI YueCong1,2,CAO XianYong1,2,WANG XueLi1,2 & ZHANG LiYan1,2 1 College of Resources and Environmental Sciences,Hebei Normal University,Shijiazhuang 050016,China
Investigation of 78 surface pollen samples from warm temperate hilly areas of eastern China shows that pollen assemblages in areas of different land use are significantly different.Pollen concentrations in wastelands are higher than in plantations;these,in turn,are higher than in farmlands;implying that pollen concentration decreases with increasing human impact.Arboreal pollen dominated by Pinus and Quercus is common in all samples.Herbaceous pollen percentages are higher while shrub pollen,fern spores and fern allies are lower in farmlands than in wastelands.Crop pollen is only detectable in and near farmlands;its percentages and concentrations decrease in wastelands.Cereal and Cruciferae pollen percentages average 16.7% and 6.7% in farmland respectively,but Cereal reduces to less than 3% and Cruciferae to less than 0.5% in nearby wastelands.Principle coordinates analysis and clustering analysis indicate that pollen assemblages from farmlands are distinguishable from those under other vegetation types.Occurrence of Poaceae,Chenopodiaceae,Artemisia,and Compositae pollen and Selaginella sinensis spores are closely related to human activities,and their types and frequencies indicate intensity of human impact.The spatial distribution of crops,Chenopodiaceae,and Artemisia reflects changes in both natural environments and human activities.Percentages of cereal and Cruciferae pollen,for example,increase with decreasing altitude,but decrease with increasing latitude.Understanding pollen assemblages under artificial and human-disturbed vegetation in hilly areas may aid understanding of human impacts on the plains during the early-middle Holocene.
DING Wei PANG RuiMing XU QingHai LI YueCong CAO XianYong
Pollen analysis is one of the best and possible approaches for the quantitative reconstruction of paleobotany and paleoclimate,and discrimination of human activities.In this paper,we reveal the characteristics of pollen assemblages in different agricultural units and their spatial distribution of major pollen taxa in the Anyang area where the human influences are serious,so as to get more information about climate change and human activities from pollen records.The pollen assemblages of total 122 surface soil samples from different agricultural units (farm lands,vegetable plots,wastelands,cape-lands,woodlands,etc.) indicate that herbaceous pollen dominates the pollen assemblages with an average of 73%,mainly from Poaceae,Artemisia,Chenopodiaceae and Cruciferae;arboreal pollen percentages reach 18%,mainly from Pinus and Ulmus;shrub pollen and fern spores have very low percentages.In general,pollen assemblages are consistent with vegetation composition,though some differences also exist in different agricultural units.In farmlands and vegetable lands,Poaceae pollen has the highest percentages (averaging 27%) compared to other agricultural units with dominant corn or wheat pollen,while in wastelands and woodlands,arboreal and Artemisia pollen percentages have higher values (averaging 20% and 19% respectively).Cruciferae has the highest pollen percentages (70%) in rape-lands.Both pollen assemblages and PCoA can generally identify the vegetable plots,farmlands,woodlands,wastelands,and rape-lands.Pinus and Artemisia pollens mainly appear in the western part of Anyang,which is consistent with the parent plants;Poaceae pollen mainly exist in the eastern part with more farmlands;Chenopodiaceae pollen mainly appear in the urban areas and near major roads where human influences are stronger,Cruciferae pollen can mainly be found in the urban area and in the northwest part of Anyang where more vegetables are planted.
WANG XueLi1,2,LI YueCong1,2,XU QingHai1,2,CAO XianYong1,2,ZHANG LiYan1,2 & TIAN Fang1,2 1 College of Resource and Environmental Sciences,Hebei Normal University,Shijiazhuang 050016,China
The pollen flux in coniferous and deciduous broadleaved mixed forest in the Changbai Mountains is presented in one year's experiments. The results indicate that arboreal pollen percentages are more than 65% and pollen flux is higher than 5000 grain·cm-2·a-1,while less than 2% and lower than 1000 grain·cm-2·a-1 for shrubby pollen,and less than 20% and lower than 3000 grain·cm-1·a-1 for herbaceous pollen for most samples at different heights. The pollen assemblages are similar to those in the samples under 8 m height where Pinus and Ouercus are dominant and followed by the few non-local pollen types,and Fraxinus percentages are high with a few non-local pollen types at 16 m to 32 m height as well as non-local pollen clearly increased at 40 m height. Comparisons between pollen assemblages and vegetation composition suggest that similarities are higher for pollen trap samples than for surface moss samples.
