巢湖地区现代花粉-植被-人类活动关系研究

Study on the relationship of modern pollen, vegetation and human activities in the Chaohu Lake area

巢湖地区的孢粉研究多集中于化石孢粉,相对缺少现代孢粉研究的支持。选取巢湖地区苔藓表土样品及湖泊表层底泥样品共49个进行孢粉分析,探讨现代花粉与植被分布及人类活动的关系。结果表明:花粉组合与当地植被有着很好的对应关系,可以反映出当地的植被状况,松属、栗属、落叶栎类、榆科、朴属、柳属、枫杨属、蔷薇科、十字花科、蒿属、紫菀属、禾本科(≤37μm)、藜科和眼子菜属为花粉主要类型。现代花粉和钻孔花粉的匹配度较高,可以为反演古植被古气候提供科学依据。花粉图谱和聚类分析将所有的采样点划分为4个土地利用类型。主成分分析相对划分出3个不同程度的人类活动影响区域:(1)农田区—人类活动影响最强烈的区域;(2)公园绿地区—人类活动影响较强的区域;(3)次生林和湖心区—人类活动影响较弱的区域。巢湖地区十字花科花粉含量的变化在一定程度上可以区分人类活动的强弱,有较强的指示作用。此外,由于大规模开发、人工栽培以及次生林生长等因素均可能对花粉含量产生较大影响,结合钻孔孢粉分析推测近1000年来巢湖地区松属、十字花科和谷物类禾本科花粉大量增加的主要影响因素极有可能是人为因素而非自然因素。

The pollen research in Chaohu area is mostly focused on fossil pollen, while the related studies of modern pollen are relatively scarce. A total of 49 moss surface soil samples and lake surface sediment samples in Chaohu area were selected for pollen analysis to explore the relationship of modern pollen, vegetation distribution and human activities. The results show that pollen assemblage has a good correspondence with local vegetation, which can well reflect the status of local vegetation, dominated by Pinus, Castanea, Quercus D, Ulmaceae, Celtis, Salix, Liquidambar, Rosaceae, Brassicaceae,Artemisia, Aster, Poaceae(≤37 μm), Chenopodiaceae and Potamogeton. The matching degree of modern pollen and fossil pollen is good, which can provide support for the restoration of paleovegetation and paleoclimate. Pollen diagram and cluster analysis can divide all sampling points into 4 land use types. Principal component analysis can be divided into three regions with different impact degrees of human activities:(1) Farmland areas-areas most strongly affected by human activities;(2)Park green areas-areas with strong impact of human activities;(3) Secondary forest and Lake Center areas-areas with weak impact of human activities. The change of Brassicaceae pollen content in the study area can distinguish the strength of human activities to a certain extent, and has a strong indicating effect. In addition, large-scale development, artificial cultivation and secondary forest growth may have a great impact on pollen percentage content. Combined with fossil pollen analysis, human activities rather than natural factors are likely to be the main factors affecting the large increase of Pinus, Brassicaceae and Cereal type pollen in Chaohu Area in recent 1000 years.