Vegetation-Sensing Properties of Pollen and Plant Macrofossil Assembleges: Effect of Lake Size, Pollen Dispersal, and Vegetation Pattern

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The objective of this research is to understand the vegetation-sensing properties of pollen and plant macrofossil data, which are the primary sources of information on past vegetation. Of specific concern will be the documentation of effective pollen source areas for important tree taxa in the northeastern United States and understanding the factors that affect them. Understanding of these factors, which include lake size, pollen dispersal properties, and vegetation patterns, is crucial to the design and interpretation of paleoecological studies, because pollen source area determines the spatial scale at which vegetation is recorded by fossil pollen data. Understanding of how plant macrofossils record vegetation composition is also important because macrofossils represent the absolute limits to spatial resolution attainable from paleoecological data. Modern pollen assemblages will be studied from 20 small lakes (2 ha) and 40 medium-sized lakes (5-30 ha) in addition to data from 19 small lakes which have been studied previously. Pollen percentages will be compared with tree abundances within different radial distances (20 m to 30 km) surrounding the lakes. Scatter plots and regression analyses will be used to identify pollen source areas and test models of pollen dispersal and representation. Modern macrofossil assembleges from the small lakes will be compared with forest composition within 20 m of the lakes using similar methods.