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Methods of reconstructing changes in plant traits over long time scales are needed to understand the impact of changing environmental conditions on ecosystem processes and services. Although Holocene pollen have been extensively used to provide records of vegetation history, few studies have adopted a functional trait approach that is pertinent to changes in ecosystem processes. Here, for woody and herbaceous fen peatland communities, we use modern pollen and vegetation data combined with pollen records from Holocene deposits to reconstruct vegetation functional dynamics. The six traits chosen (measures of leaf area-to-mass ratio and leaf nutrient content) are known to modulate species’ fitness and to vary with changes in ecosystem processes. We fitted linear mixed effects models between community weighted mean (CWM) trait values of the modern pollen and vegetation to determine whether traits assigned to pollen types could be used to reconstruct traits found in the vegetation from pollen assemblages. We used relative pollen productivity (RPP) correction factors in an attempt to improve this relationship. For traits showing the best fit between modern pollen and vegetation, we applied the model to dated Holocene pollen sequences from Fenland and Romney Marsh in eastern and southern England and reconstructed temporal changes in trait composition. RPP adjustment did not improve the linear relationship between modern pollen and vegetation. Leaf nutrient traits (leaf C and N) were generally more predictable from pollen data than mass-area traits. We show that inferences about biomass accumulation and decomposition rates can be made using Holocene trait reconstructions. While it is possible to reconstruct community-level trends for some leaf traits from pollen assemblages preserved in sedimentary archives in wetlands, we show the importance of testing methods in modern systems first and encourage further development of this approach to address issues concerning the pollen

Methods of reconstructing changes in plant traits over long time scales are needed to understand the impact of changing environmental conditions on ecosystem processes and services. Although Holocene pollen have been extensively used to provide records of vegetation history, few studies have adopted a functional trait approach that is pertinent to changes in ecosystem processes. Here, for woody and herbaceous fen peatland communities, we use modern pollen and vegetation data combined with pollen records from Holocene deposits to reconstruct vegetation functional dynamics. The six traits chosen (measures of leaf area-to-mass ratio and leaf nutrient content) are known to modulate species’ fitness and to vary with changes in ecosystem processes. We fitted linear mixed effects models between community weighted mean (CWM) trait values of the modern pollen and vegetation to determine whether traits assigned to pollen types could be used to reconstruct traits found in the vegetation from pollen assemblages. We used relative pollen productivity (RPP) correction factors in an attempt to improve this relationship. For traits showing the best fit between modern pollen and vegetation, we applied the model to dated Holocene pollen sequences from Fenland and Romney Marsh in eastern and southern England and reconstructed temporal changes in trait composition. RPP adjustment did not improve the linear relationship between modern pollen and vegetation. Leaf nutrient traits (leaf C and N) were generally more predictable from pollen data than mass-area traits. We show that inferences about biomass accumulation and decomposition rates can be made using Holocene trait reconstructions. While it is possible to reconstruct community-level trends for some leaf traits from pollen assemblages preserved in sedimentary archives in wetlands, we show the importance of testing methods in modern systems first and encourage further development of this approach to address issues concerning the pollen

Thick deposits of peat derived from fen environments accumulated in the coastal lowland areas adjacent to theNorth Sea during the middle and late Holocene. These sediments are frequently used in pollen-based reconstruc-tions ofin situand more distant vegetation. However, discriminating between wetland and dry land originatingpollen signals, and between the potential fen communities present in the wetland, is complex. In this study, asuite of analytical approaches are used to explore the pollen signal of modern fen communities and comparethem against Holocene pollen assemblages. At two sites in eastern England, Woodwalton Fen and UptonBroad, vegetation composition was recorded around a series of moss polster sampling points. The communitiesinvestigated included herbaceous fen communities under different cutting regimes, a grazed area, glades, andwoodland with canopies dominated byAlnus glutinosaandBetula. Cluster analysis is used to provide an overviewof, and compare the structure within, the datasets consisting of the vegetation, the vegetation converted to pal-ynologicalequivalents, and thepollen data.Itis demonstratedthat any loss of taxonomic precision in pollen iden-tifications does not pose particular problems when attempting to identify fen communities, including tall-herbaceous vegetation, in the pollen record. Indices of Association imply pollen presence can be interpreted asindicating the local presence for some taxa, though few of these are confined to a particular community. Herba-ceous fen vegetation subject to different management regimes are, however, shown to produce distinctive pollensignatures. Middle and late Holocene pollen assemblages from eastern (Fenland) and southern (Romney Marsh)England, interpreted as derived from fen vegetation, are compared against the modern pollen dataset using or-dination.Mostof the fossilsamples plot out within or adjacent to the groupings produced by the modernsamplesin the ordinations. While these investigations dem