Natural and Human-Transformed Vegetation and Landscape Reflected by Modern Pollen Data in the Boreonemoral Zone of Northeastern Europe

Normunds Stivrins,Liva Trasune,Alekss Maksims,Agrita Briede,Zigmars Rendenieks,Jurijs Jeskins,Dace Steinberga,Laimdota Kalnina,Nauris Jasiunas

doi:10.3390/f12091166

Normunds Stivrins, Liva Trasune + Show 7 more

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https://doi.org/10.3390/f12091166

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Abstract

Modern pollen composition obtained from waterbody surface sediment represents surrounding vegetation and landscape features. A lack of detailed information on modern pollen from Latvia potentially limits the strength of various pollen-based reconstructions (vegetation composition, climate, landscape, human impact) for this territory. The aim of this study is to compare how modern pollen from natural and human-made waterbodies reflects the actual vegetation composition and landscape characteristics. Modern pollen analyses from surface sediment samples of 36 waterbodies from Latvia alongside oceanic-continental, lowland-upland, urban-rural and forested-agricultural gradients have been studied. In addition, we considered the dominant Quaternary sediment, soil type and land use around the studied waterbodies in buffer zones with widths of one and four km. The information on climate for the last 30 years from the closest meteorological station for each study site was obtained. Data were analyzed using Pearson correlation and principal component analysis. Results show that relative pollen values from surface sediment of waterbodies reflect dominant vegetation type and land use. Modern forest biomass had a positive correlation with pollen accumulation rate, indicating the potential use of pollen-based forest biomass reconstructions for the boreonemoral zone after additional research and calibration.

Highlights

Pollen is one of the most abundant microfossils preserved in sediment archives, whose sedimentary assemblages are related to regional and local vegetation [1,2].Whilst fossil pollen can be found in lake sediments extending back for thousands of years, modern pollen surface samples are a component of that fossil record found in the last decades
An increased amount of pollen from grasses and sedges can be considered as an effect of human activity, indicating the intensity of the overgrowth of the lake
Pine has a close connection to glaciolacustrine and eolian sediment distribution where most sites forest coverage is >40% as is reflected by the results of principal components analysis (PCA) (Figure 5)

Summary

Introduction

Pollen is one of the most abundant microfossils (sub-fossils) preserved in sediment archives, whose sedimentary assemblages are related to regional and local vegetation [1,2]. Whilst fossil pollen can be found in lake sediments extending back for thousands of years, modern pollen surface samples are a component of that fossil record found in the last decades. Modern pollen samples from lake surface sediment reflect differences in vegetation in a similar way to moss pollsters, pollen traps, and might be combined for vegetation or climate calibration purposes [3]. Modeling of climate, environmental change, forest biomass reconstructions or distribution of biota, vegetation functionality and phylogenetic diversity require input data and validation [4,5,6,7,8,9]. Limited in spatial coverage and affected by uncertainties [10], proxy records are used in model-data comparisons and quantitative

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