Modern pollen–plant richness and diversity relationships exist along a vegetational gradient in southern Norway

Abstract

The relationships between modern pollen and floristic plant richness, diversity and evenness are assessed using pollen assemblages and associated vegetation data from 52 lakes along an elevational and vegetational gradient in the Setesdal valley of south-central Norway. Various data transformations were applied to minimise bias in the vegetation and pollen datasets. Plant species were transformed to their pollen or spore equivalents to reduce taxonomic biases. Pollen counts were transformed using Andersen’s general pollen-representation values for northern European trees and shrubs and the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model with pollen-productivity estimates (PPEs) appropriate for Setesdal to minimise pollen-representation bias. Pollen count-size bias (before or after transformation) was eliminated by rarefaction analysis based on bootstrap resampling. Richness and diversity were quantified using Hill numbers ( N0, N1, N2), and evenness was estimated as the ratios of N0, N1 and N2. Diversity partitioning was used to estimate β diversity. The strongest correlations between pollen and plant richness and diversity are with pollen counts transformed using Andersen’s representation values and rarefied to a common count size and with plants transformed to their pollen equivalents. However, if sites from the low-alpine zone are excluded where there are high values of far-transported tree pollen, the richness and diversity relationships are also statistically significant for untransformed pollen data and plants transformed into their pollen equivalents. The effects of data transformation on diversity partitioning and estimates of β diversity are explored. We demonstrate that there are statistically significant positive relationships between pollen and plant richness and diversity along the entire elevational gradient after transforming the datasets to minimise biases due to taxonomic differences, differential pollen representation, and pollen-count size, and similar significant positive relationships along the forested parts of the gradient (nemoral, boreonemoral, southern boreal, middle boreal) after transforming the datasets to minimise biases due to taxonomic differences and pollen-count size.

Vegetation assemblages of central Mexico through the late Quaternary: modern analogs and compositional turnover

“…; Felde et al. ). This issue is especially critical in central Mexico, where the highly diverse taxa such as Pinus and Quercus (Richardson ; Nixon ) are represented only by one pollen taxon each that represents on average 35.5% and 15.7% of the pollen counts, respectively.…”

“…However, it has been proven that, although pollen represents vegetation in an imperfect way, there are positive relationships between pollen and vegetation richness and diversity (Felde et al. ). Thus, our analyses do reflect general community diversity, and although percentages of Pinus and Quercus are dominant through the studied time period (Fig.…”

Are diversity trends in western Scandinavia influenced by post‐glacial dispersal limitation?

“…,b; Felde et al. ). Composition of pollen assemblages and vegetation in southern Norway corresponds well within and between different vegetation zones, except for sites near the tree line and in the low‐alpine zone (Felde et al.…”

Patterns of modern pollen and plant richness across northern Europe

“…The relationship between pollen and plant richness is influenced by interspecific differences in pollen production and dispersal causing over‐representation of some taxa and under‐representation or absence of other taxa in pollen assemblages (Birks, Felde, Bjune et al, ; Odgaard, ; Weng, Hooghiemstra, & Duivenvoorden, ). One proposed solution is to use representation factors that downweight the influence of numerically dominant pollen taxa (Andersen, ; Felde et al, ) or to look separately at groups of taxa with different pollination types, for example wind‐pollination versus insect‐pollination (Weng et al, ).…”