A statistical sub-sampling tool for extracting vegetation community and diversity information from pollen assemblage data

Keen, Hayley Frances; Gosling, William D.; Hanke, Felix; Miller, Charlotte; Montoya, Encarni; Valencia, Bryan G.; Williams, Joseph J.

doi:10.1016/j.palaeo.2014.05.001

Cited by 25 publications

(26 citation statements)

References 30 publications

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“…The pollen data are limited by the original pollen counts in the samples and any transformation can only work within the limits of the original counts. To overcome this problem, methods adjusting the maximum pollen count during the counting process have been proposed—allowing pollen counts to be developed relative to the evenness and richness of the specific sample rather than a fixed number (Keen et al, ). Our analyses together with earlier studies (Felde et al, ; Matthias et al, ) suggest that methods accommodating pollen‐representation bias in pollen richness studies warrant further attention and should become as widely used as pollen‐production transformations in land‐cover reconstruction studies (e.g.…”

Section: Discussionmentioning

confidence: 99%

Patterns of modern pollen and plant richness across northern Europe

et al. 2019

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Sedimentary pollen offers excellent opportunities to reconstruct vegetation changes over past millennia. Number of different pollen taxa or pollen richness is used to characterise past plant richness. To improve the interpretation of sedimentary pollen richness, it is essential to understand the relationship between pollen and plant richness in contemporary landscapes. This study presents a regional‐scale comparison of pollen and plant richness from northern Europe and evaluates the importance of environmental variables on pollen and plant richness. We use a pollen dataset of 511 lake‐surface pollen samples ranging through temperate, boreal and tundra biomes. To characterise plant diversity, we use a dataset formulated from the two largest plant atlases available in Europe. We compare pollen and plant richness estimates in different groups of taxa (wind‐pollinated vs. non‐wind‐pollinated, trees and shrubs vs. herbs and grasses) and test their relationships with climate and landscape variables. Pollen richness is significantly positively correlated with plant richness (r = 0.53). The pollen plant richness correlation improves (r = 0.63) when high pollen producers are downweighted prior to estimating richness minimising the influence of pollen production on the pollen richness estimate. This suggests that methods accommodating pollen‐production differences in richness estimates deserve further attention and should become more widely used in Quaternary pollen diversity studies. The highest correlations are found between pollen and plant richness of trees and shrubs (r = 0.83) and of wind‐pollinated taxa (r = 0.75) suggesting that these are the best measures of broad‐scale plant richness over several thousands of square kilometres. Mean annual temperature is the strongest predictor of both pollen and plant richness. Landscape openness is positively associated with pollen richness but not with plant richness. Pollen richness values from extremely open and/or cold areas where pollen production is low should be interpreted with caution because low local pollen production increases the proportion of extra‐regional pollen. Synthesis. Our results confirm that pollen data can provide insights into past plant richness changes in northern Europe, and with careful consideration of pollen‐production differences and spatial scale represented, pollen data make it possible to investigate vegetation diversity trends over long time‐scales and under changing climatic and habitat conditions.

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Section: Discussionmentioning

confidence: 99%

Patterns of modern pollen and plant richness across northern Europe

et al. 2019

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“…1a). Target pollen sums for the Ghanaian traps were estimated using model 1 of the sample specific count method developed by Keen et al (2014). Application of the Keen et al (2014) model 1 resulted in pollen sums of > 5,500 grains per vegetation study plot (Table 1; Fig.…”

Section: Methodsmentioning

confidence: 99%

Pollen-vegetation richness and diversity relationships in the tropics

Gosling

Julier

Adu‐Bredu

et al. 2017

Veget Hist Archaeobot

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Tracking changes in biodiversity through time requires an understanding of the relationship between modern diversity and how this diversity is preserved in the fossil record. Fossil pollen is one way in which past vegetation diversity can be reconstructed. However, there is limited understanding of modern pollen-vegetation diversity relationships from biodiverse tropical ecosystems. Here, pollen (palynological) richness and diversity (Hill N 1 ) are compared with vegetation richness and diversity from forest and savannah ecosystems in the New World and Old World tropics (Neotropics and Palaeotropics). Modern pollen data were obtained from artificial pollen traps deployed in 1-ha vegetation study plots from which vegetation inventories had been completed in Bolivia and Ghana. Pollen counts were obtained from 15 to 22 traps per plot, and aggregated pollen sums for each plot were > 2,500. The palynological richness/diversity values from the Neotropics were moist evergreen forest = 86/6.8, semi-deciduous dry forest = 111/21.9, wooded savannah = 138/31.5, and from the Palaeotropics wet evergreen forest = 144/28.3, semi-deciduous moist forest = 104/4.4, forest-savannah transition = 121/14.1; the corresponding vegetation richness/diversity was 100/36.7, 80/38.7 and 71/39.4 (Neotropics), and 101/54.8, 87/45.5 and 71/34.5 (Palaeotropics). No consistent relationship was found between palynological richness/diversity, and plot vegetation richness/diversity, due to the differential influence of other factors such as landscape diversity, pollination strategy, and pollen source area. Palynological richness exceeded vegetation richness, while pollen diversity was lower than vegetation diversity. The relatively high global diversity of tropical vegetation was found to be reflected in the pollen rain.

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“…To estimate the changes in taxonomic diversity between single samples and different pollen zones (PZs) within seam 1, several calculations for species richness and evenness were applied, using tools for biodiversity analysis as provided by [56, 57]. Richness is simply the number of taxa within an ecosystem, which is here calculated as the total number of palynological taxa within a sample or a PZ [58]. It can be measured at different scales, for which mainly the three terms alpha, beta, and gamma diversity have been used [59].…”

Section: Methodsmentioning

confidence: 99%

Greenhouse conditions in lower Eocene coastal wetlands? – Lessons from Schöningen, Northern Germany

Lenz

Riegel

Wilde

2020

Preprint

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The Paleogene succession of the Helmstedt Lignite Mining District in Northern Germany includes coastal peat mire records from the latest Paleocene to the middle Eocene at the southern edge of the Proto-North Sea. Therefore, it covers the different long- and short-term climate perturbations of the Paleogene greenhouse. 56 samples from three individual sections of a Lower Eocene seam in the record capture the typical succession of the vegetation in a coastal wetland during a period that was not affected by climate perturbation. This allows to distinguish facies-dependent vegetational changes from those that were climate induced. Cluster analyses and NMDS of well-preserved palynomorph assemblages reveal four successional stages in the vegetation during peat accumulation: (1) a near-coastal vegetation, (2) a lowland mire, (3) a transitional mire, and (4) a terminal mire. Biodiversity measures show that plant diversity decreased significantly in the successive stages. The highly diverse vegetation at the coast and in the adjacent lowland mire was replaced by low diversity communities adapted to wet acidic environments and nutrient deficiency. The palynomorph assemblages are dominated by elements such as Alnus or Sphagnum. Typical tropical elements which are characteristic for the Middle Eocene part of the succession are missing. This indicates that a more temperate climate prevailed in northwestern Germany during the early Lower Eocene.

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A statistical sub-sampling tool for extracting vegetation community and diversity information from pollen assemblage data

Cited by 25 publications

References 30 publications

Patterns of modern pollen and plant richness across northern Europe

Patterns of modern pollen and plant richness across northern Europe

Pollen-vegetation richness and diversity relationships in the tropics

Greenhouse conditions in lower Eocene coastal wetlands? – Lessons from Schöningen, Northern Germany

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