Disturbance and regeneration phases in pollen diagrams and their relevance to concepts of marginality

2018 ◽  
pp. 61-66
Author(s):  
Kevin J Edwards ◽  
Graeme Waittington
Keyword(s):  
Pollen Diagrams

scholarly journals Testing the potential of pollen assemblages to capture composition, diversity and ecological gradients of surrounding vegetation in two biogeographical regions of southeastern Europe

2021 ◽  
Author(s):  
Maria Papadopoulou ◽  
Ioannis Tsiripidis ◽  
Sampson Panajiotidis ◽  
Georgios Fotiadis ◽  
Daniel Veres ◽  
...  
Keyword(s):  
Vegetation Structure ◽  
Diversity Indices ◽  
Life Forms ◽  
Ecological Gradients ◽  
Vegetation Diversity ◽  
North Central ◽  
Plant Life Forms ◽  
Pollen Diagrams ◽  
Biogeographical Regions ◽  
Species Specific

AbstractDue to the complex relationship between pollen and vegetation, it is not yet clear how pollen diagrams may be interpreted with respect to changes in floristic diversity and only a few studies have hitherto investigated this problem. We compare pollen assemblages from moss samples in two southeastern European forests with the surrounding vegetation to investigate (a) their compositional similarity, (b) the association between their diversity characteristics in both terms of richness and evenness, and (c) the correspondence of the main ecological gradients that can be revealed by them. Two biogeographical regions with different vegetation characteristics, the Pieria mountains (north central Greece) and the slopes of Ciomadul volcano (eastern Romania), were chosen as divergent examples of floristic regions, vegetation structure and landscape openness. Pollen assemblages are efficient in capturing the presence or absence, rather than the abundance in distribution of plants in the surrounding area and this bias increases along with landscape openness and vegetation diversity, which is higher in the Pieria mountains. Pollen assemblages and vegetation correlate better in terms of richness, that is, low order diversity indices. Relatively high correlation, in terms of evenness, could be potentially found in homogenous and species poor ecosystems as for Ciomadul. Composition and diversity of woody, rather than herb, vegetation is better reflected in pollen assemblages of both areas, especially for Pieria where a direct comparison of the two components was feasible, although this depends on the species-specific pollen production and dispersal, the openness of landscape and the overall diversity of vegetation. Gradients revealed by pollen assemblages are highly and significantly correlated with those existing in vegetation. Pollen assemblages may represent the vegetation well in terms of composition, diversity (mainly richness) and ecological gradients, but this potential depends on land use, vegetation structure, biogeographical factors and plant life forms.

Pollen evidence for the postglacial origins of Nova Scotia's forests

1987 ◽  
Vol 65 (6) ◽  
pp. 1163-1179 ◽  
Author(s):  
David G. Green
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
New England ◽  
Ice Sheets ◽  
Arrival Times ◽  
Local Environments ◽  
Pollen Diagrams ◽  
Propagule Dispersal ◽  
Coastal Shelf ◽  
Maritime Canada

Pollen diagrams from sites in southwest Nova Scotia and close to the New Brunswick – Nova Scotia border show that after retreat of the Wisconsin ice sheets, most tree taxa arrived in the extreme southwest of Nova Scotia earlier than anywhere else in the province. For most tree taxa, arrival times at sites in maritime Canada and in northeastern New England are consistent with very early dispersal of individuals along the coastal strip via the exposed coastal shelf and with their entering Nova Scotia from the southwest. These scattered pioneer populations acted as centres for major population expansions, which followed much later in some cases. Local environments, fire, and interspecies competition appear to have been more important than propagule dispersal rates as factors limiting the spread of most taxa.

Pollen diagrams from interior Labrador

1970 ◽  
Vol 48 (11) ◽  
pp. 1957-1975 ◽  
Author(s):  
Alastair Morrison
Keyword(s):  
Primary Succession ◽  
Vegetation Changes ◽  
Bare Ground ◽  
Radiocarbon Dates ◽  
River Watershed ◽  
Pollen Diagrams ◽  
Glacier Ice ◽  
Lake Waters

Six pollen zones can be distinguished in interior Labrador. The earlier zones represent the primary succession of vegetation from bare ground to boreal woodland or forest, which occupied about 500 years between 5700 and 5200 B.P. There have been only minor fluctuations in the nature of the vegetation since 5200 B.P. Radiocarbon dates show that the zones are contemporaneous over that part of the Lake Plateau within the Churchill River watershed, but similar vegetation changes occurred 1000 years earlier in the Kaniapiskau basin, further north, in New Quebec. These two areas must have been freed of a cover of glacier ice or lake waters immediately before 5700 B.P. and 6700 B.P. respectively.

scholarly journals Late Glacial and Holocene plant cover in Węgliny, Lubsza Plain, south-west Poland, based on pollen analysis

2013 ◽  
Vol 53 (2) ◽  
pp. 191-233 ◽  
Author(s):  
Aleksandra Jurochnik ◽  
Dorota Nalepka
Keyword(s):  
Pollen Analysis ◽  
Plant Cover ◽  
Late Glacial ◽  
Anaerobic Sediments ◽  
The North ◽  
South West ◽  
Pollen Diagrams ◽  
Laacher See Tephra ◽  
Late Glacial And Holocene

ABSTRACT Late Glacial (since Oldest Dryas) and Holocene (to Subatlantic) changes of vegetation at the Węgliny site (south-west Poland) are reconstructed based mainly on pollen analysis of five cores from the palaeobasin (anaerobic sediments). The chronology of the described events is based on palynological comparison with the Lubsza Plain environs, based on LPAZs from several published pollen diagrams on 14C data, and multiple cryptotephra levels determined in the Węgliny profiles. The Węgliny record integrates well into the north European Holocene and Late Glacial biostratigraphic framework. The Węgliny site is the next (fourth) locality in Poland where the Laacher See Tephra (LST) horizon within the Allerød chronozone was identified.

scholarly journals Holocene stratigraphy and vegetation history in the Scoresby Sund area, East Greenland

1978 ◽  
Vol 129 ◽  
pp. 1-66
Author(s):  
S Funder
Keyword(s):  
Vegetation History ◽  
High Arctic ◽  
Dwarf Shrub ◽  
Betula Nana ◽  
Isostatic Uplift ◽  
Cassiope Tetragona ◽  
Pollen Diagrams ◽  
Salix Arctica ◽  
Low Arctic ◽  
Holocene Stratigraphy

The Holocene stratigraphy in Scoresby Sund is based on climatic change as reflected by fluctuations in fjord and valley glaciers, immigration and extinction of marine molluscs, and the vegetation history recorded in pollen diagrams from five lakes. The histories are dated by C-14, and indirectly by emergence curves showing the patterns of isostatic uplift. From c. 10100-10400 to 9400 yr BP the major fjord glaciers showed oscillatory retreat with abundant moraine formation, the period of the Milne Land Moraines. The vegetation in the ice-free areas was a sparse type of fell field vegetation but with thermophilous elements indicating temperatures similar to the present. From 9400 yr BP the fjord glaciers retreated rapidly in the narrow fjords, the few moraines formed are referred to the Rødefjord stages and indicate topographically conditioned stillstands. At 8000 yr BP the low arctic Betula nana immigrated into the area, and in the period until 5000 yr BP dense dwarf shrub heath grew in areas where it is now absent. In the fjords the subarctic Mytilus edulis and Pecten islandica lived, suggesting a climate warmer than the present. From c. 5000 yr BP the dense dwarf shrub heath began to disappear in the coastal areas, and a 'poor' heath dominated by the high arctic Salix Arctica and Cassiope tetragona expanded. These two species, which are now extremely common, apparently did not grow in the area until c. 6000 yr BP. In lakes in the coastal area minerogenic sedimentation at c. 2800 yr BP, reflecting the general climatic deterioration.

Pollen Diagrams from Holderness, North Humberside

1981 ◽  
Vol 8 (3) ◽  
pp. 177 ◽  
Author(s):  
S. C. Beckett
Keyword(s):  
Pollen Diagrams

Did prehistoric landscape management retard the post-glacial spread of woodland in Southwest Asia?

Antiquity ◽  
2002 ◽  
Vol 76 (294) ◽  
pp. 1002-1010 ◽  
Author(s):  
Neil Roberts
Keyword(s):  
Bronze Age ◽  
Human Impacts ◽  
Landscape Management ◽  
Southwest Asia ◽  
Mediterranean Environment ◽  
East Mediterranean ◽  
Late Season ◽  
Pollen Diagrams ◽  
New Evidence ◽  
Trees And Shrubs

Pre-Bronze Age human impacts on the East Mediterranean environment have been hard to detect in pollen diagrams and other off-site contexts. New evidence shows that despite a relatively rapid post-glacial wetting-up of the climate, the re-advance of oak woodland across Southwest Asia was slow. Among the factors likely to have contributed to the apparent disjunction between climate and vegetation is Neolithic landscape management, particularly through regular use of late-season ground fires to encourage grasses at the expense of trees and shrubs.

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