Development of a peatland complex in boreal western Canada: lateral site expansion and local variability in vegetation succession and long-term peat accumulation

2003 ◽  
Vol 81 (8) ◽  
pp. 833-847 ◽  
Author(s):  
Ilka E Bauer ◽  
L Dennis Gignac ◽  
Dale H Vitt
Keyword(s):  
Vegetation History ◽  
Community Change ◽  
Vegetation Succession ◽  
Peat Accumulation ◽  
Radiocarbon Dates ◽  
Nucleation Sites ◽  
Peatland Development ◽  
Water Tables ◽  
History Of

The spatial development and vegetation history of a large boreal peatland complex in east-central Alberta was reconstructed to examine factors that control peatland development in continental regions. Peat depth throughout the site was interpolated from over 300 depth measurements, and basal radiocarbon dates were obtained from 16 cores. Peat first initiated about 7400 calibrated 14C years BP (cal. BP), and early peat-forming communities were wet fens or marshes. Rates of expansion from these nucleation sites were dependent on both moisture availability and topography, with asynchronous expansion in different regions. Basal macrofossil assemblages suggest that paludification on slopes of large basins was the result of flooding caused by rising peatland water tables. In many areas that initiated after 3000 cal. BP, paludification involved invasion of upland forest by Sphagnum. Long-term apparent rates of peat accumulation were fastest in wet, moderate-rich fen areas where little community change has occurred over time. Macrofossil analysis of core profiles reveals a tendency for sites that initiated wet and minerotrophic to eventually be colonized by Sphagnum. However, the thickness of surficial Sphagnum layers differs between cores, and there are several examples of minimal or apparently reverse successional development.Key words: peatlands, boreal, paleoecology, vegetation succession, peat accumulation, paludification.

Archaeology, genetics and a population bottleneck in prehistoric Finland

Antiquity ◽  
2014 ◽  
Vol 88 (342) ◽  
pp. 1132-1147 ◽  
Author(s):  
Tarja Sundell ◽  
Juhana Kammonen ◽  
Petri Halinen ◽  
Petro Pesonen ◽  
Päivi Onkamo
Keyword(s):  
Population Bottleneck ◽  
Genetic Profile ◽  
Neolithic Period ◽  
Late Neolithic ◽  
Finnish Population ◽  
Radiocarbon Dates ◽  
Combined Use ◽  
History Of ◽  
Stone Artefact

The long-term history of prehistoric populations is a challenging but important subject that can now be addressed through combined use of archaeological and genetic evidence. In this study a multidisciplinary team uses these approaches to document the existence of a major population bottleneck in Finland during the Late Neolithic period, the effects of which are still detectable in the genetic profile of the Finnish population today. The postglacial recolonisation of Finland was tracked through space and time using radiocarbon dates and stone artefact distributions to provide a robust framework of evidence against which the genetic simulations could be compared.

The Great Kod of Pulu: Mutual Historical Emergence of Ceremonial Sites and Social Groups in Torres Strait, Northeast Australia

2009 ◽  
Vol 19 (3) ◽  
pp. 291-317 ◽  
Author(s):  
Ian J. McNiven ◽  
Bruno David ◽  
Goemulgau Kod ◽  
Judith Fitzpatrick
Keyword(s):  
Social Groups ◽  
Structural Basis ◽  
Emergent Properties ◽  
Radiocarbon Dates ◽  
Dynamic Relationship ◽  
The Status ◽  
Island Communities ◽  
History Of ◽  
Torres Strait

Communal ceremonial sites and social groups often share mutually reinforcing and structuring properties. As a result of this dynamic relationship, ceremonial sites and social groups exhibit ever-emergent properties as long-term works-in-progress. Ceremonial kod sites featuring shrines of trumpet shells and dugong bones were central to the communal ritual life of Torres Strait Islanders. Continuously formed over the generations by ritual additions, these shrines were linked to ongoing maintenance, legitimization and cohesion of totemic clans and moieties that formed the structural basis of island communities. As such, understanding the history of kod sites provides an opportunity to investigate the historical emergence of ethnographically-known social groups in Torres Strait. This mutual emergence is investigated archaeologically at the kod on Pulu islet which is owned and operated by the Goemulgal people of nearby Mabuyag island. Multiple radiocarbon dates from shell and bone shrines and an underlying village midden indicate that the kod, and by association the Goemulgal and their totemic clan and moiety system, emerged over the past 400 years. Aided by local oral history and ethnography, it is argued further that establishment of the kod saw the status of Pulu change from a residential to a ceremonial and sacred place.

scholarly journals From Climatic to Anthropogenic Drivers: A Multi-Proxy Reconstruction of Vegetation and Peatland Development in the French Jura Mountains

Quaternary ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 38 ◽  
Author(s):  
Emilie Gauthier ◽  
Vincent E.J. Jassey ◽  
Edward A.D. Mitchell ◽  
Mariusz Lamentowicz ◽  
Richard Payne ◽  
...  
Keyword(s):  
Human Impact ◽  
Iron Age ◽  
Vegetation History ◽  
Testate Amoebae ◽  
Water Levels ◽  
Radiocarbon Dates ◽  
Surface Wetness ◽  
Peatland Development ◽  
Main Driver ◽  
Age Model

A 4 m core was extracted from the center of a peatland located in the Drugeon valley (France). Thirteen radiocarbon dates were used to build a robust age model. Testate amoebae were used for reconstructing mire surface wetness. High-resolution pollen analysis of the sequence reconstructed 9 millennia of development of the peatland and its surrounding vegetation. During the early/middle Holocene (9500 to 5800 cal BP), warm conditions led to high evapotranspiration and low water levels. The vegetation history is characterized by the development of a Pinus and a mixed Quercus forest. From 5800 cal BP, testate amoebae show wetter conditions, indicating the onset of the cooler Neoglacial period. The cooling is also evidenced by the development of Abies and Fagus trees, replacing the oak forest. The first indicators of human impact appear at about 4800 cal BP, and indicators of farming activity remains very rare until ca. 2600 cal BP, at the beginning of the Iron Age. The development of the peatland responded to climatic fluctuation until 2600 cal BP, after which human impact became the main driver. The last millennium has been characterized by sudden drying and the spread of pine on the peatland.

Vegetation History of Pleasant Island, Southeastern Alaska, since 13,000 yr B.P.

1996 ◽  
Vol 46 (2) ◽  
pp. 161-175 ◽  
Author(s):  
Barbara C. S. Hansen ◽  
Daniel R. Engstrom
Keyword(s):  
Vegetation History ◽  
Lodgepole Pine ◽  
Late Quaternary ◽  
Lacustrine Sediments ◽  
Tsuga Heterophylla ◽  
Temperature And Precipitation ◽  
Early Arrival ◽  
Peatland Development ◽  
History Of ◽  
Lake Catchment

A 13,000-year history of late-Quaternary vegetational and climatic change has been derived from lacustrine sediments from Pleasant Island in the Glacier Bay region of southeastern Alaska. Early arrival of lodgepole pine and mountain hemlock, indicated by the presence of pollen and conifer stomata, suggests expansion from refugia in the Alexander Archipelago. A short-term climatic reversal, possibly correlated with the European Younger Dryas, is inferred from the expansion of tundra elements and deposition of inorganic sediments between 10,600 and 9900 14C yr B.P. Two peat cores from the lake catchment verify Holocene vegetation changes and aid in the separation of biogenic from climatic forces affecting vegetation history. Differences in pollen representation among the three cores illustrate the variation among pollen-collecting substrates, as well as the spatial heterogeneity of peatland development and its dependence on local hydrology. Initial peat accumulation and soil paludification, occasioned by increases in temperature and precipitation in the early Holocene, allowed western and mountain hemlock to replace sitka spruce 8500–8000 yr B. P. Open muskeg became widespread about 7000 yr B. P. and allowed lodgepole pine to reinvade the region after a 2000-yr absence. The extensive replacement of fen elements by bog taxa at 3400 yr B. P. suggests increased paludification due to changing hydrologic conditions; its correlation with the upland expansion of Tsuga heterophylla suggests the onset of a cooler/wetter Neoglacial climate in southeastern Alaska.

The world recreated: redating Silbury Hill in its monumental landscape

Antiquity ◽  
2007 ◽  
Vol 81 (311) ◽  
pp. 26-53 ◽  
Author(s):  
Alex Bayliss ◽  
Fachtna McAvoy ◽  
Alasdair Whittle
Keyword(s):  
Radiocarbon Dates ◽  
The World ◽  
History Of ◽  
Ritual Landscape

A classic exposition of the difficulties of dating a major monument and why it matters. Silbury Hill, one of the world's largest prehistoric earth mounds, is too valuable to take apart, so we are reliant on samples taken from tunnels and chance exposures. Presenting a new edition of thirty radiocarbon dates, the authors offer models of short- or long-term construction, and their implications for the ritual landscape of Silbury and Stonehenge. The sequence in which monuments, and bits of monuments, were built gives us the kind and history of societies doing the building. So nothing matters more than the dates…

A long-term vegetation history of the Mojave-Colorado desert ecotone at Joshua Tree National Park

2010 ◽  
Vol 25 (2) ◽  
pp. 222-236 ◽  
Author(s):  
Camille A. Holmgren ◽  
Julio L. Betancourt ◽  
Kate A. Rylander
Keyword(s):  
National Park ◽  
Vegetation History ◽  
Colorado Desert ◽  
Joshua Tree National Park ◽  
History Of

scholarly journals The role of hydrological transience in peatland pattern formation

2013 ◽  
Vol 1 (1) ◽  
pp. 31-66 ◽  
Author(s):  
P. J. Morris ◽  
A. J. Baird ◽  
L. R. Belyea
Keyword(s):  
Steady State ◽  
Hydraulic Properties ◽  
Plant Litter ◽  
Future Climate Change ◽  
Litter Production ◽  
Landscape Models ◽  
Peatland Development ◽  
Water Tables ◽  
Response To Water

Abstract. The sloping flanks of peatlands are commonly patterned with non-random, contour-parallel stripes of distinct microhabitats such as hummocks, lawns and hollows. Patterning seems to be governed by feedbacks among peatland hydrological processes, plant micro-succession, plant litter production and peat decomposition. An improved understanding of peatland patterning may provide important insights into broader aspects of the long-term development of peatlands and their likely response to future climate change. We recreated a cellular simulation model from the literature, as well as three subtle variants, to explore the controls over peatland patterning. Our models each consist of three submodels, which simulate: peatland water tables in a gridded landscape; a simple representation of microhabitat dynamics in response to water-table depths; and changes in peat hydraulic properties. We found that the strength and nature of simulated patterning was highly dependent on the degree to which water tables had reached a steady state in response to hydrological inputs. Contrary to previous studies, we found that under a true steady state the models predict largely unpatterned landscapes that cycle rapidly between contrasting dry and wet states, dominated by hummocks and hollows, respectively. Realistic patterning only developed when simulated water tables were still transient. Literal interpretation of the degree of hydrological transience required for patterning suggests that the model should be discarded; however, the transient water tables appear to have captured some aspect of real peatland behaviour that generates patterning. Recently-buried peat layers may remain hydrologically active despite no longer reflecting current vegetation patterns, providing a form of ecological memory. Furthermore, the models were highly sensitive to the assumed values of peat hydraulic properties, which we take to indicate that the models are missing an important negative feedback between peat decomposition and dynamic changes in peat hydraulic properties. Understanding peatland patterning likely requires the unification of cellular landscape models such as ours with cohort-based models of long-term peatland development.

Past and Present Vegetation of Marshes Swamp in South-Eastern South Australia

1975 ◽  
Vol 23 (1) ◽  
pp. 123 ◽  
Author(s):  
JR Dodson ◽  
IB Wilson
Keyword(s):  
Climatic Change ◽  
Vegetation History ◽  
South Australia ◽  
Plant Succession ◽  
Radiocarbon Dates ◽  
Tea Tree ◽  
South Eastern ◽  
Form Part ◽  
History Of ◽  
Insight Into

The swamp and sclerophyll vegetation of Marshes Swamp is discussed in terms of soils and water regimes. Two swamps, Mt. Burr Swamp and Blue Tea Tree Swamp, which form part of Marshes Swamp, are looked at in particular and their stratigraphy and history are reconstructed. Cores from the swamp were pollen-analysed and the vegetation history of the swamps is described in terms of plant succession and local climatic change. Four radiocarbon dates were obtained and these were used to date the major local vegetational history events following dune build-up and vulcanism. These also allowed some insight into the age of soil development in the swamp.

A Vegetation History of the Far North of New Zealand during the Late Otira (Last) Glaciation

1993 ◽  
Vol 39 (3) ◽  
pp. 361-372 ◽  
Author(s):  
Rewi Newnham ◽  
John Ogden ◽  
Dallas Mildenhall
Keyword(s):  
New Zealand ◽  
Forest Cover ◽  
Vegetation History ◽  
Mixed Forest ◽  
Radiocarbon Dates ◽  
Substantial Loss ◽  
Far North ◽  
Last Glaciation ◽  
Pollen Diagrams ◽  
History Of

AbstractDuring the latter part of the last (Otira) glaciation the forest cover of New Zealand was much reduced. It has frequently been postulated, however, that diverse mixed forest communities survived in the far north of North Island. Pollen diagrams and radiocarbon dates from two last glacial and postglacial (Aranuian) sits on the Aupouri Peninsula in the far north of New Zealand are compared with other published palynological and plant macrofossil evidence from the region. Mixed kauri/podocarp/angiosperm forest was present at times during the late Otiran (and Aranuian) and no evidence was found for substantial loss of forest. However, radiocarbon samples from one site, at least, seem to have been contaminated with young carbon; this introduces uncertainty into the chronology established at that site. Possibly nondeposition or erosion has obscured part or all of the late Otiran record at all the sites studied so that very much reduced forest cover at that time cannot be ruled out.

Holocene vegetation history of Banks Island, Northwest Territories, Canada

2000 ◽  
Vol 78 (4) ◽  
pp. 430-436 ◽  
Author(s):  
K Gajewski ◽  
R J Mott ◽  
J C Ritchie ◽  
K Hadden
Keyword(s):  
Northwest Territories ◽  
Vegetation History ◽  
Middle Zone ◽  
Pollen Diagram ◽  
Radiocarbon Dates ◽  
Banks Island ◽  
Pollen Diagrams ◽  
Pollen Types ◽  
History Of ◽  
Lower Frequencies

Four pollen diagrams from Banks Island, Northwest Territories, provide the first records of the postglacial vegetation of the region. Chronologies are estimated from radiocarbon dates and by correlation of the exotic-pollen curves to data from the mainland. The pollen stratigraphies from all sites can be divided into three zones, where the middle zone, dating from 7000 to 2000 BP, corresponds to the warmest time. Although both the first and third zones correspond to cooler periods, the vegetation of the earliest zone was not identical to that of the latest, indicated by lower frequencies of key pollen types such as those of Dryas and Saxifraga.Key words: Banks Island, Holocene, pollen diagram, Arctic, paleoecology, Quaternary.

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