CONTRIBUTIONS TO THE HOLOCENE PALEOECOLOGY OF WESTCENTRAL CANADA: A LATE-GLACIAL DEPOSIT FROM THE MISSOURI COTEAU

1964 ◽  
Vol 42 (6) ◽  
pp. 677-692 ◽  
Author(s):  
J. C. Ritchie ◽  
Bernard de Vries
Keyword(s):  
Great Plains ◽  
Late Glacial ◽  
Pollen Spectrum ◽  
Pollen Diagram ◽  
Glacial Deposit ◽  
Carbon 14 ◽  
Missouri Coteau ◽  
Plant Assemblages ◽  
Mixed Prairie ◽  
Artemisia Pollen

A buried deposit of limnic sediment was excavated from a site on the Missouri Coteau of Saskatchewan, within the Mixed Prairie section of the Great Plains. Carbon-14 determinations indicate that the section is late-glacial, possibly deposited during an interstadial terminated by the Condie (= Valders?) re-advance. On the basis of the records of about 60 taxa of Tracheophyta and a pollen diagram, the section is characterized by lower, middle, and upper plant assemblages. It is suggested that the lower and upper assemblages, distinguished mainly by a Picea – Shepherdia canadensis – Salix – Artemisia pollen spectrum, indicate the prevalence on mesic sites of a spruce forest. The middle assemblage, having an array of macrofossils and a few microfossils of temperate geographical affinity and a pollen spectrum suggesting relatively less spruce and (or) more herbaceous vegetation, is interpreted in terms of a mixed spruce–poplar forest on mesic sites with shrub and grassland communities on the more xeric habitats. This tripartite division of the section in terms of ecologically concordant plant assemblages suggests an amelioration of environment followed by a deterioration which was probably correlative with the Condie re-advance.

BRYOPHYTE SUBFOSSILS OF A LATE-GLACIAL DEPOSIT FROM THE MISSOURI COTEAU, SASKATCHEWAN

1965 ◽  
Vol 43 (8) ◽  
pp. 947-953 ◽  
Author(s):  
B. de Vries ◽  
C. D. Bird
Keyword(s):  
Boreal Forest ◽  
Higher Plants ◽  
Late Glacial ◽  
Organic Layer ◽  
Middle Zone ◽  
Higher Plant ◽  
Glacial Deposit ◽  
Boreal Species ◽  
The North ◽  
Missouri Coteau

Bryophyte and associated macro-subfossils were recovered from a kettle located in prairie southwest of Moose Jaw in the Missouri Coteau of southern Saskatchewan. The higher plants were discussed in an earlier paper.Three samples taken from the organic layer gave C14 datings ranging from 11,650 ± 150 to 10,270 ± 150 B.P.Sixteen species and one variety of Musci were recovered. Eleven of these were found in the lowermost zone at a depth of 510–450 cm. This zone was composed of bryophytes and higher plants characteristic of a modern Picea forest. Fifteen bryophyte taxa were recovered from the middle zone at a depth of 450–290 cm. The macro-subfossils in this zone are typical of a present-day Populus–Picea forest. No bryophytes were found in the upper layer, 290–280 cm characterized by higher plant macro-subfossils and pollen typical of a modern Picea forest.All bryophytes recovered belong to present-day taxa; however, many of the boreal species are not now found in the region as the southern margin of the boreal forest is now 200 miles to the north.

Late Glacial and Holocene history of Plešné Lake and its surrounding landscape based on pollen and palaeoalgological analyses

Biologia ◽  
2006 ◽  
Vol 61 (20) ◽  
Author(s):  
Vlasta Jankovská
Keyword(s):  
Late Glacial ◽  
Forest Steppe ◽  
Southern Europe ◽  
Pollen Diagram ◽  
History Of ◽  
The Bohemian Forest ◽  
Surrounding Landscape ◽  
Late Glacial And Holocene ◽  
High Degree ◽  
Biostratigraphic Units

AbstractPollen analysis has been carried out on a 549 cm thick sediment profile from lake Plešné jezero (Plešné Lake) in the Bohemian Forest (Šumava, Czech Republic; 1090 m a.s.l.; 48°47′ N; 13°52′ E). Analyses of 67 samples characterise the development of the lake biotope and the surrounding landscape during the last ca. 14,000 years. The pollen diagram shows a very distinct transition between the Late Glacial and the Holocene biostratigraphic units at a depth of ca. 312 cm. In the surroundings of Plešné Lake the vegetation was treeless during the entire Late Glacial. The alpine tree limit, formed by Betula and Pinus with undergrowth of shrubs, might have been at ca. 500 m a.s.l. Pollen transported from long distances was significant due to the openness of the landscape, coming from southern Europe and even Africa, and including high numbers of Artemisia, Poaceae, Chenopodiaceae, and some other herbs and shrubs from steppe and forest-steppe areas in southern Europe or Africa (likely Ephedra, certainly Lygeum spartum). The expansion of shrubs, particularly Juniperus, preceded the expansion of trees near the end of the Late Glacial. Afforestation of the region by thin stands of Betula and Pinus occurred during the Preboreal. Significant warming in the Boreal resulted in the expansion of Corylus, Quercetum mixtum (QM) trees, and probably also Picea and Alnus. Picea as well as QM trees were further expanding during the Early Atlantic. Picea was the dominant tree during the Late Atlantic and Fagus started to spread towards its end. Abrupt expansion of Abies marks the Subboreal. A high degree of afforestation (Abies, Fagus, Picea) was characteristic for the Early Subatlantic. During Late Subatlantic, pollen of synanthropic plants appears. Phases of the lake biotope development were defined on the basis of coccal green algae and Isoëtes.

Production characteristics of the mixed prairie: constraints and potential

1993 ◽  
Vol 73 (4) ◽  
pp. 765-778 ◽  
Author(s):  
W. D. Willms ◽  
P. G. Jefferson
Keyword(s):  
Species Composition ◽  
Great Plains ◽  
Warm Season ◽  
Bouteloua Gracilis ◽  
Fertilizer Application ◽  
Plant Litter ◽  
Northern Great Plains ◽  
Forage Production ◽  
Canadian Prairies ◽  
Mixed Prairie

The mixed prairie represents the most arid region of the Northern Great Plains in Canada. Approximately 6.5 M ha of the original total of 24 M ha have retained their native character. The native prairie supports about 5.3 M animal–unit–months or about 15% of all beef cattle present on the Canadian prairies. A large portion of the area is dominated by either needle-and-thread (Stipa comata Trin. + Rupr.) or western wheatgrass (Agropyron smithii Rydb.), both cool season grasses, and associated with blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Steud.] a warm season grass. These species define the major plant communities of the mixed prairie and determine their production potential. However, their production is limited by available water during the growing season and by soil nutrients; factors which also influence their species composition. Grazing imposes a significant impact on the grasslands by altering the water and nutrient cycles, through defoliation and reduced plant litter, and eventually by affecting the species composition. Removing litter may reduce forage production by up to 60% and repeated defoliation will favour the more drought tolerant but less productive species. Forage production may be increased by seeding introduced species, which have a greater shoot to root ratio than native grasses, or with fertilizer application. Livestock production may be increased with the use of grazing systems. However, the benefits of each practice on the mixed prairie must be assessed in terms of their cost, their impact on the environment, and the reduced or lost value for other users. Key words: Biomass, above-ground, below-ground, water-use efficiency, reseeding, soil fertility, grazing efficiency

scholarly journals Multi-proxy reconstruction of mire development in the Poręby Wojsławskie ecosystem (Sandomierz Basin, southeastern Poland)

2013 ◽  
Vol 40 (3) ◽  
pp. 177-186
Author(s):  
Jacek Chodorowski ◽  
Andrzej Plak ◽  
Irena Pidek ◽  
Radosław Dobrowolski
Keyword(s):  
Water Supply ◽  
Human Impact ◽  
Radiocarbon Dating ◽  
Late Glacial ◽  
Geochemical Data ◽  
Pollen Diagram ◽  
The Holocene ◽  
Se Poland ◽  
Mire Ecosystem ◽  
Precipitation And Temperature

AbstractMulti-proxy analysis (sedimentological, palaeobotanical, geochemical data and results of radiocarbon dating) of the biogenic sediments from a small mire ecosystem in the Sandomierz Basin (SE Poland) is presented. The ecosystem contains a full hydroseral sequence from minerotrophic to ombrotrophic wetland. It is one of the few sites in this region which is so thoroughly investigated in terms of the palaeoenvironmental record. Changes in the water supply of the mire area, and consequently the changes in the plant and sediment succession, were well correlated with the regional tendencies in precipitation and temperature during the Late Glacial/Holocene transition and in the Holocene. Human impact is very well recorded in pollen diagram from the Subboreal period.

Black Mats, Spring-Fed Streams, and Late-Glacial-Age Recharge in the Southern Great Basin

1998 ◽  
Vol 49 (2) ◽  
pp. 129-148 ◽  
Author(s):  
Jay Quade ◽  
Richard M. Forester ◽  
William L. Pratt ◽  
Claire Carter
Keyword(s):  
Great Basin ◽  
Age Distribution ◽  
Younger Dryas ◽  
Late Glacial ◽  
Land Snails ◽  
Spring Discharge ◽  
Carbon 14 ◽  
Total Absence ◽  
Stratigraphic Record ◽  
Shallow Ponds

Black mats are prominent features of the late Pleistocene and Holocene stratigraphic record in the southern Great Basin. Faunal, geochemical, and sedimentological evidence shows that the black mats formed in several microenvironments related to spring discharge, ranging from wet meadows to shallow ponds. Small land snails such as Gastrocopta tappaniana and Vertigo berryi are the most common mollusk taxa present. Semiaquatic and aquatic taxa are less abundant and include Catinellids, Fossaria parva, Gyraulus parvus, and others living today in and around perennial seeps and ponds. The ostracodes Cypridopsis okeechobi and Scottia tumida, typical of seeps and low-discharge springs today, as well as other taxa typical of springs and wetlands, are common in the black mats. Several new species that lived in the saturated subsurface also are present, but lacustrine ostracodes are absent. The δ13C values of organic matter in the black mats range from −12 to −26‰, reflecting contributions of tissue from both C3 (sedges, most shrubs and trees) and C4 (saltbush, saltgrass) plants. Carbon-14 dates on the humate fraction of 55 black mats fall between 11,800 to 6300 and 2300 14C yr B.P. to modern. The total absence of mats in our sample between 6300 and 2300 14C yr B.P. likely reflects increased aridity associated with the mid-Holocene Altithermal. The oldest black mats date to 11,800–11,600 14C yr B.P., and the peak in the 14C black mat distribution falls at ∼10,000 14C yr B.P. As the formation of black mats is spring related, their abundance reflects refilling of valley aquifers starting no later than 11,800 and peaking after 11,000 14C yr B.P. Reactivation of spring-fed channels shortly before 11,200 14C yr B.P. is also apparent in the stratigraphic records from the Las Vegas and Pahrump Valleys. This age distribution suggests that black mats and related spring-fed channels in part may have formed in response to Younger Dryas (YD)-age recharge in the region. However, the inception of black mat formation precedes that of the YD by at least 40014C yr, and hydrological change is gradual, not rapid.

scholarly journals Macrofossils from a Late-Glacial Deposit at Cambridge, Massachusetts

1962 ◽  
Vol 67 (1) ◽  
pp. 106 ◽  
Author(s):  
George W. Argus ◽  
Margaret B. Davis
Keyword(s):  
Late Glacial ◽  
Glacial Deposit

scholarly journals New Archaeological, Paleoenvironmental, and 14C Data from the Šventoji Neolithic Sites, NW Lithuania

Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 1017-1031 ◽  
Author(s):  
Gytis Piličiauskas ◽  
Jonas Mažeika ◽  
Andrejus Gaidamavičius ◽  
Giedrė Vaikutienė ◽  
Albertas Bitinas ◽  
...  
Keyword(s):  
Human Activity ◽  
Environmental Changes ◽  
Plantago Lanceolata ◽  
Late Glacial ◽  
Fishing Gear ◽  
Pollen Diagram ◽  
Remote Areas ◽  
The Baltic ◽  
Late Glacial And Holocene

Archaeological, geological, and paleoecological investigations supported by radiocarbon dating enabled us to present a reconstruction of chronologically based paleoenvironmental and human activity changes in the Šventoji region, NW Lithuania, during the period 4000–800 cal BC. In addition, we describe the main stages of the Late Glacial and Holocene periods in the area. The Baltic Ice Lake regression was succeeded by a terrestrial period until the Littorina Sea maximal transgression at 5700–5400 cal BC. A marine bay with brackish water was transformed into a freshwater lagoon before the oldest archaeological evidence of human presence, i.e. 4000/3700 cal BC. However, the presence of Cerealia type and Plantago lanceolata pollen dating back to about 4400–4300 cal BC suggests earlier farming activities in the area. Pollen analyses show the minor but continuous role of cereal cultivation after 3250 cal BC. Due to the predominance of the boggy landscape in the immediate vicinity of the Šventoji sites, agricultural fields were situated further away from the sites themselves. Exploitation of remote areas of the freshwater basin by diverse fishing gear was proven by the discovery of a new fishing site, Šventoji 41 (2900–2600 cal BC). This finding together with data of previous research suggest a complex and elaborate coastal economy involving seal hunting and year-round freshwater fishing during the 3rd millennium cal BC. A decline in human activity is seen in the pollen diagram after 1800 cal BC, which could be due to significant environmental changes, including overgrowth of the freshwater lagoon basin with vegetation.

CONTRIBUTIONS TO THE HOLOCENE PALEOECOLOGY OF WESTCENTRAL CANADA: I. THE RIDING MOUNTAIN AREA

1964 ◽  
Vol 42 (2) ◽  
pp. 181-196 ◽  
Author(s):  
J. C. Ritchie
Keyword(s):  
Boreal Forest ◽  
Lake Sediment ◽  
Pollen Analysis ◽  
Deciduous Forests ◽  
Pollen Spectrum ◽  
Spruce Forest ◽  
Mountain Area ◽  
The Holocene ◽  
Carbon 14 ◽  
Spruce Wood

The results of pollen analysis of three sections of lake sediment, sampled in the Riding Mountain area of Manitoba, suggest a tentative division of each into four zones. The lower, interpreted as representing a closed white spruce forest, is followed by an apparently treeless episode tentatively interpreted as a grassland phase; this is followed by a zone which suggests indirectly the prevalence of deciduous forests, possibly dominated by poplar, birch, and oak. The development of the mixed boreal forest, which prevails today, is marked by a rise in the spruce and alder curves. The suggestion that the sections are post-Valders in age is corroborated to some extent by a carbon-14 age measurement of 9570 years from a sample of spruce wood excavated from the bottom of a filled-in kettle in the vicinity; associated gyttja yielded a pollen spectrum very similar to the I zones of the diagrams.

Sign in / Sign up

Export Citation Format

Share Document