Pollen stratigraphy of Eaglenest Lake, northeastern Alberta

1986 ◽  
Vol 23 (1) ◽  
pp. 11-20 ◽  
Author(s):  
R. E. Vance
Keyword(s):  
Boreal Forest ◽  
Sediment Core ◽  
Pollen Analysis ◽  
Climatic Conditions ◽  
Solar Insolation ◽  
Pollen Stratigraphy ◽  
Dry Conditions ◽  
Summer Temperatures ◽  
Northeastern Alberta

Pollen analysis of a 7.65 m sediment core from Eaglenest Lake (57°46′N, 112°06′W) provides evidence of the postglacial development of vegetation in the mixedwood section of the Boreal Forest. From the time of deglaciation (approximately 12 000 – 11 500 years BP) to 11 000 BP the area was colonized by mainly nonarboreal flora dominated by Artemisia and Gramineae. Populus, the only tree taxon present, grew in sheltered areas, while Salix and Cyperaceae were common on poorly drained sites. Open parkland prevailed under a dry, windy climate. Summer temperatures were rising rapidly from glacial minima in response to increased solar insolation. By 11 000 BP Picea (initially P. glauca) and Betula (mainly tree Betula) migrated to the area. Forest prevailed, but the canopy was likely more open than at present. By 9000 BP peak warm and dry conditions had passed, although conditions warmer and drier than at present persisted. Alnus migrated to the area 8450 BP. Pinus reached the Birch Mountains about 7500 BP. No major changes in vegetation have occurred since that time, suggesting that modern climatic conditions were established by 7500 BP.

A 14,000-Year Pollen Record from Sithylemenkat Lake, North-Central Alaska

1990 ◽  
Vol 33 (3) ◽  
pp. 400-404 ◽  
Author(s):  
Patricia M. Anderson ◽  
Richard E. Reanier ◽  
Linda B. Brubaker
Keyword(s):  
Boreal Forest ◽  
Sediment Core ◽  
Pollen Analysis ◽  
Picea Glauca ◽  
Pollen Record ◽  
North Central ◽  
The Holocene ◽  
Unusual Combination ◽  
Shrub Tundra ◽  
History Of

AbstractPollen analysis of a 14,000-yr-old sediment core from Sithylemenkat Lake provides the first Holocene vegetational history for the Kanuti Flats of north-central Alaska. Basal samples contain a curious and unusual combination of tundra and boreal taxa. Pollen assemblages dating from 13,500 to 9000 yr B.P. are more typical of southern Brooks Range sites and indicate the presence ofBetulashrub tundra with increasedPopulusca. 10,000 to 9000 yr B.P.Picea glaucaappeared ca. 9000 yr B.P. andAlnusca. 8000 yr B.P.P. glaucapopulations declined between 7800 and 5000 yr B.P. with a subsequent reforestation byP. marianaandP. glauca. This pattern is seen at other sites in northeastern Alaska and suggests that the Holocene history of boreal forest is more complex than thought previously.

DENDROCHRONOLOGICAL RESEARCHES IN ARTIFICIAL PLANTINGS OF NUR-SULTAN CITY

2020 ◽  
Author(s):  
A N. Kabanov ◽  
◽  
S.A. Kabanova ◽  
Keyword(s):  
Pinus Sylvestris ◽  
Radial Growth ◽  
Climatic Conditions ◽  
Solar Insolation ◽  
Dendrochronological Analysis ◽  
Different Ages ◽  
Green Zone

Dendrochronological analysis was carried out in forest cultures of Pinus sylvestris of different ages growing in the green zone of Nur-Sultan city. It was found that the value of the annual radial growth is subject to a cycle with a period of 10-11 years. This is due to climatic conditions, in particular, with periods of solar insolation, which is confirmed by researches of other authors.

scholarly journals A preliminary study of the behaviour of water buffaloes (<i>Bubalus bubalis</i>) imported to Poland (Short Communication)

2012 ◽  
Vol 55 (5) ◽  
pp. 415-419 ◽  
Author(s):  
I. Antkowiak ◽  
J. Pytlewski ◽  
A. Purczyńska ◽  
R. Skrzypek
Keyword(s):  
Short Communication ◽  
Growing Season ◽  
Bubalus Bubalis ◽  
Climatic Conditions ◽  
Drainage Ditch ◽  
Short Period ◽  
Summer Temperatures ◽  
Preliminary Study ◽  
Time Of Year ◽  
Lying Down

Abstract. This study was carried out on 26 adult water (river) buffaloes (25 females and 1 male) imported in 2006 to an eco-tourism farm in the Wielkopolska province, Poland. During the growing season, animals were kept on a logged pasture covering an area of about 15 ha. The pasture was divided into three approximately equal parts, each with a different facility available for wallowing; i.e. pond, drainage ditch and stream. Behavioural observations were carried out three times in July and August 2007 in approximately 14-d intervals, each time during one day on a different part of the pasture, always between 06.00 and 16.00. The method of registration was instantaneous scan sampling, performed at approximately 60 min intervals. On the days of observations mean daily temperature varied from 20.2 to 20.8 °C. Grazing was the behaviour shown by the highest percentage of animals in the herd (58.6%), followed by rumination (28.2%), lying down (26.5%), wallowing (12.9%) and standing (1.4%). When they had access to a pond or ditch, the proportion of animals wallowing was twice as much compared to stream access (P<0.05). It was concluded that the welfare of the investigated buffaloes was not compromised during the high summer temperatures that can be encountered in Poland. Results also indicate that the highest level of welfare can be reached in this time of year when animals are provided with access to ample facility for wallowing. Under our climatic conditions facilities with still or slowly moving water appeared to be preferred by river buffaloes. However, this study has a limitation which is short period of observation, thus it is possible that a longer and more representative period of observations could change these conclusions.

scholarly journals Glacial and Postglacial History of the White Cloud Peaks-Boulder Mountains, Idaho, U.S.A.

2007 ◽  
Vol 40 (3) ◽  
pp. 229-238 ◽  
Author(s):  
James F. P. Cotter ◽  
James M. Bloomfield ◽  
Edward B. Evenson
Keyword(s):  
Sediment Accumulation ◽  
Climatic Conditions ◽  
The North ◽  
Stratigraphic Model ◽  
Glaciofluvial Deposits ◽  
Dry Conditions ◽  
Minimum Age ◽  
Late Wisconsinan ◽  
Mount St Helens ◽  
Peak Set

ABSTRACT Glacial and glaciofluvial deposits are mapped and differentiated to develop new local, relative-age (RD) stratigraphies for the North Fork of the Big Lost River, Slate Creek and Pole Creek drainages in the White Cloud Peaks and Boulder Mountains, Idaho. This stratigraphic model expands the areal extent of the "Idaho glacial model". Volcanic ash samples collected from the study area are petrographically characterized and correlated, on the basis of mineralogy and glass geochemistry, to reference samples of identified Cascade Range tephras. Four distinct tephras are recognized including; Mount St. Helens-Set S (13,600-13,300 yr BP), Glacier Peak-Set B (11,250 yr BP), Mount Mazama (6600 yr BP) and Mount St. Helens-Set Ye (4350 yr BP). A core of lake sediments containing two tephra units was obtained from a site called "Pole Creek kettle". Pollen and sediment analyses indicate three intervals of late Pleistocene and Holocene climatic change. Cool and wet climatic conditions prevailed in the region shortly before and immediately following the deposition of the Glacier Peak-Set B ash (11,250 yr BP). Climatic warming occurred from approximately 10,500 to 6600 yr BP after which warm, dry conditions prevailed. Sediment accumulation in the kettle ceased by 4350 yr BP. The presence of Glacier Peak-Set B tephra in the base of the Pole Creek kettle core provides a minimum age of 11,250 yr BP for the retreat of valley glaciers from their Late Wisconsinan maximum position. A radiocarbon date of 8450 + 85 yr BP (SI-5181), and the presence of Mount Mazama ash (6600 yr BP) up-core support the Glacier Peak-Set B identification.

Plant and Insect Remains from the Wisconsinan Interstadial/Stadial Transition at Wedron, North-Central Illinois

1990 ◽  
Vol 33 (3) ◽  
pp. 387-399 ◽  
Author(s):  
Clarke E. Garry ◽  
Donald P. Schwert ◽  
Richard G. Baker ◽  
Tim J. Kemmis ◽  
Diana G. Horton ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Ground Beetle ◽  
Plant Macrofossils ◽  
Climatic Conditions ◽  
Silica Sand ◽  
Insect Fauna ◽  
Vaccinium Uliginosum ◽  
Radiocarbon Age ◽  
Late Wisconsinan ◽  
Central Illinois

AbstractOrganic material exposed within a small swale fill in Pit 6 of the Wedron Silica Sand Co. near Wedron in LaSalle County, Illinois, includes well-preserved pollen, plant macrofossils, and insect remains. This material occurs in slackwater sediment in the lower part of the Peddicord Formation, which was deposited as existing valleys were dammed by fluvial aggradation during the initial late Wisconsinan advance of Laurentide ice into the Wedron area. Wood from the organic horizon has a radiocarbon age of 21,460 ± 470 yr B.P. (ISGS-1486). The pollen spectrum is dominated byPicea, Pinus, and Cyperaceae. Plant macrofossils comprise a mix of boreal-forest taxa, includingPicea, Larix laricina, and the mossCampylium stellatum; subarctic species includingBetula glandulosa, Empetrum nigrum, andSelaginella selaginoides; along with the predominantly arcticVaccinium uliginosumvar.alpinum, Dryas integrifolia, andRhododendron lapponicum. The insect fauna contains the western montane ground beetleOpisthius richardsoni; several arctic-subarctic ground beetles includingDiacheila polita, Helophorus sibiricus, andPterostichus (Cryobius) caribou; and a diverse assemblage of insects that today inhabit the boreal forest. We interpret the biotic record to record a phase in the transition from closed boreal forest to open tundra as climatic conditions deteriorated in advance of continental glaciation.

Insect faunas of late Devensian and Flandrian age from Church Stretton, Shropshire

1972 ◽  
Vol 263 (852) ◽  
pp. 327-367 ◽  
Keyword(s):  
Pollen Analysis ◽  
Thermal Environment ◽  
Radiocarbon Date ◽  
Radiocarbon Dates ◽  
Number Of Species ◽  
Summer Temperatures ◽  
Zone Ii ◽  
Climatic Optimum ◽  
The Church

Invertebrate faunas consisting mainly of insects, from deposits in the Church Stretton valley, are described and discussed. These deposits fall into two periods: ( a ) Late Devensian, which follows an episode of glaciation and precedes a period of accumulation of frost-shattered gravel fans; and ( b ) Flandrian, which post-dates the gravels and has been placed in the post-Glacial pollen zones VI and VII. The faunas of these two episodes are dealt with separately in Parts I and II respectively. Part I. From two sites in which sequences containing clays, peats and silts were examined five radiocarbon dates are available, the oldest being 13 555 ± 620 years B.P. and the most recent 11 000 ± 200 years B.P. The faunas include a substantial number of species not now found in Shropshire, many not in Britain. Inferences on the changing ecology and thermal environment of the area are drawn from these faunas and are compared with the pollen analytical zones. This comparison shows that, according to the insects, the warmest part of the episode was late zone I, and that zone II (the Allerod), often considered to be the climatic optimum of the period, appears to have been a time of gradually deteriorating summer temperatures. Part II. Deposits from three late Flandrian sites are discussed. Although only one radiocarbon date was obtained, of 8101 ± 138 years B.P., pollen analysis was carried out by Rowlands throughout each sequence and this showed that the earliest deposit, at Little Stretton, dated from zone VI a and at all three localities deposition continued into zone VII b. An examination of the insect assemblages shows that completely different biotopes, from open pasture to dense woodland, were existing side by side in the Church Stretton valley in late Flandrian time. Summer temperatures at least as high as those of today are inferred. The possibility exists that during the period represented here the climate was even warmer than that of the present but until more information is available it is not possible to be more definite on this point.

scholarly journals Pollen analysis: state of the art

2010 ◽  
Vol 31 (1-2) ◽  
pp. 151-159 ◽  
Author(s):  
Gordon J. Ogden
Keyword(s):  
North America ◽  
Pollen Analysis ◽  
Sediment Cores ◽  
Data Bank ◽  
Sedimentation Rates ◽  
Data Set ◽  
Radiocarbon Dates ◽  
Surface Pollen ◽  
Pollen Stratigraphy ◽  
Better Than

Although nearly 50 years have passed since P.B. Sears introduced pollen analysis to North America, it remains an occult art. Dramatic improvements in sampling and analytic techniques continue to be limited by intractable problems of differential production, dispersal, ballistics, sedimentation, and preservation. It is a basic tenet of pollen stratigraphy that the data set, consisting primarily of microfossils preserved in sediments, is better than anything we have yet been able to do with it. Basic agreement between late- and postglacial pollen records has been confirmed wherever the method has been applied. Quantitative sampling techniques, sample preparation, and analytic procedures, together with multiple radiocarbon dates, permits calculation of sedimentation rates and absolute pollen influx. Of approximately 300 sediment cores from northeastern North America, fewer than 30 have more than 3 radiocarbon determinations from which least squares power curve regressions can be reliably calculated in the determination of sedimentation rates. Analogy with modern environments represented by surface pollen spectra is limited by an insufficient number of samples of uniform quality to characterize a vegetational mosaic covering 40 degrees of latitude (40-80°N) and longitude (60-100°W). The present surface pollen data bank includes about 700 samples, unevenly spaced and of uneven quality, permitting a grid resolution of no better than 10,000 km2.

Observations and Experiments on some Larval Trematodes of Freshwater Snails and Fish from Southern Iceland

1973 ◽  
Vol 47 (4) ◽  
pp. 409-414 ◽  
Author(s):  
David Blair
Keyword(s):  
Life Cycle ◽  
Liver Fluke ◽  
Migratory Birds ◽  
Fasciola Hepatica ◽  
Climatic Conditions ◽  
Life Cycles ◽  
Freshwater Snails ◽  
Apparent Absence ◽  
Summer Temperatures

During the Glasgow University Iceland Expedition in 1972 freshwater snails and fish in southern Iceland were sampled for larval trematodes. This survey was prompted by the lack of literature concerning larval trematodes there. Indeed, the apparent absence of liver fluke Fasciola hepatica (L.1758) from Iceland, (Palsson, pers. comm.) despite the presence of its molluscan and definitive hosts and the low summer temperatures, might lead to the supposition that climatic conditions are too harsh to permit completion of many trematode life-cycles. A number of adult trematodes have been reported from migratory birds in Iceland (Brinkmann 1956), although these parasites could have been acquired elsewhere. However, Crepidostomum farionis (Müller, 1784) from the gut of trout and char in Iceland (Brinkmann 1956) presumably completes its life cycle in freshwater there, although this has yet to be demonstrated.

scholarly journals Neonicotinoid Residues in Sugar Beet Plants and Soil under Different Agro-Climatic Conditions

Agriculture ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 484
Author(s):  
Helena Viric Gasparic ◽  
Mirela Grubelic ◽  
Verica Dragovic Uzelac ◽  
Renata Bazok ◽  
Maja Cacija ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Seed Treatment ◽  
Climatic Conditions ◽  
Climatic Regions ◽  
Growing Seasons ◽  
Maximum Residue Level ◽  
Commission Regulation ◽  
Dry Conditions ◽  
Near Future ◽  
The Eu

European sugar beet was mostly grown from seeds treated by neonicotinoids which provided efficient control of some important sugar beet pests (aphids and flea beetles). The EU commission regulation from 2018 to ultimately restrict the outdoor application of imidacloprid, thiamethoxam, and clothianidin could significantly affect European sugar beet production. Although alternative insecticides (spinosad, chlorantraniliprole, neem) are shown to have certain effects on particular pests when applied as seed treatment, it is not likely that in near future any insecticide will be identified as a good candidate for neonicotinoids’ substitution. The aim of this research is to evaluate residue levels (LC-MS/MS method) of imidacloprid and thiamethoxam applied as seed dressing in sugar beet plants during two growing seasons in fields located in different agro-climatic regions and in greenhouse trials. In 2015, 25 to 27 days post planting (PP) maximum of 0.028% of imidacloprid and 0.077% of thiamethoxam were recovered from the emerged plants, respectively. In 2016, the recovery rate from the emerged plants 40 days PP was 0.003% for imidacloprid and 50 days PP was up to 0.022% for thiamethoxam. There were no neonicotinoid residues above the maximum residue level in roots at the time of harvesting, except in case of samples from thiamethoxam variant collected from greenhouse trials in 2016 (0.053 mg/kg). The results of this research lead to the conclusion that the seed treatment of sugar beet leaves minimal trace in plants because of the complete degradation while different behavior has been observed in the two fields and a glasshouse trial regarding the residues in soil. Dry conditions, leaching incapacity, or irregular flushing can result in higher concentrations in soil which can present potential risk for the succeeding crops. The results of our study could provide additional arguments about possible risk assessment for seed treatment in sugar beet.

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