Problems Relating to the Neothermal Climatic Sequence

1964 ◽  
Vol 29 (3) ◽  
pp. 307-315 ◽  
Author(s):  
Alan Lyle Bryan ◽  
Ruth Gruhn
Keyword(s):  
North America ◽  
Direct Evidence ◽  
Climatic Conditions ◽  
Temperature Curve ◽  
Ecological Diversity ◽  
Independent Evidence ◽  
Absolute Dating ◽  
Historic Development ◽  
Time Periods ◽  
Variable Radio

AbstractThe sequence of three phases (Anathermal, Altithermal, Medithermal) of the Postglacial or Neothermal temperature curve, although demonstrably a reality, has been used improperly to determine absolute dates and past climatic conditions from archaeological deposits. A review of the historic development of the concept of the three sequent Neothermal temperature phases reveals the assumptions on which absolute dating of these phases has been based. Analysis of the variable radio-carbon dates now available for deposits attributed to these phases in a number of different localities in North America indicates that these phases cannot be considered as universal time periods bracketed by definite absolute dates; and consideration of the ecological diversity within North America at any particular time, especially in the West, indicates that climatic conditions inferred for a given span of Neothermal time in one area cannot be projected into another area without direct independent evidence of the actual climatic conditions which existed in the second area at that time. It is suggested that Anathermal, Altithermal, and Medithermal be used not as time periods with fixed absolute dates or climatic periods with defined characteristics, but rather be considered as phases of the Neothermal temperature curve which in different ecological areas resulted in locally varying climatic conditions which must be determined by direct evidence, dated by independent means, and designated by local terms.

scholarly journals Release of Postsenescent Dormancy in Leafy Spurge (Euphorbia esula) by Chilling

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 784-786 ◽  
Author(s):  
Stephen J. Harvey ◽  
Robert M. Nowierski
Keyword(s):  
Growth Rate ◽  
North America ◽  
Growth And Development ◽  
Leafy Spurge ◽  
Climatic Conditions ◽  
Euphorbia Esula ◽  
Flower Buds ◽  
Significant Growth ◽  
Number Of Stems

The growth and development of leafy spurge (Euphorbia esulaL. #3EPHES) collected during postsenescent dormancy and grown in the greenhouse was increasingly stimulated by chilling treatments longer than 14 days duration at 0 to 6 C. Production of stems with flower buds, primary flowers, and secondary flowers was greater in plants chilled for 42 days or more. The effects of chilling on total number of stems, number of strictly vegetative stems, or number of stems with vegetative branching were not significant. The height of the tallest stem per pot was influenced by chilling longer than 42 days. Growth rate also increased as a function of chilling duration. Based on our findings, we believe that there is little possibility that any significant growth can occur in the postsenescent period because of the prevailing climatic conditions found in areas of leafy spurge distribution in North America.

Anadromous Sturgeons: Habitats, Threats, and Management

2007 ◽  
Keyword(s):  
North America ◽  
Middle Ages ◽  
North Atlantic Ocean ◽  
Atlantic Coast ◽  
Climatic Conditions ◽  
Temperature Adaptation ◽  
Atlantic Sturgeon ◽  
The North ◽  
European Sturgeon ◽  
The Baltic

<em>Abstract.</em> - Sea sturgeons are closely related anadromous fishes inhabiting both shores of the North Atlantic Ocean. They are classified in two species: the European sturgeon <em>Acipenser sturio</em> in Europe and the Atlantic sturgeon <em>A. oxyrinchus</em> in North America. The Atlantic sturgeon is further separated into two subspecies: Atlantic sturgeon (North American East Coast populations) <em>A. o. oxyrinchus</em> and Gulf sturgeon <em>A. o. desotoi. </em>Most recent studies of morphology and genetics support these classifications. Furthermore, they produced evidence for a trans-Atlantic colonization event during the early Middle Ages. Atlantic sturgeon colonized Baltic waters, founding a self-reproducing population before they became extinct due to anthropogenic reasons. Today, populations of Atlantic sturgeon are found along the Atlantic Coast from the St. Johns River, Florida to the St. Lawrence River, Quebec, whereas only one relict spawning population of European sturgeon still exists in the Gironde River, France. The evidence of a population of Atlantic sturgeon in Baltic waters requires a detailed comparison of both sea sturgeon species, describing differences and similarities, which may influence the ongoing restoration projects in Europe as well as concerning conservation efforts in North America. This article reviews similarities and differences in the fields of genetics, morphology, and ecological adaptation of European sturgeon and Atlantic sturgeon, concluding that, besides morphological and genetic differences, a wider range of spawning temperatures in Atlantic sturgeon is evident. This wider temperature adaptation may be a selective advantage under fast-changing climatic conditions, possibly the mechanism that enabled the species shift in the Baltic Sea during the Middle Ages.

scholarly journals Continentality and Oceanity in the Mid and High Latitudes of the Northern Hemisphere and Their Links to Atmospheric Circulation

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Edvinas Stonevicius ◽  
Gintautas Stankunavicius ◽  
Egidijus Rimkus
Keyword(s):  
North America ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Climatic Conditions ◽  
High Latitudes ◽  
Teleconnection Patterns ◽  
The Pacific ◽  
The Impact

The climate continentality or oceanity is one of the main characteristics of the local climatic conditions, which varies with global and regional climate change. This paper analyzes indexes of continentality and oceanity, as well as their variations in the middle and high latitudes of the Northern Hemisphere in the period 1950–2015. Climatology and changes in continentality and oceanity are examined using Conrad’s Continentality Index (CCI) and Kerner’s Oceanity Index (KOI). The impact of Northern Hemisphere teleconnection patterns on continentality/oceanity conditions was also evaluated. According to CCI, continentality is more significant in Northeast Siberia and lower along the Pacific coast of North America as well as in coastal areas in the northern part of the Atlantic Ocean. However, according to KOI, areas of high continentality do not precisely correspond with those of low oceanity, appearing to the south and west of those identified by CCI. The spatial patterns of changes in continentality thus seem to be different. According to CCI, a statistically significant increase in continentality has only been found in Northeast Siberia. In contrast, in the western part of North America and the majority of Asia, continentality has weakened. According to KOI, the climate has become increasingly continental in Northern Europe and the majority of North America and East Asia. Oceanity has increased in the Canadian Arctic Archipelago and in some parts of the Mediterranean region. Changes in continentality were primarily related to the increased temperature of the coldest month as a consequence of changes in atmospheric circulation: the positive phase of North Atlantic Oscillation (NAO) and East Atlantic (EA) patterns has dominated in winter in recent decades. Trends in oceanity may be connected with the diminishing extent of seasonal sea ice and an associated increase in sea surface temperature.

scholarly journals Snow Stratigraphic Record at South Pole: Potential for Paleoclimatic Reconstruction

1985 ◽  
Vol 7 ◽  
pp. 26-33 ◽  
Author(s):  
E. Mosley-Thompson ◽  
P.D. Kruss ◽  
L.G. Thompson ◽  
M. Pourchet ◽  
P. Grootes
Keyword(s):  
Time Series ◽  
Temporal Resolution ◽  
Time Scale ◽  
Ice Core ◽  
Climatic Conditions ◽  
South Pole ◽  
Accumulation Rates ◽  
Geochemical Parameters ◽  
Absolute Dating ◽  
Oxygen Isotopic

An extensive investigation of the visible stratigraphy, microparticle concentration, liquid conductivity, oxygen isotopes and beta-radioactivity was conducted in pits excavated at Amundsen-Scott South Pole station. The objectives of the investigation were to assess the spatial representativeness of the geochemical and physical records preserved within the snow strata and to ascertain the temporal resolution which can be obtained from such ice-core records. Accurate interpretation of the time scale and reconstruction of climatic conditions from these time series requires (1) the analysis of as many stratigraphic parameters as possible and (2) the synthesis of data from a suite of cores in the study area. For periods of 10 a or less, regionally representative accumulation rates cannot be obtained from annual accumulation time series reconstructed at a single site. Although the microparticle concentrations, liquid conductivity and oxygen isotopic abundances all exhibit a seasonal cycle in the firn, the construction of an accurate time scale requires all three parameters in conjunction with the beta-radioactivity. Absolute dating will be impossible for cores from South Pole where entire accumulation years may be missing. Nevertheless, for East Antarctica, where accumulation rates are low (<0.1 m a−1 water equivalent), the good temporal resolution and the preservation of a distinct annual signal in some geochemical parameters makes the South Pole a very attractive site for deep ice-core drilling.

THE BIOGEOGRAPHY OF CANADIAN GRYLLOPTERA AND ORTHOPTERA

1989 ◽  
Vol 121 (4-5) ◽  
pp. 389-424 ◽  
Author(s):  
V.R. Vickery
Keyword(s):  
North America ◽  
Fossil Record ◽  
Neotropical Region ◽  
Climatic Conditions ◽  
Land Bridge ◽  
Recent Immigrants ◽  
Extant Species ◽  
The World ◽  
Land Mass ◽  
Orthopteroid Insects

AbstractThe saltatorial orthopteroid insects did not originate in North America. Five avenues of entry were utilized in migration from other parts of the world. These were: (1) ancestral forms migrated to this region in Pangaean times when all continents formed a single land mass; (2) later in time, taxa migrated from Europe when Eurasia and North America were still joined, or later via an Atlantic land bridge; (3) ancestral forms migrated northward from the Neotropical region before the separation of the two continents or, much later, when the two continents became rejoined; (4) later arriving taxa entered North America during the Pleistocene via a Beringian land bridge; (5) some species are very recent immigrants, either because of the activities of man or by migration into Canadian territory from the south.The fossil record is very incomplete. It indicates past climatic conditions, but is of limited assistance concerning extant taxa.Pleistocene glaciation had a profound effect upon the distribution of extant species. Many species were forced to move southward to escape the advancing ice. Some species probably were eliminated. It is clear that most of the extant species have migrated northward since the recession of the Wisconsin glacier.

scholarly journals Monarch butterflies cross the Appalachians from the west to recolonize the east coast of North America

2010 ◽  
Vol 7 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Nathan G. Miller ◽  
Leonard I. Wassenaar ◽  
Keith A. Hobson ◽  
D. Ryan Norris
Keyword(s):  
North America ◽  
Direct Evidence ◽  
East Coast ◽  
Gulf Coast ◽  
Danaus Plexippus ◽  
Early Spring ◽  
Eastern United States ◽  
The West ◽  
Monarch Butterflies ◽  
The Usa

Each spring, millions of monarch butterflies ( Danaus plexippus ) migrate from overwintering sites in Mexico to recolonize eastern North America. However, few monarchs are found along the east coast of the USA until mid-summer. Brower (Brower, L. P. 1996 J. Exp. Biol. 199, 93–103.) proposed that east coast recolonization is accomplished by individuals migrating from the west over the Appalachians, but to date no evidence exists to support this hypothesis. We used hydrogen ( δ D) and carbon ( δ 13 C) stable isotope measurements to estimate natal origins of 90 monarchs sampled from 17 sites along the eastern United States coast. We found the majority of monarchs (88%) originated in the mid-west and Great Lakes regions, providing, to our knowledge, the first direct evidence that second generation monarchs born in June complete a ( trans -) longitudinal migration across the Appalachian mountains. The remaining individuals (12%) originated from parents that migrated directly from the Gulf coast during early spring. Our results provide evidence of a west to east longitudinal migration and provide additional rationale for conserving east coast populations by identifying breeding sources.

WINTERHARDINESS OF ALFALFA CULTIVARS IN SOUTHERN SASKATCHEWAN

1973 ◽  
Vol 53 (4) ◽  
pp. 773-777 ◽  
Author(s):  
D. H. HEINRICHS
Keyword(s):  
North America ◽  
Medicago Sativa ◽  
Great Plains ◽  
Climatic Conditions ◽  
Northern Great Plains ◽  
Dry Land ◽  
The Third ◽  
The Usa ◽  
Medicago Sativa L

Winter injury occurring at Swift Current, Saskatchewan, was recorded in 17 tests during the period 1962–72. Cultivars developed in the Northern Great Plains Region of the USA and in Canada were generally more winter-hardy than cultivars developed in other regions of North America or in Europe. Cultivars classified as Medicago media Pers. were more winter-hardy than those classified as Medicago sativa L. Very few USA cultivars were more winter-hardy than Vernal, but most Canadian cultivars were. In nonhardy cultivars winter injury never occurred during the first winter, but it often occurred in the second winter and frequently in the third winter. There was considerably more winter injury among alfalfa cultivars on irrigated land than on dry land. Based on results from these tests, 50 cultivars and strains have been classified for relative winterhardiness under climatic conditions in southern Saskatchewan, Canada.

scholarly journals Geburtsverhalten und Kälberaufzucht beim Bison (<i>Bison bison</i>) in landwirtschaftlicher Haltung

2005 ◽  
Vol 48 (2) ◽  
pp. 157-173
Author(s):  
T. Haßpacher ◽  
H. H. Sambraus
Keyword(s):  
North America ◽  
Central Europe ◽  
Climatic Conditions ◽  
Bison Bison ◽  
Natural Reproduction ◽  
Species Specific ◽  
Behavioural Aspects

Abstract. Title of the paper: Parturient behaviour and raising of calves in bison (Bison bison) kept on farms The American Bison (Bison bison) is getting an increasing economical importance in Europe. Currently approx. 600 individuals of this species are kept on farms in Germany. There is little known if Bison can be kept species specific in Central Europe. In two bison herds with 52 respectively eight cows kept in Bavaria some behavioural aspects were examined, especially the calving and suckling behaviour. The behavioural observations were carried out during a period from spring to autumn, some days per week and each day from dawn till dusk. The calving lasted averagely 2 h (n = 19). 11 cows stood up within 1 min p.p.. The calves could stand after 20 min on average and had found the udder within half an hour p.p.. The number of suckling acts decreased from 1,7 per hour from the day of birth to as little as 0,2 times per hour in the 7th month. The duration of an individual suckling process increased to an average of 6 min in week 5 to 6 and then decreased to 4 min averagely in the 7th month. As bisons are still underlying a natural reproduction rhythm (calving almost only from May to July) damage to the calves as a result of unfavourable climatic conditions is not to be expected. The bison behaviour observed agreed mainly with that described in the literature for bison living in North America, despite smaller paddocks, more intense management and different ecosystems. Concerning the studied aspects, there is nothing that tells against keeping these animals, which originally come from another continent, under the described keeping conditions in Germany.

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