Seismic anisotropy and mantle flow beneath the northern Great Plains of North America

2014 ◽  
Vol 119 (3) ◽  
pp. 1971-1985 ◽  
Author(s):  
Bin B. Yang ◽  
Stephen S. Gao ◽  
Kelly H. Liu ◽  
Ahmed A. Elsheikh ◽  
Awad A. Lemnifi ◽  
...  
Keyword(s):  
North America ◽  
Great Plains ◽  
Seismic Anisotropy ◽  
Northern Great Plains ◽  
Mantle Flow

Diversity dynamics of mammals in relation to tectonic and climatic history: comparison of three Neogene records from North America

Paleobiology ◽  
10.1666/12024 ◽  
2013 ◽  
Vol 39 (3) ◽  
pp. 373-399 ◽  
Author(s):  
Catherine Badgley ◽  
John A. Finarelli
Keyword(s):  
North America ◽  
Pacific Northwest ◽  
Great Plains ◽  
Large Scale ◽  
Landscape History ◽  
Northern Great Plains ◽  
Faunal Composition ◽  
Topographic Complexity ◽  
Depositional Processes ◽  
Climatic Optimum

In modern ecosystems, regions of topographic heterogeneity, when compared with nearby topographically homogeneous regions, support high species densities of mammals and other groups. This biogeographic pattern could be explained by either greater diversification rates or greater accommodation of species in topographically complex regions. In this context, we assess the hypothesis that changes in landscape history have stimulated diversification in mammals. Landscape history includes tectonic and climatic processes that influence topographic complexity at regional scales. We evaluated the influence of changes in topographic complexity and climate on origination and extinction rates of rodents, the most diverse clade of mammals.We compared the Neogene records of rodent diversity for three regions in North America. The Columbia Basin of the Pacific Northwest (Region 1) and the northern Rocky Mountains (Region 2) were tectonically active over much of the Cenozoic and are characterized by high topographic complexity today. The northern Great Plains (Region 3) have been tectonically quiescent, with low relief, throughout the Cenozoic. These three regions have distinctive geologic histories and substantial fossil records. All three regions showed significant changes in diversification and faunal composition over the Neogene. In the montane regions, originations and extinctions peaked at the onset and close, respectively, of the Miocene Climatic Optimum (17–14 Ma), with significant changes in faunal composition accompanying these episodes of diversification. In the Great Plains, rodents showed considerable turnover but infrequent diversification. Peak Neogene diversity in the Great Plains occurred during cooling after the Miocene Climatic Optimum. These histories suggest that climatic changes interacting with increasing topographic complexity intensify macroevolutionary processes. In addition, close tracking of diversity and fossil productivity with the stratigraphic record suggests either large-scale sampling biases or the mutual response of diversity and depositional processes to changes in landscape history.

Diatom Assemblages and Ionic Characterization of Lakes of the Northern Great Plains, North America: A Tool for Reconstructing Past Salinity and Climate Fluctuations

1993 ◽  
Vol 50 (9) ◽  
pp. 1844-1856 ◽  
Author(s):  
S. C. Fritz ◽  
S. Juggins ◽  
R. W. Battarbee
Keyword(s):  
North America ◽  
Great Plains ◽  
Environmental Gradient ◽  
Surface Sediments ◽  
Weighted Averaging ◽  
Northern Great Plains ◽  
Climate Fluctuations ◽  
Sulfate Salts ◽  
Highly Correlated

The distribution of diatoms with respect to salinity and ionic gradients was studied in lakes of the northern Great Plains of North America. The lakes range from freshwater to hypersaline (0.65–270 g∙L−1) and include a variety of brine types, although the majority are dominated by sulfate salts. Canonical correspondence analysis of diatoms in the surface sediments of 66 lakes and associated water chemistry data indicates that diatom distributions are highly correlated with salinity. The ordination also suggests that brine type forms a significant environmental gradient and separates taxa characteristic of bicarbonate/carbonate lakes from those of sulfate-dominated systems. The salinityoptima and tolerances of diatom species are calculated by weighted averaging regression, and these data provide a tool for the reconstruction of past salinity and the inferance of climatic change in arid and semiarid regions.

scholarly journals Evaluation of Elite Wheat Germ Plasm for Resistance to Tan Spot

Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1320-1325 ◽  
Author(s):  
P. K. Singh ◽  
M. Mergoum ◽  
S. Ali ◽  
T. B. Adhikari ◽  
E. M. Elias ◽  
...  
Keyword(s):  
North America ◽  
Great Plains ◽  
Wheat Germ ◽  
Management Practices ◽  
Germ Plasm ◽  
The United States ◽  
Tan Spot ◽  
Northern Great Plains ◽  
Breeding Lines ◽  
Resistant Varieties

Tan spot, caused by Pyrenophora tritici-repentis, is a serious foliar disease of wheat (Triticum aestivum) in North America. Control of tan spot through management practices and fungicide application is possible; however, the use of resistant varieties is the most effective and economical means of controlling tan spot. This study was conducted to determine the disease reaction of 126 elite hard red spring, white, and durum wheat varieties and advanced breeding lines collected from the northern Great Plains of the United States and Canada to individual races/toxins of P. tritici-repentis. Seedling evaluation of the 126 genotypes was done under controlled environmental conditions with virulent races 2, 3, and 5 of P. tritici-repentis and toxins Ptr ToxA and Ptr ToxB. Based on disease reactions, two resistant varieties and two advanced breeding lines adapted to the northern Great Plains were found to be resistant to all the races and insensitive to the toxins tested. Additionally, six genetically diverse lines/varieties were identified to be resistant to tan spot; however, these sources may not be well adapted to the northern Great Plains. These results suggest that the wheat germ plasm contains a broad genetic base for resistance to the most prevalent races of P. tritici-repentis in North America, and the resistant sources identified in this study may be utilized in wheat breeding programs to develop tan spot resistant varieties.

scholarly journals Whence the beardogs? Reappraisal of the Middle to Late Eocene ‘ Miacis ’ from Texas, USA, and the origin of Amphicyonidae (Mammalia, Carnivora)

2016 ◽  
Vol 3 (10) ◽  
pp. 160518 ◽  
Author(s):  
Susumu Tomiya ◽  
Zhijie Jack Tseng
Keyword(s):  
North America ◽  
Great Plains ◽  
Geographical Origin ◽  
Middle Eocene ◽  
Cladistic Analysis ◽  
Rocky Mountain ◽  
Late Eocene ◽  
Northern Great Plains ◽  
Mammalian Fauna ◽  
Additional Support

The Middle to Late Eocene sediments of Texas have yielded a wealth of fossil material that offers a rare window on a diverse and highly endemic mammalian fauna from that time in the southern part of North America. These faunal data are particularly significant because the narrative of mammalian evolution in the Paleogene of North America has traditionally been dominated by taxa that are known from higher latitudes, primarily in the Rocky Mountain and northern Great Plains regions. Here we report on the affinities of two peculiar carnivoraforms from the Chambers Tuff of Trans-Pecos, Texas, that were first described 30 years ago as Miacis cognitus and M. australis . Re-examination of previously described specimens and their inclusion in a cladistic analysis revealed the two taxa to be diminutive basal amphicyonids; as such, they are assigned to new genera Gustafsonia and Angelarctocyon , respectively. These two taxa fill in some of the morphological gaps between the earliest-known amphicyonid genus, Daphoenus , and other Middle-Eocene carnivoraforms, and lend additional support for a basal caniform position of the beardogs outside the Canoidea. The amphicyonid lineage had evidently given rise to at least five rather distinct forms by the end of the Middle Eocene. Their precise geographical origin remains uncertain, but it is plausible that southern North America served as an important stage for a very early phase of amphicyonid radiation.

Distribution and population fluctuations of wintering Snowy Owls (Nyctea scandiaca) in North America

1985 ◽  
Vol 63 (8) ◽  
pp. 1829-1834 ◽  
Author(s):  
P. Kerlinger ◽  
M. Ross Lein ◽  
Brian J. Sevick
Keyword(s):  
North America ◽  
Great Plains ◽  
East Coast ◽  
Northern Great Plains ◽  
Population Fluctuations ◽  
Winter Range ◽  
Christmas Bird Count ◽  
Continental Population ◽  
America South ◽  
Time Series Analyses

Christmas Bird Count data from 1952 to 1981 were used to examine the geographic distribution and population fluctuations of wintering Snowy Owls (Nyctea scandiaca) in North America south of the breeding range. Wintering owls were most abundant and regular in occurrence in the northern Great Plains and Midwest regions of North America. To the south of these locales, and on both east and west coasts, owl abundance averaged 10–100 times lower and varied dramatically from year to year. Numbers of Snowy Owls fluctuated synchronously within the east coast area, the west coast area, and possibly the Great Plains, but fluctuations were not synchronous among these three areas. Time-series analyses did not support the hypothesis of cyclic winter invasions. Earlier studies from eastern North America included only a small portion of the continental population of Snowy Owls and, consequently, their conclusions may have been biased. Our findings strongly suggest that Snowy Owls may not be cyclic invaders, but rather are regular migrants over much of their winter range.

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 Isotope constraints on water, carbon, and heat fluxes from the northern Great Plains region of North America

2007 ◽  
Vol 21 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Paul R. Ferguson ◽  
Nicole Weinrauch ◽  
Leonard I. Wassenaar ◽  
Bernhard Mayer ◽  
Ján Veizer
Keyword(s):  
North America ◽  
Great Plains ◽  
Heat Fluxes ◽  
Northern Great Plains

A 13-YEAR SURVEY OF THE APHIDOPHAGOUS COCCINELLIDAE IN MAIZE FIELDS IN EASTERN SOUTH DAKOTA

1990 ◽  
Vol 122 (3) ◽  
pp. 579-581 ◽  
Author(s):  
R.W. Kieckhefer ◽  
N.C. Elliott
Keyword(s):  
United States ◽  
Zea Mays ◽  
North America ◽  
South Dakota ◽  
Great Plains ◽  
The United States ◽  
Northern Great Plains ◽  
Eastern Canada

Coccinellids are a conspicuous group of aphidophagous predators in maize, Zea mays L., in the Northern Great Plains of the United States. Numerous studies have been conducted on the ecology of coccinellids in maize in North America (Ewert and Chiang 1966a, 1966b; Smith 1971; Foott 1973; Wright and Laing 1980; Corderre and Tourneur 1986; Corderre et al. 1987). However, there have been few long-term surveys of coccinellids in maize. Foott (1973) reported on the abundance of coccinellid species inhabiting maize in eastern Canada over a 4-year period; no surveys of this type have been reported for the Northern Great Plains. We sampled coccinellids in maize fields at three sites in eastern South Dakota for 13 consecutive years to determine the species inhabiting the crop and levels of variation in their abundances among sites and years.

Sign in / Sign up

Export Citation Format

Share Document