Hydrologic Variation in the Northern Great Plains During the Last Two Millennia

AbstractReconstructions of lake-water salinity at decadal resolution for the last 2000 yr are compared among three lakes in North Dakota to infer regional patterns of drought. The intersite comparisons are used to distinguish local variation in climate or hydrology from regional patterns of change. At one lake, diatom-inferred salinity and lake-water Mg/Ca inferred from ostracode shell chemistry are coherent, both in terms of direction and magnitude of change, indicating that each is a robust technique for reconstructing lake-water chemistry. The data show that the last 2000 yr have been characterized by frequent shifts between high and low salinity, suggesting shifts between dry and moist periods. Long intervals of high salinity suggest periods of multiple decades when droughts were intense and frequent, thus indicating times when drought was more persistent than in the 20th century. Both the Medieval Period and Little Ice Age were hydrologically complex, and there is no clear evidence to suggest that either interval was coherent or unusual in effective moisture relative to long-term patterns. Differences among the three sites may be attributed to variation in local hydrology, and these differences emphasize the need for multiple sites in deriving regional climate interpretations from paleoecological data.

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Holocene eolian sand deposition linked to climatic variability, Northern Great Plains, Canada

The Holocene ◽

10.1177/0959683616670223 ◽

2016 ◽

Vol 27 (4) ◽

pp. 579-593 ◽

Cited By ~ 3

Author(s):

Stephen A Wolfe ◽

Olav B Lian ◽

Christopher H Hugenholtz ◽

Justine R Riches

Keyword(s):

Great Plains ◽

Climatic Variability ◽

Sediment Cores ◽

Soil Formation ◽

Temporal Variations ◽

Ice Age ◽

Northern Great Plains ◽

Eolian Sand ◽

Sand Accumulation ◽

Sand Deposition

The Bigstick and Seward Sand Hills are possibly two of the oldest dune fields within the late Wisconsin glaciated regions of the Northern Great Plains. As with most Northern Great Plains dune fields, source sediments are former proglacial outwash sands. Thus, Holocene dune construction is primarily related to spatial–temporal variations in surface cover and transport capacity, rather than renewed sediment input. However, eolian landscape reconstructions on the Northern Great Plains have been temporally constrained to recent periods of activity, as older episodes of deposition are typically reworked by younger events. In this study, sediment cores from shallow lacustrine basins and interdune areas provide an improved record of Holocene eolian sand deposition. Eolian sand accumulation in the interdunes and basins occurred between 150 and 270 years ago, 1.9 and 3.0 ka, 5.4 and 8.6 ka, and prior to ca. 10.8 ka. These episodes of sand accumulation were bracketed by lacustrine deposition and soil formation, which represented wetter conditions. Other than mid-Holocene dune activity, which may be related to peak warmth and aridity, most periods of eolian sand accumulation coincided with cooler but drier climatic events such as the Younger Dryas, late-Holocene cooling prior to the Medieval Climatic Anomaly, and the ‘Little Ice Age’. These depositional episodes are also spatially represented by other dune fields in the region, providing a broad-scale view of the connections between past climatic events and eolian landscape evolution on the Northern Great Plains.

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Climatic and hydrologic variability during the past millennium in the eastern Rocky Mountains and northern Great Plains of western Canada

Quaternary Research ◽

10.1016/j.yqres.2008.04.013 ◽

2008 ◽

Vol 70 (2) ◽

pp. 188-197 ◽

Cited By ~ 58

Author(s):

Thomas W.D. Edwards ◽

S. Jean Birks ◽

Brian H. Luckman ◽

Glen M. MacDonald

Keyword(s):

Great Plains ◽

Rocky Mountains ◽

Ice Age ◽

Northern Great Plains ◽

Western Canada ◽

Medieval Climate Anomaly ◽

Air Masses ◽

The Past ◽

Hydrologic Variability ◽

Atmospheric Relative Humidity

AbstractModelling of tree-ring δ13C and δ18O data from the Columbia Icefield area in the eastern Rocky Mountains of western Canada provides fuller understanding of climatic and hydrologic variability over the past 1000 yr in this region, based on reconstruction of changes in growth season atmospheric relative humidity (RHgrs), winter temperature (Twin) and the precipitation δ18O–Twin relation. The Little Ice Age (~ AD 1530s–1890s) is marked by low RHgrs and Twin and a δ18O–Twin relation offset from that of the present, reflecting enhanced meridional circulation and persistent influence of Arctic air masses. Independent proxy hydrologic evidence suggests that snowmelt sustained relatively abundant streamflow at this time in rivers draining the eastern Rockies. In contrast, the early millennium was marked by higher RHgrs and Twin and a δ18O–Twin relation like that of the 20th century, consistent with pervasive influence of Pacific air masses because of strong zonal circulation. Especially mild conditions prevailed during the “Medieval Climate Anomaly” ~ AD 1100–1250, corresponding with evidence for reduced discharge in rivers draining the eastern Rockies and extensive hydrological drought in neighbouring western USA.

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Regional Frequencies of Virulence in Oat Crown Rust in the United States from 1990 Through 2000

Plant Disease ◽

10.1094/pdis.2003.87.11.1301 ◽

2003 ◽

Vol 87 (11) ◽

pp. 1301-1310 ◽

Cited By ~ 27

Author(s):

K. J. Leonard

Keyword(s):

United States ◽

New York ◽

Great Plains ◽

Single Gene ◽

Atlantic Coast ◽

The United States ◽

Northern Great Plains ◽

Stabilizing Selection ◽

Alternate Host ◽

Regional Patterns

More than 2,000 isolates of Puccinia coronata f. sp. avenae collected in national virulence surveys were analyzed to determine regional patterns of virulence on 28 single-gene oat lines. From 1990 to 2000, frequencies of virulence to eight differentials increased significantly in Texas, and virulence frequencies of four of the eight also increased in the northern Great Plains. No significant changes occurred for the other 20 differentials. Isolates from northern states from the Dakotas to New York had similar patterns of virulence frequencies on these 20 differentials. The pattern of virulence frequencies in the north differed from that of southern states from Texas to the Carolinas. There was a gradient of similarity values in state by state comparisons from Texas to the Atlantic Coast. Isolates from California were distinctly different from those elsewhere in the United States. Isolates from the South and from California had greater mean virulence complexity than isolates from northern states. Collections from the central Great Plains were intermediate between northern and southern isolates. Uredinial isolates from oat and aecial isolates from the alternate host Rhamnus cathartica in Minnesota had similar frequencies of virulence, as did isolates from cultivated oat and wild Avena fatua in North Dakota. Maintenance of large numbers of stable virulence polymorphisms with different regional allele frequencies is consistent with the operation of some form of stabilizing selection.

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Regional Patterns in Prevelar Raising

American Speech ◽

10.1215/00031283-9308384 ◽

2021 ◽

pp. 1-50

Author(s):

Joseph A. Stanley

Keyword(s):

Pacific Northwest ◽

Great Plains ◽

Online Survey ◽

Regional Distribution ◽

Northern Great Plains ◽

Upper Midwest ◽

The West ◽

Regional Patterns ◽

The North ◽

The Pacific

Prevelar raising is the raising of TRAP and DRESS vowels before voiced velars. While BAG-and BEG-raising have been described in Canada, the Upper Midwest, and the Pacific Northwest, an in-depth investigation of their distribution across North America is lacking, especially for BEG. Using an online survey distributed to over 5,000 participants via Reddit (which skews towards younger White males) and ordinary kriging for spatial interpolation, this study finds that prevelar raising is more widespread than previously reported. BAG-raising is found in much of the North and the Upper Midwest. BEG-raising is far more variable and is common across much of the Midlands and the West, with concentrated pockets in the Northern Great Plains and various other regions. This data suggests that the two can occur independently, with areas like the upper Midwest exhibiting BAG-raising alone, and the Midlands and the West reporting BEG-raising alone. These findings suggest that additional research on prevelar raising and other infrequent phonological variables is required to uncover their regional distribution and social meaning.

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