Staurothele nemorum sp. nov. (Ascomycota: Verrucariaceae), with a revised key to North American Staurothele s. lat.

2019 ◽  
Vol 51 (6) ◽  
pp. 495-506 ◽  
Author(s):  
Caleb A. MORSE ◽  
Douglas LADD
Keyword(s):  
North America ◽  
Great Plains ◽  
North American ◽  
The South ◽  
Southern Great Plains ◽  
The North ◽  
Western Great Plains

AbstractStaurothele nemorum is described as new to science from the southern Great Plains of central North America. The species is characterized by a thin, areolate, epilithic thallus, sessile perithecia, globose to oblong hymenial algal cells and 8-spored asci. Staurothele hymenogonia is restored to the North American flora, based on material from the south-western Great Plains. An updated key to North American members of Staurothele s. lat. is provided.

Ecogeography and the Great American Interchange

Paleobiology ◽  
1991 ◽  
Vol 17 (3) ◽  
pp. 266-280 ◽  
Author(s):  
S. David Webb
Keyword(s):  
North America ◽  
South America ◽  
North American ◽  
Mammalian Fauna ◽  
The South ◽  
Land Bridge ◽  
Southern Mexico ◽  
The North ◽  
Land Mammal ◽  
The Impact

When the isthmian land bridge triggered the Great American Interchange, a large majority of land-mammal families crossed reciprocally between North and South America at about 2.5 Ma (i.e., Late Pliocene). Initially land-mammal dynamics proceeded as predicted by equilibrium theory, with roughly equal reciprocal mingling on both continents. Also as predicted, the impact of the interchange faded in North America after about 1 m.y. In South America, contrary to such predictions, the interchange became decidedly unbalanced: during the Pleistocene, groups of North American origin continued to diversify at exponential rates. Whereas only about 10% of North American genera are derived from southern immigrants, more than half of the modern mammalian fauna of South America, measured at the generic level, stems from northern immigrants. In addition, extinctions more severely decimated interchange taxa in North America, where six families were lost, than in South America, where only two immigrant families became extinct.This paper presents a two-phase ecogeographic model to explain the asymmetrical results of the land-mammal interchange. During the humid interglacial phase, the tropics were dominated by rain forests, and the principal biotic movement was from Amazonia to Central America and southern Mexico. During the more arid glacial phase, savanna habitats extended broadly right through tropical latitudes. Because the source area in the temperate north was six times as large as that in the south, immigrants from the north outnumbered those from the south. One prediction of this hypothesis is that immigrants from the north generally should reach higher latitudes in South America than the opposing contingent of land-mammal taxa in North America. Another prediction is that successful interchange families from the north should experience much of their phylogenetic diversification in low latitudes of North America before the interchange. Insofar as these predictions can be tested, they appear to be upheld.

scholarly journals Prediction of Seasonal Meteorological Drought Onset and Termination over the Southern Great Plains in the North American Multimodel Ensemble

2020 ◽  
Vol 21 (10) ◽  
pp. 2237-2255
Author(s):  
Richard Seager ◽  
Jennifer Nakamura ◽  
Mingfang Ting
Keyword(s):  
Great Plains ◽  
North American ◽  
Time Scale ◽  
Meteorological Drought ◽  
Atmospheric Variability ◽  
Multimodel Ensemble ◽  
Southern Great Plains ◽  
The North ◽  
Seasonal Time Scale ◽  
North American Multimodel Ensemble

AbstractThe predictability on the seasonal time scale of meteorological drought onsets and terminations over the southern Great Plains is examined within the North American Multimodel Ensemble. The drought onsets and terminations were those identified based on soil moisture transitions in land data assimilation systems and shown to be driven by precipitation anomalies. Sea surface temperature (SST) forcing explains about a quarter of variance of seasonal mean precipitation in the region. However, at lead times of a season, forecast SSTs only explain about 10% of seasonal mean precipitation variance. For the three identified drought onsets, fall 2010 is confidently predicted and spring 2012 is predicted with some skill, and fall 2005 was not predicted at all. None of the drought terminations were predicted on the seasonal time scale. Predictability of drought onset arises from La Niña–like conditions, but there is no indication that El Niño conditions lead to drought terminations in the southern Great Plains. Spring 2012 and fall 2000 are further examined. The limited predictability of onset in spring 2012 arises from cool tropical Pacific SSTs, but internal atmospheric variability played a very important role. Drought termination in fall 2000 was predicted at the 1-month time scale but not at the seasonal time scale, likely because of failure to predict warm SST anomalies directly east of subtropical Asia. The work suggests that improved SST prediction offers some potential for improved prediction of both drought onsets and terminations in the southern Great Plains, but that many onsets and terminations will not be predictable even a season in advance.

scholarly journals Prospects for Advancing Drought Understanding, Monitoring, and Prediction

2015 ◽  
Vol 16 (4) ◽  
pp. 1636-1657 ◽  
Author(s):  
Eric F. Wood ◽  
Siegfried D. Schubert ◽  
Andrew W. Wood ◽  
Christa D. Peters-Lidard ◽  
Kingtse C. Mo ◽  
...  
Keyword(s):  
Great Plains ◽  
North American ◽  
Land Surface ◽  
Task Force ◽  
Atmospheric Variability ◽  
Southern Great Plains ◽  
The North ◽  
Drought Prediction ◽  
Seasonal Model

Abstract This paper summarizes and synthesizes the research carried out under the NOAA Drought Task Force (DTF) and submitted in this special collection. The DTF is organized and supported by NOAA’s Climate Program Office with the National Integrated Drought Information System (NIDIS) and involves scientists from across NOAA, academia, and other agencies. The synthesis includes an assessment of successes and remaining challenges in monitoring and prediction capabilities, as well as a perspective of the current understanding of North American drought and key research gaps. Results from the DTF papers indicate that key successes for drought monitoring include the application of modern land surface hydrological models that can be used for objective drought analysis, including extended retrospective forcing datasets to support hydrologic reanalyses, and the expansion of near-real-time satellite-based monitoring and analyses, particularly those describing vegetation and evapotranspiration. In the area of drought prediction, successes highlighted in the papers include the development of the North American Multimodel Ensemble (NMME) suite of seasonal model forecasts, an established basis for the importance of La Niña in drought events over the southern Great Plains, and an appreciation of the role of internal atmospheric variability related to drought events. Despite such progress, there are still important limitations in our ability to predict various aspects of drought, including onset, duration, severity, and recovery. Critical challenges include (i) the development of objective, science-based integration approaches for merging multiple information sources; (ii) long, consistent hydrometeorological records to better characterize drought; and (iii) extending skillful precipitation forecasts beyond a 1-month lead time.

Ancestral trans−North American Bell River system recorded in late Oligocene to early Miocene sediments in the Labrador Sea and Canadian Great Plains

2021 ◽  
Author(s):  
Julia I. Corradino ◽  
Alex Pullen ◽  
Andrew L. Leier ◽  
David L. Barbeau Jr. ◽  
Howie D. Scher ◽  
...  
Keyword(s):  
North America ◽  
Great Plains ◽  
North American ◽  
Detrital Zircon ◽  
Detrital Zircons ◽  
Labrador Sea ◽  
Western Canada ◽  
Zircon Age ◽  
North American Cordillera ◽  
The North

The Bell River hypothesis proposes that an ancestral, transcontinental river occupied much of northern North America during the Cenozoic Era, transporting water and sediment from the North American Cordillera to the Saglek Basin on the eastern margin of the Labrador Sea. To explore this hypothesis and reconstruct Cenozoic North American drainage patterns, we analyzed detrital zircon grains from the Oligocene−Miocene Mokami and Saglek formations of the Saglek Basin and Oligocene−Miocene fluvial conglomerates in the Great Plains of western Canada. U-Pb detrital zircon age populations in the Mokami and Saglek formations include clusters at <250 Ma, 950−1250 Ma, 1600−2000 Ma, and 2400−3200 Ma. Detrital zircons with ages of <250 Ma were derived from the North American Cordillera, supporting the transcontinental Bell River hypothesis. Oligocene−Miocene fluvial strata in western Canada contain detrital zircon age populations similar to those in the Saglek Basin and are interpreted to represent the western headwaters of the ancient Bell River drainage. Strontium-isotope ratios of marine shell fragments from the Mokami and Saglek formations yielded ages between 25.63 and 18.08 Ma. The same shells have εNd values of −10.2 to −12.0 (average = −11.2), which are consistent with values of Paleozoic strata in western North America but are more radiogenic than the modern Labrador Current, Labrador Sea Water, and North Atlantic Deep Water values (εNd ∼−12 to −25). As a freshwater source, the existence and termination of the Bell River may have been important for Labrador Sea circulation, stratification, and chemistry.

Jake Bluff: Clovis Bison Hunting on the Southern Plains of North America

2010 ◽  
Vol 75 (4) ◽  
pp. 907-933 ◽  
Author(s):  
Leland C. Bement ◽  
Brian J. Carter
Keyword(s):  
North America ◽  
Great Plains ◽  
North American ◽  
Southern Plains ◽  
Projectile Points ◽  
The North ◽  
Hunting Strategies ◽  
Bison Antiquus ◽  
Large Animals

Clovis hunters of the North American Great Plains are known for their ability to hunt and scavenge mammoths. Less is known of their hunting strategies for other large animals, such as horse, camel, and bison, although remains of these animals have been found at several Clovis camps. Recent investigations of the Jake Bluff site on the southern Plains have identified a Clovis bison kill in an arroyo. The apparent use of an arroyo style trap for bison hunting provides the opportunity to study Clovis hunting strategies that came to be widely used during later Paleoindian times. The arroyo style bison trap is generally attributed to Folsom and later groups, and yet the Jake Bluff site yielded an association of Clovis-style projectile points with the remains of 22 Bison antiquus at the bottom of a short arroyo. The late date of 12,838 cal. BP suggests that the site spans the gap between the Clovis mammoth hunter and the Folsom bison hunter, indicating that some Clovis hunters developed the arroyo style bison trap to capture multiple bison at the same time, and as mammoths were extirpated from certain areas during the Pleistocene to Holocene transition.

13,000 years of communal bison hunting in western North America

2017 ◽  
Author(s):  
John D. Speth
Keyword(s):  
North America ◽  
Great Plains ◽  
North American ◽  
Bison Bison ◽  
Early Winter ◽  
Western North America ◽  
The Past ◽  
The North ◽  
Late Fall

For the past 13,000 years Indians in the North American Great Plains hunted bison (Bison bison and B. antiquus) in large communally organized drive operations. This chapter briefly describes the taxonomy of fossil and living bison, the behaviour of modern bison, and what is known from ethnohistoric and archaeological sources about the ways that Indians conducted these drives, including the use of foot surrounds, cliff jumps, arroyo traps, and pounds (corrals). The chapter concludes by considering whether such drives were conducted annually in the late fall and/or early winter as a means of winter provisioning; or instead were conducted periodically, but not necessarily annually, and at many different times of year, as a socio-political mechanism for integrating otherwise widely dispersed and highly mobile hunting bands.

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