Floristic similarity, diversity, and endemism as indicators of refugia characteristics and needs in the West

2020 ◽  
Author(s):  
George P Malanson ◽  
Dale L Zimmerman ◽  
Daniel B Fagre
Keyword(s):  
Sierra Nevada ◽  
Great Basin ◽  
Community Assembly ◽  
Rocky Mountains ◽  
Initial Conditions ◽  
Geographic Distance ◽  
Stepping Stones ◽  
The West ◽  
Floristic Similarity ◽  
Mountain Ranges

The floras of mountain ranges, and their similarity, beta diversity, and endemism, are indicative of processes of community assembly; they are also the initial conditions for coming disassembly and reassembly in response to climate change. As such, these characteristics can inform thinking on refugia. The published floras or approximations for 42 mountain ranges in the three major mountain systems (Sierra-Cascades, Rocky Mountains, and Great Basin ranges) across the western USA and southwestern Canada were analyzed. The similarity is higher among the ranges of the Rockies while equally low among the ranges of the Sierra-Cascades and Great Basin. Mantel correlations of similarity with geographic distance are also higher for the Rocky Mountains. Endemism is relatively high, but is highest in the Sierra-Cascades (due to the Sierra Nevada as the single largest range) and lowest in the Great Basin, where assemblages are allochthonous. These differences indicate that the geologic substrates of the Cascade volcanoes, which are much younger than any others, play a role in addition to geographic isolation in community assembly. The pattern of similarity and endemism indicates that the ranges of the Cascades will not function well as stepping stones and the endemic species that they harbor may need more protection than those of the Rocky Mountains. The geometry of the ranges is complemented by geology in setting the stage for similarity and the potential for refugia across the West. Understanding the geographic template as initial conditions for the future can guide the forecast of refugia and related monitoring or protection efforts.

The Intermontane Western Tradition

1962 ◽  
Vol 28 (2) ◽  
pp. 144-150 ◽  
Author(s):  
Richard D. Daugherty
Keyword(s):  
Conceptual Framework ◽  
Sierra Nevada ◽  
Great Basin ◽  
Rocky Mountains ◽  
Environmental Changes ◽  
Glacial Period ◽  
Western Tradition ◽  
The West ◽  
Northern Mexico ◽  
The North

AbstractThe hypothesis of an Intermontane Western tradition is advanced as a conceptual framework within which it is possible to achieve a greater understanding of the cultural histories of the Plateau, Great Basin, and Southwest culture areas, including broad and specific relationships and also the developing differences.Geographically, the Intermontane Western tradition extended throughout the intermontane region between the Cascade-Sierra Nevada ranges on the west, and the Rocky Mountains on the east, and from southern British Columbia on the north to northern Mexico on the south. Temporally, the Intermontane Western tradition existed throughout the post-glacial period.Within the major tradition, the Southwest Agricultural, Desert, and Northwest Riverine Areal traditions are seen developing, partly in response to environmental changes.

Mountain Climates of North America

2000 ◽  
Author(s):  
C. David Whiteman
Keyword(s):  
United States ◽  
North America ◽  
Sierra Nevada ◽  
Rocky Mountains ◽  
Climatic Conditions ◽  
Cascade Range ◽  
Coast Range ◽  
Alaska Range ◽  
Mountain Ranges ◽  
The Pacific

The basic climatic characteristics of the major mountain ranges in the United States—the Appalachians, the Coast Range, the Alaska Range, the Cascade Range, the Sierra Nevada, and the Rocky Mountains—can be described in terms of the four factors discussed in chapter 1. The mountains of North America extend latitudinally all the way from the Arctic Circle (66.5°N) to the tropic of Cancer (23.5°N) (figure 2.1). There are significant differences in day length and angle of solar radiation over this latitude belt that result in large seasonal and diurnal differences in the weather from north to south. Elevations in the contiguous United States extend from below sea level at Death Valley to over 14,000 ft (4270 m) in the Cascade Range, the Sierra Nevada, and the Rocky Mountains. Several prominent peaks along the Coast Range in Alaska and Canada (e.g., Mount St. Elias and Mount Logan) reach elevations above 18,000 ft (5486 m). Denali (20,320 ft or 6194 m) in the Alaska Range is the highest peak in North America. The highest peak in the Canadian Rockies is Mt. Robson, with an elevation of 12,972 ft (3954 m). The climates of the Coast Range, the Cascade Range, and the Sierra Nevada, all near the Pacific Ocean, are primarily maritime. The Appalachian Mountains of the eastern United States are subject to a maritime influence from the Atlantic Ocean and the Gulf of Mexico, but they are also affected by the prevailing westerly winds that bring continental climatic conditions. Only the climate of the Rocky Mountains, far from both the Pacific and Atlantic Oceans, is primarily continental. Each of the mountain ranges is influenced by regional circulations. For example, the Appalachians are exposed to the warm, moist winds brought northward by the Bermuda-Azores High and to the influence of the Gulf Stream. Similarly, the Coast Range feels the impact of the Pacific High, the Aleutian low, and the Japanese Current. A mountain range, depending on its size, shape, orientation, and location relative to air mass source regions, can itself affect the regional climate by acting as a barrier to regional flows.

scholarly journals Systematic Patterns of the Inconsistency between Snow Water Equivalent and Accumulated Precipitation as Reported by the Snowpack Telemetry Network

2012 ◽  
Vol 13 (6) ◽  
pp. 1970-1976 ◽  
Author(s):  
Jonathan D. D. Meyer ◽  
Jiming Jin ◽  
Shih-Yu Wang
Keyword(s):  
Sierra Nevada ◽  
Rocky Mountains ◽  
Snow Water Equivalent ◽  
Systematic Bias ◽  
Mountain Ranges ◽  
Wind Speeds ◽  
Drifting Snow ◽  
Snow Water ◽  
Interior West ◽  
One Year

Abstract The authors investigated the accuracy of snow water equivalent (SWE) observations compiled by 748 Snowpack Telemetry stations and attributed the systematic bias introduced to SWE measurements to drifting snow. Often observed, SWE outpaces accumulated precipitation (AP), which can be statistically and physically explained through 1) precipitation undercatchment and/or 2) drifting snow. Forty-four percent of the 748 stations reported at least one year where the maximum SWE was greater than AP, while 16% of the stations showed this inconsistency for at least 20% of the observed years. Regions with a higher likelihood of inconsistency contained drier snow and are exposed to higher winds speeds, both of which are positively correlated to drifting snow potential as well as gauge undercatch. Differentiating between gauge undercatch and potential drifting scenarios, days when SWE increased but AP remained zero were used. These drift days occurred on an average of 13.3 days per year for all stations, with 31% greater wind speeds at 10 m for such days (using reanalysis winds). Findings suggest marked consistency between SWE and AP throughout the Cascade Mountains and lower elevations of the interior west while indicating notable inconsistency between these two variables throughout the higher elevations of the Rocky Mountains, Utah mountain ranges, and the Sierra Nevada.

A NEW CALIFORNIA EUPHYDRYAS (LEPID., RHOPALOCERA)

1929 ◽  
Vol 61 (2) ◽  
pp. 44-45
Author(s):  
J. D. Gunder
Keyword(s):  
New Mexico ◽  
Sierra Nevada ◽  
Great Basin ◽  
Rocky Mountains ◽  
National Park ◽  
Western Montana ◽  
Sequoia National Park ◽  
Parental Stock ◽  
Sierra Nevada Mountains

The chain of Rocky Mountains extending south from Canada through western Montana. Wyoming, Colorado and into northern New Mexico produce a series of butterflies which are at prespnt referable under an anicia-brucei classification. Various races from this supposed parental stock are found in southwestern Colorado, Utah, the Great Basin of Nevada and elsewhere with members of the clan branching down into New Mexico. For several years I have been hoping to find representatives of this group reaching over into the Sierra Nevada Mountains of California. In 1927 when on Alta Peak in Sequoia National Park, I took two males and in 1928 Mr. Walter Ireland captured four females in the same locality which I find to be closely related to the above mentioned breed.

scholarly journals Geochemical study of Cenozoic mafic volcanism in the west-central Great Basin, western Nevada, and the Ancestral Cascades Arc, California

Geosphere ◽  
2020 ◽  
Vol 16 (5) ◽  
pp. 1179-1207
Author(s):  
Ann C. Timmermans ◽  
Brian L. Cousens ◽  
Christopher D. Henry
Keyword(s):  
Sierra Nevada ◽  
Great Basin ◽  
Lithospheric Mantle ◽  
Mantle Wedge ◽  
Volcanic Rocks ◽  
Small Subset ◽  
The West ◽  
West Central ◽  
Shallow Subduction ◽  
Mafic Lavas

Abstract Processes linked to shallow subduction, slab rollback, and extension are recorded in the whole-rock major-, trace-element, and Sr, Nd, and Pb isotopic compositions of mafic magmatic rocks in both time and space over southwestern United States. Eocene to Mio-Pliocene volcanic rocks were sampled along a transect across the west-central Great Basin (GB) in Nevada to the Ancestral Cascade Arc (ACA) in the northern Sierra Nevada, California (∼39°–40° latitude), which are interpreted to represent a critical segment of a magmatic sweep that occurred as a result of subduction from east-northeast convergence between the Farallon and North American plates and extension related to the change from a convergent to a transform margin along the western edge of North America. Mafic volcanic rocks from the study area can be spatially divided into three broad regions: GB (5–35 Ma), eastern ACA, and western ACA (2.5–16 Ma). The volcanic products are dominantly calc-alkalic but transition to alkalic toward the east. Great Basin lavas erupted far inland from the continental margin and have higher K, P, Ti, and La/Sm as well as lower (Sr/P)pmn, Th/Rb, and Ba/Nb compared to ACA lavas. Higher Pb isotopic values, combined with lower Ce/Ce* and high Th/Nb ratios in some ACA lavas, are interpreted to come from slab sediment. Mafic lavas from the GB and ACA have overlapping 87Sr/86Sr and 143Nd/144Nd values that are consistent with mantle wedge melts mixing with a subduction-modified lithospheric mantle source. Eastern and western ACA lavas largely overlap in age and elemental and isotopic composition, with the exception of a small subset of lavas from the westernmost ACA region; these lavas show lower 87Sr/86Sr at a given 143Nd/144Nd. Results show that although extension contributes to melting in some regions (e.g., selected lavas in the GB and Pyramid Lake), chemical signatures for most mafic melts are dominated by subduction-related mantle wedge and a lithospheric mantle component.

Climatic implications of latest Pleistocene and earliest Holocene mammalian sympatries in eastern Washington state, USA

2008 ◽  
Vol 70 (3) ◽  
pp. 426-432 ◽  
Author(s):  
R. Lee Lyman
Keyword(s):  
North America ◽  
Late Pleistocene ◽  
Rocky Mountains ◽  
Taxonomic Composition ◽  
Washington State ◽  
The West ◽  
Mammalian Faunas ◽  
Eastern Washington

AbstractFor more than fifty years it has been known that mammalian faunas of late-Pleistocene age are taxonomically unique and lack modern analogs. It has long been thought that nonanalog mammalian faunas are limited in North America to areas east of the Rocky Mountains and that late-Pleistocene mammalian faunas in the west were modern in taxonomic composition. A late-Pleistocene fauna from Marmes Rockshelter in southeastern Washington State has no modern analog and defines an area of maximum sympatry that indicates significantly cooler summers than are found in the area today. An earliest Holocene fauna from Marmes Rockshelter defines an area of maximum sympatry, including the site area, but contains a single tentatively identified taxon that may indicate slightly cooler than modern summers.

Great Basin Prehistory and Uto-Aztecan

1965 ◽  
Vol 31 (1) ◽  
pp. 48-60 ◽  
Author(s):  
Nicholas A. Hopkins
Keyword(s):  
Great Basin ◽  
Rocky Mountains ◽  
The Other ◽  
Early Age ◽  
Alternate Hypothesis ◽  
Linguistic Evidence

AbstractStudies of the Great Basin show that the Desert cultures of 8000 B.C. closely resemble the historic cultures of that area, but linguistic evidence indicates that the ancestors of the historic inhabitants moved into the Great Basin as late as 1000 years ago. The linguistic affiliation of the prehistoric cultures thus cannot be directly inferred. Taylor has proposed that Hokaltecans settled in the Great Basin at an early age and were only recently replaced by Uto-Aztecans who moved in from the northeast—an offshoot from a major Uto-Aztecan movement down the western flanks of the Rocky Mountains. This hypothesis does not satisfactorily account for the distribution of the major subdivisions of Uto-Aztecan and directly contradicts the implications of the distribution of Numic (Plateau Shoshonean) languages. An alternate hypothesis is proposed, namely, that Uto-Aztecans moved southward from the northern Great Basin as the Altithermal began; that they moved in two major branches which skirted the Great Basin, one along the Rocky Mountains, the other along the Sierras; and that, as the Medithermal set in, the Numic branch (northernmost Sierran branch) began to move back into the Great Basin proper, this movement being retarded until about 1000 years ago by the presence of horticulturists. This hypothesis is supported by correlations between lexico-statistical dating of the separation of Uto-Aztecan languages and the dates of climatic periods, and by the distributions of the major Uto-Aztecan branches. Identification of these branches follows recent linguistic studies by Voegelin and Hale. Previous classifications of Uto-Aztecan languages, theories concerning the location of the ancestral Uto-Aztecan community, and the implications of these for the present hypothesis are discussed.

The Cedar Mountain, Nevada, earthquake of December 20, 1932*

1934 ◽  
Vol 24 (4) ◽  
pp. 345-384 ◽  
Author(s):  
Vincent P. Gianella ◽  
Eugene Callaghan
Keyword(s):  
Sierra Nevada ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Relative Movement ◽  
East Side ◽  
Owens Valley ◽  
The West ◽  
Horizontal Movement ◽  
San Andreas

Summary The Cedar Mountain, Nevada, earthquake took place at about 10h 10m 04s p.m., December 20, 1932. It was preceded by a foreshock noted locally and followed by thousands of aftershocks, which were reported as still continuing in January 1934. No lives were lost and there was very little damage. The earthquake originated in southwest central Nevada, east of Mina. A belt of rifts or faults in echelon lies in the valley between Gabbs Valley Range and Pilot Mountains on the west and Cedar Mountain and Paradise Range on the east. The length of this belt is thirty-eight miles in a northwesterly direction, and the width ranges from four to nine miles. The rifts consist of zones of fissures which commonly reveal vertical displacement and in a number of places show horizontal displacement. The length of the rifts ranges from a few hundred feet to nearly four miles, and the width may be as much as 400 feet. The actual as well as indicated horizontal displacement is represented by a relative southward movement of the east side of each rift. The echelon pattern of the rifts within the rift area indicates that the relative movement of the adjoining mountain masses is the same. The direction of relative horizontal movement corresponds to that along the east front of the Sierra Nevada at Owens Valley and on the San Andreas rift.

Sierra Nevada-Great Basin boundary zone: Earthquake hazard related to structure, active tectonic processes, and anomalous patterns of earthquake occurrence

1980 ◽  
Vol 70 (5) ◽  
pp. 1557-1572
Author(s):  
J. D. VanWormer ◽  
Alan S. Ryall
Keyword(s):  
Sierra Nevada ◽  
Great Basin ◽  
Temporal Variations ◽  
Mono Lake ◽  
Local Network ◽  
Low Velocity ◽  
Owens Valley ◽  
Walker Lake ◽  
Fault Plane Solutions ◽  
The North

abstract Precise epicentral determinations based on local network recordings are compared with mapped faults and volcanic features in the western Great Basin. This region is structurally and seismically complex, and seismogenic processes vary within it. In the area north of the rupture zone of the 1872 Owens Valley earthquake, dispersed clusters of epicenters agree with a shatter zone of faults that extend the 1872 breaks to the north and northwest. An area of frequent earthquake swarms east of Mono Lake is characterized by northeast-striking faults and a crustal low-velocity zone; seismicity in this area appears to be related to volcanic processes that produced thick Pliocene basalt flows in the Adobe Hills and minor historic activity in Mono Lake. In the Garfield Hills between Walker Lake and the Excelsior Mountains, there is some clustering of epicenters along a north-trending zone that does not correlate with major Cenozoic structures. In an area west of Walker Lake, low seismicity supports a previous suggestion by Gilbert and Reynolds (1973) that deformation in that area has been primarily by folding and not by faulting. To the north, clusters of earthquakes are observed at both ends of a 70-km-long fault zone that forms the eastern boundary of the Sierra Nevada from Markleeville to Reno. Clusters of events also appear at both ends of the Dog Valley Fault in the Sierra west of Reno, and at Virginia City to the east. Fault-plane solutions for the belt in which major earthquakes have occurred in Nevada during the historic period (from Pleasant Valley in the north to the Excelsior Mountains on the California-Nevada Border) correspond to normaloblique slip and are similar to that found by Romney (1957) for the 1954 Fairview Peak shock. However, mechanisms of recent moderate earthquakes within the SNGBZ are related to right- or left-lateral slip, respectively, on nearly vertical, northwest-, or northeast-striking planes. These mechanisms are explained by a block faulting model of the SNGBZ in which the main fault segments trend north, have normal-oblique slip, and are offset or terminated by northwest-trending strike-slip faults. This is supported by the observation that seismicity during the period of observation has been concentrated at places where major faults terminate or intersect. Anomalous temporal variations, consisting of a general decrease in seismicity in the southern part of the SNGBZ from October 1977 to September 1978, followed by a burst of moderate earthquakes that has continued for more than 18 months, is suggestive of a pattern that several authors have identified as precursory to large earthquakes. The 1977 to 1979 variations are particularly noteworthy because they occurred over the entire SNGBZ, indicating a regional rather than local cause for the observed changes.

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