Glacial Lake Missoula, Clark Fork ice dam, and the floods outburst area: Northern Idaho and western Montana

2003 ◽  
pp. 1-15 ◽  
Author(s):  
Norman B. Smyers ◽  
Roy M. Breckenridge
Keyword(s):  
Western Montana ◽  
Glacial Lake ◽  
Northern Idaho

Periodic JöKulhlaups from Pleistocene Glacial Lake Missoula—New Evidence from Varved Sediment in Northern Idaho and Washington

1984 ◽  
Vol 22 (1) ◽  
pp. 46-58 ◽  
Author(s):  
Richard B. Waitt
Keyword(s):  
Ice Sheet ◽  
Glacial Lake ◽  
Gravel Beds ◽  
Varved Sediment ◽  
Cordilleran Ice Sheet ◽  
Northern Idaho ◽  
New Evidence ◽  
Stratigraphic Succession ◽  
Conventional Idea ◽  
Sand Beds

Newly examined exposures in northern Idaho and Washington show that catastrophic floods from glacial Lake Missoula during late Wisconsin time were repeated, brief jökulhlaups separated by decades of quiet glaciolacustrine and subaerial conditions. Glacial Priest Lake, dammed in the Priest River valley by a tongue of the Purcell trench lobe of the Cordilleran ice sheet, generally accumulated varved mud; the varved mud is sharply interrupted by 14 sand beds deposited by upvalley-running currents. The sand beds are texturally and structurally similar to slackwater sediment in valleys in southern Washington that were backflooded by outbursts from glacial Lake Missoula. Beds of varved mud also accumulated in glacial Lake Spokane (or Columbia?) in Latah Creek valley and elsewhere in northeastern Washington; the mud beds were disrupted, in places violently, during emplacement of each of 16 or more thick flood-gravel beds. This history corroborates evidence from southern Washington that only one graded bed is deposited per flood, refuting a conventional idea that many beds accumulated per flood. The total number of such floodlaid beds in stratigraphic succession near Spokane is at least 28. The mud beds between most of the floodlaid beds in these valleys each consist of between 20 and 55 silt-to-clay varves. Lacustrine environments in northern Idaho and Washington therefore persisted for two to six decades between regularly recurring, colossal floods from glacial Lake Missoula.

Clonal diversity within and among introduced populations of the apomictic vine Bryonia alba (Cucurbitaceae)

2000 ◽  
Vol 78 (11) ◽  
pp. 1469-1481 ◽  
Author(s):  
Stephen J Novak ◽  
Richard N Mack
Keyword(s):  
United States ◽  
Clonal Diversity ◽  
Western Montana ◽  
Western United States ◽  
Single Population ◽  
Multiple Introductions ◽  
Introduced Populations ◽  
Northern Utah ◽  
Northern Idaho ◽  
Eastern Washington

Bryonia alba L. (Cucurbitaceae) is a herbaceous Eurasian vine that predominantly reproduces clonally (asexually) through apomixis. We assessed the magnitude and distribution of clonal diversity within and among 23 recently established populations of B. alba in its new range in the western United States, based on the distribution of multilocus isozyme genotypes. Fifty-two unique clones were detected: 30 in the nine populations from eastern Washington and northern Idaho, and the remaining 22 in 14 populations from western Montana, northern Utah, and southern Idaho. On average, each population of B. alba was composed of 6.4 clones, and the proportion of distinguishable clones was 0.275. Multilocus diversity (D) was 0.632 and multilocus evenness (E) was 0.556. Twenty-six of 52 clones (50%) were restricted to a single population, and, on average, each clone occurred in 2.83 populations. Compared with other clonally reproducing plant species, this vine possesses moderate to high levels of clonal diversity in its new range in the western United States. This diversity appears to be a consequence of the events associated with its introduction (including multiple introductions), founder effects, and the proportion of sexual to apomictic reproduction within populations.Key words: invasive vine, apomixis, multilocus genotypes, clonal diversity and evenness, Bryonia alba, Cucurbitaceae.

A soil-site study for inland Douglas-fir

1990 ◽  
Vol 20 (6) ◽  
pp. 686-695 ◽  
Author(s):  
Robert A. Monserud ◽  
Ula Moody ◽  
David W. Breuer
Keyword(s):  
Habitat Type ◽  
Site Index ◽  
Douglas Fir ◽  
Soil Survey ◽  
Western Montana ◽  
Disappointing Result ◽  
Site Factor ◽  
Soil Site ◽  
Northern Idaho ◽  
Factor Interactions

A soil-site study was conducted for inland Douglas-fir growing in northern Idaho and north western Montana. The hypothesis was that standard soil survey procedures would provide edaphic data that could predict site index in the absence of site trees. Soil profile descriptions and physical analyses were obtained on 133 plots, along with several physiographic site descriptors. Chemical analyses were performed on soil samples from a third of these plots, and moisture availability was determined on 60% of the plots. Site index was based on felled-tree stem analyses. Elevation was the strongest predictor, accounting for a third of the variation in site index. The addition of habitat type information resulted in a significant improvement (as did longitude and precipitation), but still left over half the variation unexplained. After examining numerous soil properties the standard error could only be reduced 0.3 m, a disappointing result in light of the considerable time and expense necessary for soil sampling. The causes of these low soil–site correlations could not be conclusively determined, but the most likely explanations are (i) that the number of important site factor interactions occurring in this large and complex study area far exceeded the sample size, and (ii) failure to measure the true causes of site productivity.

Fire-Dependent Forests in the Northern Rocky Mountains

1973 ◽  
Vol 3 (3) ◽  
pp. 408-424 ◽  
Author(s):  
James R. Habeck ◽  
Robert W. Mutch
Keyword(s):  
Rocky Mountains ◽  
Fire Ecology ◽  
Western Montana ◽  
Fire Control ◽  
Northern Rocky Mountains ◽  
Northern Idaho ◽  
Coniferous Ecosystems ◽  
Natural Incidence

AbstractOne objective of wilderness and parkland fire-ecology research is to describe the relationships between fire and unmanaged ecosystems, so that strategies can be determined that will provide a more nearly natural incidence of fire. More than 50 yr of efforts directed toward exclusion of wildland fires in the Northern Rocky Mountains (western Montana and northern Idaho) have resulted in a definite and observable impact on the forest ecosystems in this region. Fire-ecology investigations in Glacier National Park and the Selway-Bitterroot Wilderness have helped to reveal the nature of this impact and to provide a better understanding of the natural role of fire within these coniferous ecosystems. Such areas provide a unique opportunity to study and test approaches designed to perpetuate unmodified ecosystems. However, we still don't understand all of the long-term consequences of fire control in those forest communities that have evolved fire-dependent characteristics.

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