Appendix A. The Late Wisconsin age of mounds on the Columbia Plateau of eastern Washington

Author(s):  
Roald H. Fryxell
Botany ◽  
2014 ◽  
Vol 92 (5) ◽  
pp. 340-347 ◽  
Author(s):  
Peter Lesica

Populations at the periphery of a species range are thought to be less viable than those in the center because they are at the limit of their ecological tolerances. Plant population viability is determined primarily by mortality and recruitment, thus knowing differences in vital rates between central and peripheral populations is key to understanding range limits. Silene spaldingii S. Watson is a long-lived iteroparous plant that occurs throughout the eastern Columbia Plateau region of eastern Washington and adjacent Idaho and Oregon and is disjunct in northwest Montana. I recorded the fate of mapped S. spaldingii plants annually for 10 years in four populations, two from eastern Washington and two from Montana. Recruitment averaged three times higher and relatively constant at two central populations in Washington compared with two peripheral sites in Montana. Mortality was three times higher at one of the central populations compared with the remaining three sites due to vole predation. Vole activity was observed at the second central population but came too late in the study to be certain that it resulted in mortality. Vole predation was not observed in the peripheral populations. My results suggest that peripheral populations of S. spaldingii may only be able to persist as long as predation or other sources of mortality remain low and that intrinsic low and variable recruitment rates coupled with predation may help define the eastern range margin of this species.


1982 ◽  
Vol 36 (1-2) ◽  
pp. 15-34 ◽  
Author(s):  
William J. Deutsch ◽  
Everett A. Jenne ◽  
Kenneth M. Krupka

1978 ◽  
Vol 10 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Donal R. Mullineaux ◽  
Ray E. Wilcox ◽  
Walter F. Ebaugh ◽  
Roald Fryxell ◽  
Meyer Rubin

Pumice layers of set S from Mount St. Helens can be correlated with certain ash beds associated with young flood deposits of the channeled scabland. The correlation points to an age of about 13,000 14C yr B.P. for the last major flood to have crossed the scabland. Until recently, the last major episode of flooding was thought to be closer to 20,000 yr B.P., an age inferred chiefly from the relation of the flood to glacial events of the northern Rocky Mountains. Several investigations within the last few years have suggested that the last major flood occurred well after 20,000 yr B.P. Tentative correlations of ash beds of the scabland with set S pumice layers, the relations of flood and glacial events along the northwestern margin of the Columbia Plateau, and a radiocarbon date from the Snake River drainage southeast of the plateau all indicate an age much younger than 20,000 yr. The postulated age of about 13,000 yr B.P. is further supported by a radiocarbon date in the Columbia River valley downstream from the scabland tract. Basal peat from a bog on the Portland delta of Bretz, which is a downvalley deposit of the last major scabland flood, has been dated as 13,080 ± 300 yr B.P. (W-3404).


Author(s):  
Peter Mitchell

This chapter looks at three more regions of North America: the Columbia Plateau and adjacent areas of the Pacific Northwest Coast; the Great Basin; and California. It also focuses on three main themes: the development of new identities as many groups adapted aspects of the lifestyle and customs of those on the Plains and more coherent tribal entities emerged; raiding for captives; and raiding for horses. A fourth topic, which casts these into relief, is why some groups rejected the horse, or chose to adopt it very late in their history. The Great Basin was the first of the three areas to receive the horse. It is an arid region of desert, salt lakes, and mountains where rainfall is unpredictable and low, but increases eastward (Plate 15). Except for the Colorado along its southern edge and the headwaters in the rockies of streams draining towards the Missouri, none of its rivers reach the sea. Fremont farmers had once made a living across Utah, but by the 1600s cultivation was restricted to a few groups in the south and west. Elsewhere, the Basin’s inhabitants depended entirely on hunting and gathering, though strategies like burning enhanced the productivity of wild plants and game. Very broadly, two subsistence patterns were followed: one emphasized fish and waterfowl around wetlands, the other a more mobile, broadly based foraging economy in deserts and mountains in which pine nuts (piñons), grass seeds, rabbits, and larger game were important. Except for the Washoe near Lake Tahoe in eastern California, all the region’s historic inhabitants spoke Numic languages. Major groups included Utes in the southeast, Shoshones in the north and centre, and Paiutes in the west and southwest. To the north of the Great Basin lies the Plateau, centred on the Columbia River and its tributaries, which collectively send their waters into the Pacific Ocean (Plate 16). Coniferous forest covers its northern and eastern parts (including several ranges running parallel to but west of the Rockies), but the drier, hilly country of Oregon and eastern Washington is more steppe-like, with sagebrush common and trees more localized.


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