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The mating, egg‐laying, and larval development of tailed frogs occur in dynamic mountain streams. During the lengthy (up to 5 years) aquatic residency these species are vulnerable to channel disturbances that can be exacerbated by land... more
The mating, egg‐laying, and larval development of tailed frogs occur in dynamic mountain streams. During the lengthy (up to 5 years) aquatic residency these species are vulnerable to channel disturbances that can be exacerbated by land uses. Researchers have highlighted specific tailed frog habitat associations but never in the context of fluvial system processes. Based on an extensive regional study with a watershed‐wide sampling strategy, we demonstrate that the Rocky Mountain tailed frog (Ascaphus montanus) is limited to contributing basins of roughly 0.3–100 km2 in size, with peak numbers in basins up to 35 km2. We conclude that the primary determinant of tailed frog distribution patterns in a watershed is basin area, a proximate variable for channel process domain and regional stream discharge: tailed frogs are adapted to cascade and step‐pool channel morphologies that characterize these small basins, presumably because they afford more bedform stability and pore‐space refugia than do smaller, colluvial headwaters, or larger, floodplain‐forming plane bed and pool‐riffle bedforms of mainstem rivers. Secondarily, climate and physiography interact to influence occurrence and abundance at the watershed level by controlling such variables as runoff, water temperature, and sedimentation regime. This point has important management implications because it forces us to recognize that in complex ecosystems, wildlife habitat associations are contingent on site‐specific interactions amongst fluvial system control variables: significance levels of any one variable to tailed frog distribution will not necessarily be consistent among basins. The study clearly shows that case studies can produce conflicting results when they lack a process‐based understanding of ecological response.
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A new Holocene relative-sea-level (RSL) curve is proposed for the central west coast of Vancouver Island based on topographic surveys of coastal landforms and the stratigraphy of coastal deposits. Six study sites are described on Vargas... more
A new Holocene relative-sea-level (RSL) curve is proposed for the central west coast of Vancouver Island based on topographic surveys of coastal landforms and the stratigraphy of coastal deposits. Six study sites are described on Vargas Island and Esowista and Ucluth peninsulas and 23 previously unpublished radiocarbon ages that constrain mean-sea-level (MSL) position are presented. A long-term rise in RSL from an early Holocene (> 7000 BP) lowstand below −3 m asl is documented from dates on tree stumps in the intertidal zone and salt-marsh peats and forest-floor deposits buried by marine sands and gravels. Submergence culminated in a stillstand from 6000 to 4800 BP, marked by the development of a strandline at 6 m asl (MSL ≈ 3.2 m asl). A fall in RSL is documented by a strandline at 4.0–4.5 m asl, which dates from 2700 to 2000 BP (MSL ≈ 2.0 m asl). Little is known of the dynamics of emergence between 4800 and 2700 BP or from 2000 BP to the present, although the absence of strandlines below 4 m asl suggests continuous emergence during the last two millenia. This submergence–emergence cycle is unique in southern British Columbia. A simple simulation model suggests that late Holocene emergence was induced by tectonic uplift of the edge of the America plate margin.
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The Ring Creek lava flow, extending from Opal Cone, generally is considered to be the youngest volcanic feature in the southern section of the Mount Garibaldi volcanic field, southwestern British Columbia. An in situ stump dated... more
The Ring Creek lava flow, extending from Opal Cone, generally is considered to be the youngest volcanic feature in the southern section of the Mount Garibaldi volcanic field, southwestern British Columbia. An in situ stump dated 10 650 ± 70 BP (Beta 43865) obtained from a raised delta partially overridden by the lava flow indicates that the lava was extruded after ca. 10.7 ka. At the Skookum Creek and Mamquam River confluence, sediments eroded from the Ring Creek lava flow form an alluvial fan that contains charcoal dated 9360 ± 160 BP (Beta 38914), which indicates that the extrusion probably occurred before ca. 9.3 ka. Thus these radiocarbon ages bracket the age of the Ring Creek lava flow and indicate that volcanic activity in the southern section of the Mount Garibaldi volcanic field has been dormant since at least ca. 9.3 ka.
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Research Interests: Earth Sciences, Geology, Geomorphology, Holocene, Volcano, and 3 moreDebris Flow, Glacier, and Debris
Research Interests: Archaeology, Geology, Pleistocene, Quaternary, Younger Dryas, and 4 moreFjord, Deglaciation, Glacier, and Ice Sheets
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Construction of frequency–magnitude (F–M) relationships of debris floods and debris flows is challenging because of few direct observations, discontinuous event occurrence, loss of field evidence, the difficulty of accessing the sediment... more
Construction of frequency–magnitude (F–M) relationships of debris floods and debris flows is challenging because of few direct observations, discontinuous event occurrence, loss of field evidence, the difficulty of accessing the sediment archive and the challenge of finding suitable statistical methods to analyse the dataset. Consultants often face budget limitations that prohibit application of the full gamut of absolute dating methods, stratigraphic analysis and analytical tools necessary to fully resolve the F–M legacy. In some cases, F–M curves are needed for watersheds without local information, or where obtaining this information is prohibitively expensive. For such watersheds, the F–M relationship may be estimated where several F–M curves have already been assembled in a specific region. Individual F–M curves are normalized by fan area or fan volume, then stratified by process type and geomorphic activity level. This paper describes the development of regional F–M curves for debris flows in southwestern British Columbia and debris flows and debris floods in the Bow River valley near Canmore, Alberta. We apply the regional relationships to other cases in Canada and the United States and demonstrate that the method can be globalized. The regional approach is compared to cases where detailed F–M relationships have been established by other means. Strong negative deviations from the regional debris‐flow or debris‐flood magnitude trends could signal inherent watershed stability, while strong positive deviations could signal extraordinary landslide processes, or suggest that the fan may be largely of paraglacial origin. We highlight some of these outlying cases and develop a method whereby the regional curves can be meaningfully adjusted, or reliance can be placed on lower or upper confidence bounds of the F–M curves. We caution against the indiscriminate use of the regionally based F–M curves, especially in watersheds where multiple geomorphic processes are active. © 2020 John Wiley & Sons, Ltd.
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Research Interests: Civil Engineering, Geology, Geomorphology, Landslides, Medicine, and 4 moreDebris Flow, Landslide, Debris, and Rockfall
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The Lillooet-Harrison watershed (7870 km2 in area, of which 459 km2 is glacierized) contains recurring morphological landscape elements that differ in terms of their level of connectivity with Lillooet River. First, ridge tops with low... more
The Lillooet-Harrison watershed (7870 km2 in area, of which 459 km2 is glacierized) contains recurring morphological landscape elements that differ in terms of their level of connectivity with Lillooet River. First, ridge tops with low local relief are connected to Lillooet River primarily through dissolved solids moving along subsurface pathways. Second, small glaciers have little direct connection with Lillooet River because of their numerous proximal lakes, whereas larger valley glaciers are directly linked to Lillooet River. Third, hillslopes subject to infrequent, large mass movements are episodically connected, and fourth, debris flow channels are directly linked with valley-bottom rivers. Fifth, mid-valley and lower valley-bottom sites are sediment storage areas that are episodically coupled to the adjacent river channel. The Mount Meager Volcanic Complex dominates the supply of coarse clastic sediment to Lillooet River and is primarily responsible for the rapid rates of Lillooet delta progradation and aggradation. The 6 % of the watershed that is glacierized provides a high proportion of the fine clastic sediments to Lillooet and Harrison lakes, whereas solute production that has little influence on morphological elements is important in assessing the overall rate of landscape denudation in the Lillooet-Harrison watershed. More frequent extreme rainfall events and rapid glacier retreat together with intensified human occupancy in the valley can be expected to increase the coupling of each of the morphological elements to Lillooet River and expedite the movement of water, sediments, and solutes through the watershed.
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Research Interests: Geology, Multidisciplinary, Sediment, Landslide, Fjord, and 5 moreDeglaciation, Glacier, Debris, mudflow, and Flood Myth
Introduction First Nations people have actively inhabited and engaged with the landscapes of the Lower Fraser River Region for many thousands of years, exploiting both its topographic and vegetative richness. Long before the remembered... more
Introduction First Nations people have actively inhabited and engaged with the landscapes of the Lower Fraser River Region for many thousands of years, exploiting both its topographic and vegetative richness. Long before the remembered past, Northwest Coast First Nations relied on the seasonal bounty of plant foods, medicines, and technologies for their livelihoods (Table 1) (Deur and Turner 2005; Turner 2005, 2014; Turner and Peacock 2005). These resources were carefully cultivated and managed to enhance and sustain their productivity, size, taste, and other critical properties. Plants were managed at multiple scales from the individual to the community and landscape levels (Lepofsky and Lertzman 2008). This paper describes palaeoethnobotanical research in the Lower Fraser River Region that has characterized a spectrum of ancient plant use practices, from local small-scale harvesting to full-scale cultivation. The Lower Fraser River is one of the richest and most diverse natural re...
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Introduction This chapter presents the results of 2010 excavations conducted at Lhó:leqwet (aka Chocolate Bar) rock shelter (DhRl 2), a multi-use site located on the Harrison River in Chehalis (Sts'ailes) territory (Figures 1 and 2).... more
Introduction This chapter presents the results of 2010 excavations conducted at Lhó:leqwet (aka Chocolate Bar) rock shelter (DhRl 2), a multi-use site located on the Harrison River in Chehalis (Sts'ailes) territory (Figures 1 and 2). Lhó:leqwet is culturally important to the Sts’ailes because of its traditional association with spirit questing, other ceremonial activities, and high concentration of pictographs. Cliff overhangs and boulder shelters offer unique “windows” into aspects of human behaviour that are often difficult to incorporate and address in settlement or household studies, such as spirit questing and creation of rock art. A number of other rock shelter sites have been excavated (e.g., Arnett 2012; 2016; Angelbeck 2015; Croes 2005; Hall et al. 2007; Hammond 2009; Reimer 2004, 2006; Ritchie and Sellers 2016) and surveyed (Acheson and Riley 1976, 1977) in the Salish Sea region but only Lhó:leqwet and several small boulder shelters at the South Yale site (DjRi 7) (Cha...
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Introduction and Background Hill-Tout first described the Marpole site in 1895, in a paper entitled Later Prehistoric Man in British Columbia. The Marpole site (DhRs-1) is located on the North bank along the North arm of the Fraser River... more
Introduction and Background Hill-Tout first described the Marpole site in 1895, in a paper entitled Later Prehistoric Man in British Columbia. The Marpole site (DhRs-1) is located on the North bank along the North arm of the Fraser River opposite Sea Island and when occupied was positioned at the outer margin of the Fraser delta (Figures 1 to 3). Hill-Tout was particularly awestruck by the size of the site, posed the questions, “When and for what reasons was this ancient camping ground abandoned” (Hill-Tout 1895:104) and described the Great Fraser midden to be “... upwards of 1,400 feet in length and 300 feet in breadth; and covers to an average depth of about 5. and to a maximum depth of over 15. feet an area exceeding 4 1⁄2 acres in extent”, and remarked that Marpole, “... exceeds in mass and area the largest middens of Denmark, and abounds in interesting ethnological data (1895: 103). Charles Hill-Tout was obviously impressed by the size and complexity of the Marpole site, and fo...
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Introduction and Background From 1858 to 1865 the township of Port Douglas was one of several important early settlements in the Colony of British Columbia. Located on the north shore of Little Harrison Lake (Figures 1 and 2), Port... more
Introduction and Background From 1858 to 1865 the township of Port Douglas was one of several important early settlements in the Colony of British Columbia. Located on the north shore of Little Harrison Lake (Figures 1 and 2), Port Douglas was situated at the center of the only route offering access to the upper Fraser River gold fields. This chapter considers the township within a broader political and social context, and discusses two prominent factors that contributed to the geographical placement of Port Douglas and the Harrison-Lillooet road. They include: (1) threat of American influence over British held territory during the mid-19 century; and (2) violent confrontations between miners and members of the Nlaka’pamux Nation during the “Fraser Canyon War” and persistence of Nlaka’pamux territorial authority within the mid-Fraser Canyon.
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Introduction and Background The South Yale site (DjRi 7) is situated on the east bank of the Fraser River opposite the small historic gold-rush era town of Yale, B.C., and immediately south of the very southern end of the most rugged... more
Introduction and Background The South Yale site (DjRi 7) is situated on the east bank of the Fraser River opposite the small historic gold-rush era town of Yale, B.C., and immediately south of the very southern end of the most rugged section of the Fraser Canyon (Figures 1 to 3). It is a very large site, measuring about 4.0 km N-S by 1.0 km E-W at its widest point, and it occupies a series of prominent stepped terraces created by early Holocene riverine down-cutting. The site is quite unique in that it contains an extinct “hanging” channel of the Fraser River passing through it that was created around 8000 years BP. The geomorphological history of the site is complex and interesting (Chapter 4), and relevant to this chapter are both sides of the extinct river channel, a large cluster of boulders situated on “South Yale Ridge” (a.k.a. South Yale block-field), and the extensive upper early Holocene river terraces to the southeast. The site lies within the Coastal Western Hemlock bioge...
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Research Interests: Geography and Archaeology
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An important paradigm in geomorphology is paraglacial sedimentation, a phrase first used almost 40 years ago to describe reworking of glacial sediment by mass wasting and streams during and after continental-scale deglaciation. The... more
An important paradigm in geomorphology is paraglacial sedimentation, a phrase first used almost 40 years ago to describe reworking of glacial sediment by mass wasting and streams during and after continental-scale deglaciation. The concept has been extended to include nonglacial landforms and landscapes conditioned by glaciation. In this paper we apply the paraglacial concept to volcanoes in southern British Columbia, Canada, that formed, in part, in contact with glacier ice. The Cheekye River basin, a small watershed on the flank of a volcano that erupted against the decaying Cordilleran ice sheet, has a Holocene history marked by an exponential decay in debris-flow activity and sediment yield. Its history is consistent with the primary exhaustion model of the paraglacial cycle. At larger spatial scales, this primary sediment is reworked by rivers and transported downstream and augmented by stochastic geomorphic events. Repeated large landslides from Mount Meager volcano in souther...