Browsing Geography and Environment by Title
Now showing 1 - 20 of 96
Results Per Page
- ItemThe 1999 Mallard fire: Lessons learned(The Faculty of Health Sciences - The University of Lethbridge, 2010) Kulig, Judith Celene; Kimmel, A.; Gullacher, A.; Reimer, B.; Townshend, Ivan; Edge, Dana; Lightfoot, Nancy; McKay, M.; Barnett, M.; Clague, J.; Coghlan, A.La Ronge is located in northern Saskatchewan on the shore of Lac La Ronge. It is adjacent to the Lac La Ronge Indian band and the northern village of Air Ronge. La Ronge is the largest community in northern Saskatchewan with over 2700 people residing in the town, 2000 people on the adjacent First Nations lands of the Lac la Ronge Indian band, and approximately 1000 people residing in the bordering Métis settlement of Air Ronge. La Ronge acts as the service centre for almost all of Northern Saskatchewan. Firefighters battled the Mallard Fire that caused the evacuation of the entire community of La Ronge on May 27, 1999. The fire, which was started by lightning, stretched over a distance of 8 kilometres and it took one week, 248 firefighters, and several water bombers to extinguish it. The damage included the destruction of 8 homes in Eagle Point, 1 trailer on Riese Drive and 1 bush home. Some commer-cial buildings were also destroyed within the town boundaries; however, no injuries were reported.
- ItemAboveground biomass allocation of boreal shrubs and short-stature trees in northwestern Canada(MDPI, 2021) Flade, Linda; Hopkinson, Christopher; Chasmer, LauraIn this follow-on study on aboveground biomass of shrubs and short-stature trees, we provide plant component aboveground biomass (herein ‘AGB’) as well as plant component AGB allometric models for five common boreal shrub and four common boreal short-stature tree genera/species. The analyzed plant components consist of stem, branch, and leaf organs. We found similar ratios of component biomass to total AGB for stems, branches, and leaves amongst shrubs and deciduous tree genera/species across the southern Northwest Territories, while the evergreen Picea genus differed in the biomass allocation to aboveground plant organs compared to the deciduous genera/species. Shrub component AGB allometric models were derived using the three-dimensional variable volume as predictor, determined as the sum of line-intercept cover, upper foliage width, and maximum height above ground. Tree component AGB was modeled using the cross-sectional area of the stem diameter as predictor variable, measured at 0.30 m along the stem length. For shrub component AGB, we achieved better model fits for stem biomass (60.33 g ≤ RMSE ≤ 163.59 g; 0.651 ≤ R2 ≤ 0.885) compared to leaf biomass (12.62 g ≤ RMSE ≤ 35.04 g; 0.380 ≤ R2 ≤ 0.735), as has been reported by others. For short-stature trees, leaf biomass predictions resulted in similar model fits (18.21 g ≤ RMSE ≤ 70.0 g; 0.702 ≤ R2 ≤ 0.882) compared to branch biomass (6.88 g ≤ RMSE ≤ 45.08 g; 0.736 ≤ R2 ≤ 0.923) and only slightly better model fits for stem biomass (30.87 g ≤ RMSE ≤ 11.72 g; 0.887 ≤ R2 ≤ 0.960), which suggests that leaf AGB of short-stature trees (<4.5 m) can be more accurately predicted using cross-sectional area as opposed to diameter at breast height for tall-stature trees. Our multi-species shrub and short-stature tree allometric models showed promising results for predicting plant component AGB, which can be utilized for remote sensing applications where plant functional types cannot always be distinguished. This study provides critical information on plant AGB allocation as well as component AGB modeling, required for understanding boreal AGB and aboveground carbon pools within the dynamic and rapidly changing Taiga Plains and Taiga Shield ecozones. In addition, the structural information and component AGB equations are important for integrating shrubs and short-stature tree AGB into carbon accounting strategies in order to improve our understanding of the rapidly changing boreal ecosystem function.
- ItemAeolian dune field geomorphology modulates the stabilization rate imposed by climate(Blackwell Publishing Ltd., 2012-06-14) Barchyn, Thomas E.; Hugenholtz, Chris H.The activity of inland aeolian dune fields is typically related to the external forcing imposed by climate: active (bare) dunes are associated with windy and/or arid settings, and inactive (vegetated) dunes are associated with humid and/or calm environments. When a climate shifts the dune field reacts; however, the behavior, rate, and potential impact of diverse dune geomorphologies on these transitions are poorly understood. Here, we use a numerical model to systematically investigate the influence of dune field geomorphology (dune height, organization and collisions) on the time a dune field takes to stabilize. To generate diverse initial un-vegetated dune field geomorphologies under unidirectional winds, we varied pre-stabilization growth time and initial sediment thickness (termed equivalent sediment thickness: EST). Following dune field development from a flat bed, we introduced vegetation (simulating a climate shift) and transport-vegetation feedbacks slowly stabilized the dune fields. Qualitatively, very young and immature dune fields stabilized quickly, whereas older dune fields took longer. Dune fields with greater EST stabilized quicker than those with less EST. Larger dunes stabilized quicker because of low celerity, which facilitated higher vegetation growth rates. Extended stabilization times were associated with the extension of parabolic dunes. Dune-dune collisions resulted in premature stabilization; the frequency of collisions was related to dune spacing. Quantitatively comparing the distribution of deposition rates in a dune field to the deposition tolerance of vegetation provides a promising predictor of relative stabilization time. Dune fields with deposition rates dominantly above the deposition tolerance of vegetation advanced unimpeded and prolonged stabilization as parabolic dunes. Paleoenvironmental reconstructions or predictions of dune field activity should not assume that dune activity directly translates to climate, considerable lags to stabilizing climate shifts may exist in unidirectional dune forms.
- ItemAllometric equations for shrubs and short-stature tree aboveground biomass within boreal ecosystems of northwestern Canada(MDPI, 2020) Flade, Linda; Hopkinson, Christopher; Chasmer, LauraAboveground biomass (AGB) of short-stature shrubs and trees contain a substantial part of the total carbon pool within boreal ecosystems. These ecosystems, however, are changing rapidly due to climate-mediated atmospheric changes, with overall observed decline in woody plant AGB in boreal northwestern Canada. Allometric equations provide a means to quantify woody plant AGB and are useful to understand aboveground carbon stocks as well as changes through time in unmanaged boreal ecosystems. In this paper, we provide allometric equations, regression coefficients, and error statistics to quantify total AGB of shrubs and short-stature trees. We provide species- and genus-specific as well as multispecies allometric models for shrub and tree species commonly found in northwestern boreal forest and peatland ecosystems. We found that the three-dimensional field variable (volume) provided the most accurate prediction of shrub multispecies AGB (R2 = 0.79, p < 0.001), as opposed to the commonly used one-dimensional variable (basal diameter) measured on the longest and thickest stem (R2 = 0.23, p < 0.001). Short-stature tree AGB was most accurately predicted by stem diameter measured at 0.3 m along the stem length (R2 = 0.99, p < 0.001) rather than stem length (R2 = 0.29, p < 0.001). Via the two-dimensional variable cross-sectional area, small-stature shrub AGB was combined with small-stature tree AGB within one single allometric model (R2 = 0.78, p < 0.001). The AGB models provided in this paper will improve our understanding of shrub and tree AGB within rapidly changing boreal environments.
- ItemBetting the Farm: Food Safety, Risk Society, and the Canadian Cattle and Beef Commodity Chain(House of Anansi Press, 2004) MacLachlan, Ian
- ItemBiostratigraphic evidence relating to the age-old question of Hannibal's invasion of Italy, I: history and geological reconstruction(Wiley, 2016) Mahaney, William C.; Allen, Christopher C. R.; Pentlavalli, Prasanna; Kulakova, Anna; Young, Jonathan M.; Dirszowsky, Randy W.; West, Allen; Kelleher, Brian; Jordan, Sean; Pulleyblank, C; O'Reilly, Shane; Murphy, B. T.; Lasberg, Katrin; Somelar, Peeter; Garneau, Michelle; Finkelstein, S. A.; Sobol, M. K.; Kalm, Volli; Costa, Pedro J. M.; Hancock, Ronald G. V.; Hart, Kris M.; Tricart, Pierre; Barendregt, René W.; Bunch, Ted E.; Milner, Michael W.Controversy over the alpine route that Hannibal of Carthage followed from the Rhône Basin into Italia has raged amongst classicists and ancient historians for over two millennia. The motivation for identifying the route taken by the Punic Army through the Alps lies in its potential for identifying sites of historical archaeological significance and for the resolution of one of history's most enduring quandaries. Here, we present stratigraphic, geochemical and microbiological evidence recovered from an alluvial floodplain mire located below the Col de la Traversette (~3000 m asl—above sea level) on the French/Italian border that potentially identifies the invasion route as the one originally proposed by Sir Gavin de Beer (de Beer 1974). The dated layer is termed the MAD bed (mass animal deposition) based on disrupted bedding, greatly increased organic carbon and key/specialized biological components/compounds, the latter reported in Part II of this paper. We propose that the highly abnormal churned up (bioturbated) bed was contaminated by the passage of Hannibal's animals, possibly thousands, feeding and watering at the site, during the early stage of Hannibal's invasion of Italia (218 bc).
- ItemBiostratigraphic evidence relating to the age-old question of Hannibal's invasion of Italy, II: chemical biomarkers and microbial signatures(Wiley, 2017) Mahaney, William C.; Allen, Christopher C. R.; Pentlavalli, Prasanna; Kulakova, Anna; Young, Jonathan M.; Dirszowsky, Randy W.; West, Allen; Kelleher, Brian; Jordan, Sean; Pulleyblank, C.; O'Reilly, Shane; Murphy, B. T.; Lasberg, Katrin; Somelar, Peeter; Garneau, Michelle; Finkelstein, S. A.; Sobol, M. K.; Kalm, Volli; Costa, Pedro J. M.; Hancock, Ronald G. V.; Hart, Kris M.; Tricart, Pierre; Barendregt, René W.; Bunch, Ted E.; Milner, Michael W.As discussed in Part I, a large accumulation of mammalian faeces at the mire site in the upper Guil Valley near Mt. Viso, dated to 2168 cal 14C yr., provides the first evidence of the passage of substantial but indeterminate numbers of mammals within the time frame of the Punic invasion of Italia. Specialized organic biomarkers bound up in a highly convoluted and bioturbated bed constitute an unusual anomaly in a histosol comprised of fibric and hemist horizons that are usually expected to display horizontal bedding. The presence of deoxycholic acid and ethylcoprostanol derived from faecal matter, coupled with high relative numbers of Clostridia 16S rRNA genes, suggests a substantial accumulation of mammalian faeces at the site over 2000 years ago. The results reported here constitute the first chemical and biological evidence of the passage of large numbers of mammals, possibly indicating the route of the Hannibalic army at this time. Combined with the geological analysis reported in Part I, these data provide a background supporting the need for further historical archaeological exploration in this area.
- ItemA bloody offal nuisance: The persistence of private slaughter-houses in nineteenth century London(Cambridge University Press, 2007) MacLachlan, IanBritish slaughter-house reformers campaigned to abolish private urban slaughter-houses and establish public abattoirs in the nineteenth century. Abolition of London’s private slaughter-houses was motivated by the congestion created by livestock in city streets, the nuisance of slaughter-house refuse in residential neighbourhoods and public health concerns about diseased meat in the food supply. The butchers successfully defended their private slaughter-houses, illustrating the persistence of the craftsman’s workshop and the importance of laissez-faire sentiments in opposition to municipalization in Victorian London.
- ItemCelluloid Esther: the literary carnivalesque as transformed through the lens of the cinematic epic(De Gruyter, 2017) McGeough, Kevin M.The reception of Esther has often been fraught with attempts to make the book more palatable to the audience receiving it and to interpret the book in a manner more consistent with the values of that community. This is evidence in cinematic adaptations of the book, where the story is transformed to better suit the genre expectations of the Biblical epic and the perspectives of the intended viewers. By examining two films based on Esther – Esther and the King (1960) and One Night with the King (2006) – some of the interpretive issues surrounding the tone and content of the Biblical source become apparent. If Esther is best understood as a carnivalesque work, as many scholars have suggested, then the expectations of this kind of work have not been met in the cinematic adaptations. Given the importance of film in contemporary Biblical reception, these new readings of Esther are perhaps particularly influential, at least within the restricted communities who view these movies. Likewise, analysis of these changes highlights the values of the makers of these films and the audiences who consume them.
- ItemChanging livestock geographies and global meat consumption: what are the implications(University of Lethbridge, 2014) MacLachlan, IanExamines the local livestock industry and the effects of current global meat consumption trends on Canada’s economy
- ItemCharacterization of Lower and Middle Pleistocene tephra beds in the southern plains of western Canada(Canadian Science Publishing, 2022) Westgate, John A.; Naeser, Nancy D.; Barendregt, René W.; Pearce, Nicholas J. G.Wellsch Valley tephra, near Swift Current, southwestern Saskatchewan, and Galt Island tephra, near Medicine Hat, southeastern Alberta, have been referenced in the literature since the 1970s, but little is available on their physical and chemical attributes — necessary information if they are to be recognized elsewhere. This study seeks to remedy this situation. Both have a calc-alkaline rhyolitic composition with hornblende, biotite, plagioclase, pyroxene, and Fe–Ti oxides being dominant. They have a similar composition but are not the same. Wellsch Valley tephra has a glass fission-track age of 0.75 ± 0.05 Ma, a reversed magnetic polarity, and was deposited at the close of the Matuyama Chron. Galt Island tephra has an age of 0.49 ± 0.05 Ma, a normal magnetic polarity, and was deposited during the early Brunhes Chron. Rich fossil vertebrate faunas occur in sediments close to them. Major- and trace-element concentrations in their glass shards indicate a source in the Cascade Range of the Pacific Northwest, USA, but differences in trace-element ratios suggest they are not consanguineous.
- ItemChronology and extent of late Cenozoic ice sheets in North America: a magnetostratigraphical assessment(Elsevier, 2011) Barendregt, René W.; Duk-Rodkin, AlejandraThis paper summarises the advances which have been made in the magnetostratigraphic assessment of glacial and interglacial events of the past 3.0 million years, to facilitate the assignment of sediments to the Chrons and subchrons of the geomagnetic polarity timescale. In the absence of absolute dating tools, magnetostratigraphy affords a valuable means of assigning terrestrial ice age deposits to the geologic timescale, and most importantly, allows a correlation to be made with the more complete marine sedimentary record, where oxygen isotopic data also provide a robust paleotemperature record.
- ItemCoup de Grâce: Humane Slaughter in Nineteenth Century Britain(Brepols, 2006) MacLachlan, IanCalls for humane cattle slaughter in Britain emerged as part of a broader urban-based animal welfare and slaughterhouse reform movement in the nineteenth century. Humanitarian groups advocated the humane slaughter principle: that no animal should be slaughtered without first being stunned into insensibility. Traditional techniques based on the pole-axe, nape-stab, and Jewish ritual slaughter were too unreliable or too slow to ensure insensibility prior to exsanguination. New stunning technologies including slaughter masks and captive bolt pistols were developed and tested through the nineteenth century but were successfully opposed by the butchers' trade organization. Thus the humane slaughter principle did not receive legislative sanction until the 1930s.
- ItemCultivating a New Cattle Culture: Beef Production and Grassland Management in Alberta(Springer, 2005) MacLachlan, Ian; Bateman, Nancy G.; Johnston, Thomas R. R.This chapter illustrates how views about pasture land management have developed in Canada.
- ItemEarly and Middle Pleistocene glaciation of the southern Patagonian plain(Elsevier, 2022) Griffing, Corinne Y.; Clague, John J.; Barendregt, René W.; Ercolano, Bettina; Corbella, Hugo; Rabassa, Jorge; Roberts, Nicholas J.Evidence of at least three Early to Middle Pleistocene glaciations is recorded in the stratigraphic exposures near the outer limit of glaciation in southern Patagonia. At Cabo Vírgenes, at the mouth of the Strait of Magellan, up to 70 m of till, gravel, sand, and stony silt were deposited in a grounding-line environment at the front of the Magellan lobe along a front several tens of kilometres wide. Accommodation space for the sediments was produced by glacio-isostatic depression resulting from the advance of the Magellan lobe to the Atlantic coast. At that time, the ‘moat’ in which the sediments accumulated may have been seaward of the modern Atlantic shoreline because the continental shelf is shallow and sea level was much lower than it is today. The sediments at Cabo Vírgenes are normally magnetized, carry no reversed overprints, and thus probably date to the Brunhes Chron (<0.774 Ma). Seacliff exposures south of the Strait of Magellan along the Atlantic coast of northern Tierra de Fuego expose two tills separated by glaciofluvial sediments. Although not dated, the tills record two advances of the Magellan lobe onto the Atlantic continental shelf. The location of the exposures relative to Cabo Vírgenes indicates that the upper of the two tills may correlate with the Cabo Vírgenes drift. The Tres de Enero highway cut, 90 km northwest of Cabo Vírgenes, exposes lodgement tills deposited during the Great Patagonian glaciation (GPG) – two stacked, normally magnetized tills overlie a reversely magnetized till. Truncated sand wedges separate each of the three tills, indicating that the tills record three separate Early to Middle Pleistocene glaciations. The younger of the two normally magnetized tills, and perhaps both, were deposited in the Brunhes Chron; the lowest, reversely magnetized till records extensive glaciation late during the Matuyama Chron (2.608–0.780 Ma). At Bella Vista in the Río Gallegos valley, a 0.89-Ma-old basalt flow caps a thick unit of normally magnetized glaciofluvial gravel, which was probably deposited during the Jaramillo Subchron (1.075–0.991 Ma), but certainly not later. Sediments at Tres de Enero and Bella Vista show that the GPG is not a single event as originally thought, but rather at least three glaciations, perhaps spanning several hundred thousand years.
- ItemEconomic development and industrial employment: A thousand points of light?(Alberta Association, Canadian Institute of Planners, 1991) MacLachlan, IanThis paper disputes some of the empirical analysis on small firm job creation and argues that small enterprises are responsible for a relatively modest share of employment and employment growth at the national, provincial, and municipal levels. While the importance of small business should not be gainsaid, the traditional large firm sector is still a vital component in municipal economic growth and decline. The shortcomings of data on small enterprises are discussed to encourage a more skeptical interpretation of research findings on employment creation. Economic development strategy should include the attraction of new large enterprises and the needs of existing large employers must be addressed if the community economic base is to be sustained.
- ItemEducating the next generation of remote sensing specialists: skills and industry needs in a changing world(Taylor & Francis, 2021) Chasmer, Laura; Ryerson, Robert A.; Coburn, Craig A.The landscape of post-secondary education has experienced a dramatic change in student outcomes over the past 20 years. The expectation for students in advanced education was a career in research and toward gaining employment in either academia or in government science. From our survey of university students and early career professionals, it was clear that there is an expectation gap between desired and probable post-secondary education outcomes. Our survey indicated that the majority of trainees, regardless of level of education, undervalue the importance of written and oral communication skills and overvalue specific methodological understanding relative to those employed in the field. While some of these dichotomies can be explained by the relative lack of experience of students, it also points to the nature of the foci of our training. While we are concerned with the production of the next leaders in remote sensing science, most will have careers that are different from their training. There is an opportunity to optimize the post-secondary education experience (student and faculty) with the inclusion of a broader view toward career outcomes.
- ItemThe effects of dune stabilization on the spatiotemporal distribution of soil moisture resources, Northern Great Plains, Canada(Lethbridge, Alta. : University of Lethbridge, Dept. of Geography, c2012, 2012) Koenig, Daniel Edgar; Hugenholtz, Chris H.; Letts, Matthew G.In dryland environments, the availability of soil moisture is the primary control on plant species’ distributions. In the sandhill regions of the northern Great Plains, vegetation establishment has transformed highly mobile, desert-like dune fields into stabilized landscapes covered by mixed-grassland prairie. This study examines how dune stabilization has modified the spatiotemporal distribution of soil moisture resources. An ergodic (space-for-time) approach was used, comparing soil moisture dynamics on active and vegetation-stabilized dunes in the Bigstick Sand Hills of southwestern Saskatchewan. Results indicate that while dune stabilization has enhanced near-surface soil moisture availability, deeper profile soil moisture recharge is reduced. Through better understanding how vegetation has modified soil moisture dynamics in stabilizing sandhill regions, better management practices may be implemented to maintain water resource availability and ecosystem health.
- ItemEsther the hero: going beyond "wisdom" in heroic narratives(Catholic Biblical Association of America, 2008) McGeough, Kevin
- ItemEvidence for Early Pleistocene glaciation from borecore stratigraphy in north-central Alberta(Alberta Energy Regulator, 2016-07) Andriashek, L. D.; Barendregt, René W.Borecores collected from Quaternary sediments in north-central Alberta, Canada, were sampled and studied for paleomagnetic remanence characteristics. A magnetostratigraphy has been established for sediments previously assumed to represent multiple continental (Laurentide) glaciations but for which no geochronology was available. Based on the Quaternary record elsewhere in Alberta and Saskatchewan, it was thought that some of these sediments were deposited during pre-late Wisconsinan glaciations. The Quaternary sedimentary succession of north-central Alberta attains thicknesses up to 300 m within buried valleys and is composed of diamict interbedded with glaciolacustrine and outwash sediments. Most of the sampled units are not accessible from outcrop and their sedimentology and stratigraphy is derived from core data only. In 4 of 16 borecores sampled to date, diamict that correlates with the Bronson Lake Formation till is reversely magnetized, indicating an Early Pleistocene age. Depending on location, this formation is underlain by either Empress Formation sediments or Colorado Group shales, and is overlain by one or more normally magnetized glacigenic sedimentary units of the Bonnyville, Marie Creek, and Grand Centre formations, respectively. This new record of Early Pleistocene glaciation in north-central Alberta places the westernmost extent of earliest Laurentide ice at least 300 km farther west than its previously established limit in the Saskatoon and Regina regions of the Canadian Interior Plains, but still to the east of the maximum extent of the late Wisconsinan (Late Pleistocene) Laurentide Ice Sheet, which extended into the foothills of the Alberta and Montana Rocky Mountains.