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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

An Examination of the potential impacts of food safety management programs on community farms

Hughes, Kathryn 11 April 2012 (has links)
On-farm food safety management programs are increasingly a part of business for horticultural and livestock producers. Originally designed for export oriented food manufacturers, they are now promoted to smaller and domestically oriented farms as well. This thesis explores the potential impacts these programs can have on on small scale, ecological and locally oriented "community" farms. The food safety management approach explored involves a HACCP analysis, "Good Agricultural Practices" and an audit-based verification system. The research is based largely on interviews with community farmers on southern Vancouver Island, British Columbia. Findings indicate that in addition to the (widely acknowledged) financial disadvantages that these programs can present to small scale businesses they can also have significant socio-cultural impacts on community farms specifically. In particular, food safety programs can require farmers to focus on food safety objectives to the exclusion of other priorities. This can compromise their ability to practice ecological methods of food production. Also, the HACCP programs explored impose a commercial-style administrative model onto farms to facilitate a textually enacted demonstration of "safe food production". Such an approach does not account for the social regulatory mechanisms in place in localized markets and could require considerable reorganization for community farms. Finally, HACCP programs redefine the role of farmers such that their authority and autonomy are diminished, and the nature of farm work becomes managerially oriented. The impacts identified suggest that the community agricultural sector merits particular consideration in the development and implementation of food safety policies and programs. / Graduate
22

Late Quaternary vegetation, climate, fire history, and GIS mapping of Holocene climates on southern Vancouver Island, British Columbia, Canada

Brown, Kendrick Jonathan 05 February 2018 (has links)
Pollen and microscopic charcoal fragments from seven sites (East Sooke Fen and Pixie, Whyac, Porphyry, Walker, Enos, and Boomerang lakes) were used to reconstruct the post-glacial vegetation, climate, and fire disturbance history on southern Vancouver Island, British Columbia, Canada. A non-arboreal pollen and spore zone occurs in the basal clays at Porphyry Lake and likely represents a tundra or tundra-steppe ecosystem. This zone precedes the Pimis contorta (lodgepole pine) biogeochron that is generally considered to have colonised deglaciated landscapes and may represent a late Wisconsinan glacial refugium. An open Pinus contorta woodland characterised the landscape in the late-glacial interval. Fires were rare or absent and a cool and dry climate influenced by “continental-scale katabatic” easterly winds dominated. Closed lowland forests consisting of Picea (spruce), Abies (fir), Tsuga heterophylla (western hemlock), and Tsuga mertensiana (mountain hemlock) with P. contorta and Alnus (alder) and subalpine forests containing Picea, Abies, and T. mertensiana with P. contorta replaced the P. contorta biogeochron in the late Pleistocene. Fires became more common during this interval even though climate seems to have been cool and moist. Open Pseudotsuga menziesii (Douglas-fir) forests with Pteridium (bracken fern) in the understory and Alnus in moist and disturbed sites expanded westward during the warm dry early Holocene. At this time closed Picea, T. heterophylla, and possibly Alnus forests grew in the wettest part of southern Vancouver Island at Whyac Lake. At high elevations, forests consisting of T. heterophylla and Pseudotsuga coupled with Alnus expanded during the early Holocene. Fires occurred frequently in lowland forested ecosystems during this interval, although East Sooke Fen in a dry, open region experienced less fire. At high elevations, charcoal increased somewhat from the late Pleistocene, indicating slightly more fires and reflecting continued moist conditions at high elevations. The mid and late Holocene was characterized by increasing precipitation and decreasing temperature respectively. Mid Holocene lowland forests were dominated by Pseudotsuga with T. heterophylla and Alnus in southeastern regions, T. heterophylla and Thuja plicata (western red-cedar) in southern regions, and T. heterophylla and Picea in southwestern regions. An overall decrease in charcoal influx suggests a decrease in lowland fires, although locally isolated fire events are evident in most sites. Quercus garryana (Garry oak) stands spread westward during the mid Holocene, attaining maximum extent between East Sooke Fen and Pixie Lake, approximately 50 km beyond their modem limit. Lowland sites record a general decrease in fires at this time. At high elevation, mid Holocene forests were dominated by T. heterophylla, Picea, and Abies with Alnus. An overall increase in charcoal influx at high elevations may reflect an increase in the number of charcoal fragments entering the basins by overland flow as opposed to an increase in fire incidence because climate was moister. In the late Holocene, closed T. heterophylla and T. plicata forests became established in wetter western regions, Pseudotsuga forests occupied drier eastern portions, and T. mertensiana and Cupressaceae, likely Chamaecyparis nootkatensis (Alaska yellow cedar), forests were established in sub-alpine sites. Lowland fires were infrequent in wet western regions but frequent in drier eastern regions. A slight reduction in charcoal influx generally occurs at high elevations, implying fewer fires. A recent increase in charcoal influx at East Sooke Fen and Whyac, Walker, Enos, and Boomerang lakes may reflect anthropogenic burning. Holocene paleoclimates were reconstructed at 1,000 year intervals through a geographic information system (GIS) using contemporary climate data and surface and fossil pollen assemblages by establishing empirical regression equations that calibrated contemporary precipitation and temperatures to present day Douglas-fir-western hemlock (DWHI) and T. heterophylla-T. mertensiana (THMl) pollen ratios. / Graduate
23

Summer sea surface temperature variability off Vancouver Island from satellite data, 1984-1991

Fang, Wendong 11 1900 (has links)
Satellite-sensed Advanced Very High Resolution Radiometer (AVHRR) Sea Surface Temperature (SST) data over eight summers (1984-1991) were used to analyze the summer SST patterns of variability off the west coast of Vancouver Island. Empirical Orthogonal Function (EOF) analysis of the spatial variance for 133 nearly cloud-free summer images was performed. The first EOF mode, which resembled the mean of all images, showed a strong cool water band located at the northwest corner of Vancouver Island, a cool tongue extending seaward from the Strait of Juan de Fuca and a warm patch off Barkley Sound. The second mode revealed topographically controlled upwelling -- coolwater over the shelf region with its seaward boundary roughly following the 200-m depth contour, plus a cold eddy located just north of the Juan de Fuca Canyon. The third mode displayed cool water extending southwestward off Brooks Peninsula, while the fourth mode showed a cool water plume extending off Cape Scott at the northern tip of Vancouver Island. These 4 modes accounted for respectively, 33, 12, 10 and 5% of the SST variance. With the first 4 modes accounting for 60% of the total variance, the EOF method is highly effective in condensing the huge amount of satellite data. The temporal amplitude of the EOF modes revealed how the SST features changed as summer progressed. From these images, we also constructed an overall seasonal coolness index, which revealed the summers of 1986 and 1991 to have the coolest coastal water, with both summers immediately preceding an El Nino. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
24

Patterns of variation in Pacific silver fir (Abies amabilis [Dougl.] Forbes) on Vancouver Island

Davidson, Roberta H. January 1990 (has links)
This thesis describes patterns of variation in several cone, seed and seedling characteristics of Pacific silver fir (Abies amabilis [Doug.] Forbes) sampled from Vancouver Island, B.C. Cone collections kept separate by tree were made at eight locations during the fall of 1983 to provide material for the study. The inheritance patterns of 13 enzyme loci were determined from seed tissues of 87 trees, and seven loci were found to possess at least two allozyme variants. These loci conformed to the assumptions of Mendelian-type inheritance, although AAT-2 displayed marked segregation distortion. No linkage groups could be established at the sampling intensity available (20 seeds per tree). Significant levels of inbreeding, based on a multilocus estimate of outcrossing, were detected in five of seven populations and indirect evidence suggests related matings other than selfing may be occurring. Variation among populations in outcrossing rate was evident (0.725 < tm ≤ 1.0) and appears positively correlated with seed size (measured by 1000-seed weight). High levels of allozyme variation were found to exist within populations (95-98%) and estimates of the extent of population differentiation were shown to differ depending upon the particular analytic method employed. Maternal (extant) trees appeared more heterozygous than did viable embryos and populations sampled on southern Vancouver Island appeared more genetically diverse than did populations sampled on northern Vancouver Island. A sub-sample consisting of two populations, each with seven trees, from northern, mid and southern Vancouver Island provided material for a germination test and open-pollinated progeny study. Seed dormancy was not pronounced among populations. Large family differences in germination responses were detected, irrespective of pregermination treatment, suggesting a high degree of genetic control of germination in Pacific silver fir. Anomalous germination behavior in one population was attributed to sub-optimal stratification conditions and proliferation of mold. Improvement in production of seedlings of Pacific silver fir may be achieved by collecting and germinating seeds on a family-by-family basis. Germinants from the first count of the germination test provided open-pollinated progeny for measurement of growth variables. Seedlings were grown in a greenhouse alongside production Abies stock for 29 weeks. Population differences accounted for a considerable part of variance in cone and seed size. The effect of population on height of seedlings at eight weeks was significant but declined to virtually zero by the end of the test. Populations had negligible influence on growth rate of seedlings as well. Variation in growth rate among open-pollinated families was statistically significant but accounted for only 20% of the total variation. Significant population differences were detected in root weight of harvested seedlings. Family differences in this and other biomass variables were at most 20%, with the majority of variation in seedling growth traits residing within families. / Forestry, Faculty of / Graduate
25

The Sooke gabbro

Mitchell, William Sutherland January 1973 (has links)
The geology of the East Sooke peninsula comprises a core of olivine gabbro, peripherally uralitized and bounded on the north and east by upper Eocene Metchosin basalts of submarine origin. The gabbro intrudes the basalts which are unconformably overlain by sediments of the Sooke Formation of Miocene-Oligocene age. The Sooke gabbro intrusion is an elliptical body of slightly differentiated olivine gabbro which is composed of calcic plagioclase and clino-pyroxene with minor olivine and orthopyroxene. The gabbro does not exhibit any obvious cryptic or cumulate layering of the type which characterises many other layered basic igneous intrusions. Instead steeply dipping structures such as weak layering, foliation and lineation are believed to be flow structures. Intensity of uralitization of the olivine gabbro increases near the margin of the intrusion and towards fractures which appear to have acted as channelways for a convective flow of hydrous fluids within and around the hot intrusion. Concentrations of copper sulphides, deposited from these fluids, are found in structurally favourable areas. The gabbro intrusion is thought to mark the position of a volcanic neck or feeder, now exposed by erosion of a thick sequence of Eocene submarine basalts which built up from ocean floor in a manner similar to the Hawaiian chain of oceanic islands. An hypothesis of oceanic origin for the basalt and gabbro sequence is complemented by reinterpretation of the geophysical data from south Vancouver Island. The Metchosin basalts and gabbro intrusions are thought to represent an oceanic suite of rocks emplaced by ohduction on the southern tip of Vancouver Island. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
26

Genesis of a Podzol sequence on the West Coast of Vancouver Island

Bhoojedhur, Seewant January 1969 (has links)
A study was undertaken on the pedogenesis of a Podzol sequence of soils on the West Coast of Vancouver Island. The area is one of abundant rainfall and rather luxuriant vegetation. The soils occur on relatively level topography (glacial fluvial deposits) and have varying degrees of development of placic (pan) horizons. The objectives of the study included characterization, classification and genesis of the soils, based on physical, chemical and mineralogical investigations. Four soils were chosen for the study. Three of the soils comprised the Ucluelet soil series, while one soil was a member of the Wreck Bay soil series. The soils were described morphologically, sampled and selected analyses were performed on the major genetic horizons. More detailed analyses, including differential thermal analyses, were conducted on the placic materials. The soils were classified into the Canadian Classification Scheme as as follows: Ucluelet I Placic Ferro-Humic Podzol Ucluelet II Orthic Humo-Ferric Podzol Ucluelet III Placic Humo-Ferric Podzol Wreck Bay Gleyed Placic Ferro-Humic Podzol Analyses of the placic materials indicated, that although the material appeared vitreous in the field, no crystallinity could be determined by X-ray diffraction. It appeared that the major component of the placic horizon is composed of iron and organic matter, probably in some intimate association. It was observed that the placic horizon could form in materials of initially low iron contents. From the foregoing observations the following chronosequence of soil development appears to be justified: Orthic Humo-Ferric Podzol (Ucluelet II) → Placic Humo-Ferric Podzol (Ucluelet III) → Placic Ferro-Humic Podzol (Ucluelet I) → Gleyed Placic Ferro-Humic Podzol (Wreck Bay) The differences in pedogenic age of the three Ucluelet sites can be attributed to degrees of "churning" by the trees at these sites. / Land and Food Systems, Faculty of / Graduate
27

A new model for the crust in the vicinity of Vancouver Island

Tseng, Kuang-Hsing January 1968 (has links)
Seismic explosion data obtained by the Dominion Observatory in the Vancouver Island region from 1953 to 1963 have been restudied by both the travel-time and the time-term methods. From the first method, a new four layer model crust was constructed: In addition to the sedimentary, a granitic, and basaltic layers, suggested by White (1962), an ultrabasic layer of more than 22 km in thickness and Vp = 7.1 km/sec was recognized. From the time-term method, this layer structure was supported and the possibility of a major structural feature running across the island is suggested by the faults on each side and the gravity anomaly extending between them. The Mohorovicic discontinuity was not observed. A possibility interpretation of the abnormal character is given, and the complementary gravity and geomagnetic depth sounding evidence presented. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
28

A regional study of social welfare measurements : no. 4 (Vancouver Island) : an exploration of the regional assessment of demographic and social welfare statistics for British Columbia, 1951-1961

Cumming, Robert Coulter January 1965 (has links)
This study of social welfare measurements in Region I (Vancouver Island) is the fourth in a series of regional assessments. A similar study of Region VI (The Okanagan) is presently being completed. Three previous studies have been done; one in an unorganized area of Northern British Columbia, the second Region III (The Fraser Valley), and the third was a comprehensive study of Metropolitan Vancouver including several of the surrounding districts. Region I of the Department of Social Welfare very closely coincides with census division 5 of British Columbia. This has overcome the discrepancy that often exists between census material boundaries and welfare regional boundaries. Census division 5 actually includes some islands and isolated areas of the north coast of British Columbia lying adjacent to Vancouver Island. These areas are very sparsely populated and are more readily accessible from the mainland than from Vancouver Island, and are therefore not included in Welfare Region I. Basic statistical data was compiled and computed from the Dominion Bureau of Statistics. Extensive use was made of 1961 data with selective reference being made to the 1951 data available. In some instances the census subdivision boundaries were changed within the bench work decade (1951-1961). Therefore some of the changes in social and economic conditions could not be measured. In these instances it was necessary to rely on the 1961 data. The welfare statistics were compiled primarily from the monthly reports of the Provincial Department of Social Welfare for the years 1951 and 1961. However, in Metropolitan Victoria there are numerous private social agencies and one major one serving families and children. This latter was chosen to examine more fully the welfare services offered in this area. This is an initial exploratory study of Vancouver Island as a welfare region. Further studies in detail of the kind initiated in Nanaimo to measure the appropriateness and effectiveness of welfare services should be carried out. These would provide information for comprehensive planning for the welfare needs of the people who live in this region. / Arts, Faculty of / Social Work, School of / Freyman, Anna; Hollick-Kenyon, Grace Agnes; Macdonald, Janet Mary / Graduate
29

Forest vegetation of west-central Vancouver Island, British Columbia

Gagnon, Daniel January 1985 (has links)
The objective of this study was to quantitatively describe the structure, composition and ecological relationships of old-growth forests of west-central Vancouver Island. Data were obtained by sampling 172 plots, at elevations up to 1000 m, located within thirteen drainage areas. Hypothesized relationships between vegetation and environmental variation were examined using gradient analysis and multivariate methods. Successive reciprocal averaging ordination of the vegetation data led to the recognition of six vegetation groups (floodplain, subalpine, Pinus contorta, Pseudotsuga, Thuja, Abies) and twenty-three community types. Data from the tree, sapling, seedling, shrub, herb and bryophyte-lichen strata were used. Vegetation groups are differentiated along macro-climatic and soil parent material gradients. The vegetation of the Pseudotsuga group, dominant inland, appears to respond to gradients of elevation and soil moisture. The Thuja group is found only near the coast, and its vegetation varies along gradients of soil nutrients and elevation; soil moisture having little effect. The vegetation patterns of the Abies group are correlated to elevation and soil moisture. Canonical variates analyses revealed a close relationship between vegetational and environmental patterns within most vegetation groups. A precipitation continentality gradient was identified as the major determinant of modal vegetation variation. Along this gradient, alpha and beta diversity increased towards the drier and more continental interior as predicted. Tree size-class distribution data indicate that Pseudotsuga menziesii is a seral species in most community types. The dominance of Thuja plicata near the coast may be maintained because of its longevity and, possibly, its wind damage resistance. Attention is drawn to the ecological mechanisms operating in coastal forests which have important implications for their successful management. / Science, Faculty of / Botany, Department of / Graduate
30

Coastal upwelling along the west coast of Vancouver Island

Jardine, Ian David January 1990 (has links)
Wind-driven up welling events near Brooks Peninsula off the west coast of Vancouver Island have been identified during the summers of 1988 and 1989 from sea surface NOAA AVHRR thermal imagery obtained at the UBC Satellite Oceanography and Meteorology Laboratory. Software has been developed to characterize the strength and extent of the surface cooling associated with the upwelling. A two-dimensional, 2-layer finite difference model with 1 km resolution has been formulated to examine the small-scale dynamics of the upwelling events. The model uses local wind and includes realistic coastline and bathymetry. The wind-stress and coastline configuration appear to be the main factors contributing to favourable upwelling regions. The results of the model compare favourably to the observed starting location of the upwelling. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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