No description available.

No description available.

This study represents a continuation of the historical trend in the analysis of the relationships between climate and vegetation. The focus of the work is on an examination of the association of functioning plants and climatic processes and on the interaction of structured vegetation communities with their environment. Satellite observations and remote sensing technology provide new opportunities for studying the geo-biosphere at high temporal frequencies and for large geographic areas. Integration of spectral vegetation indices and thermal measurements from space is the prime methodology used in this study. The integration of thermal information with vegetation indices has the potential to result in an important contribution to ecological remote sensing. This study has investigated the triangular distribution pattern which has been repetitively observed in spectral domains defined by thermal measurements and vegetation indices. Results show that the triangular shape of an AVHRR data cluster can be consistently observed on different continents and at different times of the year. The triangular data pattern has also been observed using a seasonally averaged data set, representing the mean thermal and biomass conditions of a growing season. The triangular shape of the data spread in feature space clearly suggests an ecosystem triangle model for simulation of the global ecology. A closer analysis of 15 test sites representing the major biomes in the U.S. Southwest study area has shown that each biome has a stable territory in the two dimensional space of temperature and biomass. If the territory of each test site in the triangle can be viewed as a vegetation cell, the ecosystem as a whole may be modeled by using this cell structure. The ecosystem triangle model and the concept of the cell structure have been applied in a vegetation classification exercise. The significant improvement achieved in the vegetation classification supports the conclusion that the ecosystem triangle model is a reflection of surface biomes, and may be used as a tool to study the structure, organization, and function of the biosphere.

No description available.

No description available.

Buffer strips alongside watercourses are now a widely accepted method of reducing nutrient and sediment run-off from agricultural land thereby improving water quality and meeting policy goals. However, this change in land use may have consequences for riparian biodiversity which have yet to be fully understood. This study investigated the impact of buffering on various aspects of biodiversity by comparing three types of margins in three river catchments in north east Scotland. Margins were categorised as unbuffered (open and unfenced), buffered (fenced-off vegetated) and wooded (long established woody vegetation - fenced and unfenced). Components of biodiversity studied included vegetation patterns, and the abundance, diversity, movement and assemblage composition of ground-dwelling arthropods focussing primarily, though not exclusively, on ground beetles (Coleoptera, Carabidae). This study further considered management options which may improve or enhance biodiversity. Evidenced changes in vegetation were associated with soil parameters (including decreasing pH), channel morphology, decreasing light availability and tree canopy cover, and bryophyte abundance along a successional gradient from unbuffered-buffered-wooded sites. Buffered and wooded sites showed lower activity density and species richness of ground beetles, but while one measure of functional diversity was high for wooded sites, buffered sites were found to have significantly lower values. Both species and trait assemblage structure of ground beetles were influenced by soil and vegetation, but also by features of buffer strip design such as width, length and age. Active management of sites through grazing or cutting increased ground beetle abundance, particularly hygrophilous species, but did not affect diversity. Radiotracking showed increased movement of ground beetles was correlated with intensity of grazing. Few truly riparian plant or arthropod species were identified indicating the process of buffering essentially 'terrestrialises' the riparian margins. The presence of a tree canopy layer appears to be the key instigator of change in soil conditions with vegetation and arthropods responding accordingly. Therefore planting and maintaining trees in buffer strips could be crucial to ensuring that functional diversity and associated ecosystem services are maintained. Active management through grazing or cutting could help in this regard. The results from this study suggest that rather than buffering all riparian margins within catchments, it is fundamentally important for biodiversity to maintain a mosaic of different successional stages and a diversity of habitats.

Key words: End zone, prestress transfer, wire tendon, transmission length, pull-in, plain wire, indented wire, concrete strength, size of wire, gradual release, sudden release, shock release, time dependent effects.An empirical investigation into the transfer of prestress force from wire tendons to concrete in the end zones of pretensioned prestressed concrete beams was accomplished in this project. The experimental tests featured 56 small scale prestressed concrete beams.Some of the factors influencing prestress transfer which were considered in the current tests are as follows:(a) type of release - gradual, sudden or shock(b) surface condition of the wire - plain or indented(c) size of the wire(d) concrete compressive strength at the time of transfer(e) time dependent effectsMost of the tests involved gradual release of steel tendons with the prestressing force transferred in approximately ten equal increments. Sudden release in a single step was achieved by allowing the supporting abutments to retract rapidly. Shock release was implemented in some beams by angle grinding the wires. The type of release which gave the best quality of prestress transfer was gradual release. This was followed by sudden and shock releases respectively.There were four types of wires used in the laboratory tests: namely the 5 mm dia. Plain, 5 mm dia. Chevron indented, 7 mm dia. Plain and 7 mm dia. Belgian indented wires. Transmission lengths were determined from strain distributions for these wires. Pull-ins of the wire tendons at the ends of the beams were also measured.There was significant scatter in the experimental data. Different ranges of transmission lengths and pull-ins were obtained for the various types of wires used.Three equations were derived for the 5 mm dia. Plain, 5 mm dia. Chevron and 7 mm dia. Plain wires, which linearly correlated pull-ins to the transmission lengths. ++ / These relationships provide a qualitative and quantitative method of indirectly monitoring for the transmission lengths through the measurements of pull-in.Statistical inference tests proved that indented wires were superior in performance compared to plain wires, but the differences were more apparent for the pull-ins than for the transmission lengths.Comparisons on the influence of tendon size substantiated that greater pull-ins occurred for larger wires but the differences were not significant for the transmission lengths.For concrete strength at the time of transfer of less than 32 MPa, the transmission lengths and pull-ins were significantly larger than those for higher strengths. It is recommended that concrete strength at transfer be at least 32 MPa for pretensioned prestressed concrete.Apart from the maturity and strength of concrete, the quality of a mix also influenced the transmission length and there was limited data to suggest that a better grade mix despite having lower strength at a more tender age could outperform a lower grade mix with greater strength released after a longer curing period.Formulae for plain and indented wires were found by dimensional analysis which correlated the transmission length to the diameter of wire tendon and the stress/strength ratio of the prestressed beams.Pull-ins increased significantly over 6 months but the changes in the transmission lengths were small. Normalised longitudinal strain distributions did not indicate that transmission lengths would remain unchanged over time.

The coastal zone is a valuable resource which provides a diversity of benefits. The difficulties facing the coastal zone tend to fall into three categories: (1) Pressure and conflict on resources. The beach residence value, an indicator of land use pressure, implies that, of the Australian states, New South Wales' coastal zone is under the greatest pressure. Associated with population is development pressure. Many forms of development are not compatible, hence conflicts of interest can arise. (2) The dynamic nature of the coast. That is, the physical and biological aspects of the coastal zone are in a state of flux. The dynamics make predictions for management controversial. (3) Organisational problems. The lack of direction, lack of coordination and fragmentation of management leads to ad hoc management of this valuable resource. This evaluation identified and confirmed the relevance of coastal issues which led to the enactment of the Coastal Protection Act, 1979. The coastal issues investigated were: coastal erosion and development; coastal erosion and protection works; coastal land degradation; degradation of coastal habitats, fish and wildlife resources; recreation opportunities; pollution; and increasing population pressure and competition betweeen alternative uses. The administrative arrangements for management of the issues were investigated. A broad range of coastal issues were evaluated using a mix of indicators with standards of comparison to measure progress. Management tools, policies and strategies used to address the issues were investigated. Finally prescriptions to further address the issues were made as was how to implement the prescriptions. The evaluation noted: increasing coastal population and development pressure; numerous examples of conflicts of interest; complex and often bewildering administrative arrangements for coastal zone management; widely varying levels of performance by agencies; and a lack of direction and co-ordination from State authorities. The principal conclusion was that strategic planning needed to be undertaken through a lead coastal agency. The lead agency should clarify and improve direction, co-ordination and co-operation in coastal management. This should improve the effectiveness of management and reduce the incidence and duration of conflict among the different and competing coastal values. This evaluation of the effectiveness of coastal management, at a State level, should not only assist New South Wales but also other States in the management of this valuable resource.

Graduation date: 1997

Thesis (M.S.)--Oregon State University, 1973. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.