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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.
61

Modelling landscape connectivity for highly-mobile terrestrial animals: a continuous and scalable approach

Galpern, Paul 08 1900 (has links)
Assessments of landscape connectivity are increasingly required in natural resource management. Understanding how landscape structure affects the movement and dispersal of animals may be essential for ensuring the long-term persistence of species of conservation concern. Functional connectivity models describing how features on the landscape influence animal movement behaviour have been produced in two different ways. The resistance surface models landscape connectivity as its inverse, the resistance to movement and dispersal, while the landscape graph represents landscape connectivity by describing the relationships among resource patches. Both methods have limitations that make them less effective for modelling highly-mobile and wide-ranging species such as ungulates and carnivores. This thesis develops a method called grains of connectivity that combines the continuous representation of landscape connectivity provided by resistance surfaces and the scalability provided by landscape graphs to create a flexible modelling framework for these species. The first half of the thesis reviews the conceptual origins of the grains of connectivity method and examines its properties using simulated landscapes. In the second half, empirical evidence of movement and dispersal in a boreal woodland caribou (Rangifer tarandus caribou) population is used to validate functional connectivity hypotheses generated using the method. Connectivity for caribou at the temporal scale of generations is examined using a landscape genetics approach, while connectivity at the seasonal scale is assessed using the distribution of caribou telemetry locations. Grains of connectivity may be most useful for study systems where animals are not found exclusively in well-defined resource patches and there is uncertainty in the behavioural parameters influencing movement and dispersal. Additionally, the scalability of the analysis can be used to selectively remove spatial heterogeneity that may be uncorrelated with movement and dispersal giving an improved description of the pattern affecting the landscape connectivity process.
62

Interacting Disturbances in the Boreal Forest and the Importance of Spatial Legacies at Multiple Scales

James, Patrick Michael Arthur 03 March 2010 (has links)
Forest disturbances and the spatial patterns they create affect ecosystem processes through their influence on forest vegetation from individual trees to landscapes. In the boreal and mixed-wood forests of eastern Canada the main agents of disturbance are logging, fire, and defoliation by the spruce budworm (SBW, Choristoneura fumiferana). These disturbances are similar in that they remove forest biomass and influence forest succession but also distinct in that logging creates patterns that are different than those created by natural disturbances. All disturbances are indirectly linked to each other through their mutual effects on forest spatial structure and succession. Through such feedbacks, spatial disturbance legacies can facilitate or constrain further disturbances, including forest management. Surprisingly, the long term spatial consequences of interactions among multiple natural and anthropogenic disturbances remain largely unexplored. This thesis investigates how, and at what spatial scale, legacies in forest composition and age structure influence natural disturbance dynamics, and how natural disturbances constrain forest management. I address four specific questions: (i) For how long do spatial legacies of different forest management strategies persist on the landscape? (ii) How do interactions among logging, fire, SBW, and succession affect timber availability and long term forest patterns in age and composition? (iii) How do these patterns differ from those created by each disturbance individually? And, (iv) How can management be used to reduce the extent and severity of fires and SBW defoliation through the manipulation of forest structure? The key scientific innovations of this thesis are: (i) Characterization of the duration and influence of spatial legacies on forest disturbances and sustainability; (ii) Development of a dynamic spatial forest simulation model that includes distinct successional rules that respond to different types of disturbance and shifts in disturbance regimes; and, (iii) Development and application of a wavelet-based significance testing framework to identify key scales of expression in forest spatial patterns. These innovations provide a scientific basis for landscape level forest management strategies designed to reduce the long term impacts of defoliating insects and to meet multiple objectives.
63

Modeling unplanned landscape change: A Colombian case study

Etter, A. Unknown Date (has links)
No description available.
64

Modeling unplanned landscape change: A Colombian case study

Etter, A. Unknown Date (has links)
No description available.
65

Development and application of a GIS based evaluation for prioritization of wetland restoration opportunities /

Kauffman, Jennifer L. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 30-34). Also available via Humboldt Digital Scholar.
66

The influence of landscape structure on the fine-scale movement behavior and meso-scale dispersion of two species of Calopterygid damselfly /

Jonsen, Ian David. January 1900 (has links)
Thesis (M.Sc.)--Acadia University, 1998. / Includes bibliographical references (leaves 90-95). Also available on the Internet via the World Wide Web.
67

Relationship between landscape structure and avian abundance patterns in the Oregon Coast Range /

McGarigal, Kevin. January 1993 (has links)
Thesis (Ph. D.)--Oregon State University, 1994. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.
68

Modeling land cover change under conditions of multi-scaled spatial data : an application of landscape ecology in environmental planning /

Logsdon, Miles G. January 1997 (has links)
Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [125]-131).
69

Effects of agricultural and urban land uses on birds breeding in forest fragments near Ottawa, Ontario /

Dunford, Wendy January 1900 (has links)
Thesis (M. Sc.)--Carleton University, 2001. / Includes bibliographical references (p. 41-51). Also available in electronic format on the Internet.
70

The ecological legacy of Indian burning practices in southwestern Oregon /

Carloni, Kenneth R. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 165-181). Also available on the World Wide Web.

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