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Temporal changes in the environmental conditions upon which life depend are ubiquitous in nature, acting at every level of organisation from cells to ecosystems. Although the actions themselves are often poorly understood, they strongly depend on the temporal and hierarchical (organisational) scales at which they are measured; ecosystems are relatively stable through time while their species composition may undergo vast changes. Likewise any hierarchical level may be relatively stable in the short-term, but undergo vast long-term changes. This thesis aims to better understand the importance of these scales for mediating the impact of environmental variability on ecological systems. / The approach used herein employs both mathematical models and empirical data which represent food webs responding to environmental variability at different hierarchical scales. Within each of these representative food webs, the influence of environmental variability on the stability of the food web is determined using an approach which accounts for the effects of temporal scale. This thesis demonstrates that the stability of simple model food webs (high hierarchical scale) is tightly linked to environmental variability and the temporal scales at which these changes occur dictate which species in the model are most affected. At lower scales of organisation, empirical data indicate that environmental variability generally has a lesser impact on stability and that only certain temporal scales are responsible for this trend. At these temporal scales some species respond differently to environmental variability, negative changes in one species (or group) are offset by positive changes in another - a process known as compensation. These results highlight the importance of both temporal and hierarchical scale in mediating the response of food webs to environmental variability. Ultimately, they will serve to better understand how models and experiments should scale-up from low to high hierarchical and temporal scales.

Thesis (M.Sc.)--University of Waikato, 2007. / Title from PDF cover (viewed March 18, 2008) Includes bibliographical references.

Thesis (M.S.)--Texas State University-San Marcos, 2008. / Vita. Appendices: leaves 87-105. Includes bibliographical references (leaves 106-118). Also available on microfilm.

Thesis (Ph. D.)--University of Sydney, 1999. / Title from title screen (viewed Apr. 21, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Dept. of Chemical Engineering, Graduate School of Engineering. Includes bibliography. Also available in print form.

Thesis (Ph. D.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 118-132). Also available via the World Wide Web.

Thesis (Ph. D.)--Michigan State University. Dept. of Fisheries and Wildlife, 2008. / Title from PDF t.p. (viewed on July 23, 2009) Includes bibliographical references (p. 160-179). Also issued in print.

Thesis (M.F.A.)--University of Wyoming, 2009. / Title from PDF title page (viewed on Apr. 16, 2010).

Thesis (Ph. D.)--University of Chicago, 1940. / Lithoprinted. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." Bibliography: p. 180-206.