Document Type

Thesis

Degree Name

Master of Arts (MA)

Department

Geography & Environmental Studies

Faculty/School

Faculty of Arts

First Advisor

Kenneth Hewitt

Advisor Role

Thesis Supervisor

Abstract

There have been several recent calls in the biogeography and vegetation ecology literature to investigate more thoroughly the role of recurrent disturbance or perturbation in the dynamics of subalpine communities, by assessing persistence and change in the dominant species population. In order to study the relationship between conifer regenerative effectiveness, disturbance effects, and the nature of the vegetation pattern, a field study was made of the vegetative cover (composition, abundance, dominance) and its performance (survival, vigour, and reproductive mode) in the upper subalpine zone in the Valley of the Ten Peaks, Banff National Park, Alberta. The occurrence of stresses and disturbances is both spatially and temporally sporadic in this zone, and this variable disturbance regime contributes significantly to the ‘patchiness’ in vegetation cover and performance. There seems insufficient grounds for labeling this field situation an ‘abnormality,’ or a ‘severely-delayed’ secondary succession, as no overall replacement community is indicated. Since it is true in all ecological systems that (A) disturbance effects are spatially and temporally sporadic, and (B) that just as this environmental change and heterogeneity is ongoing, so will species and population have ever-readjusting and differential responses, some problems with the strictly developmental scheme of vegetation change emerge. These shortcomings are discussed particularly as they hamper accurate interpretation of a patchy mosaic ecotone.

Convocation Year

1982

Convocation Season

Fall

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