| Summary: | Extensive hydroelectric facilities were constructed in the upper watershed of Labrador's Churchill River during the 1960's and 70's. Two additional dams and generating stations are now planned for the lower reaches of the river. Despite the fact that cumulative effects assessment is a legal requirement under Canadian law, and is expected by people who hold aboriginal title to the land and wish to take a highly precautionary approach to further industrial development, environmental research to date has been restricted to a very narrow temporal and spatial scope, virtually ignoring changes that have already occurred throughout watershed. River shorelines and their ecosystems are important parts of ecological and cultural landscapes and are always considerably changed by large-scale river regulation. The objective of this study is to demonstrate that despite the lack of formal data collection in the past, a rich understanding of patterns of change in the hydrological regimes and riparian vegetation communities of the Churchill River can be attained, and can contribute to a meaningful understanding of the cumulative effects of hydroelectric development. Labrador Innu and Inuit/Metis shared empirical observations of changes in the river shorelines, and offered personal opinions about the significance of these changes. They also participated in botanical survey work in several reaches of the main stem of the river to collect data on riparian plant communities. Existing hydrological records were analyzed to relate pre-and post-development flow patterns to plant species richness and cover. Historical observations by travelers and scientists, time series air and ground photography, and research on the effects of flow regulation on riparian habitats in other boreal regions also informed the study. Hydroelectric development has already had extensive and severe effects on the riparian zones of the river. It has reduced biodiversity, especially in the reservoirs, and has destroyed places of cultural value. Land use along several affected river corridors, as well as the traditional knowledge that developed within these riverine landscapes has been eroded. The river valley riparian zones downstream of the existing power stations have been altered, but continue to maintain substantial ecological and cultural integrity. The construction of additional dams on the lower Churchill River would further decrease the structural complexity and species richness of riparian zones, and flood almost all remaining sites of cultural significance along the main stem shores of the river. Thesis (Ph.D.)--Dalhousie University (Canada), 2007.
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