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Zoe Dewson

Doctor of Philosophy, (Ecology)
Study Completed: 2007
College of Sciences


Thesis Title
Small stream ecosystems and irrigation: An ecological assessment of water abstration impacts

Ms Dewson examined the impacts of water removal on aquatic invertebrates and ecosystem functioning in rivers and streams. The removal of water from streams, for uses such as irrigation and domestic water supply, is common in rural New Zealand and worldwide. Initially, the research focused on assessing the instream characteristics and invertebrate communities of streams with existing water extractions. In subsequent experiments, Ms Dewson used weirs and diversions to manipulate stream flow in small streams and tested the responses of invertebrates to decreases in flow over time. Findings showed that water extraction from streams can affect stream invertebrates. The research also demonstrated how stream water quality and the magnitude and duration of decreases in flow influence the outcomes of water removal for stream ecosystems. These results have implications for the sustainable management of water allocation from rivers and streams.

Professor Russell Death
Dr Ian Henderson

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