Shears, NLawrence, Kaitlin2020-06-242019https://hdl.handle.net/2292/51731Full Text is available to authenticated members of The University of Auckland only.Kelp forests are one of the most diverse and productive ecosystems in the biosphere; however, they can be at risk of deforestation due to the indirect effects of overfishing whereby, the removal of predators results in an increase in sea urchins and the formation of urchin barrens. The production of habitat maps over long time scale provides a tool for examining large-scale changes in these ecosystems and understanding the effectiveness of different marine management strategies. In this study habitat maps were produced for three different locations in north eastern New Zealand using satellite imagery and remote sensing methods. These locations were all mapped in the 1970s and have since been managed with different regulations including a fully fished site (Mokohinau Islands), partial marine protection (Mimiwhangata) and a no-take marine reserve (Leigh). This provided a unique opportunity to examine the long-term response of reef habitats under different management regimes in north eastern NZ. Using satellite imagery, supervised classification of habitats was completed using GIS software. Ground truth imagery was also used in order to accurately assess results. The accuracy of the habitat maps produced ranged from 62% to 82% and was similar to studies using remote sensing methods of a similar nature. The maps provide an effective tool for long term comparisons in shallow rocky reef habitats, particularly urchin barrens. The extent of urchin barrens was found to increase significantly over time for fished and partially protected locations. Only the no-take marine reserve showed a clear decline in urchin barren extents over the almost 40-year time frame. Urchin barrens did however remain prevalent in shallow reefs outside the marine reserve. These findings further demonstrate the effects of fishing on reef ecosystems via trophic cascade and that these effects can be reversed in marine reserves. It highlights that partial protection does not achieve similar conservation outcomes as no-take reserves These mapping methods provide an effective tool for monitoring ecosystem change on shallow reefs. Given that these ecosystems may face further change over time from differing factors, habitat mapping should be used to continue to monitor these changes and inform management decisions.Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.Restricted Item. Full Text is available to authenticated members of The University of Auckland only.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmhttps://creativecommons.org/licenses/by-nc-sa/3.0/nz/ThesisCopyright: The authorQ112949155