Author

Louisa Lovasz

Year

2022

Degree Name

Bachelor of Environmental Science (Honours)

Department

School of Earth, Atmospheric and Life Sciences

Advisor(s)

Kerrylee Rogers

Abstract

Changes in the extent of mangrove and saltmarsh in NSW has been associated with urbanisation, floodplain drainage, changes to tidal dynamics and wetland hydrology, and recent changes in sea level. These pressures are projected to increase in the coming decades in alignment with projected climate change and increasing coastal development, which will likely result in changes to the extent and composition of intertidal wetlands. Monitoring the effects of these pressures on wetland extent is essential for identifying management activities that maintain or improve delivery of ecosystem services. NSW Department of Primary Industries (DPI) Fisheries developed estuary specific Marine Vegetation Management Strategies (MVMS) under the Marine Estate Management Strategy (MEMS), to identify high priority areas of mangrove and saltmarsh, considering geophysical condition, current anthropogenic threats and risks, and vulnerability to sea-level rise. This study developed a systematic approach for assessing impacts and land cover change at high priority sites, identified in the MVMS, at Lake Illawarra and Minnamurra River using RPAs (remotely piloted aircraft i.e., drones) and traditional remote sensing techniques. Photogrammetry was highlighted as an important tool for managing areas of conservation priority. Structure-from-motion photogrammetry using RPAs provided high-resolution imagery to effectively identify impacts to mangrove and saltmarsh. These outputs were compared to historical aerial imagery, Nearmap, RapidEye, and LiDAR to detect change over time. Using RPAs for high priority areas closes the scale gap between aerial photography and ground-based fieldwork as RPAs allow for much greater detail than aerial photography and can cover greater spatial and temporal extents than field surveys. Based on results, a workflow was developed to recommend which data type should be used for mapping depending on the scale of impacts at the site and available resources. The results will help inform Fisheries (and other management agencies and local councils) on the areas best suited for cost effective rehabilitation work and contribute to DPI Fisheries vegetation monitoring protocols.

FoR codes (2020)

410402 Environmental assessment and monitoring

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.