Grazing by herbivorous fish and echinoderms is an essential process in the maintenance of hard corals in coral reef ecosystems. Due to the vulnerable nature of the world’s coral reefs, quantifying grazing and shifts in benthic cover through time and space from remote sensors is essential to successful management of coral reefs. Using three high-resolution satellite images (World View 2, GeoEye, and Quickbird), this research seeks to quantify changes in the special extent of grazing in the South Water Caye Marine Preserve, Belize, from 2005 -2015.
Previous research, during the OEFS course, explored the methodologies associated with implementing water column corrections for shallow water coastal images. Water column corrections will be completed for each of the images based on refined depth data collected in the field during June 2015.
The proposed research will focus on two main objectives:
- to measure shifts in benthic cover from 2005-2015 and
- to quantify shifts in grazing halos surrounding coral patch reefs in continuous seagrass/macroaglae plains.
The analysis will be conducted using feature extraction and classification techniques, including supervised classifications using field-verified training regions. Specifically, this work is testing the hypothesis that the spatial extent of grazing is correlated with local predator abundance. Satellite-derived measures of grazing will be correlated with field-surveys of fish community structure, and historical data of shifts in fish community structure over the last 15 years.