Response to Sheppard, C. Atoll Rim Expansion or Erosion in Diego Garcia Atoll, Indian Ocean? Comment on Hamylton, S.; East, H. A Geospatial Appraisal of Ecological and Geomorphic Change on Diego Garcia Atoll, Chagos Islands (British Indian Ocean Territory). Remote Sens. 2012, 4, 3444–3461

Sarah Hamylton,Holly East

doi:10.3390/rs6032468

Abstract

We welcome Sheppard’s comments on our recent assessment of both ecological and geomorphic change at Diego Garcia Atoll in the central Indian Ocean [1]. Whilst our assessment incorporated numerous aspects of change, including movements of the lagoon rim shorelines, changes in the terrestrial vegetation on the lagoon rim and amendments to the bathymetry of the lagoon basin through dredging activities [2], this comment solely addresses the estimates of shoreline change. Here we make some brief remarks relating to this shoreline assessment of Diego Garcia and elaborate on some of the complexities of the geomorphic processes that underpin shoreline dynamics. These complexities have important implications for understanding reef island shoreline dynamics, both at this site and globally.

Highlights

Whilst our assessment incorporated numerous aspects of change, including movements of the lagoon rim shorelines, changes in the terrestrial vegetation on the lagoon rim and amendments to the bathymetry of the lagoon basin through dredging activities [2], this comment solely addresses the estimates of shoreline change
We make some brief remarks relating to this shoreline assessment of Diego Garcia and elaborate on some of the complexities of the geomorphic processes that underpin shoreline dynamics
It is often the case that historical maps and aerial photographs represent the only available record of past reef island shorelines and, while these are of differing scales and quality [5] they offer the best opportunity available for determining reef island change over time [6]

Summary

Introduction

Change on Diego Garcia Atoll, Chagos Islands We welcome Sheppard’s comments on our recent assessment of both ecological and geomorphic change at Diego Garcia Atoll in the central Indian Ocean [1]. The contrast between our estimations of shoreline change at Diego Garcia and Sheppard’s in situ observations appears to be overstated.

Results

Conclusion