Abstract

Monitoring programmes are an important component in the conservation, management and sustainable use of coral reef ecosystems. In this study, the performance of the photoquadrat (PQ) method adopted by the newly re- activated Global Coral Reef Monitoring Network (GCRMN – Caribbean) was compared against the linear point intercept (LPI) method utilized by the long-term Barbados Reef Survey Programme, in order to make an informed decision on whether or not the PQ protocol should be adopted. Fifteen sites across bank, fringing and patch reefs were surveyed using both methods concurrently, and (1) the percent cover of major benthic categories, (2) species diversity and (3) time required to obtain data in usable form were compared. At a coarse scale the methods produced broadly similar results (e.g. same importance ranking of key benthic categories across reef types), however, at a more detailed level, results differed significantly depending on major benthic category and reef type. The PQ method detected fewer species, lower percent cover of hard corals, sponges and macroalgae, and higher percent cover of gorgonians, encrusting algae and turf algae than the LPI method. Furthermore, whilst data collection times in the field were similar between PQ and LPI, analysis of the photographs took, on average, double the time needed for LPI data entry. As the differences between methods are not limited to the method itself, but dependent on benthic category and reef type, the two methods are not easily comparable. As such, we warn against transition between these two methods in long-term reef survey programmes.

PDF Preview