Quantifying acceptable levels of visitor use on Red Sea reef flats

Abstract

Abstract The effects of trampling by visitors walking over the reef flat to snorkel or swim along the reef edge were studied at Ras Um Sidd, a popular fringing reef site at Sharm El Sheikh, and in the Ras Mohammed National Park, South Sinai, Egypt. Twelve stations showed a sequence of events linked to increased frequency and extent of trampling, with the intensities of trampling ranging from 0.1 to 324 tramplers m−2 yr−1. Heavily trampled stations had a reduced coral cover (in particular branching corals), higher amounts of coral damage, less old dead coral, less obligate corallivorous fishes and more herbivores. Wave exposure was crucial in determining the susceptibility of coral communities to trampling. Exposed communities were dominated by branching corals and were mechanically more resistant, since wave stress had favoured stockier growth forms. The applicability of the ‘carrying capacity concept’ was investigated as a management tool for determining how much use is sustainable. Examination of the relationship between hard coral cover and intensity of trampling suggested that carrying capacity could be set at approximately 50 tramplers m−2 yr−1. The actual amount of damage caused by trampling showed a linear increase with increasing trampling intensities, so that the carrying capacity concept, as defined in this study, was not applicable to the relationship since no threshold existed. Instead, the ‘limits of acceptable change’ approach would be more practicable, with managers deciding what amount of coral damage they permit before limiting access. To establish meaningful limits of change, more knowledge is required about ecological as well as social consequences (e.g. visitor satisfaction) of such limits. Copyright © 2007 John Wiley & Sons, Ltd.