Significant effect of human trampling on subtidal seagrass beds

Human trampling in subtidal nearshore waters is often an unavoidable consequence of routine activities carried out by local people living in small islands, especially during low tide. An experiment was conducted around Barrang Lompo Island in South Sulawesi, Indonesia to determine the effect of human trampling on the multi-species subtidal seagrass beds. Two daily trampling treatments (by an adult and by children) were applied to seagrass beds for about two weeks. Seagrass density was significantly decreased by human trampling, although the impact of trampling by an adult and by children was not significantly different. In terms of leaf loss, the seagrass most heavily impacted by trampling activities was Cymodocea rotundata which was also the densest species. Two species were significantly differently affected by adult and children trampling: Syringodium isoetifolium leaf loss was much higher when trampled by children, while Halodule uninervis suffered much more from uprooting and rhizome damage when trampled by an adult. The results suggest that daily human trampling activities can potentially cause significant damage to seagrass communities, with the extent of damage determined mostly by the properties and relative abundance of each species rather than differences in tramply by adults and children. This indicates a need for further research on the relationship between the specific traits of seagrasses and environmental factors that influence seagrass response to and recovery from mechanical disturbances such as trampling. Key Words: human trampling, subtidal, Cymodocea rotundata, Syringodium isoetifolium, Halodule uninervis.