The effects of trampling on Hawaiian corals along a gradient of human use

Coral transplantation was used to evaluate the response of corals to trampling by determining growth and mortality at sites that ranged along a gradient of human use. Human use was measured with observational sampling. A clear progression of coral survivorship along the gradient was evident. Survivorship dropped from 70% at the low impact site to 55% at the medium impact site. Total loss (0% survivorship) was reported from the high impact site after only 8 months, equivalent to less than 200,000 total visitors or 63 people in the water per hour. Where transplanted corals survived, there was no difference in growth, presumably due to the control of activities of people in the water at those sites.