Coral Conservation Counts: Evaluating the Accuracy of Citizen Science Surveys in Hawaiian Coral Reefs

Abstract

As coral reef cover declines globally due to climate change and anthropogenic stressors, accurate survey methods are necessary to collect coral data and inform conservation efforts. However, current methods exhibit a tradeoff between resource efficiency and taxonomic detail. Utilizing citizen science for coral reef surveying has been proposed as a resource-efficient technique to gather both wide-scale and detailed coral reef data. Studies have demonstrated promising results in locations such as the Great Barrier Reef but have yet to thoroughly evaluate the method in other reef ecosystems such as those in Hawaii. This study investigated the accuracy of citizen scientists in identifying coral coverage for five types native to the Hawaiian archipelago – antler, cauliflower, finger, lobe, and rice coral. By comparing citizen scientist cover estimates to expert estimates, this study found that citizen scientists can measure all individual coral types and total coverage within 20% accuracy of expert estimates, an ecologically acceptable range. Antler, cauliflower, finger, and rice coral all fell within 5% of expert values while lobe coral exhibited the greatest overestimation at 14.9%. Additionally, most coral types reached a ±0.05 precision threshold in less than 50 images while lobe coral and total cover did not reach this threshold at any number with the given dataset. While a larger dataset is required to draw definitive conclusions, these preliminary findings suggest that citizen science is a promising tool to accurately survey Hawaiian coral reefs and support conservation efforts.