Recovery of the endangered Caribbean staghorn coral Acropora cervicornis following predation by the fireworm Hemodice carunculata in teh Florida Keys National Marine Sanctuary: testing intervention strategies to mitigate damage and increase survivorship
The staghorn coral Acropora cervicornis was historically one of the principal branching reef-building species in the Caribbean, and was once a dominant species in shallow reefs of the Florida Keys. However, over the last ~35 years, white band disease, hurricanes, bleaching, corallivorous predation, and additional anthropogenic impacts such as sedimentation, have all contributed to its decline. For this project I tested the effectiveness of human intervention to mitigate and increase the recovery potential of 16 colonies of A. cervicornis after an episode of heavy predation by the fireworm Hermodice carunculata. Installing a wire shield over preyed tips did not have a significant influence on colony recovery, but removing the preyed branch tips entirely decreased the time of recovery by 50% compared to untreated controls. This suggests that removing dead tips, rather than leaving them to bioerode, is a useful strategy to increase A. cervicornis recovery from predation. A survival analysis of photographs from 2011, 2012 and 2013 indicated a probability of ~60% that preyed tips were not healed after 130 days of monitoring. The mean time to healing for natural recovery was about 110 days +/- 6 days (95% confidence). For human-influenced recovery, the mean time to formation of an apical tip was 46 days (range: 22 – 92 days). In 2013, 80% of the branches whose tips had been cut showed signs of re-growth, while only 16.5% of the control branches which had not been cut showed signs of healing. Manually cutting the preyed branches may help increase the survivorship and/or growth of coral nursery and restoration projects. Future work should continue to monitor the influence of predation on A. cervicornis and assess the effectiveness of this mitigation strategy over a longer period of time. A greater understanding of the biology and ecology of Hermodice carunculata would also help assess the relationship between corals and fireworms.
Marmet, Christina, "Recovery of the endangered Caribbean staghorn coral Acropora cervicornis following predation by the fireworm Hemodice carunculata in teh Florida Keys National Marine Sanctuary: testing intervention strategies to mitigate damage and increase survivorship" (2013). Internship Reports (Restricted). 181.
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