Diego Lirman and Stephanie A. Schopmeyer

Occupation dynamics and impacts of damselfish territoriality and gardening activities on recovering populations of the threatened staghorn coral Acropora cervicornis

2016

University of Miami

"Large-scale coral and coral reef restoration are needed to help recover lost structure and function of degraded coral reef ecosystems. Active coral propagation and reef restoration efforts have scaled up significantly in past decades, particularly for the threatened Caribbean staghorn coral, Acropora cervicornis, to the point where 10,000s of nursery-grown staghorn corals are outplanted onto Florida reefs yearly. While we have developed best practices for the propagation and outplanting process, limited attention has been focused on the fate of corals once they are back onto the wild reefs and the factors that influence their growth and survivorship once outplanted. One of the research gaps identified is the role that native predators, such as farming damselfishes, have on the success of coral outplanting and reef restoration. This is the first study to document the prevalence of resident damselfish and significant negative effects of algal lawns on A. cervicornis along the Florida Reef Tract. Impacts of damselfish lawns on A. cervicornis colonies were more prevalent than those of other sources of mortality (i.e., disease, predation, and algal/sponge overgrowth), and damselfish activities caused the highest levels of tissue mortality among all the coral stressors evaluated. The presence of a resident damselfish decreased predation by other corallivores, but coral growth rates were significantly lower in colonies with damselfish lawns and the probability of the existence of a damselfish lawn increased as coral colony size and complexity increased. Lower predation by damselfish and other corallivores was documented within protected zones indicating management strategies may alleviate some predation pressure. While the rates of damselfish occupation and creation of algal lawns observed raise concern for the survival of impacted colonies, the long-term success of active restoration programs designed to enhance staghorn coral populations can drastically increase local populations and may allow A. cervicornis to continue to fulfill critical functional roles on local coral reefs. The effects of damselfish predation are, and will continue to be, pervasive, but innovative restoration efforts and strategic outplanting designs may help overcome damselfish damage over time while also providing important information to educate future conservation and management decisions."

FY2013; CRCP Project ID: 198; Project Title: Domestic Coral Reef Conservation Grant Programs; Principal Investigator: Jenny Waddell; Grant Number: NA13NOS4820017