PhD Candidate, James Cook University and ARC Centre of Excellence for Coral Reef Studies
How will coral bleaching impact coral reef fishes?
Territorial damselfish play a key role in the structure of coral reefs through their influence as small-bodied consumers, abundant holders of space, and aggression. Their competitive and feisty behavior keeps reefs healthy and diverse by influencing other bottom-feeding fish through unwelcomed management of who gets dinner where. By looking at competition and the ecological characteristics of damselfish on healthy and degraded reefs, we can better understand how these species influence the underwater community as a whole. This is becoming more important on the Great Barrier Reef as the frequency of cyclones and other climate change associated threats increase. Lizard Island, GBR offers a rare natural laboratory to compare degraded reefs, hit by two cyclones, to healthy reefs within a close proximity. Using these comparisons, ecological surveys, and competition experiments, this project addresses novel questions about how the ecology of damselfish is altered by habitat loss and the resulting community effects.
Effects of physical disturbance (e.g., cyclones, hurricanes) on benthic composition has been well documented in coral reefs around the world (Hughes 1994; Russ 2003; Hughes et al. 2007; Mumby 2009). Long term data has been widely used to assess the impacts of these events to examine community dynamics of coral reefs (Hughes and Connell 1999). However, the majority of these projects survey reefs for abundance and distribution and lack understanding on how ecological parameters change when a disturbance happens. By focusing on one guild of fishes extensively, this project addresses if and how fish may alter their resource use and their versatility post-disturbance. Coral reef fishes are known to represent both ends of the ecological versatility spectrum, referred to as specialists and generalists, but there is limited knowledge to the extent of if species can switch (or become more versatile) after a heavy impact (but see Berkström et al. 2012, 2014). Territorial damselfish are typically classified as specialists with a defined niche breadth but this may be problematic as results are typically derived from projects that focus on a single location or homogenous habitats (Brown 1984; Wilson and Bellwood 1997; Ceccarelli 2007). By comparing damselfish ecology on recently degraded reefs to healthy reefs within a similar geographic location, this project uniquely addresses their versatility and how this may affect other species through competition.