Fishes, particularly parrotfishes (Scaridae), are the dominant herbivores on Caribbean coral reefs. Recent literature has focused heavily on the foraging behavior of parrotfishes, while little attention has been paid to role of territoriality in driving the spatiotemporal scales at which this foraging occurs. The effect of herbivores on benthic coral reef communities likely depends upon the spatiotemporal scales at which they forage. We hypothesize that (1) territoriality among terminal phase, male parrotfish will constrain their foraging, and that (2) this will lead to spatial patterns in benthic community structure on coral reefs. We are using a movement ecology framework and applying spatial statistics to elucidate the role of parrotfish territoriality in mediating trophic interactions on fringing coral reefs in Bonaire, Netherlands. In January and May – July 2019, we tracked individuals of five common parrotfishes at five fringing reefs and analyzed the movement trajectories of each individual. Kernel density estimation (KDE) using least squares cross-validation bandwidth optimization was used to estimate home range area, and we modeled the relationship between movement patterns and characteristics of benthic and fish community structure.
Results/Conclusions
We found that mean home range size varied significantly by species (p < 0.001) but that there were no differences in home range sizes among sites. Additionally, we found no relationship between home range sizes and site scale characteristics of the benthic (e.g., coral cover and macroalgal cover) and fish (e.g., conspecific parrotfish densities) communities. In order for territorially-constrained grazing to affect spatial patterns in the benthic community, there needs to be some degree of territorial permanency. We found that the locations of individual home ranges were consistent through time, as evidenced by high overlap (40-60%) among KDE home range estimates of individuals tracked in January and again in the summer, as well as of individuals repeatedly tracked during our May – July sampling effort. Additionally, we found that while intraspecific home range overlap was low, there was high interspecific home range overlap. This may indicate high intraspecific competition relative to interspecific interactions. Territoriality, trophic interactions, and resource partitioning among species will be discussed in the context of these patterns.