ARPHA Preprints, doi: 10.3897/arphapreprints.e97321
The impacts of the invasive lionfish on Caribbean food webs
expand article infoCourtney Tiffany Cameron, Peter D. Roopnarine§
‡ University of California, Irvine, Irvine, United States of America§ California Academy of Sciences, San Francisco, California, United States of America
Open Access

Increased rates of species extirpation or extinction have often been attributed to the foraging behavior of invasive predators, with drastic effects on native food webs. In the Caribbean, the invasive red lionfish (Pterois volitans) is of primary concern, as it reduces the overall recruitment and biomass of reef fishes by as much as 80% and 65%, respectively. Understanding the functional role that this predator plays in the context of entire communities is critical to assessing how it impacts those that have already experienced regime shifts due to disturbance. Here, a trait-based ecospace was employed to characterize the functional role of red lionfish trophic behavior, focusing on a regional pool of reef fishes from Jamaica, Cuba, and the Cayman Islands. A high-resolution model of a Greater Antilles coral reef food web, including micro- and macrobiota, producers and consumers, and invertebrates and vertebrates, was used to assess the impacts of P. volitans on community structural parameters such as food chain length, the number of interactions, modularity, and trophic position. Results indicate that lionfish select prey based on specific traits, foraging primarily on those that are diurnal, below a threshold of total length, occur higher in the water column, do not possess a physical defense, and are either herbivorous, invertivorous, or omnivorous. The functional role of lionfish significantly overlaps with a number of endemic high trophic level predators, such as Rhizoprionodon porosus, Negaprion brevirostris, and Scomberomorus regalis. Lionfish could be fulfilling trophic roles previously vacated by extirpated species, as the prey of the lionfish were found to be functionally indiscriminate relative to those of extirpated predators such as Sphyrna tiburo, Carcharhinus acronotus, and Galeocerdo cuvier. In addition, food web results suggest that lionfish alter the trophic dynamics of the entire reef community by increasing the total number of interactions and changing trophic level structure. Interestingly, the invasive lionfish may be restoring and augmenting some effects of predation otherwise lost to species extirpation, providing an alternative view to its detrimental effects on resilience of Caribbean marine systems.

Caribbean Sea, food webs, functional diversity, invasive species, lionfish, trophic behavior