Reefscapes of fear assess tradeoffs of risk and reward on coral reefs

Degradation of coral reef habitats changes the abundance and community composition of fishes due in part to changes in the ecology of fear. The ecology of fear sees the predator-prey system as a dynamic game of behavioral responses to perceived risk with population and community level consequences. We measure spatial variation in predation risk as landscapes of fear. We consider changes in predation risk with habitat quality and examine the effects of fear on coral reefs in Kāne‘ohe Bay, O‘ahu, Hawai‘i. First, we associate fish and benthic communities on patch reefs with varying degradation due to invasive algae (Euchema spp. and Kappaphycus spp.). Next, we quantify the spatio-temporal variation of risk (reefscape of fear) of a common Hawaiian fish (saddle wrasse, hīnālea lau wili, Thalassoma duperrey) across reefs of varying degradation. Finally, we assess the tradeoffs in resource availability and predation risk on these reefs. At the scale of whole reefs, saddle wrasse responded to perceived risk. Intensity of patch use (measured by giving-up densities) by wrasse indicated risky reefs. Such reefs differed in benthic and fish community composition. We demonstrated the impact of an altered reefscape of fear due to habitat degradation. Habitat degradation seems to influence the tradeoff between resource availability and safety. From wrasse abundances and their patch use behavior we can classify the reefs into categories based on risk and resource availability. Allowing fish to reveal their perceptions of habitat qualities through their behaviors provides critical information for assessing and monitoring reefs.