Abstract
Asymmetries in responses to climate change have the potential to alter importantpredator–prey interactions, in part by altering the location and size of spatial refugiafor prey. We evaluated the effect of ocean warming on interactions between fourimportant piscivores and four of their prey in the U.S. Northeast Shelf by examiningspecies overlap under historical conditions (1968–2014) and with a doubling in CO2.Because both predator and prey shift their distributions in response to changingocean conditions, the net impact of warming or cooling on predator–prey interac-tions was not determined a priori from the range extent of either predator or preyalone. For Atlantic cod, an historically dominant piscivore in the region, we foundthat both historical and future warming led to a decline in the proportion of preyspecies’ range it occupied and caused a potential reduction in its ability to exerttop-down control on these prey. In contrast, the potential for overlap of spiny dog-fish with prey species was enhanced by warming, expanding their importance aspredators in this system. In sum, the decline in the ecological role for cod thatbegan with overfishing in this ecosystem will likely be exacerbated by warming, butthis loss may be counteracted by the rise in dominance of other piscivores withcontrasting thermal preferences. Functional diversity in thermal affinity within thepiscivore guild may therefore buffer against the impact of warming on marineecosystems, suggesting a novel mechanism by which diversity confers resilience.