Data from: The impact of a range-shifting predator is affected by prey preference and composition

Global biodiversity is undergoing a grand reshuffling with species across
taxa and biomes shifting their ranges in response to climate change.
Research on the ecological impacts of range-shifting species has
prioritized linking the traits of the range-shifting species themselves to
impacts, with studies giving more limited attention to the characteristics
of the recipient community. Understanding how community composition and
structure can alter the impact of novel species is important for
predicting and managing ecological changes. We used the range-shifting
predatory whelk Mexacanthina lugubris as a case study to investigate how
the presence of shellfish prey might influence range shift impacts. We
hypothesized that the structure of a recipient community would influence
Mexacanthina lugubris’ consumptive effects. We tested this hypothesis via
a field experiment in southern California, where we caged whelks at a
gradient of densities and observed their predation on mussels, barnacles
living on bare rock, and barnacles living on mussels over eight weeks. We
found that Mexacanthina lugubris consumed barnacles on bare rock
preferentially before consuming barnacles on mussels and mussels
themselves. Our findings demonstrate that the composition and structure of
the recipient community (i.e., the presence of mussels) can mitigate the
overall impact of the range-shifting predator by altering prey
accessibility. This context-dependent attenuation of predator effects
highlights a form of apparent facilitation among prey and underscores the
importance of considering recipient community traits when assessing or
managing the ecological consequences of range-shifting species.