Predatory walls may impair climate warming‐associated population expansion

Abstract

Climate change has a profound impact on species distribution and abundance globally, as well as local diversity, which affects ecosystem functioning. In particular, changes in population distribution and abundance may lead to changes in trophic interactions. Although species can often shift their spatial distribution when suitable habitats are available, it has been suggested that predator presence can be a constraint on climate‐related distribution shifts. We test this using two well‐studied and data‐rich marine environments. Focusing on a pair of sympatric fishes, Atlantic haddock Melanogrammus aeglefinus and cod Gadus morhua, we study the effect of the presence and abundance of the latter on the former distribution. We found that the distribution of cod and increased abundance may limit the expansion of haddock to new areas and could consequently buffer ecosystem changes due to climate change. Though marine species may track the rate and direction of climate shifts, our results demonstrate that the presence of predators may limit their expansion to thermally suitable habitats. By integrating climatic and ecological data at scales that can resolve predator–prey relationships, this analysis demonstrates the usefulness of considering trophic interactions to gain a more comprehensive understanding and to mitigate the effects of climate change on species distributions.

Decadal changes in biomass and distribution of key fisheries species on Newfoundland’s Grand Banks

“…On the other hand, predators like Atlantic cod can play a regulatory role in shaping prey populations. In the Barents Sea, Atlantic cod has been identified as a regulator of the snow crab population, impacting both its distribution and productivity [ 81 , 82 ]. A comparable phenomenon could potentially exist between these species on The Grand Banks.…”

Northeast Atlantic fish stock productivity hindcasts and forecasts from a Bayesian framework reveal pronounced climate‐induced dynamics

“…In contrast to expectations, we were, however, unable to detect different loadings for Northeast Arctic cod and haddock ( Melanogrammus aeglefinus , Gadidae); the higher cod abundance in a warmer Barents Sea should negatively affect the abundance of the sympatric haddock (Durant et al., 2020). Consequently, this ‘predatory wall’ may impair the ocean warming‐induced distribution expansion of haddock (Durant et al., 2023). These types of species interactions underscore the intricate web of relationships in marine ecosystems, and we have so far limited understanding of their impact on stock productivity.…”