Forecasting climate-driven distribution shifts of small cetaceans in the North Atlantic Ocean using species distribution models

The effects of climate change on biodiversity have increasingly been investigated, although limited studies have attempted to predict species distribution shifts due to warming ocean temperatures, including some of the most mobile but vulnerable species in marine ecosystems. Due to their high trophic positions and high metabolic rates, small cetaceans (dolphins and porpoises) have the potential to have disproportionate effects on community and ecosystem dynamics. However, there have been limited attempts to predict how climate change could affect their distribution. Here, we assess how future climate scenarios may affect the distribution of small cetaceans across the fast-warming North Atlantic. We compiled the most comprehensive occurrence dataset to date using open-source databases and developed Species Distribution Models (SDMs) to project their distributions under three CMIP6 scenarios: ‘optimistic’ (SSP1–2.6), ‘intermediate’ (SSP2–4.5), and ‘pessimistic’ (SSP5–8.5). Our results reveal a consistent poleward shift in distribution by 2100. Significant range losses are projected in tropical zones, while subtropical and temperate regions are expected to emerge as key climate refugia. Species-specific responses highlight that broadly distributed temperate species are projected to expand their range, whereas strictly tropical or subpolar species will experience range contraction. Response from primarily cold temperate species show contrasting results, but primarily range expansion to subpolar waters by 2100. These findings underscore the urgent need to integrate climate projections and small cetacean redistributions into species and ecosystem-based management strategies in the North Atlantic Ocean. • We modeled current and future distributions of 12 small cetacean species in the North Atlantic. • Poleward redistribution of 12 small cetaceans is projected by 2100. • Small cetaceans exhibit contrasting responses among species. • Tropical regions may become less suitable, leading to possible desertification. • Temperate zones emerge as key refugia for an increasing number of species.