Habitat model forecasts suggest potential redistribution of marine predators in the southern Indian Ocean

International audienceAim: Climate change will likely lead to a significant redistribution of biodiversity inmarine ecosystems. We examine the potential redistribution of a community of marinepredators by comparing current and future habitat distribution projections. Weexamine relative changes among species, indicative of potential future community-levelchanges and consider potential consequences of these changes for conservationand management.Location: Southern Indian Ocean.Methods: We used tracking data from 14 species (10 seabirds, 3 seals and 1 cetacean,totalling 538 tracks) to model the habitat selection of predators around thePrince Edward Islands. Using random forest classifiers, we modelled habitat selectionas a response to a static environmental covariate and nine dynamic environmental covariates obtained from eight IPCC-classclimate models. To project the potentialdistribution of the predators in 2071–2100,we used climate model outputs assumingtwo greenhouse gas emission scenarios: RCP 4.5 and RCP 8.5.Results: Analogous climates are projected to predominantly shift to the southeast andsouthwest. Species’ potential range shifts varied in direction and magnitude, but overallshifted slightly to the southwest. Despite the variable shifts among species, currentspecies co-occurrencepatterns and future projections were statistically similar.Our projections show that at least some important habitats will shift out of nationalwaters and marine protected areas by 2100, but important habitat area will increasein the Convention on the Conservation of Antarctic Marine Living Resources Area.Predicted areas of common use among predators decreased north of the islands andincreased to the south, suggesting that multiple predator species may use southerlyhabitats more intensively in the future. Consequently, Southern Ocean managementauthorities could implement conservation actions to partially offset these shifts.Main conclusions: Overall, we predict that marine predator biodiversity in the southernIndian Ocean will be redistributed, with ecological, conservation and managementimplications