Assessing climate hotspots and refugia for ecologically and culturally important species around the TN and AN Marine Protected Areas

Climate change effects are of concern in the Canadian Arctic as ocean warming, sea ice melting, and acidification have profound effects on marine ecosystems and the associated human communities. Marine spatial planning, including the designation of marine protected areas (MPAs), help manage the spatial and temporal distribution of human activities in marine areas to achieve ecological, economic, and social objectives. However, as anthropogenic changes impact the ocean ecosystems into the future, the purported benefits of MPAs may be threatened. This study aims to examine the impacts of climate change on marine mammal, fish, and invertebrate species in the Canadian Beaufort Sea and Amundsen Gulf to inform the climate risks and vulnerabilities in the Inuvialuit Settlement Region and the Tarium Niryutait (TN) and Anguniaqvia niqiqyuam (AN) MPAs. The exchange and co-development of knowledge through consultations with key stakeholders and committees ensured Indigenous interests were upheld in this study. We combined spatially-explicit climatic hazard indicators assessed using a fuzzy log-based algorithm with biodiversity impacts projected from species distribution modelling. We analyzed the exposure of marine species and their habitats to climatic hazards due to increasing temperature, decreasing sea ice cover, freshening, decreasing oxygen concentration, acidification, and changing net primary production by 2050 (average of 2041–2060) and 2090 (average of 2081–2100) under two Shared Socio-economic Pathways (SSP) 1–2.6 (SSP1–2.6) and SSP5–8.5. We then applied species distribution models to project the effects of the environmental variables on the habitat suitability of the species occurring in and adjacent to the Inuvialuit Settlement Region and the TN and AN MPAs. We identified areas that are projected to face large climatic hazards and risks, and decrease in habitat suitability across species as potential climate ‘hotspot’ and the contrary as ‘refugia’. Specifically, the results indicated shallow areas of the Beaufort Sea shelf are typically projected to face large climatic hazards, and are a hotspot for habitat suitability for fish species. Areas for habitat refugia were identified in northern deeper waters near the Prince of Wales Strait. Beluga whales, a key culturally important species, are projected to gain in habitat suitability with the warming shallow waters during their summer migration and calving by the mid-21^st century. Lastly, the potential migration of new species, and range constriction of resident species (e.g. Arctic cod), may alter the biodiversity and community structure of the region. The results were communicated to Indigenous People, the government, and other stakeholders in the Canadian Arctic to inform them about the potential climate impacts and adaptations for human communities through the effects on species that are important for food, livelihood, and cultural security. The model findings reveal valuable insights on the risk of climate change on biodiversity, the integration of climate change into adaptation plans, and build resilience for marine spatial planning in the Canadian Arctic, Inuvialuit Settlement Region, and the TN and AN MPAs under climate change.