Genetic hotspots for conserving Southern Ocean benthic biodiversity

As climate change intensifies, maintaining genetic diversity of natural populations is crucial to safeguard ecosystem integrity and adaptive potential. The Southern Ocean encompasses 10% of the Earth’s oceans 1 1. CCAMLR Convention area Commission for the Conservation of Antarctic Marine Living Resources, 2018 https://www.ccamlr.org/en/organisation/convention-area Google Scholar and contains a taxonomically diverse ecosystem with an extraordinarily high level of endemism (50%–90%). 2 2. Griffiths, H.J. ∙ Barnes, D.K.A. ∙ Linse, K. Towards a generalized biogeography of the Southern Ocean benthos J. Biogeogr. 2009; 36 :162-177 Crossref Scopus (194) Google Scholar , 3 3. Brandt, A. ∙ Gutt, J. Biodiversity of a unique environment: the Southern Ocean benthos shaped and threatened by climate change Zachos, F.E. ∙ Habel, J.C. (Editors) Biodiversity Hotspots: Distribution and Protection of Conservation Priority Areas Springer Berlin Heidelberg, 2011; 503-526 Crossref Google Scholar , 4 4. De Broyer, C. ∙ Danis, B. How many species in the Southern Ocean? Towards a dynamic inventory of the Antarctic marine species deep sea res. II. 2011; 58 :5-17 Crossref Scopus (124) Google Scholar As one of the fastest-changing regions on Earth, the Southern Ocean is currently under threat from climate change 5 5. Abram, N.J. ∙ Purich, A. ∙ England, M.H. ... Emerging evidence of abrupt changes in the Antarctic environment Nature. 2025; 644 :621-633 Crossref Scopus (14) PubMed Google Scholar and anthropogenic stressors, including fishing and tourism. 6 6. Wenzel, L. ∙ Gilbert, N. ∙ Goldsworthy, L. ... Polar opposites? Marine conservation tools and experiences in the changing Arctic and Antarctic Aquatic Conservation. 2016; 26 :61-84 Crossref Scopus (25) Google Scholar Targeted marine protected areas (MPAs) are popular and effective mechanisms for limiting anthropogenic stressors in sensitive marine ecosystems. 7 7. Costello, M.J. ∙ Ballantine, B. Biodiversity conservation should focus on no-take Marine Reserves: 94% of Marine Protected Areas allow fishing Trends Ecol. Evol. 2015; 30 :507-509 Full Text Full Text (PDF) Scopus (205) PubMed Google Scholar Approximately 78% of Southern Ocean species are benthic invertebrates, 4 4. De Broyer, C. ∙ Danis, B. How many species in the Southern Ocean? Towards a dynamic inventory of the Antarctic marine species deep sea res. II. 2011; 58 :5-17 Crossref Scopus (124) Google Scholar and most modern benthic taxa radiated in situ over the last 14 million years, 8 8. Crame, J.A. Key stages in the evolution of the Antarctic marine fauna J. Biogeogr. 2018; 45 :986-994 Crossref Scopus (44) Google Scholar alongside adaptation to withstand polar conditions. 9 9. Morley, S.A. ∙ Barnes, D.K.A. ∙ Dunn, M.J. Predicting which species succeed in climate-forced polar seas Front. Mar. Sci. 2019; 5 , 507 Crossref Scopus (40) Google Scholar However, their genetic information has not yet been synthesized across the region to determine priority areas for genetic conservation. Using a multi-species genetic landscape approach from 28 benthic marine invertebrate species examined at a population level, we identified hotspots of nucleotide diversity, haplotype diversity, genetic divergence, and genetic connectivity comprising 3,455,799 km 2 of the Southern Ocean. Only ∼28% of all identified genetic hotspots are currently being protected by established MPAs. Maintaining established and adopting proposed MPAs would protect ∼54% of all hotspots. The Southern Ocean is likely to face a high risk of ecosystem failure unless ecosystem resilience is sustained. 10 10. Constable, A.J. ∙ Harper, S. ∙ Dawson, J. ... Cross-Chapter Pörtner, H.-O. ∙ Roberts, D.C. ∙ Tignor, M. ... ... (Editors) In Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, 2023; 2319-2368 Google Scholar Targeted areas to safeguard Southern Ocean benthic biodiversity, informed by genetic knowledge, are now readily available for conservation assessments.