Is the southern crab Halicarcinus planatus (Fabricius, 1775) the next invader of Antarctica?

• Published in: Global change biology 2021-08, Vol.27 (15), p.3487-3504
• Main Authors: López‐Farrán, Zambra, Guillaumot, Charlène, Vargas‐Chacoff, Luis, Paschke, Kurt, Dulière, Valérie, Danis, Bruno, Poulin, Elie, Saucède, Thomas, Waters, Jonathan, Gérard, Karin
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Aquatic habitats; Biodiversity; Biodiversity and Ecology; Climate change; Colonization; Crustaceans; Current distribution; Dispersal; Distribution; Ecological models; Environmental Sciences; establishment; Greenhouse effect; Greenhouse gases; Halicarcinus planatus; Human influences; Indigenous species; Introduced species; Invasive species; Life Sciences; Marine crustaceans; Marine invertebrates; Mathematical models; Mitigation; Modelling; Mussels; niche modelling; Niches; non‐native species; Probability theory; reptant crab; Shallow water; Shellfish; Shores; Southern Ocean; Survival; thermotolerance; Translocation
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/gcb.15674

The potential for biological colonization of Antarctic shores is an increasingly important topic in the context of anthropogenic warming. Successful Antarctic invasions to date have been recorded exclusively from terrestrial habitats. While non‐native marine species such as crabs, mussels and tunicates have already been reported from Antarctic coasts, none have as yet established there. Among the potential marine invaders of Antarctic shallow waters is Halicarcinus planatus (Fabricius, 1775), a crab with a circum‐Subantarctic distribution and substantial larval dispersal capacity. An ovigerous female of this species was found in shallow waters of Deception Island, South Shetland Islands in 2010. A combination of physiological experiments and ecological modelling was used to assess the potential niche of H. planatus and estimate its future southward boundaries under climate change scenarios. We show that H. planatus has a minimum thermal limit of 1°C, and that its current distribution (assessed by sampling and niche modelling) is physiologically restricted to the Subantarctic region. While this species is presently unable to survive in Antarctica, future warming under both ‘strong mitigation’ and ‘no mitigation’ greenhouse gas emission scenarios will favour its niche expansion to the Western Antarctic Peninsula (WAP) by 2100. Future human activity also has potential to increase the probability of anthropogenic translocation of this species into Antarctic ecosystems. No decapod is currently established in the shallow Antarctic coastal waters. Halicarcinus planatus (Brachyura, Hymenosomatidae) has been observed once in the Shetland Islands in 2010. Here, the thermotolerance of this crab is evaluated and demonstrated that H. planatus can not persist in Antarctica under the present extreme conditions; however, following IPCC climate prediction (RCP 8.5), in 2100, this species may find a suitable habitat in the Antarctic Peninsula. (a) Survival rate of H. planatus from cold to polar temperatures during 90 days. Probability, from 0 (yellow) to 1 (red), associated with H. planatus geographic distribution around the Antarctic Peninsula: under present conditions (b) and IPCC RCP 8.5 climate scenario (c).