Predicting habitat preferences for Anthometrina adriani (Echinodermata) on the East Antarctic continental shelf

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The comatulid crinoid Anthometrina adriani is well represented among the suspension-feeding megaepibenthos from the continental shelf of the Dumont D'Urville Sea, Antarctica. Nearly 500 specimens were sampled during the Collaborative East Antarctic Marine Census expedition onboard the RV 'Aurora Australis' (December 2007 to January 2008), from 50 of the 87 stations over a 400 km² area. Abiotic environmental factors were measured and an ocean circulation model was used to generate near-bottom parameters. The ecological niche of A. adri- ani was described by using ecological-niche factor analysis and Mahalanobis distances factor analysis. An environmental suitability map (ESM) was developed to map the optimal habitat. A. adriani prefers moderately deep and relatively cold waters with moderate current velocity, and a substrate with low gravel content and biogenic carbonate. The ESM shows 4 optimal regions: the eastern side of the George V Basin, the eastern side of the Adelie Basin, the southern part of the Adelie Bank, and the coastal area between the Astrolabe and Mertz glaciers. The ecological niche for A. adriani appears very narrow, but the species is widely distributed across the Antarctic shelf. It suggests that local changes in limiting factors have a strong local effect on the distribution of this species and that a total eradication of this species from the shelf would need an Antarctic-wide and synchronic change in these essential parameters. Modeling modifications in environmental conditions under different climate change scenarios could help predict the effect of such changes on the distribution of this selective species.