MEPS 463:73-87 (2012)  -  DOI: https://doi.org/10.3354/meps09858

Species diversity, functional complexity and rarity in Arctic fjordic versus open shelf benthic systems

Maria Włodarska-Kowalczuk1,*, Paul E. Renaud2, Jan Marcin Węsławski1, Sabine K. J. Cochrane2, Stanislav G. Denisenko3

1Institute of Oceanology PAS, Powstańców Warszawy 55, 81-712 Sopot, Poland
2Akvaplan-niva, Fram Centre for Climate and Environment, N-9296 Tromsø, Norway
3Zoological Institute RAS, Universitetskaya nab. 1, 199034 St Petersburg, Russia

ABSTRACT: We present a cross-system comparison of benthic species pools, species diversity, functional complexity and rarity in 2 typical Arctic coastal systems: an open shelf marginal sea and fjords (semi-enclosed, geologically younger basins remaining under strong terrestrial influences). A total of 388 van Veen grab samples were collected in the Barents Sea and 3 west Spitsbergen fjords (divided into inner and outer basins). Thirty percent of species were recorded only in fjords, questioning the common notion of the fjordic communities being merely subsets of the offshore species pools. Inner fjords, outer fjords and the open shelf hosted communities that differed significantly in terms of species composition and diversity. Species richness, examined at the scales of both the ecological zone and an individual sample, was severely depleted in inner fjordic basins. The congruence of the patterns across taxonomic groups employing different life histories (benthic vs. pelagic dispersal) pointed to habitat deterioration rather than dispersal barriers as a factor responsible for the fjordic diversity clines. The between-habitat differences in functional diversity were expressed in decreased functional evenness and a decline in suspension-feeding, sedentary and large tube-dwelling species in fjords, affecting infaunal habitat complexity. Species redundancy declined across the shelf−outer fjord−inner fjord environmental gradients, suggesting a higher resilience of shelf systems. The environmental deterioration of fjordic basins did not result in the reduction of rare species. These results should be applied to strategies for managing open shelf and fjordic habitats in the Arctic.


KEY WORDS: Biodiversity · Rarity · Functional diversity · Redundancy · Benthos · Arctic


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Cite this article as: Włodarska-Kowalczuk M, Renaud PE, Węsławski JM, Cochrane SKJ, Denisenko SG (2012) Species diversity, functional complexity and rarity in Arctic fjordic versus open shelf benthic systems. Mar Ecol Prog Ser 463:73-87. https://doi.org/10.3354/meps09858

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