Zoobenthic communities on hard-bottom habitats in Kongsfjorden, Svalbard

摘要

Arctic hard-bottom locations are habitats for a variety of benthic organisms, which have been described by species occurrence, abundance, or biomass. However, only few studies have included descriptions of communities on such locations in the Arctic, whereas this has been frequently done for soft-bottom communities. Thus, the focus of this study is to determine a limited number of characteristic zoobenthic communities that occupy Arctic shallow subtidal habitats on hard-bottom locations in Kongsfjorden, Svalbard. The habitats at these locations graded from bedrock near the surface to mixed bottom with pockets of loose gravel and sediments deeper. Samples were collected by divers in August and September 1996 and 1998 from two square frames (0.25 m(2)) from each of the depths 0-2.5-5-10-15-20-25-30 m at all transects except JUTT (max. 15 m) and OSSI (max. 5 m). Seven communities were identified after considering species dominance, similarity between species associations, and the potential role of conspicuous species in the communities. The communities were described as: 1-Amphipoda community; 2-Symplectoscyphus community; 3-Branched bryozoans community; 4-"Developed fauna" community; 5-"Impoverished fauna" community; 6-Balanus community; and 7-Bivalvia community. Segregation of communities was based on species dominance (biomass), as confirmed by multivariate analyses. Species primarily responsible for the establishment of communities were determined, and particularly the importance of barnacles (Balanus balanus) and Branched bryozoans (Eucratea loricata and Tricellaria ternata) is discussed. Macroalgae were of less importance for identification of communities and distributional patterns of zoobenthos.