The resilience of macrozoobenthos of boreal coastal lagoons to non-indigenous species invasion: A case study of Taman Bay (the Sea of Azov)

The aim of the present study is to reveal the consequences of the blood ark (Anadara kagoshimensis) invasion of Taman Bay (the Sea of Azov), one of the biggest boreal brackish coastal lagoon. Anadara kagoshimensis was found there for the first time in 2003. During our work from 2003 to 2013, the blood arks were found at eleven of 83 stations in the bay. The invader was observed at 0.5–6 m depths in two habitat types: unvegetated muddy bottom and sparse Phragmithes sp. vegetation. The occurrence of both A. kagoshimensis and indigenous dominant species in the same localities varied from year to year. The ES100 index and taxonomic composition did not significantly differ between stations with and without the arks. The variation in the macrozoobenthos species abundance did not depend on whether the alien or indigenous species were dominant. The arks have integrated into the local communities with dominating native macrozoobenthos organisms. This scenario contrasts with the blood arks’ invasion into the Adriatic, Black and Azov Seas, and the adjacent Kerch Strait. There, distinct ark communities have replaced disturbed communities with native dominant species. The main factors that determine the resilience of macrozoobenthos in Taman Bay are: no pressure from the Rapa whelk (Rapana venosa); no persistent disturbances and the eurybiontic type fauna of the bay.