Disturbance-related patterns in unstable rocky benthic habitats of the north-eastern Baltic coast

Füüsilistest häiringutest tingitud põhjaelustiku levikumustrid Läänemere kirdeosa liikuvatel kivistel põhjadel

Kiran Liversage ； Jonne Kotta

《Proceedings of the Estonian Academy of Sciences》 64卷1期 (2015/03) Pp. 53-61

https://doi.org/10.3176/proc.2015.1.07

並列摘要

Distinct patterns of benthic flora and fauna are produced when unstable rocky substrata are disturbed by water motion. This study investigated occurrence of disturbance-related patterns in benthic boulder habitats on the north-eastern Baltic coast. Sessile assemblages, mostly algae on tops of boulders and barnacles and bryozoans underneath, were found to differ between small (50-150 cm^2 upperside surface area) and large (200-800 cm^2) boulders. Densities of motile gammaridean amphipods were negatively correlated with boulder size. These patterns may be due to small boulders being displaced by water motion more frequently than large ones. Most of the barnacle shells/tests were remnant empty ones, and the proportion of empty tests and living barnacles was similar underneath small and large boulders, suggesting that degradation/removal of empty tests was not influenced by disturbance associated with boulder size. There was no consistent evidence of algae being affected by boulder size, but the tops of boulders had less algae than the edges, a pattern that is typically associated with high rates of overturning. Confirmation of disturbance as having caused these patterns and thus being an important process for structuring benthic biota in this region could be achieved by further manipulative experimentation.

並列關鍵字

boulder reefs ； Baltic Sea ； Balanus improvisus ； Gammarus spp. ； filamentous algae ； physical disturbance ； overturning of boulders