Scale-dependent impact on diversity of Antarctic benthos caused by grounding of icebergs

Analysis of seabed video-strips on the Weddell Sea shelf provided evidence that the effects of iceberg scouring on megabenthic assemblages differ, depending on spatial scale. At a local scale (1 to 100 m), undisturbed glass sponge-associated habitats were significantly more diverse than disturbed ones; at a regional scale (1 to 100 km), increased habitat heterogeneity caused by iceberg scouring enhanced species diversity. The pace and succession of the recolonization exhibits high variability and is difficult to predict. The results not only underpin the concept that disturbance events are essential factors in the regulation of ecosystem dynamics, but also emphasize the relevance of scale in the evaluation and explanation of diversity patterns.