Ecological traits of benthic assemblages in shallow Antarctic waters: does ice scour disturbance select for small, mobile, secondary consumers with high dispersal potential?

Abstract

Benthic communities in nearshore habitats around Antarctica are strongly influenced by ice disturbance. It has been suggested that where ice scour disturbance is severe, the relative importance of certain ecological groups is elevated. I examined the relative contributions of mobility, size, feeding strategy and development mode groups to total faunal abundance and species richness in relation to ice disturbance at Adelaide Island, West Antarctic Peninsula. The contributions of ecological groups were assessed along a depth/disturbance gradient from 5 to 25 m depth at two sites. At one site, the relative abundance of the low mobility group was significantly greater at low disturbance levels, whilst the relative abundance of the high dispersal group (taxa with pelagic larvae) was elevated at high disturbance levels. At the other site, the relative abundance of secondary consumers was greater at high disturbance levels. Even over small spatial scales, certain ecological traits seem advantageous to a fauna shaped by intense, catastrophic ice scour.