Meeting Abstract

S10.2  Wednesday, Jan. 6  Tube building polychaetes: from ephemeral bio-engineer to reef builder CALLAWAY, R.; Swansea University, UK

Tube-building polychaetes are widely recognized as bio-engineers. It has been suggested that under certain conditions the structures created could qualify as reefs. Being designated a reef builder would have profound implications for their protection under European nature conservation law. In this presentation it is discussed what it takes for a polychaete to be classified as a reef builder. The focus will be on the sand mason Lanice conchilega (Pallas, 1766), a ubiquitous tube worm found around the European coast. As a reef, tube aggregations need to fulfill physical, biological and temporal characteristics. They have to be spatially discrete, support a diverse benthic community and possess stability properties such as resistance to disturbance or high resilience. These characteristics were assessed. The distribution patterns of L. conchilega and the spatial and temporal stability of aggregations were analyzed. The effect of tube aggregations on biodiversity and community structure was investigated in sheltered and exposed environments. Diversity and community structure turned out to be affected in all L. conchilega habitats, whether tubes were sparse or dense. It appears that just a fraction of the L. conchilega community is strongly associated with this tube dweller while most species benefit from subtly ameliorated environmental conditions in the tube lawns. The results suggest that calm hydrodynamic conditions combined with the absence of extreme weather events and regular, successful recruitment are pre-conditions for less rigid bio-engineers to develop extensive, persistent features hosting unique benthic communities.