Publication Abstract

Dense aggregations of tube-building polychaetes: response to small-scale disturbances

S.F. Bolam and T.F. Fernandes

Many species of tube-building polychaetes form dense aggregations or `patches' within marine soft-bottom habitats. Although the ecological importance of such patches has been well studied, the effect of small-scale disturbances within patches has not been investigated. On the intertidal sandflat Drum Sands, Firth of Forth, Scotland, the tube-building spionid Pygospio elegans Claparede forms patches approximately 1-1.5 m super(2), wherein its density is significantly greater than in surrounding sediments. This study explicitly investigates whether the initial communities colonising small- scale disturbances within P. elegans patches differ in terms of community structure and colonisation mode from those of surrounding sediments. Defaunated sediments (1/125 m super(2)) were implanted into the sediments within and outside patches during April, August and December 1997, and sampled after 3 weeks. The results indicated that some species colonised patches and non-patches in significantly different numbers, at least at certain times of the year. Following these controlled disturbances, P. elegans larvae colonised patches in significantly higher numbers compared to non-patch areas during April 1997, but showed the opposite trend in August 1997 when larval recruitment was relatively low. Adult P. elegans colonised patch sediments in higher numbers than non-patch ones during August and December. Capitella capitata (Fabricius) consistently colonised all defaunated areas in relatively high numbers while Cerastoderma edule (L.) and Macoma balthica (L.) colonised non-patch azoic sediments in significantly higher numbers than patch azoics during April 1997.

Reference:

S.F. Bolam and T.F. Fernandes, 2003. Dense aggregations of tube-building polychaetes: response to small-scale disturbances. Journal of Experimental Marine Biology and Ecology, 269(2): 197-222.