Spatial persistence and sediment disturbance of an arenicolid polychaete

Abstract

Field evidence suggests that biogenic sediment movement influences the distribution of infauna but also that biogenic processes account for only a small proportion of total sediment movement. This difference may be due to biogenic additions to the sediment or the mode of biogenic vs. physical deposition or to calculation of the biogenic effect as inappropriately scaled temporal and spatial averages. Spatial persistence of biogenic effects over time would bias such averages. Individuals of the arenicolid polychaete Abarenicola pacifica can be sized and mapped by the diameter and position respectively of their fecal coils. Their spatial distributions show significant clumping. Both individuals of A. pacifica and their biogenically disturbed patches have considerable spatial persistence over time. Individuals remained in the same spatial location for up to 12 d. Over 50% of all patches of biogenic sediment disturbance persisted for at least the 16‐d observation period, and the patches were highly localized. Thus spatial and temporal averages may be inappropriate for determining the importance of biogenic effects, due to nonuniform distribution of individuals and their spatial and temporal persistence.