SPATIAL AND TEMPORAL EFFECTS OF TEREBELLID POLYCHAETE TUBES ON SOFT-BOTTOM COMMUNITY STRUCTURE IN PHOSPHORESCENT BAY, PUERTO-RICO

Small-scale dispersion and short-term recruitment patterns in the tropical soft-bottom community of Phosphorescent Bay, Puerto Rico were studied. Tube-building, surface deposit-feeding polychaetes of the family Terebellidae were manipulated in order to study their effects on spatial and temporal recruitment patterns. The macrofaunal terebellids manipulated in this study had a random spatial pattern at small spatial scales 1- to 40-dm2), even spacing at intermediate (80-dm2) spatial scales, and an aggregated pattern at larger (320-dm2) spatial scales. Harpacticoid copepods, ostracods, gastropod juveniles, meiofaunal cirratulids and dorvilleids, and macrofaunal syllids had aggregated dispersion patterns. Capitellids, sabellids, phoronids, paraonids, macrofaunal magelonids and meiofaunal syllids had mixed dispersion patterns. Macrofaunal cirratulids, macrofaunal dorvilleids, and meiofaunal magelonids had random dispersion patterns. It has been proposed that recruitment in tropical marine communities is a spatially random process. Data collected in this study do not support this hypothesis. Recruiting fauna can be spatially aggregated and the type of dispersion pattern observed is dependent upon size class and taxonomic assemblage. Successional patterns were evaluated with a fixed-effects two-way ANOVA, with terebellid tube manipulation and time as the main effects, providing an objective criterion for classifying whether terebellid tubes enhanced or inhibited the recruitment of infaunal macro-and meiofauna. Only one taxonomic assemblage (cirratulids) was inhibited and 11 showed no effects. Correspondence analysis indicates that there was a shift in taxonomic composition over the two months of the succession experiment. Temporally and spatially, terebellids and/or their tubes have a small but measurable effect on the community structure in Phosphorescent Bay.