Early Successional Patterns of Invertebrates in Artificial Reefs Established at Clear and Silty Areas in Bolinao, Pangasinan, Northern Philippines

The spatio-temporal patterns of colonization and recruitment of invertebrates were investigated in 32 tent-like concrete blocks used as artificial reefs in silty and in clear reef areas in Pangasinan, northern Philippines. The abundance, species richness and percentage cover of all invertebrate recruits were recorded at 2-week intervals for the first month and monthly thereafter.Classification analysis using TWINSPAN showed that position within the blocks was observed to have an effect on the settlement patterns of invertebrates on the two sites at least on early census. This pattern is less distinct than patterns observable among AR patches in the succeeding period. The pattern observed in their position on the blocks could be attributed to phototactic preferences and silt susceptibility and/or avoidance of the organisms to silt inundation. The divergent development of the two communities in the silty and clear areas may be attributed to the predominant physical factors in the sites, but biological interactions such as grazing, commensalism and competition are also implicated.