The effects of the environmental parameters on diversity pattern and abundance of macrobenthos associated with the order Zoantharia on intertidal zone of Hormuz Island

The intertidal coral reefs are influenced by a composition of environmental parameters and biological components, which has a direct influence on communities associated with them. Hence, this study investigates the effects of some environmental parameters such as sea water factors and substrate compositions on distribution pattern of macrobenthos associated with the order Zoantharia on intertidal zone of Hormuz Island using diversity index variables and abundances data sets obtained over a period of 12 months between June 2015 and June 2016. For this purpose, line intercept transect method was performed to assess the abundances of zoanthid polyps and associated macrobenthos along 6 transects with 3 hard bottom types. The results of this study revealed significant differences in species evenness and species richness between T3 and T6 with other transects. The diversity indices of macrobenthos, tested with Bray-Curtis similarity index, was significantly homogeneous in all transects with the exception of T3 and T6, probably as a consequence of different substrate compositions in habitat heterogeneity. Pearson analysis results showed positive significant correlation among macrobenthos abundance and dissolved oxygen in all transects, so that the analysis of multiple linear regression showed this significant relationship in upper littoral zone of transects. In conclusion, substrate composition was the main factor limiting the spatial distributions of macrobenthos associated with zoanthids, although dissolved oxygen was also important. Also, the abundances data showed two distinct benthic communities and support the hypothesis that the distribution pattern of communities varies along the coastal area in a gradient from the upper to the lower portion of the intertidal zone.