Temporal and Spatial Variation of Benthic Intertidal Community of a Sandstone Reef in Pernambuco Brazil as a Tool to Evaluate Bioinvasion

Abstract

In this study, the superior and inferior intertidal areas of hard substrate were sampled during the rainy season (June and August) and dry season (October and December) of 2015 at Piedade Beach. The percent cover of Chthamalus bisinuatus, Brachidontes solisianus, Isognomon bicolor, Ulva spp. and filamentous green algae were measured with a 20 × 20 cm quadrat with one hundred intersections. The quadrats were placed randomly at the sampling sites of Piedade reef. One-way ANOVAs (Analyses of Variance) were used to test the temporal variation of the studied organisms. Chthamalus bisinuatus occurred only in the superior mesolitoral where they had an increase in percent cover during the dry season, which wasn't statistically significant. Brachidontes solisianus occurred in both superior and inferior levels and had a significant decrease in the superior intertidal during the dry season. Isognomon bicolor occurred only in the inferior level and decreased to almost zero in the December. Ulva spp. and green filamentous algae had an opposite pattern in the inferior intertidal although only the filamentous algae showed a significant decrease in the dry season. Organisms such as Chthamalus bisinuatus resists better the heat and are dominant in the superior intertidal levels of reefs and rocky coasts. Brachidontes solisianus didn't change much in the lower intertidal and showed that can coexist with the invasive Isognomon bicolor. While the filamentous green showed a decrease in the dry season probably more affected by desiccation than Ulva spp. at Piedade reef.