Vertical zonation of the hard substrata macrofauna of the Massangana River estuary, Suape Bay (Pernambuco, Brazil)

Abstract

The estuarine area of the Massangana River (Pernambuco, Brazil) undergoes several kinds of interventions as a result of the activities of the Suape Industrial and Harbor Complex, which could affect local biotic communities. Thus, this study aimed to verify the composition of the benthic macrofauna of hard substrates regarding their vertical distribution in order to support the future biomonitoring of possible changes in this complex. The invertebrates found in an area of 519 m² were collected and their distribution on the biogenic and abiogenic substrates was described. A total of 79 species were found, primarily in the mangroves and distributed in three intertidal zones: a Chthamaletum, which comprised the intertidal and upper shore, the balanid zone, with barnacles and oysters in the mid intertidal, and the Bostrychietum, in the lowest region. In general, this matched the Brazilian and international vertical distribution patterns for mangrove invertebrates. The presence of rocky substrate and the area's high salinity made possible the occurrence of 28 species- including the coral Siderastrea stellata - in an estuarine area. The enlarged distribution of the bivalve Isognomon alatus, the barnacle Amphibalanus reticulatus, and the bryozoans Biflustra savartii, Bowerbankia gracilis, and Conopeum reticulum on the Brazilian coast can be explained by the proximity to the Port of Suape, which allows for passive transportation on ships. The scattered distribution of the fouling organisms among the substrates and the absence of characteristic animals of this ecosystem (such as the mussels) suggest that the environment is already undergoing some stress due to the diverse human interventions occurring in this area.