O Uso do Gastropóde Melampus coffeus (Ellobiidae) (Linnaeus, 1758) Como Indicador Ecológico do Estado de Degradação Ambiental de Manguezais no Nordeste do Brasil

Abstract

In tropical coastal ecosystems, mangrove forests are important areas for feeding, breeding and sheltering for many marine species. The mangrove is dominant in the physiography of the Brazilian coast, however, the intense use of its natural resources and the anthropic pressure under coastal areas threatens the existence of these environments. In the present work we tested the hypothesis that Melampus coffeus gastropod is an ecological indicator of deforested mangrove areas. Thus, the general objective was to determine if there are variations in the size and population density of M. coffeus in deforested mangroves and to compare them with mangrove conservation, in addition to relating this distribution to the structural parameters of the forests. For this, three deforested mangrove areas and three conserved areas were chosen. At each site, three sites were drawn and at each site, a transectwith three plots of 100 m² each was demarcated. In each plot, the mangrove species were identified, their height estimated and the circumference measured. Next, all the individuals of M. coffeus were found that were measured for the height, width and height of the shell opening. Larger abundance and larger sizes of snails were recorded in the conserved areas. Correlation analysis indicates a relation between M. coffeus e the Rhizophora mangle density, the height and the DAP of the forest. It was concluded that the distribution of M. coffeus can be directly influenced by the availability and quality of mangrove forest resources, and can be an ecological indicator for deforested mangrove areas. Key-words: Snail. Deforestation. Estuary. In tropical coastal ecosystems, mangrove forests are important areas for feeding, breeding and sheltering for many marine species. The mangrove is dominant in the physiography of the Brazilian coast, however, the intense use of its natural resources and the anthropic pressure under coastal areas threatens the existence of these environments. In the present work we tested the hypothesis that Melampus coffeus gastropod is an ecological indicator of deforested mangrove areas. Thus, the general objective was to determine if there are variations in the size and population density of M. coffeus in deforested mangroves and to compare them with mangrove conservation, in addition to relating this distribution to the structural parameters of the forests. For this, three deforested mangrove areas and three conserved areas were chosen. At each site, three sites were drawn and at each site, a transectwith three plots of 100 m² each was demarcated. In each plot, the mangrove species were identified, their height estimated and the circumference measured. Next, all the individuals of M. coffeus were found that were measured for the height, width and height of the shell opening. Larger abundance and larger sizes of snails were recorded in the conserved areas. Correlation analysis indicates a relation between M. coffeus e the Rhizophora mangle density, the height and the DAP of the forest. It was concluded that the distribution of M. coffeus can be directly influenced by the availability and quality of mangrove forest resources, and can be an ecological indicator for deforested mangrove areas. Key-words: Snail. Deforestation. Estuary.