Diversidade funcional de assembleias de peixe em ecossistemas tropicais costeiros

Abstract

Tropical coastal ecosystems are one the most important environments on the planet because they act as transition areas may affect the structural characteristics of the environment and distribution patterns of fish species. These sites may also be affected by a process known as estuarization shelf that occurs in tropical regions of narrow continental shelves, because the extent of estuarine conditions and thus estuarine species may be responsible for changes in diversity and abundance of these sites. Among the different measures of biodiversity, functional diversity is a key to understanding ecosystem processes in coastal areas. Whereas regions of study (influence of reefs, lagoons and influence of estuarine influence ) three diferents depth ( 10 , 20 and 30 meters ) and two ( dry and wet ), seasons. The aim of this study was to evaluate comparatively the diversity functional and the most dominant processes ( niche filtering and limiting similarity ) in a stretch of tropical continental shelf of the coastal region of the southwest Atlantic . Fish sampling was conducted in three coastal regions during the rainy and dry season in three different isobaths. Related to morphology, diet and habitat use of species traits were used. The functional diversity index was used SESMPD. This study showed that the processes of assemblage rules as limiting similarity are applicable in the three coastal ecosystems and both places have high functional diversity at shallower depths thus more species are found additional functional and low redundancy conceding estuarization effects . The next to the São Francisco River in particular regions also maintains a low functional redundancy at greater depths but it was not possible to observe the effect of these estuarization isobaths due to the effect the impacts suffered along the river altering its natural flow. This demonstrates that this particular environment should be carefully evaluated, since the removal of certain species can cause drastic effects on the ecosystem.