It is essential to monitor both the mangrove coverage and the encroachment of anthropogenic activities to assess the evolution of these highly valuable and threatened ecosystems. Using the grid technique, Landsat images of three estuaries in Pernambuco, northeast Brazil, were analyzed to track changes in land use over the past three decades. This study is the first time the grid technique has been used as a precise method to quantify and localize the mangrove coverage changes at local scale. We found that the technique was a synthetical and cost-effective way of observing land-use changes over the study period, and its precision was evident for local-scale study. An increasing trend of mangrove coverage was observed and can be related to the salinization. This increase in salinization is a result of anthropogenic activities and climate change. We also found that differences in geometrical properties influenced the spatiotemporal patterns of mangroves. To mitigate adequately the negative impacts induced by anthropization and climate change, the characteristics of mangrove forest configuration and human activities should therefore both be considered.
The objective of this study was to analyse the feeding habits and trophic interactions between four oceanic predatory fish around the Fernando de Noronha Archipelago (FNA), Brazil, in the western equatorial Atlantic (3.86°S/32.42°W), internationally recognized as an environment of high economic and ecological value. For this purpose, biological samples of yellowfin tuna (Thunnus albacares), wahoo (Acanthocybium solandri), barracuda (Sphyraena barracuda) and dolphinfish (Coryphaena hippurus) were collected for stomach content and stable isotope analysis. Values of the index of relative importance revealed varied diets, with a strong presence of teleost fishes (Diodontidae and Exocoetidae) for all species, with yellowfin tuna having a greater diversity of food items. Despite being generalists/opportunists, the feeding strategy of these predators showed a tendency towards a specialized diet in the use of the available resources around the FNA. They presented a narrow trophic niche width (Levin's index, Bi < 0.6) and low overlap between species, except between barracuda and wahoo (MacArthur and Levin's, R0 = 0.72). Isotopic compositions had broad values of δ13C and δ15N, and were significantly different between species. Our results provide information about the four species' trophic organization and suggest that the predators avoid competition by preying on different prey, thus allowing their coexistence.
Highlights► Haemulidae are broadly distributed through Northeast coast of Brazil due to the complex habitat presents in this region. ► H. plumierii, H. aurolineatum and H. squamipinna were considered the most dominant species among the Family. ► The population structure, and size at first maturity were characterized for the most dominant species of Haemulidae (3 spp.) in Northeastern Brazil. ► The southern coasts of Pernambuco and Rio Grande do Norte hold high abundance, richness and concentration of juveniles.
2009). Currently, haemulids and lutjanids are commonly caught by artisanal fisheries as the target species, owing to the decrease in abundance of lobster and goatfish (LESSA et al., 2009; MARQUES & FERREIRA, 2013).Despite their ecological and economic importance, many biological aspects of this family are still unknown or knowledge is restricted in terms of spatial coverage. Available studies do not integrate information about population structure, distribution, abundance, and the habitats occupied by these species. Previous studies in Northeast Brazil have mainly investigated specific aspects of population dynamics, such as the length-weight relationship (
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.