Taxonomic and functional distinctness of the fish assemblages in three coastal environments (bays, coastal lagoons and oceanic beaches) in Southeastern Brazil M  arcia Cristina Costa Azevedo, Rafaela de Sousa Gomes-Gonçalves, Tailan Moretti Mattos, Wagner Uehara, Gustavo Henrique Soares Guedes, Francisco Gerson Araújo * Universidade Federal Rural do Rio de Janeiro, Laborat orio de Ecologia de Peixes, BR 465, Km 7 23851-930, Serop edica, RJ, Brazil article info Article history: Received 27 January 2017 Received in revised form 4 May 2017 Accepted 29 May 2017 Available online 30 May 2017 Keywords: Taxonomic indices Ecological status Coastal fishes Biodiversity Ecosystem functioning Monitoring Tropics abstract Several species of marine fish use different coastal systems especially during their early development. However, these habitats are jeopardized by anthropogenic influences threatening the success of fish populations, and urgent measures are needed to priorize areas to protect their sustainability. We applied taxonomic (Dþ) and functional (Xþ) distinctiveness indices that represent taxonomic composition and functional roles to assess biodiversity of three different costal systems: bays, coastal lagoons and oceanic beaches. We hypothesized that difference in habitat characteristics, especially in the more dynamism and habitat homogeneity of oceanic beaches compared with more habitat diversity and sheltered conditions of bays and coastal lagoons results in differences in fish richness and taxonomic and functional diversity. The main premise is that communities phylogenetically and functionally more distinct have more in- terest in conservation policies. Significant differences (P < 0.004) were found in the species richness, Dþ and Xþ among the three systems according to PERMANOVA. Fish richness was higher in bays compared with the coastal lagoons and oceanic beaches. Higher Dþ was found for the coastal lagoons compared with the bays and oceanic beaches, with the bays having some values below the confidence limit. Similar patterns were found for Xþ, although all values were within the confidence limits for the bays, sug- gesting that the absence of some taxa does not interfere in functional diversity. The hypothesis that taxonomic and functional structure of fish assemblages differ among the three systems was accepted and we suggest that coastal lagoons should be priorized in conservation programs because they support more taxonomic and functional distinctiveness. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Understanding the links between species distribution and habitat characteristics is often the first step in unraveling the mechanisms that control biodiversity distribution (Matthews and Whittaker, 2015; Vasconcelos et al., 2015; Whitfield and Pattrick, 2015; McLean et al., 2016). In this sense, the investigation of spe- cies composition and functional traits has been proposed as a means to assess the structure and dynamics of ecological com- munities. Species richness is practically always used as an explan- atory variable for ecosystem function because it is easy to estimate and assumed to be a good estimator for functional diversity (Tilman, 1999). The introduction of functional groups was an important step in estimating functional diversity, with species be- ing grouped by similar function, similar effects on ecosystem pro- cesses or similar responses to environmental pressures (Wilson, 1999; Walker and Langridge, 2002). Therefore, classifying species into groups based on taxonomic relationship and similar function is a useful approach to studying species environmental or perturba- tion influences on the coastal systems. Several species of marine fish use sandy beaches in different coastal systems especially during their early development. How- ever, this kind of habitat is at risk because of anthropogenic activ- ities, which jeopardize the success of fish populations, and urgent measures are needed to priorize areas to protect the sustainability of such natural resources. The traditional diversity indices have been used in the last decades to quantify changes in communities, reducing complexity for ecological groups to numbers that are * Corresponding author. E-mail address: gerson@ufrrj.br (F.G. Araújo). Contents lists available at ScienceDirect Marine Environmental Research journal homepage: www.elsevier.com/locate/marenvrev http://dx.doi.org/10.1016/j.marenvres.2017.05.007 0141-1136/© 2017 Elsevier Ltd. All rights reserved. Marine Environmental Research 129 (2017) 180e188