Ecological Indicators 11 (2011) 1354–1359 Contents lists available at ScienceDirect Ecological Indicators journal homepage: www.elsevier.com/locate/ecolind Original article Functional convergence of fish assemblages in urban streams of Brazil and the United States Almir M. Cunico a,b,∗ , J. David Allan c , Angelo A. Agostinho d a Graduate Course in Ecology of Inland Aquatic Ecosystems, Maringá State University, Av. Colombo, 5790, PEA, Bloco G90, CEP 87.020-900, Maringá, Paraná, Brazil b Laboratory of Ecology, Fishing and Ichthyology, Federal University of Paraná, Palotina Campus, Rua Pioneiro, 2153, Jd. Dallas, CEP 85950-000, Palotina, Paraná, Brazil c School of Nature Resources and Environment, University of Michigan, 440 Church St., Ann Arbor, MI 48109, Michigan, USA d Department of Biology/NUPELIA, Maringá State University, Av. Colombo, 5790, Bloco H90, CEP 87.020-900, Maringá, Paraná, Brazil article info Article history: Received 28 July 2010 Received in revised form 10 February 2011 Accepted 13 February 2011 Keywords: Streams Urbanization Fish assemblages abstract The aim of this study was describe functional faunal assemblages occurring in streams with high influ- ence of urbanization in USA and Brazil to answer the question whether similar biological traits of fish assemblages would be found between streams with high influence of urbanization in USA and Brazil. We compiled data on the structure and composition of freshwater fishes in 46 urban streams in the USA and 10 urban streams in Brazil. Data on functional traits was established in accordance with ordinal data on abundance. Cluster analysis was conducted to examine relationships among species composition across all sites sampled and to uncover patterns in functional traits of the fish assemblages by nonmetric mul- tidimensional scaling (NMS). The cluster analysis separated the biogeographic regions in relation to the fish fauna composition. However, the ordination analysis (NMS) did not reveal differences between func- tional traits in Brazil and USA urban fish assemblages, suggesting functional similarity of very disparate zoogeographic assemblages. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Increasing urbanization world-wide and its consequent impacts on ecosystems represents a threat to native species assemblages and a challenge to biological conservation (Vitousek et al., 2008). In 1900, only 10% of the human population lived in cities whereas today half of the world’s population dwells in urban areas, a figure expected to exceed 60% by the year 2030 (Cohen, 2003; Population Reference Bureau, 2008). This extensive and ever-increasing urban- ization creates new landscapes, alters habitat and facilitates species invasions (McKinney, 2006). Impacts on aquatic ecosystems are profound (Cuffney et al., 2010; Paul and Meyer, 2008; Price et al., 2011). Because of the well-established dependency of stream biota on the surrounding landscape (Allan, 2004), streams in urban areas are particularly vulnerable to impacts associated with changing landcover (Walsh et al., 2005). Increased areas of impermeable sur- faces can increase the frequency and magnitude of storm flows (Campana and Tucci, 2001; Zhou and Wang, 2007), elevate erosive processes, change channel morphology with subsequent effects on ∗ Corresponding author at: Laboratory of Ecology, Fishing and Ichthyology, Federal University of Paraná, Palotina Campus, Rua Pioneiro, 2153, Jd. Dallas, CEP 85950-000, Palotina, Paraná, Brazil. Tel.: +55 44 32 11 85 00; fax: +55 44 32 11 85 70. E-mail address: almircunico@ufpr.br (A.M. Cunico). streambed composition (Booth et al., 2004; Hancock, 2002; Wood and Armitage, 1997) and elevate concentrations of toxicants and nutrients in urban runoff (Hatt et al., 2004; Mainstone and Parr, 2002). Moreover, the loss of riparian vegetation reduces shade, organic matter inputs and instream habitat diversity, changing trophic processes and the structure of associated biological com- munities (Quinn et al., 2001). These changes in physical, chemical and biological aspects of urban streams show consistent trends across geographic regions, having the appearance of an urban stream syndrome (Meyer et al., 2005). This growing evidence that stream ecosystems respond simi- larly across regions to the pressures of urbanization suggests the hypothesis that biological assemblages will converge in at least some of their functional properties. It is already apparent that a typical response of fish assemblages to urbanization is an increase in the abundance of tolerant species and decrease in sensitive species (Allan, 2004), resulting in shifts in species dominance and in fish assemblages that are functionally less diverse than found in non-urban streams (Weaver and Garman, 1994). Thus it is likely that a more detailed comparison of the functional traits of fish assemblages in urbanized and less altered landscapes will provide additional insight into the response of the biological assemblages to urbanization. Indeed, stream fish are well-suited for testing the hypothesis that traits of communities in distant systems converge in response to a similar environmental constraints because lotic fish population occur in more or less isolated watersheds where they 1470-160X/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.ecolind.2011.02.009