Ecological Indicators 77 (2017) 386–396 Contents lists available at ScienceDirect Ecological Indicators jo ur nal ho me page: www.elsevier.com/locate/ ecolind Original articles A fish-based multimetric index for Brazilian savanna streams Débora Reis de Carvalho a,∗ , Cecília Gontijo Leal a,b , Nara Tadini Junqueira a , Míriam Aparecida de Castro a , Daniela Cristina Fagundes a , Carlos Bernardo Mascarenhas Alves c , Robert M. Hughes d , Paulo Santos Pompeu a a Laboratório de Ecologia de Peixes, Departamento de Biologia/Setor Ecologia, Universidade Federal de Lavras, 37200-000, Lavras, MG, Brazil b Museu Paraense Emílio Goeldi, 66077-830, Belém, PA, Brazil c Laboratório Nuvelhas, Projeto Manuelzão, Universidade Federal de Minas Gerais, 30161-970, Belo Horizonte, MG, Brazil d Amnis Opes Institute and Department of Fisheries & Wildlife, Oregon State University, 104 Nash Hall, 97331-4501 Corvallis, OR, USA a r t i c l e i n f o Article history: Received 18 November 2016 Received in revised form 16 February 2017 Accepted 20 February 2017 Keywords: Cerrado Anthropogenic disturbances Freshwater assessment Aquatic fauna Biotic integrity a b s t r a c t Multimetric indices (MMI) have been widely used to assess ecosystem conditions because they are low- cost, employ a rapid field method, and can incorporate various biological metrics at different levels of biological organization. Our objective was to create a fish-based multimetric index applicable to all streams of the Brazilian savanna biome (Cerrado), the second largest biome in Brazil and deemed a global biodiversity hotspot. We evaluated 156 sites in two river basins (Paraná and São Francisco) and selected metrics capable of distinguishing stream-sites across a gradient of anthropogenic disturbances. We employed two different MMI approaches to determine if an MMI based on natural variation-adjusted metrics performed better than one based on unadjusted metrics. In addition, we assessed the performance of the two final MMIs and their sensitivity to anthropogenic pressures at local (LDI), catchment (CDI) and both scales integrated (IDI). Finally, we employed the power of a probability sample survey design to infer headwater stream conditions across a hydrologic region of approximately 47,000 km 2 . Our final MMI for Brazilian savanna streams included six metrics: % common species; % characiform individuals; % loricariid individuals; % trichomycterid individuals; % invertivore species, and % Poecilia reticulata individuals. MMI 1 (unadjusted metrics) performed better than MMI 2 (natural variation-adjusted metrics) in discriminating least- and most-disturbed sites, but MMI 2 distinguished intermediate from most-disturbed sites better than MMI 1 . Both indices were negatively correlated with the CDI scores; however, only MMI 2 was nega- tively correlated with the IDI scores. We inferred that 709 km (9.35%) of streams in the studied hydrologic region were in good condition, 8115 km (82.73%) were intermediate, and 641 km (7.91%) were in poor condition. We conclude that the MMIs proposed in this study have great potential for widespread appli- cation because they integrate data from two of the most important Brazilian river basins included in a biome that represents more than 20% of the country. Furthermore, the metrics retained in the indexes are easy to access with a rapid low-cost field method. However, their feasibility in areas influenced by mining, as well as in different biomes, should be tested. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Streams are extremely complex and susceptible to human activities occurring both in riparian zones and elsewhere in the catchment (Allan, 2004; Stanfield and Kilgour, 2013; Leal et al., 2016). Anthropogenic changes in stream physical conditions have ∗ Corresponding author. Present address: Laboratório de Ecologia de Peixes. Departamento de Biologia/Setor Ecologia, Campus Universitário, Universidade Fed- eral de Lavras, Caixa Postal 3037, CEP 37200-000 Lavras, MG, Brazil. E-mail addresses: deboracarvalhobio@yahoo.com.br, deboracarvalhobio@gmail.com (D.R. de Carvalho). been strongly associated with changes in stream fish assemblages (Allard et al., 2015; Teresa et al., 2015; dos Santos et al., 2015), which have been used for over 100 years to assess ecosystem conditions (Simon, 1999). For instance, Karr (1981) proposed a fish- assemblage-based multimetric index (MMI) for midwestern USA streams over 25 years ago. Since then, fish MMIs have been widely used to measure the biological condition of temperate freshwater streams (Pont et al., 2006; Pont et al., 2009; Whittier et al., 2007), rivers (Mebane et al., 2003; Pont et al., 2006; Zhu and Chang, 2008), lakes (Lyons et al., 2000; Drake and Valley, 2005; Launois et al., 2011), and estuaries (Deegan et al., 1997). http://dx.doi.org/10.1016/j.ecolind.2017.02.032 1470-160X/© 2017 Elsevier Ltd. All rights reserved.