Using the relationship between taxonomic and functional diversity to assess functional redundancy in streams of an altered tropical watershed Geysa da Silva Camilo, Bianca de Freitas Terra & Francisco Gerson Araújo Environmental Biology of Fishes ISSN 0378-1909 Volume 101 Number 9 Environ Biol Fish (2018) 101:1395-1405 DOI 10.1007/s10641-018-0786-3 1 23 Your article is protected by copyright and all rights are held exclusively by Springer Nature B.V.. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com”. 1 23 Author's personal copy Environ Biol Fish (2018) 101:1395–1405 https://doi.org/10.1007/s10641-018-0786-3 Using the relationship between taxonomic and functional diversity to assess functional redundancy in streams of an altered tropical watershed Geysa da Silva Camilo & Bianca de Freitas Terra & Francisco Gerson Araújo Received: 22 June 2017 /Accepted: 25 June 2018 /Published online: 5 July 2018 # Springer Nature B.V. 2018 Abstract The relationship between taxonomic and because of the loss of many intolerant species caused functional diversity indices has been used to better de- by anthropogenic uses. The taxonomic diversity indices scribe and understand the structure of biological com- were Species Richness (SR) and Simpson’s Diversity munities. Functional diversity is expected to have an (SD), while the functional diversity indices were the asymptotic relationship with species richness because at Functional Richness (FRic) and Functional Dispersion some point, the addition of new species will increase (FDisp). The two taxonomic and two functional diver- some of the already established functional groups (func- sity indices showed a significant positive relationship tional redundancy). However, the asymptotic relation- that never reached an asymptote, suggesting low func- ship may not be reached in intermediately disturbed tional redundancy in the fish communities. Our results systems once many intolerant species that would have indicate that care is needed in the management of the played a redundant role or even represented some func- studied streams because assemblies with low functional tional groups have been lost. This study aimed to ad- redundancy are more susceptible to loss of functions in dress such a relationship (taxonomic and functional the case of species loss. indices) and to evaluate the functional redundancy in intermediately disturbed streams in the Atlantic Keywords Freshwater fishes . Streams . Ecology. Traits Rainforest domain. We expected a positive linear rela- tionship between taxonomic and functional diversity; however, we did not expect to find an asymptotic rela- Introduction tionship between richness and functional diversity Diversity indices based on taxonomic composition have been widely used as descriptors of community structure Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10641-018-0786-3) contains and as tools to assess environmental changes across supplementary material, which is available to authorized users. changing gradients. Recently, some concerns have been : raised about the limitations of these classic taxonomic G. da Silva Camilo F. G. Araújo (*) indices because they consider only species abundance Departamento de Biologia Animal, Laboratório de Ecologia de and richness, omitting the identity of species and their Peixes, Universidade Federal Rural do Rio de Janeiro, BR 465, Km 7, Seropédica, RJ 23890-00, Brazil role and function in the ecosystem (Mokany et al. 2008). e-mail: [email protected] This fact limits their predictive capacity for community structure and functioning (Diaz and Cabido 2001; B. de Freitas Terra Ricotta 2005; Cianciaruso et al. 2009). On the other Curso de Ciências Biológicas, Centro de Ciências Agrárias e Biológicas, Universidade Estadual Vale do Acaraú, Campus da hand, the rise of functional diversity indices enabled Betânia, Sobral, CE 62040-370, Brazil the discussion and better understanding of ecosystem Author's personal copy 1396 Environ Biol Fish (2018) 101:1395–1405 functioning (Cianciaruso et al. 2009). These indices are test for relationships between taxonomic and functional related to the functions (e.g., nutrient cycle, defence diversity indices and their use to detect functional re- against predation, resource acquisition and storage) that dundancy of fish communities. We hypothesized that species develop as part of their role in the ecosystem these indices are positively related and that intermedi- (Diaz and Cabido 2001; Manna et al. 2013), considering ately disturbed systems present low redundancy of func- their individual characteristics and their interaction with tional groups, even with increasing species richness. other species (Mokany et al. 2008). Functional diversity is based on species functional traits that are measurable expressions of the form, physiology, behaviour, ecology Materials and methods or life cycle of an organism in the environment (Frimpong and Angermeier 2010). Study area The concept of functional redundancy as the number of taxonomically distinct species that have similar eco- We conducted this study in five streams of the Paraíba logical functions (Walker 1992) has become the focus of do Sul river basin in the Atlantic Rainforest domain, some ecological questions. Mainly, this is because the southeastern Brazil. The basin area is approximately level of functional redundancy is related to the suscep- 57,000 km2 and drains one of the most developed in- tibility of communities to the loss of species (Sasaki dustrial areas of Brazil. Its waters are used for industrial et al. 2009), and how the loss of diversity affects the and domestic purposes, hydroelectric power generation, ecosystem is not clear (Fetzer et al. 2015). Therefore, and water supply for ca. 15,000,000 people in the cities determining the relationships between taxonomic and of Rio de Janeiro and São Paulo. Located in a metro- functional diversities that imply the analysis of function- politan region, the Paraíba do Sul basin has few rem- al redundancy has important implications for predicting nants of Atlantic Rainforest and mostly consists of the consequences of disturbance or management re- urban areas interspersed with large areas destined to be gimes for the functioning of a given ecosystem (Sasaki used for agriculture and pastures. The climate is et al. 2009). Although the number of studies that relate mesothermic type Cwa according to Köppen classifica- taxonomic and functional diversity indices (see tion, with an average annual temperature of 20.5 °C (18- Hoeinghaus et al. 2007; Teresa and Casatti 2012; 24 °C) and average annual rainfall of 1500 mm Cheng et al. 2014; Carvalho and Tejerino-Garro 2015; (Carvalho and Torres 2002). The wet season Cilleros et al. 2016) and investigate functional redun- (December to March) has accumulated rainfall between dancy (see Micheli and Halpern 2005; Halpern and 200 and 250 mm month-1, and the dry season (May to Floeter 2008;Riceetal.2013;Mouillotetal.2014; August) has accumulated rainfall less than 50 mm Casatti et al. 2015; Aguilar-Medrano and Calderon- month-1 (Marengo and Alves 2005). The streams select- Aguilera 2016) of different communities has grown, ed for this study are located along a 30-km stretch in the there are many questions to be answered about this middle-lower reaches of the Paraíba do Sul basin. These issue. Some of these questions are, for example, how reaches feature an average altitude of 300 m, and the these indices are related and how this may reflect the middle-lower section of the Paraíba do Sul River has an functional redundancy of biological communities. extension of approximately 480 km (Marengo and Streams are a good system in which to analyse the Alves 2005). relationship between functional and taxonomic diversity and thus to investigate functional redundancy. These Fish collections systems are suitable to this investigation because they are dynamic water bodies with complex spatial hetero- Fish sampling was carried out quarterly in two periods: geneity (Schlosser 1991) and high endemism (Ribeiro from February 2008 to May 2009 (seven excursions) 2006), and they are highly vulnerable to environmental and from October 2012 to July 2013 (four excursions). changes, mainly those that result in habitat homogeni- Each stream was sampled at two sites (upper and lower zation. In the present study, we selected five Neotropical stream) in the first period (2008-2009) and at a single streams that are moderately altered (i.e., although suf- site (middle stream) in the second period (2012-2013) fering from anthropogenic influences, they still maintain (Fig. 1). Sampling effort was standardized to cover a considerable habitat diversity to support fish fauna) to stream length of ca. 100 m. A total of 70 samples were Author's personal copy Environ Biol Fish (2018) 101:1395–1405 1397 Fig. 1 Study area, Paraíba do Sul river basin, southeastern Brazil. Sampling sites from February 2008 to May 2009 (●), and October 2012 to July 2013 (▲). Streams code: T1, Jacu Stream; T2, Morro Grande Stream; T3, Claro Stream; T4, Entupido Stream; T5, São Roque Stream performed in the first period (five streams × two sites × 984, 995, 1037, 1039, 1040, 1066, 1072-1075, 1087, seven excursions), and 20 samples were collected in the and 1088-1090. second period (five streams × one site × four excursions). Habitat characteristics In each site, the sampling unit was the sum of all fish collected by using 10 sieves (80 cm diameter; 1 mm In each of the sampled sites, three to five transects were mesh size), 10 casting nets (3 m diameter; mesh size marked.