Response of fish communities to intense drought in Brazilian savanna streams

Revista Ambiente & Água. 2017;12(4):618-628 DOI 10.4136/ambi-agua.2093


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Journal Title: Revista Ambiente & Água

ISSN: 1980-993X (Online)

Publisher: Instituto de Pesquisas Ambientais em Bacias Hidrográficas (IPABHi)

LCC Subject Category: Geography. Anthropology. Recreation: Environmental sciences

Country of publisher: Brazil

Language of fulltext: Spanish, English, Portuguese

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Dianne Michelle Alves da Silva (Universidade de Brasília (UnB), Planaltina, DF, Brasil)
Fabrício Barreto Teresa (Universidade Estadual de Goiás (UEG), Anápolis, GO, Brasil)


Double blind peer review

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Time From Submission to Publication: 22 weeks


Abstract | Full Text

The physical structures of streams are subjected to intense changes throughout the seasons. Intense drought in dry periods has been frequent and potentially harmful to aquatic species. In this study, we tested whether the changes in the habitat structure of the streams during the dry period determine the organization of fish communities. Five streams in the Upper Tocantins River were studied in the dry and rainy seasons. The species were characterized by 13 functional traits based on morphological measurements. The descriptors of functional diversity were: mean pairwise functional distance of species in the community (MPD) and mean functionally nearest species distance (MNTD). We also calculated the standardized effect size for MPD and MNTD, an indicator of functional redundancy, and compared the observed patterns with those expected by chance. Streams differed between seasons with respect to environmental variables. Functional diversity in the rainy season did not differ from the pattern expected by chance for both metrics. While functional diversity in the dry season has not differed from the pattern expected by chance for SESMPD, a greater functional redundancy for SESMNTD was found in this season. These results indicate that environmental changes in the streams during the dry season are important constraints for fish occurrence, preventing the occurrence of functionally original species. Therefore, a prospective scenario of dry-period intensification could result in functionally redundant communities, with functional homogenization of the regional species pool.