More of the Same High Functional Redundancy in St

Authors: Lilian Casatti Fabrício Barreto Teresa Jaquelini de Oliveira Zeni Mariela Domiciano Ribeiro Gabriel Lourenço Brejão Mônica CenevivaBastos

Publish Date: 2015/03/31

Volume: 55, Issue: 6, Pages: 1300-1314

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Abstract

In this study we investigated the influence of environmental variables predictor variables on the species richness species diversity functional diversity and functional redundancy response variables of stream fish assemblages in an agroecosystem that harbor a gradient of degradation We hypothesized that despite presenting high richness or diversity in some occasions fish communities will be more functionally redundant with stream degradation Species richness species diversity and functional redundancy were predicted by the percentage of grass on the banks which is a characteristic that indicates degraded conditions whereas the percentage of coarse substrate in the stream bottom was an important predictor of all response variables and indicates more preserved conditions Despite being more numerous and diverse the groups of species living in streams with an abundance of grass on the banks perform similar functions in the ecosystem We found that riparian and watershed land use had low predictive power in comparison to the instream habitat If there is any interest in promoting ecosystem functions and fish diversity conservation strategies should seek to restore forests in watersheds and riparian buffers protect instream habitats from siltation provide wood debris and mitigate the proliferation of grass on stream banks Such actions will work better if they are planned together with good farming practices because these basins will continue to be used for agriculture and livestock in the futureWe thank our colleagues from the Ichthyology Laboratory for their help during fieldwork IBILCEUNESP for the use of their facilities IBAMA for the collecting license 001/2003 landowners for permission to conduct research on their properties Francisco Langeani for fish identification and Thiago G Souza for help with the statistical analysis Anonymous reviewers provided several suggestions that improved this manuscript LC is supported by National Counsel of Technological and Scientific Development CNPq 301755/20132 FBT by University Research and Scientific Production Support Program PROBIP/UEG JOZ MDC GLB and MCB by São Paulo Research Foundation FAPESP

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