&lt;b&gt;Habitat structure determining the spatial distribution of ichthyofauna in a Brazilian stream

Débora Reis De Carvalho,Rafaela Bastos Pereira,Paulo Santos Pompeu,Ruanny Casarim

doi:10.4025/actascibiolsci.v37i4.28063

<b>Habitat structure determining the spatial distribution of ichthyofauna in a Brazilian stream

Débora Reis De Carvalho, Rafaela Bastos Pereira + Show 2 more

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https://doi.org/10.4025/actascibiolsci.v37i4.28063

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Abstract

This work aimed to evaluate the relationship between parameters of fish communities and the habitat structure of a stream. Twenty three stretches six meters long were evaluated in the Samambaia stream located inside the Sumidouro Park, Rio das Velhas basin, state of Minas Gerais, Brazil. Fish samplings and habitat characterization were made for each stretch. Seven variables of habitat (vegetal cover, width, depth, substrate, flow, presence of aquatic plants and leaf litter) and two variables characterizing the longitudinal gradient (altitude and distance from the Sumidouro lagoon) were assessed. The fish community responded to habitat changes, presenting variation in richness and composition of species. Richness was positively influenced by the presence of leaf litter and aquatic plants. Furthermore, through similarity data (NMDS) and habitat structure (PCA), it was possible to observe the separation of the 23 stretches into two groups with a dissimilarity of approximately 90%. We concluded that the variation in richness and composition of species throughout the stream was strongly related to the variables of habitat structure. This variation is clearer when considering the longitudinal gradient which highlights a great difference between stretches nearer and farther from the mouth of Samambaia stream.

Highlights

Changes in the structure of aquatic communities are determined mainly by the combined effect of environmental factors and biotic interactions
In order to characterize the physical structure of the habitat we evaluated, in each stretch, the vegetal cover, mean width, mean depth, predominant substrate, flow, percentage of water surface covered by aquatic plants and presence of leaf litter
3113 specimens belonging to nine families and 14 species of fishes were collected in the 23 sampled transects of the Samambaia stream

Summary

Introduction

Changes in the structure of aquatic communities are determined mainly by the combined effect of environmental factors and biotic interactions. Environmental factors limit the amplitude of potential distribution of species, while biotic interactions may act determining the actual distribution (WELLBORN et al, 1996). Physical variables of the habitat (inside and surrounding a stream) are strongly related to the structure of riparian vegetation (GREGORY et al, 1991).The presence of vegetation in streams promotes the stability of margins but Maringá, v. Physical conditions of the habitat may influence the biotic structure and organization within aquatic systems (MUGODO et al, 2006), what may reflect both on the community of benthic macroinvertebrates (CALLISTO et al, 2001; REZENDE et al, 2014) and fish assemblages (GORMAN; KARR, 1978; BÜHRNHEIM; COX FERNANDES, 2003; CASATTI et al, 2006)

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