Longitudinal habitat disruption in Neotropical streams: fish assemblages under the influence of culverts

Abstract

This study assessed differences in fish assemblages existing upstream and downstream two types of culverts, one on each of two different Neotropical streams. We analyzed the composition and structure of the ichthyofauna and tested for spatial patterns. Fish sampling was carried out monthly between November 2009 and October 2010 using different fishing gears. We collected 2,220 fish of 33 species; 901 in stretches of the Lopeí stream -circular culvert and 1,310 in stretches of the Pindorama stream -box culvert. Fish abundance was similar in upstream and downstream stretches of the circular culvert, whereas it was slightly higher in the upstream than downstream stretch for the box culvert. Characiformes predominated in the upstream stretch of both culverts. On the other hand, Siluriformes was abundant in the downstream stretch of the circular culvert, with similar abundance in the stretches of the box culvert. Species richness and diversity (Shannon-Weiner Index) were higher in the downstream stretch of the circular culvert, but they were similar in both stretches of the box culvert. The most abundant species were Astyanax altiparanae, A. paranae, A. fasciatus, Ancistrus sp., and Hypostomus sp. The last two species were more abundant in the downstream stretch of the circular culvert, and similar in stretches of the box culvert. Our study indicated variations in the species abundance, richness, and diversity between upstream and downstream stretches in particular of the circular culvert in the Lopeí stream, suggesting that fish movements are restrained more intensively in this culvert, especially for Siluriformes. The drop in the circular culvert outlet probably created passage barriers especially for those fish that has no ability to jump, where downstream erosion could lead to culvert perching. Studies on appropriate road crossing design or installation are fundamental whereas improvements in these structures can restore the connectivity of fish populations and communities in streams.Este estudo avaliou diferenças nas assembleias de peixes existentes a montante e a jusante dois tipos de bueiros, um em cada um de dois diferentes riachos Neotropicais. A composição e a estrutura da ictiofauna foram avaliadas e seus possíveis padrões espaciais. As amostragens para a ictiofauna foram realizadas mensalmente, entre novembro de 2009 e outubro de 2010, com diversos apetrechos de pesca. Durante o período foram coletados 2.220 indivíduos, sendo 901 peixes nos trechos do riacho Lopeí -bueiro circular e 1.310 peixes nos trechos do riacho Pindorama -bueiro quadrado, pertencentes a 33 espécies. As capturas foram similares nos trechos de montante e jusante no bueiro circular, enquanto que para o bueiro quadrado a abundância de peixes foi um pouco superior no trecho a montante em relação à jusante. Os Characiformes predominaram no trecho a montante de ambos os bueiros. Por outro lado, os Siluriformes foram abundantes no trecho a jusante do bueiro circular, com abundâncias similares entre os trechos do bueiro quadrado. A riqueza e...

Fish assemblages and barriers in an urban stream network

“…Our choice to include both variables in full models, despite their relatedness, was based on the distinction that they represented 2 different processes for fish communities (Smith et al 2009). We were able to distinguish the effects of both variables for our responses because changes in fish distribution related to ocean distance would appear as gradual and smooth gradients (Jackson et al 2001), whereas changes driven by number of downstream culverts would be marked by discrete shifts (Mariano et al 2012). In some instances, ocean distance and cumulative number of culverts were present together in top models.…”

Survey of fish species from plateau streams of the Miranda River Basin in the Upper Paraguay River Region, Brazil

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Composição De Espécies Da Ictiofauna Do Córrego Severo Alta Floresta-Mt

“…Posteriormente os exemplares foram identificados através das chaves de identificação de (GÉRY, 1977;REIS et al, 2003 A dominância da ordem Characiformes observada na coleta realizada Córrego Severo é um padrão comum dos córregos da região neotropical (CASATTI et al, 2001;BUCKUP et al, 2007). A prevalência desta ordem está relacionada com sua alta mobilidade no ambiente, em bueiros de riachos neotropicais observou o predomínio da ordem Characiformes e Siluriformes (MARIANO, 2012).…”