Habitat use by two species of Hypostomus (Pisces, Loricariidae) in southeastern brazilian streams

Abstract

In this study, habitat use of the armored catfishes Hypostomus ancistroides and Hypostomus sp. was investigated in 21 streams from the Upper Rio Paraná system in São Paulo State, Brazil, a pasture dominated region. The abundance of Hypostomus sp. was positively correlated with the amount of riffles and riparian vegetation condition, whereas H. ancistroides abundance was negatively correlated with riparian vegetation condition. Thirteen ecomorphological attributes analyzed by principal component analysis showed that when compared to H. ancistroides, Hypostomus sp. presented a wider mouth and more flattened body, suggesting an adapted body to faster waters. The most abundant populations of Hypostomus sp. were predominantly associated with good riffle availability and good riparian quality, suggesting that populational features of this species may be incorporated in the stream biotic integrity assessment in that region. Key words: armored catfishes, upper Rio Paraná, ecomorphology, diet, habitat partitioning ResumoNeste estudo investigamos o uso do hábitat dos cascudos Hypostomus ancistroides e Hypostomus sp. em 21 riachos localizados em uma paisagem dominada por pastagens no sistema do Alto Rio Paraná no Estado de São Paulo, Brasil. A abundância de Hypostomus sp. foi positivamente correlacionada com a extensão de corredeiras e condição da vegetação ripária enquanto que a abundância de H. ancistroides foi negativamente correlacionada com a condição da vegetação ripária. Treze atributos ecomorfológicos, processados em uma análise de componentes principais, mostraram que quando comparada com H. ancistroides, Hypostomus sp. possui abertura bucal mais ampla e corpo mais achatado, sugerindo uma forma de corpo adaptada a ambientes correntosos. Populações mais abundantes de Hypostomus sp. estiveram predominantemente associadas a riachos com boa disponibilidade de corredeiras e boa qualidade ripária, sugerindo que atributos populacionais dessa espécie possam ser posteriormente incorporados à avaliação da integridade biótica dos riachos de nossa região. Palavras

Vertical segregation of two species of Hyphessobrycon(Characiformes: Characidae) in the Cabiúnas coastal lagoon, southeastern Brazil

“…This suggests, as established in previous studies (Ross, 1986;Peres-Neto, 1999;Casatti et al, 2005), that the use of habitat and microhabitat per se, rather than competition, must be the main factor in resource partitioning between fish species.…”

Ecomorphological differences between Rhamdia (Bleeker, 1858) populations from the Iguaçu River basin

“…Casatti et al 2005, Balassa et al 2004, Santos et al 2011). Resource partitioning is considered the principal factor in structuring the aquatic communities (Ross 1986).…”

Feeding ecology of Hypostomus punctatus Valenciennes, 1840 (Osteichthyes, Loricariidae) in a costal stream from Southeast Brazil

“…The importance of the surrounding landscape in the diet of fish species has been recognised (Vitule et al, 2003) and it has been frequently mentioned that environmental conditions are very important to the Loricariidae species as their diet is strongly associated to the substrate and the amount of available organic matter/detritus (Casatti et al, 2005;Cardone et al, 2006). Thus, diet modification of Loricariidae species was frequently associated to altered environments as a consequence of differences in the formation of periphyton and organic matter deposition (e.g.…”