When habitat complexity increases predation risk: experiments with invasive and neotropical native fishes

Abstract

We tested the predator–prey relationships between a native piscivore (Salminus brasiliensis) and introduced and native fish species of the Paraná River, Brazil. We hypothesised that S. brasiliensis can exert biotic resistance against invasive fishes but not at the same degree for all species. Three invasive (Cichla piquiti, Oreochromis niloticus and Ictalurus punctatus) and two native (Astyanax altiparanae and Prochilodus lineatus) species were offered as prey to S. brasiliensis in 300 L aquaria trials at three levels of cover (0%, 50% and 100% of artificial macrophytes). S. brasiliensis had a greater ability to capture prey in complex habitats, so predation success did not decrease with habitat complexity and even increased on I. punctatus. Prey survival was variable through time and among species, being high for I. punctatus. The three most consumed species (P. lineatus, C. piquiti, and O. niloticus) were less active and occupied the aquaria surfaces, changing strongly their behaviour with habitat complexity. Except for P. lineatus and C. piquiti, S. brasiliensis preferably preyed on smaller individuals of the other species. Our experiments support that S. brasiliensis is an interesting candidate to resist the invasion by C. piquiti and O. niloticus but not to control the abundance of I. punctatus.

Evaluation of factors associated with dynamics of Cichla ocellaris invasion of the Upper Paraná River floodplain system, Brazil

“…The filling of Itaipu Reservoir submerged the Sete Quedas Falls and allowed the upstream spread of fish species previously restricted to the Lower Paraná River Basin (Júlio et al 2009;Vitule et al 2012), and consequently increased fish diversity of the Upper Paraná River Basin (Britton and Orsi 2012). In addition to the direct adverse effects on native fish assemblages, such as habitat changes, blockage of migratory routes, and disturbances on ecosystem functioning (Agostinho et al 2005(Agostinho et al , 2008Gubiani et al 2007;Júlio et al 2009), the presence of Itaipu Reservoir and other impoundments in the basin probably have also contributed to the invasion and establishment of many nonnative fish species, including C. ocellaris, in the UPRF (Santos et al 2009(Santos et al , 2012(Santos et al , 2013. C. ocellaris took seven years to invade the UPRF, where it remained at low densities (,5 individuals per sample) in floodplain lakes and secondary channels of all three rivers until 2001 ( Fig.…”

Environmental enrichment for fish in captive environments: effects of physical structures and substrates

“…; Santos et al . ). A study on Atlantic salmon even suggests that the mere presence of a shelter (i.e.…”

“…Added shelters are indeed often utilized by the captive fish, at least in species which typically uses shelters in their natural environment (e.g. Brown et al 1970;Slav ık et al 2012;Santos et al 2013). A study on Atlantic salmon even suggests that the mere presence of a shelter (i.e.…”

Assessing the impacts of the introduced channel catfish Ictalurus punctatus using the comparative functional response approach

“…It is important to consider other factors that may alter FR results, such as habitat complexity (Alexander, Dick, O'Connor, Haddaway & Farnsworth, ; Barrios‐O'Neill, Dick, Emmerson, Ricciardi & MacIsaac, ), which in some cases can change the FR type and parameters. This can occur if habitat complexity acts as a refuge for prey in low density (Alexander, Kaiser, Weyl & Dick, ) or contributes to predation of ambush predators, resulting in a higher consumption rate (Santos, García‐Berthou, Hayashi & Santos, ). This context‐dependency factor may also be an important feature to be tested in the FR of I. punctatus , as the River Guaraguaçu has been invaded by the African signal grass Urochloa arrecta , a macrophyte that increases habitat complexity (Michelan, Thomaz, Mormul & Carvalho, ; Thomaz & Cunha, ; Vitule, Umbria & Aranha, ).…”