Ichthyofauna diet changes in response to urbanization: the case of upper Paranapanema River basin (Brazil)

Abstract

Alterations in stream environments can alter fish food availability, but there is little research data related to the impacts of urbanization on fish diets in tropical streams. Thus, we sought to compare the diet of ten fish species in urbanized and nonurbanized streams reaches. Fish stomach contents were obtained for four urban and five non-urban stream reaches from two medium-sized cities. We verified the similarity of diet composition from urbanized/non-urbanized streams. In-stream features mainly related to the substrate highlighted a perturbation gradient: gravel, pebbles and cobbles were associated to the wider urban reaches while silt were representative in the narrow pools from non-urban streams. Fishes changed their diet in response to urban and non-urban treatments. Omnivorous fishes consumed more detritus and Chironomidae and less terrestrial adult insects in urban reaches, while invertivorous fish consumed more terrestrial adult insects and Trichoptera larvae in the non-urbanized stream reaches. Although the management of the physical structure of streams in Brazil has been basically focused on riparian reforestation, our results suggest that a restoration plan for urban streams cannot be limited to reforestation of its surroundings, but also need to consider the physical structure of the channel, especially the substrate, which contributes to promote in-stream variability.

Knowing biodiversity: Fishes from the Guareí River basin, a tributary of the Jurumirim reservoir, Paranapanema River, Brazil

“…Cetra et al (2012) were probably the first to record this species in the Paranapanema River basin. Later, other authors reported its presence in different waterbodies of the same watershed (Cerqueira et al 2016;Cetra et al 2016;Peressin et al 2018).…”

Environmental and spatial effects on coastal stream fishes in the Atlantic rain forest

“…However, most of the protected and preserved areas of the Atlantic Forest cover regions that include only headwaters (Baptista, Dorvillé, Buss, & Nessiamian, ) located above 100 m (100 m is the legal limit of the Serra do Mar above which human occupation is prohibited), which also turn out to be zones where fish diversity (Gonçalves & Braga, ) and also aquatic insects (Baptista et al, ) are lower. Consequently, the aquatic fauna located on the coastal plain (the most species‐rich sites, and also probably the source pool for the species in our communities) are more susceptible to anthropogenic impacts such as deforestation (which may homogenize aquatic habitats (Casatti et al, )) and urbanization (Peressin, Gonçalves, & Cetra, ), since the biggest cities in Brazil ( e.g. , Sao Paulo, Rio de Janeiro) are near the coast and their expansion surely affects the integrity of the lowermost stream reaches that are easy to access and perturb.…”

Stream fish metacommunity organisation across a Neotropical ecoregion: The role of environment, anthropogenic impact and dispersal-based processes

“…The fish samplings were performed in stream reaches from downstream to upstream along stretches of at least 50 meters, according to one of the following methods: electrofishing was utilised along a stream reach by researchers holding a net connected to a generator and using the electric discharge to stun/catch fishes [67,68] or fishes were captured with hand-nets (seines and sieves) carried out by two people along the stream reaches during approximately two hours [69]. The fish caught were fixed in formalin solution and then transferred to 70% ethanol.…”