The importance of urban floodplains for the ichthyofauna

As várzeas são ambientes de grande importância para a manutenção da ictiofauna, pois funcionam como berçários naturais abrigando suas formas jovens e oferecendo recursos alimentares. Alterações nesses ecossistemas podem causar modificações na estrutura das assembleias de peixes, modificando a disponibilidade de recursos e a sua reprodução. A Lei de Proteção da Vegetação Nativa (Lei Federal 12.651 de 25 de maio de 2012), conhecida como novo Código Florestal, não protege os ambientes de várzea, sendo que a área a ser protegida é contabilizada a partir da borda da calha do leito regular do rio, e não mais no leito maior do curso dágua, o que pode trazer sérias consequências para a manutenção das espécies de peixes. No caso das várzeas urbanas, as mesmas estão ainda mais susceptíveis à ocupação e exploração, justamente por estarem dentro das cidades, justificando a necessidade de serem inventariadas e caracterizadas para que possam se propor medidas para sua proteção e conservação. No presente trabalho foi feita a caracterização ambiental e da ictiofauna em sete trechos urbanos do rio Sorocaba e em sete várzeas correspondentes. O objetivo deste trabalho foi caracterizar as várzeas urbanas em relação à ictiofauna e fazer uma comparação entre a comunidade de peixes presente nas várzeas e no rio. Foi constatada a presença de 32 espécies de peixes, sendo 22 espécies coletadas no rio e 28 coletadas nas várzeas. Os peixes coletados estão distribuídos em 32 espécies, 6 ordens e 13 famílias, sendo Characiformes e Siluriformes as ordens mais representativas. Apesar dos ambientes analisados apresentarem alto grau de antropização, pode- se considerar que o número de espécies encontradas é relevante tratando-se especificamente de áreas urbanas e levando em consideração o que já foi inventariado anteriormente para o rio Sorocaba. De acordo com os parâmetros ambientais analisados, as várzeas amostradas encontram-se em boas condições, sendo que as que estão mais distantes da área urbana são as que apresentam uma maior riqueza de espécies de peixes. Como já era esperado, há uma maior quantidade de espécies de peixes nas várzeas, por apresentarem uma maior disponibilidade de hábitats e recursos e por estarem menos sujeitas à eventuais alterações que o rio possa sofrer, como por exemplo, interferências vindas de outros municípios.The floodplains are environments of great importance for the maintenance of the ichthyofauna, as they function as natural nurseries sheltering their young forms and offering food resources. Changes in these ecosystems may cause changes in the structure of fish assemblages, altering resource availability and reproduction. The Native Vegetation Protection Law (Federal Law 12.651 of May 25, 2012), known as the new Forest Code, does not protect floodplain environments, and the area to be protected is accounted from the edge of the regular bed gutter, no longer on the larger riverbed, which can have serious consequences for the maintenance of fish species. In the case of urban floodplains, they are even more susceptible to occupation and exploitation, precisely because they are within cities, justifying the need to be inventoried and characterized so that measures for their protection and conservation can be proposed. In the present work the environmental and ichthyofauna characterization was done in seven urban stretches of the Sorocaba river and in seven corresponding floodplains. The aim of this study was to characterize the urban floodplains in relation to the ichthyofauna and make a comparison between the fish community present in the floodplains and in the river. It was found the presence of 32 species of fish, 22 species collected in the river and 28 collected in the floodplains. The collected fish are distributed in 32 species, 6 orders and 13 families, being Characiformes and Siluriformes the most representative orders. Although the analyzed environments present a high degree of anthropization, it can be considered that the number of species found is relevant, dealing specifically with urban areas and taking into account what was previously inventoried for the Sorocaba River. According to the environmental parameters analyzed, the floodplains sampled are in good condition, and those that are farthest from the urban area are those that present the largest amount of fish species. As expected, there is a greater number of fish species in the floodplains, as they have a greater availability of habitats and resources and are less subject to any changes that the river may suffer, such as interference from other municipalities

A ictiofauna do rio Tatuí, SP, Brasil e sua relação com impactos ambientais

O crescimento das cidades no interior do estado de São Paulo tem causado grandes impactos nos ecossistemas aquáticos, como é o caso do rio Tatuí que faz parte da bacia do rio Sorocaba e Médio Tietê. Estudos sobre sua ictiofauna são relevantes para a conservação e o monitoramento desse rio, sob a óptica de que o rio Tatuí é um dos afluentes que mais contribui com a poluição do rio Sorocaba. Esse trabalho teve como objetivo inventariar a ictiofauna do rio Tatuí e relacioná-las com as interferências antrópicas as quais é submetido. Foram realizadas coletas nos períodos seco e chuvoso de 2010 onde foram identificadas 18 espécies de peixes, distribuídas em 9 famílias e 2 ordens. A família mais representativa foi Characidae, com 5 espécies seguido pela família Loricariidae, com 3 espécies. A espécie mais abundante foi Hypostomus margaritifer, seguido por Hypostomus ancistroides. Considerando todos os trabalhos já realizados no rio Tatuí, um total de 53 espécies de peixes foram identificadas. Estes resultados corroboram com outros trabalhos realizados no Alto Paraná e na bacia do rio Sorocaba. Foi obtida correlação inversa entre sólidos totais dissolvidos, riqueza e diversidade, o que pode ser explicado pelo fato do rio Tatuí encontrar-se impactado em toda a sua extensão, principalmente pela falta de vegetação ciliar, assoreamento e lançamento de esgoto doméstico e industrial.

First record of the exotic species platyfish Xiphophorus maculatus (Günther, 1866) in an urban floodplain of a Brazilian neotropical river

Abstract: Aim This work reports the first occurrence of the exotic species Xiphophorus maculatus (Günther, 1866) in the Sorocaba River Basin. The introduction of non-native fish species has become common and many species have been introduced mainly through sport fishing, aquaculture and aquarium keeping. In the case of the Poeciliidae, most of the introduced species that have been recorded come aquarium keeping. The environment where the specimens were captured had a large number of macrophytes due to anthropization and is located in a strictly urbanized area of the municipality. Methods The collection was done through a rectangular dip net, with measures of 70 cm x 60 cm and a mesh of 1 mm. The specimens were anesthetized in eugenol solution, fixed in 10% formalin solution and preserved in 70% alcohol. The specimens were later deposited in a scientific collection. Results The record includes two female specimens from an urban wetland on the Sorocaba River, São Paulo State, Brazil. Conclusions In the municipality of Sorocaba, 63 species of fish have already been identified, belonging to 7 orders and 19 families and 6 are exotic, such as the Xiphophorus maculatus. Urban floodplains are poorly studied environments, thus presenting great potential for the occurrence of species that have not yet been inventoried. The monitoring and inventory of exotic species must be carried out systematically so that mitigating measures can be proposed in relation to the control of these species, and this is one of the major causes of biodiversity loss. In addition, developing a program for returning unwanted fish to aquarium stores can be effective in preventing the introduction of new aquarium fish and displaying warnings informing of the negative ecological effects of releasing aquarium fish in all bags, fish plastics, and aquarium store websites

An updated list of the ichthyofauna of Ipanema National Forest, São Paulo, Brazil

The Ipanema National Forest has been thoroughly studied in the last 25 years, and 50 species of fish species (47 native and three invasive) were reported in 2013. Intensive inventory work carried out by us between 2012 and 2017 found 39 additional species distributed in five orders and 13 families. Our study provides new data which may help efforts to preserve the Ipanema National Forest

Changes in fish species composition in the middle and lower Tietê River (São Paulo, Brazil) throughout the centuries, emphasizing rheophilic and introduced species

Abstract Aim: This paper is aimed at describing the changes of fish species in the middle and lower courses of the Tietê River, emphasizing rheophilic and invasive fish species as well as identifying the causes for such alterations. Methods Data collection consisted in: intense revision of publications, dissertations and thesis regarding the subject; information at the Zoology Museum at USP (MZUSP); revision in species identification through MUZUSP collection; historical survey of introduced species based on the literature and samplings in the years of 2000 and 2001. Results The main impacts identified in the Tietê River with consequence to the ichthyofauna were: domestic and industrial pollution, deforestation, damming, course rectification, silting and species introduction. From the 80 species identified in the study area, 28 were invasive. Many fish species have been introduced in the Tietê River since the late 19th Century with carpa (Cyprinus carpio) being the first one, followed by the introduction of black bass (Mycropterus salmonoides) at the beginning of 20th Century. Other species such as corvina (Plagioscion squamosissimus ) have been introduced by electricity companies, which has contributed to the species composition changes. Migratory species as dourado (Salminus brasiliensis ), pacú (Piaractus mesopotamicus) and pintado ( Pseudoplatystoma corruscans), which used to be abundant have become rare or absent after the construction of reservoirs, mainly because reservoirs in cascade have been built. Piracanjuba (Brycon orbignyanus), typically herbivore species, had its stock decreased due to the lack of ciliary vegetation and damming. Conclusions Following the building of the reservoirs there have been important alterations in the composition of ichthyofauna, leading to the nearly complete absence of migratory species and the prevalent species are the ones which adapted to the new conditions. In addition to the damming, lack of ciliary vegetation and pollution also caused alterations in the ichthyological community

Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications