Plastic use by a Brazilian freshwater bird species in its nesting activities

Here we report the use of plastics by Chrysomus ruficapillus (Vieillot, 1819) (Passeriformes: Icteridae), popularly known as “Garibaldi”, in its nesting activities. The phenomenon was registered on October 17, 2020 near Furnas reservoir, upper Paraná River Basin, in Minas Gerais, southeastern Brazil. We also discuss the possible negative effects — e.g., asphyxiation, entanglement — for C. ruficapillus using plastic materials in nesting activities. Finally, we call attention to the need for further investigations about similar events in other Brazilian watersheds

Fish passages in South America: an overview of studied facilities and research effort

ABSTRACT River regulation has fragmented fluvial ecosystems in South America, affecting fish migration and dispersion dynamics. In response, authorities have installed fish passage facilities (FPF) to mitigate impacts. However, little is known about the geographical distribution of these facilities, and no synthesis of the research effort applied to understanding their functioning and limitations exists. To address this issue, our study gathered the available scientific literature about fishways in South America to provide an overview of studied FPF and associated research effort. We found 80 studies that investigated 25 FPF, mostly ladders installed in the upper reaches of large rivers, particularly in the Paraná River Basin. One important finding is that most facilities do not lead to upstream and/or downstream sites due to the presence of other dams with no FPF. Though the number of studies has increased over the past 10 years, there is no consistent trend towards increased research effort. Overall, studies have focused on the fishway itself (i.e. upstream passage), and rarely evaluated broader issues (i.e. habitat distribution, population dynamics, conservation and management success). Our research therefore identified technical limitations of past studies, and revealed important gaps in the knowledge of FPF as a management tool

A long-term study on crustacean plankton of a shallow tropical lake: the role of invertebrate predation

The primary factor that governs the size and species composition of zooplankton is still a controversial issue and temperature is considered the main factor responsible for latitudinal differences. In waters with a narrow temperature range, such as in the tropics, predation may be a more important factor. Nearly three decades of intermittent studies of the crustacean plankton in a shallow tropical lake revealed that the main event that led to their restructuring was the appearance of a second predator, the water mite Krendowskia sp. The new predator and larvae of the dipteran Chaoborus brasiliensis Theobald exerted a combined, although asymmetrical effect on microcrustaceans. The period when the mite was detected was followed by the restructuring of the crustacean plankton community. Predation by these two invertebrates emerged as the factor responsible for community changes, involving an increased contribution of copepods and decreases in the relative abundance of smaller cladoceran species. In the short term, the mite caused a decrease in species richness and the annual mean instantaneous composition of cladocerans, a predominance of large-sized species (Daphnia ambigua Scourfield and Daphnia gessneri Herbst) and the virtual disappearance of small species (e.g., Bosmina tubicen Brehm). The long-term impact resulted in increased species richness and the dominance of large and medium-sized cladocerans, such as D. gessneri and Ceriodaphnia richardi Sars. The larger body size of three cladocerans, the two Daphnia species and B. tubicen, in the long term, may be a response to the dominant predator, Chaoborus. The seasonal variation in the predator abundance, mainly Chaoborus larvae, allowed the prey to recover during the cool season. The copepods Tropocyclops prasinus meridionalis (Fischer) and Thermocyclops decipiens Kiefer were less affected by predation than the cladocerans; their contribution to the crustacean plankton increased 12-28% after the mite appeared. The top-down effect on crustacean plankton did not affect the phytoplankton, which remained dominated by chlorophyceans and the nanoplankton fraction before and after the zooplankton community restructuring.</p

Irrigation dams threaten Brazilian biodiversity

Brazil is among the main contributors to global biodiversity, which, in turn, provides extensive ecosystem services. Agriculture is an activity that benefits greatly from these ecosystem services, but at the same time is degrading aquatic and terrestrial ecosystems and eroding Brazilian biodiversity. This conflict is growing, as emerging unsustainable legislative proposals that will benefit the agricultural sector are likely to accelerate the decline of biodiversity. One such initiative (Bill 1282/2019) would change Brazil’s “Forest Code” (Law 12,651/2012) to facilitate construction of irrigation dams in Permanent Preservation Areas, a category that includes strips (with or without vegetation) along the edges of watercourses. Two other similar bills are advancing through committees in the Chamber of Deputies. Here we provide details of these three bills and discuss their consequences for Brazil’s biodiversity if they are approved. Expected negative impacts with changes in the legislation include: increased deforestation; siltation; habitat fragmentation; introduction of non-native species; reduction in the availability of aquatic habitats; and changes in biogeochemical process. These proposals jeopardize biodiversity and may compromise the negotiations for an agreement between Mercosur and the European Union

Plastic pollution: A focus on freshwater biodiversity

Plastics are dominant pollutants in freshwater ecosystems worldwide. Scientific studies that investigated the interaction between plastics and freshwater biodiversity are incipient, especially if compared to the marine realm. In this review, we provide a brief overview of plastic pollution in freshwater ecosystems around the world. We found evidence of plastic ingestion by 206 freshwater species, from invertebrates to mammals, in natural or semi-natural ecosystems. In addition, we reported other consequences of synthetic polymers in freshwater ecosystems—including, for instance, the entanglement of animals of different groups (e.g., birds). The problem of plastic pollution is complex and will need coordinated actions, such as recycling programs, correct disposal, stringent legislation, regular inspection, replacement of synthetic polymers with other materials, and ecological restoration. Current information indicates that the situation in freshwater ecosystems may be as detrimental as the pollution found in the ocean, although highly underappreciated.Fil: Azevedo Santos, Valter M.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Brito, Marcelo F. G.. Universidade Federal de Sergipe; BrasilFil: Manoel, Pedro S.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Perroca, Júlia F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Rodrigues-Filho, Jorge Luiz. Universidade Federal de Santa Catarina; BrasilFil: Paschoal, Lucas R. P.. No especifíca;Fil: Gonçalves, Geslaine R. L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Wolf, Milena R.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Blettler, Martin Cesar Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Andrade, Marcelo C.. Universidade Federal do Pará; BrasilFil: Nobile, André B.. No especifíca;Fil: Lima, Felipe P.. No especifíca;Fil: Ruocco, Ana M. C.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Silva, Carolina V.. No especifíca;Fil: Perbiche Neves, Gilmar. Universidade Federal do São Carlos; BrasilFil: Portinho, Jorge L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Giarrizzo, Tommaso. Universidade Federal do Pará; BrasilFil: Arcifa, Marlene S.. Universidade de Sao Paulo; BrasilFil: Pelicice, Fernando M.. No especifíca

Fragmentation of a Neotropical migratory fish population by a century-old dam

Loss of connectivity in impounded rivers is among the impacts imposed by dams, and mitigation measures such as fish passages might not accomplish their purpose of reestablishing an efficient bi-directional gene flow in the fish populations affected. As a consequence, fish populations remain fragmented, and a new interpopulational structure may develop, with increased risk of reduced genetic diversity and stochastic extinction. In order to evaluate the effects of the Gavio Peixoto Dam, which was constructed almost a century ago on the Jacar,-Gua double dagger u River in the Upper Parana River basin, Brazil, a comparative morphometric study was undertaken on the populations of the Neotropical migratory characid fish Salminus hilarii living up- and downstream of this dam. Population dynamics, spatial segregation, and habitat use by different age classes were monitored for 2 years. We found that segregation caused by the dam and long periods with no efficient connection by fish passages have led to fragmentation and interpopulational structuring of S. hilarii, as revealed by canonical variable analysis of morphometric features. The fish populations occupying the up- and downstream sections have succeeded in performing short-distance reproductive migrations in the main river and tributaries, have found suitable habitats for completing their life cycle, and have been able to maintain distinct small-sized populations so far