Explore the vast range of titles available.

Brazil has a variety of aquatic ecosystems and rich freshwater biodiversity, but these components have been constantly damaged by the expansion of unsustainable activities. An array of different conservation strategies is needed, especially the creation of protected areas (PAs, hereafter). However, Brazil’s PAs are biased towards terrestrial ecosystems and we argue that current PAs have limited efficacy in the protection of freshwater biodiversity. New PAs should better consider aquatic environments, covering entire basins, rivers and other freshwater habitats. We recommend ways to implement these PAs and provide guidance to avoid social impacts. Freshwater systems in Brazil provide essential goods and services but these ecosystems are being rapidly degraded and will be lost if not adequately protected.

Converting river flows into reservoirs is a major disturbance that triggers ecological succession, altering the functional and phylogenetic structure of aquatic communities. However, this process in off-river reservoirs remains understudied, despite its potential implications for biodiversity conservation. Here, we investigated fish assemblage colonization and establishment in a recently created off-river intermediate reservoir (IR) within the Belo Monte Hydroelectric Complex in the Amazon. Fish were sampled over seven years in the IR and compared to the main reservoir (MR) and a more pristine sector upstream (UP). Biodiversity in the IR increased over time, alongside shifts in species composition, traits, and phylogenetic structure. Dominance of large and benthic-rheophilic species rose, and the proportion of adults increased, indicating improved reproductive potential. These changes were likely influenced by environmental filtering, dispersal limitations, and resource scarcity during the initial years post-formation. Over time, the IR became more similar to the MR than the UP, reflecting species decay similarity and environmental resemblance between reservoirs. Dissimilarity between the IR and river sectors diminished as succession progressed. Our results suggest IR may serve as a refuge for endemic and rare rheophilic fish, supporting fish stocks for riverine communities and offering a conservation tool amid hydropower development and climate change. The true test of the IR’s value for local biodiversity will unfold as it ages, making consistent monitoring of the IR essential to assess its long-term ecological impact.

The introduction of non-native species (NNS) and the resulting biological invasions are conspicuous features of the Anthropocene Epoch. Parallel to these phenomena, some initiatives (political, social and scientific) have sought to value and protect invasive populations, recognizing some benefits that NNS may deliver to people and nature. Given this growing trend of valuing NNS, we considered opportune to address this issue in the context of megadiverse tropical countries. We investigated an emerging trend that has advocated the protection of highly invasive fishes by legal instruments, i.e., the protection of invasive peacock basses (genus Cichla) in Brazil. We recorded 16 bills or laws proposed between 2017 and 2022 that determine fishing restrictions to protect invasive Cichla spp. from overfishing and other impacts, in order to favor population recruitment, growth, colonization and spread. Specifically, they establish restrictions on fishing, capture, transport, trade, and processing, including quotas, compulsory catch and release, length limits, use of gears, and temporal interdictions. They also determine the naturalization of peacock basses in some main basins of South America, which include different watersheds and ecoregions, with risk of intercountry invasions. This particular case is instructive to unveil the risks of positions that emphasize positive contributions of NNS to society and nature, as these misguided conservation actions favor invasive organisms with high potential to cause environmental degradation, biodiversity losses, and social conflicts. These positions find fertile ground in some contexts, especially in tropical developing countries, where economic constraints, poor access to information, opportunism, and bad political behavior have been the norm.

The Rio Grande drainage plays a key role in supplying water and electricity to large urban centres, but some components of its rich ichthyofauna are still poorly known. Based on our field inventories in the middle section of the drainage, we recognised 10 trichomycterine endemic species, of which 6 species are new and described herein. A molecular analysis (2600 bp for 43 taxa) indicated that the species of both subgenera do not form monophyletic groups. One species of the subgenus Cryptocambeva is closely related to species from the inner Brazilian Plateau, whereas other species of this subgenus are closely related to species endemic to smaller coastal basins. The species of the subgenus Paracambeva belong to different lineages of a clade endemic to the Rio Grande drainage. These species are diagnosed by the characters of their external morphology and osteology. A key to species identification is provided. The species distribution patterns support delimitation of three areas of endemism, which may have a relevant role for proposals of conservation strategies: the Uberaba, the São João-Sapucaí, and the Tamborete areas. The last one, a small area confined between the Serra da Canastra and the Rio Grande at the Furnas dam, is particularly important for sheltering three endemic trichomycterines and two loricariid catfishes.

To understand how Neotropical freshwater fishes (NFF) benefit society, we conducted a broad literature survey to (i) map and list the ecosystem services (ES) generated by these organisms, and (ii) investigate how human activities have affected the ecosystem service chain. We found sound evidence that NFF contribute directly and indirectly to the generation of several provisioning, regulating, supporting, and cultural services. Provisioning services have been widely recognized, especially those related to fisheries, but this class also included ornamental fish, genetic pools, medicines, aquaculture, and bioindicators. Other services remain less understood and largely ignored by society. Regulating services included seed dispersal, decomposition, and top-down control, while supporting services included nutrient cycling, habitat quality, and ecosystem engineering. Cultural services associated with NFF included recreational fishing, tourism, fishkeeping, education, production of scientific knowledge, in addition to values linked to traditional communities, such as local knowledge, cosmology, and existential foundations. Human activities have negatively impacted the generation of ES, especially those related to fishing and food provisioning. This review indicates that Neotropical fishes benefit society in multiple ways, but it is imperative to improve our understanding about those benefits, and to increase conservation efforts directed to this important component of global biodiversity.

The Cambeva variegata group (CVG) is endemic to a region situated in the intersection of two endangered biodiversity hotspots, Cerrado and Atlantic Forest, and drained by two important South American river basins, the upper Rio Paraná and upper Rio São Francisco basins. Presently, CVG comprises two nominal species, besides some still undescribed. We first performed a molecular phylogenetic analysis (total of 3368 bp) for five species of the CVG and 30 outgroups, which supported the monophyly of the CVG and its inclusion in Cambeva. Most morphological character states distinguishing the CVG from congeners are also present in Scleronema, possibly consisting of plesiomorphic features. We also performed the first time-calibrated phylogeny of the group, which supported possible relationships between present geographical distribution patterns and palaeogeographical events. The estimated time of origin of CVG in the Middle Miocene is nearly contemporaneous to a past hydrographical configuration when part of the upper Rio Paraná basin was connected to the Rio São Francisco basin. The first CVG lineage split occurring in the Miocene end corresponds to a major break in that palaeo basin. Species diversification between the Pliocene and early Pleistocene is compatible with final drainage rearrangement. This study highlights the urgent need for more detailed studies on the diversity and phylogenetic relationships of still poorly known organisms in this highly diverse and threatened region.

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 seminatural 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.

Abandoned, lost or otherwise discarded fishing nets (i.e., ghost nets) strongly affect biodiversity in marine ecosystems of numerous localities around the world. Based on videos posted by different people in YouTube™, we accessed the negative effects of these gears in the Mediterranean Sea. We identified 86 species, from 12 groups, in 12 countries within the Mediterranean region (including in the Africa, Europe, and Asia). Of the species entangled in ghost nets, 10 are considered threatened with extinction according to the International Union for Conservation of Nature. Fishes and macrocrustaceans were the most recorded groups entangled in ghost nets. We also identified algae, other invertebrates (i.e., cnidarians, echinoderms, molluscs, poriferans, tunicates) and vertebrates (i.e., turtles and mammals). The larger number of ghost fishing events were recorded in Italy and Turkey. This is the most complete study showing the negative effects of ghost nets on marine biodiversity worldwide, based on data retrieved from digital media. With the available literature, our data are important to implement measures against ghost fishing nets in the Mediterranean Sea.