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The Manguruyú Zungaro jahu, endemic to the La Plata Basin, is one of the largest neotropical fish species whose life history is virtually unknown. The objectives of this study were to determine if Z. jahu is a large‐scale migratory species and to describe habitat use throughout ontogeny using the otolith Sr isotope (87Sr/86Sr) ratio. Surface water samples were collected in 2020 at four sites representing the main water courses of the Great Pantanal in Brazil (upper Paraguay, Cuiabá, São Lourenço and Vermelho rivers). Eighteen fish individuals were collected from the Paraná River (Argentina). New water 87Sr/86Sr data were incorporated into previously established statistical models to infer the fish habitat use through the otolith 87Sr/86Sr ratios. The water 87Sr/86Sr ratio of the upper Paraguay tributaries varied (0.7209 and 0.7229) and were the highest in the La Plata Basin. The dispersal area of Z. jahu was restricted to the surroundings of the confluence of the Paraná and Paraguay rivers. Fish showed chemical signatures compatible with those of the middle Paraná (88%), Paraguay‐Pilcomayo‐Bermejo (50%) and the lower/upper Paraná (66%). The discriminant analysis based on otolith core indicated natal origins from the middle Paraná (37%), upper Paraná (32%), and Paraguay sub‐basin (32%). The dispersal area of Z. jahu migrations could be restricted to the surroundings of the confluence of Paraná and Paraguay, which highlights the need to review regional fishing regulations, especially between latitudes 30°–34° S. [ABSTRACT FROM AUTHOR]

Although the species–area relationship is well known, it may interact with and be augmented or cancelled out by other factors, such as local human disturbance. We used data on site occupancy of the Endangered blonde capuchin monkey (Sapajus flavius) based primarily on a standardized program of local interviews to model the influence of past human disturbance on the occurrence of this species across remaining forest patches of northeastern Brazil within the Atlantic Forest and Caatinga biomes. To do so, we assessed environmental covariates that best represent the history of human impacts. We then used single‐species occupancy models to assess site occupancy, while controlling for detection error during sampling. Surprisingly, we obtained a higher occupancy rate in the more arid Caatinga remnants than in the more mesic Atlantic Forest. Habitat patch size, history of site protection, and annual precipitation were the best predictors of local occupancy. Historical human disturbance, including subsistence hunting, has exerted considerable impact on the modern distribution of the blonde capuchin, whose geographic range largely spans a region historically lacking any wildlife protection. Matrix vegetation structure across the Caatinga, which so far has averted large‐scale mechanized agriculture, also creates a benign landscape that likely benefits contemporary capuchin occupancy. Local extinctions of this endangered primate will most likely continue unabated unless a ban on hunting in remaining Atlantic Forest and Caatinga fragments can be enforced. Highlights: The dry forest Caatinga had more fragments with this blonde capuchin monkey than the humid tropical Atlantic Forest.The landscape that averted large‐scale mechanized agriculture benefits contemporary capuchin occupancy.Larger patches with a positive historical of protection are more capable to shelter this endangered primate. [ABSTRACT FROM AUTHOR]

Fisheries are the most common ecosystem service that fish provide to human populations, yet recreational fisheries are often overlooked when evaluating such services. Here, the socioeconomic profiles of fishers, the composition of their catches and catch per unit effort (CPUE) are described, to estimate the economic value of the recreational fishery on a stretch of the Cuiabá River in the Brazilian Pantanal. Questionnaires were used to obtain socioeconomic information and fishing yield from fishers for 2013 and 2014. Additionally, a census on the number of fishers and fishing platforms along the sampled region was conducted in 2018. This recreational fishery mostly involves middle class adult males, based mostly in the Cuiabá city metropolitan region. They invested, on average, US$41.1 (SD = US$16.5, median = $35.2) per fishing visit, catching around 19 fish species. Overall, mean CPUE from the recreational fishery was 42.20 fish/fisher.day (17.4 kg/fisher/day). Annual economic value of this recreational fishery was estimated at around US$1.8 million, which highlights the importance of this activity to the local economy. Greater environmental conservation efforts are recommend to ensure the long‐term viability of this ecosystem service. [ABSTRACT FROM AUTHOR]

Many frugivorous animals act simultaneously as seed predators and dispersers, and shifts in the abundance and mean phenotype of the frugivore population can alter the prevalence of antagonistic versus mutualistic interactions with seeds.Here, we evaluated how a reduction in the abundance and species richness of large‐bodied frugivorous fishes affects their interactions with plants in a Neotropical floodplain. Fisheries selectively harvest large frugivorous fishes, which are the most effective seed dispersers. Thus, functional extinctions of fish mutualists can cascade to secondary extinctions of plants and their biotic associates, and ecosystem‐level change.We evaluated functional responses of wetland communities to changes in fish body size by modelling the robustness of plant–frugivore networks to different extinction scenarios, using fish body size as a functional trait influencing seed dispersal and seed predation. We built ecological networks for frugivory, seed dispersal and seed predation.All networks lacked modularity and showed reduced nestedness compared with randomized networks. The three networks indicated that frugivorous fish have wide niches and low to intermediate degree of specialization. Network robustness to extinction of frugivorous fish decreased with selective loss of large individuals.Synthesis and applications. We predict that reductions in the abundance of large‐bodied fish species will enhance the dominance of plant species with small seeds and decrease plant diversity. The functionally most important species in our networks are the most susceptible to overfishing. Therefore, sustainable management in these ecosystems needs to contribute to protecting interactions and, consequently, ecological and evolutionary processes related to maintaining biodiversity in vast wetland forests. [ABSTRACT FROM AUTHOR]

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Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding the relative importance of abiotic factors and biotic interactions in determining species co‐occurrence is a fundamental goal in ecology. Most studies of ecology of freshwater fishes have focused on negative biotic interactions (competition and predation), and much less is known about more positive interactions. The goal of this study was to quantify the relative importance of habitat features and biotic interactions (positive and negative) on co‐occurrence of three pairs of feeding‐associative Leporinus (L.) fishes in rivers of central Brazil (L. friderici–L. octomaculatus, L. striatus–L. octomaculatus, L. friderici–L. striatus).We sampled 146 sites on two rivers of central Brazil and used two‐species occupancy models to examine the relative importance of habitat features and commensalistic feeding association for determining co‐occurrence of the three species pairs. Using an information–theoretic framework, we compared weight‐of‐evidence for models containing effects of habitat covariates only, biotic interactions only, and their combination.Model evidence supported the hypothesis that feeding activity of L. friderici facilitates occurrence of L. octomaculatus and that the interaction is mediated by habitat covariates. In contrast, most evidence suggested that occurrence of L. striatus is independent of L. friderici, and is instead determined entirely by habitat features. Evidence for facilitation of L. octomaculatus by L. striatus was mixed—there is evidence supporting the habitat‐only hypothesis as well as habitat‐mediated facilitation.Our results suggest that positive interactions can affect co‐occurrence among freshwater fishes, at least for species that interact strongly. More facultative interactions, such as those between L. friderici and L. striatus, may be less important, at least in certain abiotic contexts. This study indicates that biotic interactions between species of freshwater fish can be evident beyond the microhabitat scale to positively influence species co‐occurrence and adds to evidence from other groups of freshwater organisms indicating the importance of biotic interactions in facilitating species co‐occurrence. [ABSTRACT FROM AUTHOR]

The metapopulation paradigm has been central to improve the conservation and management of natural populations. However, despite the large number of studies on metapopulation dynamics, the overall support for the relationships on which the paradigm is based has not been strong. Here, we studied the occupancy dynamics of two Neotropical fishes (i.e., Pimelodella gracilis and Leporinus friderici) to investigate two fundamental premises of the metapopulation paradigm, that is, that isolation and area/habitat quality affect colonisation and extinction probabilities in predictable ways. In order to do this, we used a modification of occupancy models that allows modelling the probability of a site's occupancy as a function of the occupancy of its neighbourhood. We found a weak positive effect of neighbourhood occupancy on P. gracilis colonisation, which is consistent with the propagule rain metapopulation, that is, colonists arriving from outside the studied system. However, we found a strong negative neighbourhood effect on extinction probability, suggesting that declining populations from stream sections are rescued from extinction by neighbouring patches. In contrast, the effect of neighbourhood occupancy on the metapopulation dynamics of L. friderici was in the opposite direction, affecting positively colonisation but not affecting extinction rates, which is consistent with the classical metapopulation model. In addition, the occupancy dynamics of both species were affected by water velocity. To our knowledge, this is the first study to link directly dispersal to local population dynamics in Neotropical fishes, and one of the few studies doing inferences on spatial population dynamics based on direct estimates of neighbourhood occupancy. [ABSTRACT FROM AUTHOR]

The length–weight relationships (LWRs) were estimated of seven fish species from 22 localities in the Pantanal wetland between Mach 2006 and April 2011. Fish were sampled using seven gill nets (20 × 1.5 m; mesh size: 12, 15, 18, 20, 25, 30 and 50 mm between opposing knots) and throw traps (made of 1 m3 metal cubes, covered by a 1.5 mm nylon mesh). Standard length and weight were measured and used to calculate the LWR parameters. Values for parameter b varied from 2.87 (Apistogramma borellii) to 3.29 (Hoplerythrinus unitaeniatus) and, such values are within the expected range. [ABSTRACT FROM AUTHOR]

When species within guilds perform similar ecological roles, functional redundancy can buffer ecosystems against species loss. Using data on the frequency of interactions between fish and fruit, we assessed whether co-occurring frugivores provide redundant seed dispersal services in three species-rich Neotropical wetlands. Our study revealed that frugivorous fishes have generalized diets; however, large-bodied fishes had greater seed dispersal breadth than small species, in some cases, providing seed dispersal services not achieved by smaller fish species. As overfishing disproportionately affects big fishes, the extirpation of these species could cause larger secondary extinctions of plant species than the loss of small specialist frugivores. To evaluate the consequences of frugivore specialization for network stability, we extracted data from 39 published seed dispersal networks of frugivorous birds, mammals and fish (our networks) across ecosystems. Our analysis of interaction frequencies revealed lowfrugivore specialization and lower nestedness than analyses based on binary data (presence-absence of interactions). In that case, ecosystems may be resilient to loss of any given frugivore. However, robustness to frugivore extinction declines with specialization, such that networks composed primarily of specialist frugivores are highly susceptible to the loss of generalists. In contrast with analyses of binary data, recently developed algorithms capable of modelling interaction strengths provide opportunities to enhance our understanding of complex ecological networks by accounting for heterogeneity of frugivore–fruit interactions. [ABSTRACT FROM AUTHOR]

Density-dependent dynamics have considerable effects in many ecological processes and patterns that characterize natural populations. In the present study, we aim at evaluating the effect of density on the diet width and between-individual variability in nine different pike cichlid Crenicichla lepidota populations dwelling in floodplain lagoons. Our results indicated that low-density populations exhibit small diet breadth as well as small betweenindividual variability in their diet. In addition, these populations were characterized by a nested diet pattern, where the diet of specialist individuals represented a subset of the food items consumed by generalist individuals. Populations with intermediate densities had a larger populational diet breadth while the individual diet breadth remained unchanged. This pattern was due to an increase in between-individual variability in diet, which consequently decreases the diet overlap among individuals and thus lower diet nestedness. Finally, under high densities, the niche width at the population level decreased because of lower between-individual variability and higher diet overlap. Together, these results showed that niche width exhibits a non-linear function with density. At first, an increase in density increased the niche width because of greater between-individual diet variability. However, after a threshold density value, the effect was reversed, and the niche width decreased because of a higher diet overlap among individuals. [ABSTRACT FROM AUTHOR]

In this study, we report on shelter use by anurans during the dry season in the Pantanal, a large wetland in midwestern Brazil that is subject to periodical floods, dry periods, and sporadic fires. Field observations were made in the northern Pantanal from 2010 to 2013. We documented the use of underground burrows by seven frog species (about 20% of the known local anuran richness), including representatives of Hylidae, which tend to be arboreal. Most shelters used were galleries similar to those built by the crab Dilocarcinus pagei (Trichodactylidae). We also report on experimental and opportunistic observations on the use of termite thermal chimneys by the toad Rhinella bergi. Due to the prevalence of open areas in the Pantanal and absence of overlapping rocks and other types of shelter, underground galleries and tunnels in termite mounds may often be important refuges for anurans during the dry season and fires. Therefore, these tunnels may contribute significantly to the structuring of ground-dwelling anuran communities, which requires further studies. These studies should also address the indirect impacts of potential threats to the availability and integrity of underground burrows in the Pantanal, such as land management practices, uncontrolled crab exploitation, and extended extreme climatic events. [ABSTRACT FROM AUTHOR]

Copyright of Biota Neotropica is the property of Biota Neotropica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new policy in the Pantanal wetland, Brazil, aims to economically displace thousands of artisanal fishers from one‐third of the region. The legislation disregards several FAO Voluntary Guidelines for Securing Sustainability in Small‐Scale Fisheries' guiding principles (SSF guidelines). Considering that 2024 marks the 10th anniversary of these guidelines, this policy represents a significant setback for fish and fisheries worldwide. In this paper, we show that the legislation is part of long‐term agenda against small‐scale fishers in the Pantanal, aiming to use narratives around overfishing to justify physical and economic displacements—albeit no empirical evidence showing impact on fish stocks. We also show that, as in many other small‐scale fisheries worldwide, overfishing narratives are, in fact, used to open space for industrial activities and large infrastructure projects. The Pantanal is a telling story of that, since the new legislation will likely open space for the construction of over 50 small hydroelectric dams in the Pantanal and surrounding area. We argue that, first, it is urgent to abolish the new legislation and promote a pro‐fishers agenda in the Pantanal to protect the region. However, since this is not unique for the region, it is critical to implement international programmes that celebrate and support local fisheries worlwide and avoid physical and economic displacements. Stands out turning SSF guidelines into international agreements, implementing citizens science programmes and expanding the fisher's tenure rights through innovative mechanizes of ownership. By better protecting local small‐scale fishers in the Pantanal and worldwide we are more likely to guarantee a sustainable future for ecosystems and its peoples. [ABSTRACT FROM AUTHOR]

Building bridges between environmental and political agendas is essential nowadays in face of the increasing human pressure on natural environments, including wetlands. Wetlands provide critical ecosystem services for humanity and can generate a considerable direct or indirect income to the local communities. To meet many of the sustainable development goals, we need to move our trajectory from the current environmental destructive development to a wiser wetland use. The current article contain a proposed agenda for the Pantanal aiming the improvement of public policy for conservation in the Pantanal, one of the largest, most diverse, and continuous inland wetland in the world. We suggest and discuss a list of 11 essential interfaces between science, policy, and development in region linked to the proposed agenda. We believe that a functional science network can booster the collaborative capability to generate creative ideas and solutions to address the big challenges faced by the Pantanal wetland. [ABSTRACT FROM AUTHOR]

Defaunation is disrupting plant–animal interactions worldwide. The overhunting of frugivores disrupts seed dispersal and diminishes plant regeneration, yet investigations of frugivore overexploitation neglect an ancient guild: fruit-eating fish. For nearly five decades, Neotropical frugivorous fishes have been intensively harvested. These fishing activities have reduced population sizes of some species by up to 90% and have likely altered populations to younger, smaller individuals. Here we evaluate potential ecological consequences of overfishing frugivores for seed dispersal and recruitment dynamics. We analyzed dietary data from seven fruit-eating fish species in Amazonian and Pantanal wetlands to test the hypothesis that seed dispersal effectiveness increases with fish size within and across species. Relative to small individuals, larger fish dispersed large numbers of seeds of a higher diversity of plants and a greater range of seed sizes. For some seed species, dispersal by larger fish augmented germination success, relative to seeds dispersed by smaller fishes. Large Piaractus mesopotamicus in the Pantanal disperse seeds of 27% more species than fishes under the minimum size limit for this fishery. Our results indicate that the ongoing overexploitation of multiple frugivorous fish species could depress the quantity and diversity of seeds dispersed, as well as the quality of seed dispersal in wetland habitats that extend over 15% of the area of South America. [ABSTRACT FROM AUTHOR]

The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its logic has been applied in some other southern-hemisphere countries. The program supports all aspects of research necessary to understand biodiversity and the processes that affect it. There are presently 161 sampling sites (see some of them at Supplementary Appendix), most of which use a standardized methodology that allows comparisons across biomes and through time. To date, there are about 1200 publications associated with PPBio that cover topics ranging from natural history to genetics and species distributions. Most of the field data and metadata are available through PPBio web sites or DataONE. Metadata is available for researchers that intend to explore the different faces of Brazilian biodiversity spatio-temporal variation, as well as for managers intending to improve conservation strategies. The Program also fostered, directly and indirectly, local technical capacity building, and supported the training of hundreds of undergraduate and graduate students. The main challenge is maintaining the long-term funding necessary to understand biodiversity patterns and processes under pressure from global environmental changes.