Accounting for land-use change underlying food sector expansion is critical for conserving ecosystem integrity. This challenge is particularly acute in the Amazon, where the conversion of forests for food production is pronounced and has broad implications for global biodiversity and the cycling of water and carbon. Here, we analyze land-use transitions associated with aquaculture development in the Brazilian Amazon. We found that a 450-fold increase in aquaculture pond area from 1985 to 2022 occurred primarily on pasturelands (87%) but also included wetland conversion (4%) and deforestation (5%). Notably, continued growth can be sustained within already altered landscapes: In Rondônia, the leading aquaculture state in the Amazon, production could double by converting only 1.2% of the total degraded pasture area. While directing aquaculture expansion toward degraded pastures could reduce further natural habitat conversion and carbon costs historically associated with food production in the Amazon, realizing this potential will depend on strong governance and enforceable land-use policies to guide siting decisions.

Animals can dramatically alter ecosystem structure and function through the cycling and transport of nutrients in their waste. While birds are particularly capable of influencing nutrient cycles due to their high mobility, abundance, metabolism and functional diversity, the factors shaping variation in nutrient release among birds remain poorly understood. We examined how trophic position, phenology and body size shape the release of carbon (C), nitrogen (N) and phosphorus (P) in the waste of a diverse assemblage of songbirds. We analysed waste samples (reflecting excretion and egestion) from 151 individual songbirds (31 species) at a migratory stopover site during one spring and one fall season in upstate New York, USA. Trophic position, represented by delta 15N in waste, correlated positively with %N and negatively with C:P. Waste stoichiometry also differed between seasons with higher %N and lower C:N in spring compared to fall as birds shifted their diets from N-rich insects in spring to C-rich fruits and seeds in fall. Birds in the fall exhibited increased fattiness, and body size had the strongest influence on C, N and C:N release during this season, suggesting that fat accumulation for energy storage may shape nutrient excretion prior to migration. However, the effects of body mass and its interactions with season and trophic position were complex. Ultimately, trophic position, phenology and body mass together helped explain variation in nutrient release among songbirds. Future research may leverage this information to further explore how migratory songbirds influence stopover habitats and other ecosystems via contributions to nutrient cycling.Read the free for this article on the Journal blog.

Objective Riverine fish conservation commonly focuses on restoring connectivity for migratory fishes by removing old dams that fragment otherwise large swaths of free-flowing river. For nonmigratory fishes, the removal of these dams may not elicit the same positive response because they can complete their life cycle in small stretches of river. Many nonmigratory fishes exhibit a bell-curve-shaped distribution in density: low at their upstream and downstream extents and high at their core. We hypothesized that Redbreast Sunfish Lepomis auritus in tributaries to the lower Hudson River, New York, United States, would show lower population density and mean effective population size (Ne) in smaller streams and would show increased genetic drift when these smaller streams were impounded.Methods We developed a microsatellite genotyping panel to test for genetic isolation by distance, identify different measures of Ne across the watershed, and identify landscape features that drive pairwise genetic differentiation between populations.Results We found genetic isolation by distance and inhibition of upstream movement across dams and a waterfall. Further, Ne and catch per second of electrofishing were significantly lower in upstream reaches. Redbreast Sunfish genetic differentiation was primarily driven by river distance and intact dams, with dams on smaller streams being associated with greater differentiation than dams on larger streams.Conclusions Our findings suggest that removal of dams at the upstream fringes of a nonmigratory species' within-basin range could alleviate a greater degree of genetic differentiation than the removal of dams at the core of the species' distribution. The conservation implications of upstream barriers for imperiled nonmigratory taxa have potentially been overlooked and may lend more options to managers balancing the complex social, financial, and ecological criteria guiding the dam removal decision-making process. Ecological and genetic analyses of Redbreast Sunfish in tributaries to the lower Hudson River, New York, suggest that dams fragment populations of nonmigratory freshwater fishes, with the most negative effects occurring when small populations are isolated.

Wild fish harvests from freshwaters and oceans per person on Earth have been stagnating for decades due to increased food demand from a burgeoning global human population, raising the stakes for maximizing the nutritional benefits from limited fish stocks. Here we adopt an allocation optimization approach using biogeographic and nutrient data for the world's fishes to identify ideal portfolios of species for consumption in every country. We find that, across nations, biodiversity increases opportunities to fulfil multiple nutritional requirements with less fish biomass. This advantage emerges through complementarity among species; portfolios of complementary species provide >60% more nutrients than the same biomass of the most nutrient-rich species. Moreover, biodiverse fisheries enable harvest allocation towards species with traits enhancing fishery resilience (for example, small size, low trophic position) and offer greater redundancy, whereby a wider range of comparably nutritious species is available. Our analysis underscores that conserving fish biodiversity can improve nutrition and fishery resilience while reducing harvest pressure on already-stressed aquatic ecosystems.

Fisheries nourish billions globally, but overfishing and mercury contamination threaten aquatic biodiversity and public health. These benefits and risks of fish consumption are often siloed in consumer advisories, which tend to emphasize the risks of mercury exposure and could lead to adverse public health consequences in fisheries-dependent geographies where other nutritionally adequate foods are inaccessible. Here, we use nutrient and mercury content, price, and abundance information for 59 fishery species from the Amazon River and find that many nutrient-rich species also have low mercury content, are common, and have ecological traits conferring resilience to overexploitation. These species include many small and low-trophic-positioned species, including a diversity of characins that are common in markets across the region but not generally highly valued by consumers. Ultimately, considering these benefits and risks of fish consumption together offers promise for aligning biodiversity conservation goals within wild food systems.

Aquaculture in the Amazon holds the potential to meet increasing food demands while offering economic opportunities in a region facing deforestation and biodiversity loss. However, expanding aquaculture in this biodiverse region comes with complex environmental and social trade-offs. This Review explores how aquaculture can support sustainable development by minimizing its environmental impact, promoting equitable livelihoods and enhancing food security. It also highlights key challenges, such as greenhouse gas emissions and land-use changes, that need to be addressed for aquaculture to thrive sustainably in the Amazon. The aquaculture sector in the Amazon is an important source of food and livelihood provision; however, it is associated with environmental and ecological risks. This Review assesses aquaculture in the Amazon, offering insights into the challenges and opportunities for its sustainable growth.

Climate change and biodiversity loss are among humanity's most pressing challenges. In 2022, under the auspices of the United Nations, over 190 countries reached a historic agreement to address the alarming loss of biodiversity and restore natural ecosystems. Target 3, often referred to as "30x30", seeks to effectively protect and manage 30% of the world's terrestrial, inland water, coastal, and marine areas by 2030. In this work, we address the UN 30x30 target in the context of global freshwater fish conservation. Freshwater ecosystems are disproportionately unprotected, and their biota are declining at an alarming rate. Our goal is to select new protected areas that protect freshwater fish species as much as possible without exceeding total coverage of 30% of land area. To support this goal, we introduce the Expansion of Connected Components from Alternative Terminals Problem, a graph-based optimization problem that captures ecological priorities and connectivity constraints. We analyze its computational complexity, propose novel integer programming formulations, and develop scalable solution methods. We further evaluate its typical-case complexity under diverse settings and demonstrate that our approach scales to a global real-world scope, encompassing approximately 200,000 freshwater basins and 13,000 species, paving the way for implementing the 30x30 target on a worldwide scale.

The evolutionary and ecological diversity of animals is often reflected in the elemental composition of their bodies. Despite decades of stoichiometric research, remarkably little is known about the elemental composition of birds, the most diverse group of land vertebrates. This gap limits our understanding of vertebrate body composition and its implications for ecosystem functioning. Here, we report the body stoichiometry (%C, %N, %P, C:N, C:P, N:P) of 32 bird species spanning diverse ecological traits and phylogenetic lineages. Compared to other vertebrates, birds exhibit consistently low phosphorus content, probably reflecting two key flight adaptations: skeletal minimization (i.e. restricted investment in phosphorus-rich bone) and feather production (i.e. investment in phosphorus-poor keratin). Among birds, carbon content is associated with body fat, which has distinct stoichiometry and is known to fluctuate seasonally. Feathers constitute ~25% of a bird’s body nitrogen on average, hence variation in feather investment can produce significant differences. Unlike patterns observed in other vertebrates, body size, taxonomy, phylogeny and diet poorly predict bird stoichiometry. Instead, we infer that selective constraints arising from flight (skeletal minimization, feather investment) and phenological cycles (fat storage, feather molting) shape bird stoichiometry. These findings can inform research on avian nutrition, ecology and zoogeochemistry amid global change.

Effective recovery plans for endangered species rely on insights into species' ecology to identify risks and develop population recovery strategies. Data gaps pose challenges for many species of conservation concern, particularly those with cryptic behaviors or that occupy difficult-to-access habitats. Sounds produced by these species offer an effective means of observing many such marine and aquatic species, and for this reason, passive acoustic monitoring has emerged as an important study and assessment approach in marine systems. This approach is only just beginning to be applied for aquatic species monitoring in freshwater habitats. Atlantic sturgeon Acipenser oxyrinchus, a species of conservation concern along the US East Coast, remains poorly understood due to persistent data gaps despite years of conservation efforts. While sounds have been described for other sturgeons, sounds from Atlantic sturgeon have not yet been reported. Here, we characterized acoustic cues associated with Atlantic sturgeon in the Hudson River, New York, USA, and identified a low-frequency (44 Hz peak frequency) signal strongly correlated with the occurrence of telemetry-tagged adults which enter the river to spawn. We corroborated these efforts with recordings of captive Atlantic sturgeon, in which we detected the same sound type during a spawning period. Our findings provide an opportunity to develop passive acoustic monitoring strategies for Atlantic sturgeon, offering a non-invasive tool for understanding the spatiotemporal distribution of spawning activity across their range. We demonstrate potential applications of passive acoustic monitoring to inform sturgeon conservation and management, including characterizing habitat use, identifying cross-species interactions, and providing abundance indices.

Decomposition of plant litter is a key ecological process in streams, whose contribution to the global carbon cycle is large relative to their extent on Earth. We examined the mechanisms underlying the temperature sensitivity (TS) of instream decomposition and forecast effects of climate warming on this process. Comparing data from 41 globally distributed sites, we assessed the TS of microbial and total decomposition using litter of nine plant species combined in six mixtures. Microbial decomposition conformed to the metabolic theory of ecology and its TS was consistently higher than that of total decomposition, which was higher than found previously. Litter quality influenced the difference between microbial and total decomposition, with total decomposition of more recalcitrant litter being more sensitive to temperature. Our projections suggest that (i) warming will enhance the microbial contribution to decomposition, increasing CO2 outgassing and intensifying the warming trend, especially in colder regions; and (ii) riparian species composition will have a major influence on this process.

Species invasions spur costly and labor-intensive control efforts, yet even local eradication is seldom achieved. When control measures are initially effective, they may drive evolutionary adaptation that prevents full eradication, as has been documented for some chemical and biocontrol approaches. Although the intensity, directionality, and persistence of selection required to increase the frequency of resistant genotypes in complex natural ecosystems remains an open question, theory predicts that high mortality can cause life-history evolution even in the absence of a strong selective agent. Here, we use annually collected ecological and genetic data to show that rapid evolution of introduced smallmouth bass has undermined a 20-y manual suppression effort in a mid-sized lake. Despite nearly doubling annual mortality, our intensive control program produced a larger bass population dominated by young and early-maturing fish. These shifts were accompanied by large allele frequency changes in three genomic regions associated with earlier maturation and increased somatic growth. Our findings bear out the theoretical prediction that high mortality can drive evolutionary adaptation in target species. Controlling species invasions are worldwide practices that typically remove a substantial proportion of a population during each of many successive generations, hence life history adaptation may be commonplace. Such evolutionary responses could be salient in explaining the widespread failure of invasion control efforts. Genetic and phenotypic monitoring to detect cryptic adaptation and preemptive design of invader eradication programs to deliberately disrupt directional selection for resistance could improve invasion control outcomes.

The development of ethical AI decision-making systems requires considering multiple criteria, often resulting in a large spectrum of partially ordered solutions. At the core of this challenge lies the Pareto frontier, the set of all feasible solutions where no solution is dominated by another. In previous work, we developed both exact and approximate algorithms for generating the Pareto frontier for tree-structured networks. However, as the number of criteria grows, the Pareto frontier increases exponentially, posing a significant challenge for decision-makers. To address this challenge, we propose various strategies to efficiently compress the Pareto frontier, including an approximation method with optimality and polynomial runtime guarantees. We provide detailed empirical results on the strategies’ effectiveness in the context of strategic planning of the hydropower expansion in the Amazon basin. Our strategies offer a more manageable approach for navigating Pareto frontiers.

Reasons for geophagy (soil consumption) by herbivorous animals have long been debated. We provide direct evidence of artificial sodium (Na) enrichment driving geophagy by capybaras ( Hydrochoerus hydrochaeris ), a large herbivore in western Amazonia. Abstract in Spanish is available with online material.

Sustainability challenges inherently involve the consideration of multiple competing objectives. The Pareto frontier – the set of all optimal solutions that cannot be improved with respect to one objective without negatively affecting another – is a crucial decision-making tool for navigating sustainability challenges as it highlights the inherent trade-offs among conflicting objectives. Our research is motivated by the strategic planning of hydropower in the Amazon basin, one of the earth’s largest and most biodiverse river systems, where the need to increase energy production coincides with the pressing requirement of minimizing detrimental environmental impacts. We investigate an innovative strategy that pairs hydropower with Floating Photovoltaic Solar Panels (FPV). We provide a new extended multi-tree network formulation, which enables the consideration of multiple dam configurations. To address the computational challenge of scaling up the Pareto optimization framework to tackle multiple objectives across the entire Amazon basin, we further enhance the state-of-the-art algorithm for Pareto frontiers in tree-structured networks with two improvements. We introduce affine transformations induced by the sub-frontiers to compute Pareto dominance and provide strategies for merging sub-trees, significantly increasing the pruning of dominated solutions. Our experiments demonstrate considerable speedups, in some cases by more than an order of magnitude, while maintaining optimality guarantees, thus allowing us to more effectively approximate the Pareto frontiers. Moreover, our findings suggest significant shifts towards higher energy values in the Pareto frontier when pairing hybrid hydropower with FPV solutions, potentially amplifying energy production while mitigating adverse impacts.

Consumers vary in their excretion of nitrogen and phosphorus, altering nutrient cycles and ecosystem function. Traditional mass balance models that focus on dietary and tissue nutrients have poorly explained such variation in excretion. Here, we contrast diet and tissue nutrient models for nutrient excretion with predation risk, an often overlooked factor, using the Trinidadian guppy (Poecilia reticulata) as our model system. We surveyed guppies at 12 sites spread across two streams with parallel gradients in food quality and predation risk. At each site, we assessed guppy diet, tissue nitrogen (N), and phosphorus (P) content, and N and P excretion. Predation risk best explained guppy excretion, especially P: guppies excreted less in sites with a dominant predator, while traditional models for excretion rate based on diet quality and tissue nutrients failed to explain it. Guppy tissue N (but not P) most closely correlated with guppy diet quality, showing evidence for flexible homeostasis. Our work extends previous laboratory studies’ results to natural streams and shows that predation risk alters feeding behavior and physiology, driving substantial variation in guppy nutrient, particularly P, excretion rates. We suggest that predation risk is an important factor determining nutrient excretion variation, warranting further attention. Our results also show that tissue nutrients and excretion nutrients are decoupled.

Wild fisheries provide billions of people with a key source of multiple essential nutrients. As fisheries plateau or decline, nourishing more people will partially rely on shifting consumption to farmed animals. The environmental implications of transitions among animal-sourced foods have been scrutinized, but their nutritional substitutability remains unclear. We compared concentrations of six essential dietary nutrients across >5000 species of wild fishes, aquaculture, poultry and livestock species, representing >65% of animals consumed globally. Wild fishes are both more nutrient-dense and variable than farmed animals; achieving recommended intake of all nutrients with farmed species could require consuming almost four times more biomass than with wild fish. The challenge of substituting farmed animals for wild fishes are magnified in fishery-dependent nations with high biodiversity and prevalence of malnutrition. Ultimately, the better ability of wild fishes to meet multiple nutrients simultaneously underscores the importance of drawing upon a diverse portfolio of animal- and plant-based foods as societies seek to offset changes in fisheries while achieving healthy and sustainable diets.

Real-world decision-making often involves working with many distinct objectives. However, as we consider a larger number of objectives, performance degrades rapidly and many instances become intractable. Our goal is to approximate higher-dimensional Pareto frontiers within a reasonable amount of time. Our work is motivated by a problem in computational sustainability that evaluates the tradeoffs between various ecological impacts of hydropower dam proliferation in the Amazon river basin. The current state-of-the-art algorithm finds a good approximation of the Pareto frontier within hours for three-objective problems, but a six-objective problem cannot be solved in a reasonable amount of time. To tackle this problem, we developed two different approaches: an expansion method, which assembles Pareto-frontiers optimized with respect to subsets of the original set of criteria, and a compression method, which assembles Pareto-frontiers optimized with respect to compressed criteria, which are a weighted sum of multiple original criteria. Our experimental results show that the aggregation of the different methods can reliably provide good approximations of the true Pareto-frontiers in practice. Source code and data are available at https://github.com/gomes-lab/Dam-Portfolio-Selection-Expansion-and-Compression-CPAIOR .

The meat of sharks and rays is commonly traded in Brazil under the generic name of cação. This compromises the monitoring of which species are being traded. In the present study, molecular marker techniques were applied to the species-level identification of elasmobranch meat traded in the southwest of the State of São Paulo. A total of 15 meats purchased in 2019 were partially sequenced (up to 655 base pairs) for the mitochondrial cytochrome c oxidase subunit I (COI) gene. Of these meats, 14 were from Blue Shark, Prionace glauca, and one from Shortfin Mako Shark, Isurus oxyrinchus. Only two (13,3%) out of the 15 cação meat were species identified on its product label – the other meat was only labeled as cação. Both shark meat that had the scientific name stated on the package label correctly corresponded to the species identification obtained through DNA sequencing. It is suggested that similar studies be conducted in other non-coastal regions of the country to further understanding of the cação trade in locations where elasmobranch consumption is not habitual. The present study was the first to detect the Shortfin Mako Shark sold as cação in Brazil.Keywords: DNA Barcoding, elasmobranch, molecular marker, conservation

Characterizing dispersal traits can further our ecological understanding of Neotropical stream macroinvertebrate communities, allowing us to test fundamental questions about disturbance and functional diversity responses in these systems. We combine observational and experimental approaches to measure short-term colonization of cobbles by stream invertebrates at five headwater streams arrayed along a habitat stability gradient in the Ecuadorian Andes, along with conducting drift and benthic surveys along the same gradient. Cobbles were sampled for benthic macroinvertebrate community composition and basal resource accrual at five time points over the 23-day experimental period. We found that taxonomic richness did not show clear trends across colonization time. Invertebrate community composition in the cobble colonization experiment did not approach the background benthic and drift composition over colonization time. Focal taxa showed variation in their drift and colonization propensities, with no clear relationship to habitat stability. We also found that benthic communities from less stable streams differed greatly between experimental years, highlighting the need to account for intra- and interannual differences in colonization experiments.