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1.
Braz. j. biol ; 84: e253852, 2024. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1355905

RESUMO

Abstract The aim objective of this study was to determine the trophic ecology of juvenile and adult Acestrorhynchus falcirostris during the rising and flood (high-water) period in six island lakes adjacent to the Solimões River. As such, we investigated: i) the trophic position, through the fractional trophic niche; ii) the niche breadth; iii) niche overlap and iv) the food strategy of the species. The specimens were collected during the years 2014 to 2017, using gillnets with mesh sizes ranging from 30 to 120mm between opposite knots. Through the analysis of stomach contents, the preference in the consumption of items of animal origin was observed. Juveniles consumed insects in greater proportions (IAi% = 50%), while adults consumed fish (IAi%=99,98%). Despite the large supply of food items available in the high-water period, juveniles were the only ones to consume items of allochthonous origin, such as insects. Juveniles presented a different dietary strategy and dietary composition to adults. Juveniles were omnivores with a generalist strategy, while adults were piscivores with a specialist strategy. Thus, the food composition, niche breadth, trophic position and feeding strategy of Acestrorhynchus falcirostris change due to the stage of development.


Resumo O objetivo deste estudo foi determinar a ecologia trófica de juvenis e adultos de Acestrorhynchus falcirostris durante o período de enchente e cheia em seis lagos de ilha adjacentes ao rio Solimões. Assim, investigamos: i) a posição trófica, através do nicho trófico fracional; ii) a largura de nicho; iii) sobreposição de nicho; iv) a estratégia alimentar. Os espécimes foram coletados durante os anos de 2014 a 2017, utilizando redes de emalhar com malha variando de 30 a 120mm entre nós opostos. Por meio da análise do conteúdo estomacal, observamos a preferência no consumo de itens de origem animal. Os juvenis consumiram insetos em maiores proporções (IAi% = 50%), enquanto os adultos consumiram preferencialmente peixes (IAi% = 99,98%). Apesar da grande oferta de alimentos disponíveis no período da cheia, os juvenis eram os únicos a consumir itens de origem alóctone, como por exemplo, os insetos. Os juvenis apresentaram uma estratégia alimentar e composição alimentar diferente para os adultos. Os juvenis foram considerados onívoros com uma estratégia generalista, enquanto os adultos foram considerados piscívoros com uma estratégia alimentar mais especialista. Assim, a composição alimentar, amplitude do nicho, posição trófica e a estratégia alimentar de Acestrorhynchus falcirostris muda em função do estágio de desenvolvimento.


Assuntos
Animais , Rios , Caraciformes , Estações do Ano , Lagos , Ecossistema , Cadeia Alimentar , Peixes , Conteúdo Gastrointestinal
2.
Braz. J. Biol. ; 83: 1-7, 2023. mapas, graf, tab
Artigo em Inglês | VETINDEX | ID: vti-765402

RESUMO

In fisheries, the phenomenon known as fishing down food webs is supposed to be a consequence of overfishing, which would be reflected in a reduction in the trophic level of landings. In such scenarios, the resilience of carnivorous, top predator species is particularly affected, making these resources the first to be depleted. The Serra Spanish mackerel, Scomberomorus brasiliensis, exemplifies a predator resource historically targeted by artisanal fisheries on the Brazilian coast. The present work analyzes landings in three periods within a 50-year timescale on the Parana coast, Southern Brazil, aiming to evaluate whether historical production has supposedly declined. Simultaneously, the diet was analyzed to confirm carnivorous habits and evaluate the trophic level in this region. Surprisingly, the results show that from the 1970's to 2019 Serra Spanish mackerel production grew relatively to other resources, as well as in individual values. The trophic level was calculated as 4.238, similar to other Scomberomorus species, consisting of a case where landings increase over time, despite the high trophic level and large body size of the resource. The results agree with a recent global assessment that has demystified a necessary correlation between high trophic level and overexploitation, but possible factors acting on the present findings are discussed.(AU)


Na pesca, o fenômeno fishing down food webs, ou 'pescando teias tróficas abaixo', expressa a redução do nível trófico na composição das capturas, e tem origem tradicionalmente atribuída à sobrepesca. Sob intenso extrativismo, a resiliência das espécies carnívoras, predadoras de topo, é particularmente afetada, sendo seus estoques os primeiros a entrarem em depleção. A cavala, ou serra, ou sororoca, Scomberomorus brasiliensis, é exemplo de recurso predador historicamente alvo da pesca artesanal, de pequena escala, na costa brasileira. O presente trabalho analisa os valores de desembarque do recurso em três períodos ao longo de 50 anos na costa paranaense, sul do Brasil, com objetivo de avaliar se sua produção tem efetivamente diminuído. Ainda, estuda-se a dieta da espécie na região, para confirmar seus hábitos carnívoros e avaliar o nível trófico na região. Os resultados mostram que, surpreendentemente, dos anos 1970 para 2019 a produção de S. brasiliensis tem aumentado em valores absolutos, bem como relativamente à de outros recursos, em que pese o nível trófico 4,238, similar a outras espécies do gênero. Constata-se que a pesca da cavala na região de estudo constitui um caso de aumento nos desembarques a despeito de elevado nível trófico e grande tamanho corpóreo. Os resultados concordam com recente levantamento em nível mundial, que nega existir correlação necessária entre sobrepesca e nível trófico alto, mas fatores que podem explicar os resultados do presente trabalho são discutidos.(AU)


Assuntos
Animais , Pesqueiros , Cadeia Alimentar , Equilíbrio Ecológico/análise , Dieta
3.
Braz. j. biol ; 83: e246180, 2023. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1278550

RESUMO

Abstract In fisheries, the phenomenon known as fishing down food webs is supposed to be a consequence of overfishing, which would be reflected in a reduction in the trophic level of landings. In such scenarios, the resilience of carnivorous, top predator species is particularly affected, making these resources the first to be depleted. The Serra Spanish mackerel, Scomberomorus brasiliensis, exemplifies a predator resource historically targeted by artisanal fisheries on the Brazilian coast. The present work analyzes landings in three periods within a 50-year timescale on the Parana coast, Southern Brazil, aiming to evaluate whether historical production has supposedly declined. Simultaneously, the diet was analyzed to confirm carnivorous habits and evaluate the trophic level in this region. Surprisingly, the results show that from the 1970's to 2019 Serra Spanish mackerel production grew relatively to other resources, as well as in individual values. The trophic level was calculated as 4.238, similar to other Scomberomorus species, consisting of a case where landings increase over time, despite the high trophic level and large body size of the resource. The results agree with a recent global assessment that has demystified a necessary correlation between high trophic level and overexploitation, but possible factors acting on the present findings are discussed.


Resumo Na pesca, o fenômeno fishing down food webs, ou 'pescando teias tróficas abaixo', expressa a redução do nível trófico na composição das capturas, e tem origem tradicionalmente atribuída à sobrepesca. Sob intenso extrativismo, a resiliência das espécies carnívoras, predadoras de topo, é particularmente afetada, sendo seus estoques os primeiros a entrarem em depleção. A cavala, ou serra, ou sororoca, Scomberomorus brasiliensis, é exemplo de recurso predador historicamente alvo da pesca artesanal, de pequena escala, na costa brasileira. O presente trabalho analisa os valores de desembarque do recurso em três períodos ao longo de 50 anos na costa paranaense, sul do Brasil, com objetivo de avaliar se sua produção tem efetivamente diminuído. Ainda, estuda-se a dieta da espécie na região, para confirmar seus hábitos carnívoros e avaliar o nível trófico na região. Os resultados mostram que, surpreendentemente, dos anos 1970 para 2019 a produção de S. brasiliensis tem aumentado em valores absolutos, bem como relativamente à de outros recursos, em que pese o nível trófico 4,238, similar a outras espécies do gênero. Constata-se que a pesca da cavala na região de estudo constitui um caso de aumento nos desembarques a despeito de elevado nível trófico e grande tamanho corpóreo. Os resultados concordam com recente levantamento em nível mundial, que nega existir correlação necessária entre sobrepesca e nível trófico alto, mas fatores que podem explicar os resultados do presente trabalho são discutidos.


Assuntos
Animais , Perciformes , Pesqueiros , Brasil , Conservação dos Recursos Naturais , Cadeia Alimentar
4.
Gut Microbes ; 14(1): 2127438, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36170451

RESUMO

Lactic acid bacteria (LAB) and bifidobacteria may serve as reservoirs of antimicrobial resistance, but the risk posed by strains intentionally introduced into the agro-food chain has not yet been thoroughly investigated. The aim of our study was to evaluate whether probiotics, starter and protective cultures, and feed additives represent a risk to human health. In addition to commercial strains of LAB and bifidobacteria, isolates from human milk or colostrum, intestinal mucosa or feces, and fermented products were analyzed. Phenotypic susceptibility data of 474 strains showed that antimicrobial resistance was more common in intestinal isolates than in commercial strains. Antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs) were characterized in the whole genome sequences of 1114 strains using comparative genomics. Intrinsic ARGs were abundant in enterococci, bifidobacteria, and lactococci but were considered non-risky due to the absence of MGEs. The results revealed that 13.8% of commercial strains contained acquired ARGs, most frequently for tetracycline. We associated 75.5% of the acquired ARGs with known or novel MGEs, and their potential for transmission was assessed by examining metagenomic sequences. We confirmed that ARGs and MGEs were not as abundant or diverse in commercial strains as in human intestinal isolates or isolates from human milk, suggesting that strains intentionally introduced into the agro-food chain do not pose a significant threat. However, attention should be paid especially to individual probiotic strains containing elements that have been shown to have high potential for transferability in the gut microbiota.Abbreviations: ARG, antimicrobial resistance gene; ICE, integrative and conjugative element; IME, integrative and mobilizable element; LAB, lactic acid bacteria; MDR, multidrug resistance; MIC, minimum inhibitory concentration; MGE, mobile genetic element; TRRPP, tetracycline-resistant ribosomal protection protein; WGS, whole genome sequences.


Assuntos
Microbioma Gastrointestinal , Lactobacillales , Antibacterianos/farmacologia , Bifidobacterium/genética , Farmacorresistência Bacteriana/genética , Cadeia Alimentar , Pool Gênico , Humanos , Lactobacillales/genética , Tetraciclinas
5.
Radiat Prot Dosimetry ; 198(13-15): 1125-1130, 2022 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-36083768

RESUMO

Tritium is released into the ocean from nuclear facilities located at coastal areas. In addition, tritiated water is decided to be released into the ocean from the Fukushima Dai-ichi Nuclear Power Plant. Although released tritium concentration would be strictly controlled, impact of tritium on the marine products is major concern for the public. In this study, deuterium transfers from seawater into seaweed (ulva) and abalone were measured. In addition, organically bound deuterium (OBD) transfer from ulva into abalone was measured. OBD concentrations in ulva were saturated in 2 weeks and those in abalone were saturated in 6 months. Ulva and abalone were exposed to seawater containing 0.2% (mol-D/mol-H) deuterium. Maximum OBD concentrations in ulva were ~0.1% (mol-D/mol-H) and those in abalone muscle were ~0.035% (mol-D/mol-H). Numerical deuterium transfer model was constructed. Obtained numerical model well represented the OBD-enriched ulva feeding experiment.


Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Poluentes Radioativos da Água , Radioisótopos de Césio/análise , Deutério/análise , Cadeia Alimentar , Japão , Água do Mar/análise , Trítio/análise , Poluentes Radioativos da Água/análise
6.
Elife ; 112022 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-36069772

RESUMO

Dietary lipids (DLs), particularly sterols and fatty acids, are precursors for endogenous lipids that, unusually for macronutrients, shape cellular and organismal function long after ingestion. These functions - cell membrane structure, intracellular signalling, and hormonal activity - vary with the identity of DLs, and scale up to influence health, survival, and reproductive fitness, thereby affecting evolutionary change. Our Ecological Lipidology approach integrates biochemical mechanisms and molecular cell biology into evolution and nutritional ecology. It exposes our need to understand environmental impacts on lipidomes, the lipid specificity of cell functions, and predicts the evolution of lipid-based diet choices. Broad interdisciplinary implications of Ecological Lipidology include food web alterations, species responses to environmental change, as well as sex differences and lifestyle impacts on human nutrition, and opportunities for DL-based therapies.


Assuntos
Dieta , Gorduras na Dieta , Ácidos Graxos , Feminino , Cadeia Alimentar , Humanos , Masculino , Transdução de Sinais
7.
J Hazard Mater ; 439: 129690, 2022 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-36104924

RESUMO

The trophodynamics of toxic trace metals is significant for assessing the threat of toxic trace metals to the aquatic ecosystem and human safety. However, due to the difficulty of accurately calculating the trophic positions of freshwater aquatic organisms in the food web, the comprehensive process of trophodynamics of toxic trace metals in freshwater ecosystems was still rarely known. By integrating the compound-specific nitrogen stable isotopic analysis of amino acids (CSIA-AAs) and the Bayesian stable isotope mixing model (SIMM) as a novel approach, the present study investigated the trophodynamics of five toxic trace metals (Zn, As, Cr, Cu, and Hg) in the food web of the YangZong Lake, a plateau freshwater lake that was once heavily polluted by arsenic in Yunnan Province, China. The results revealed that Hg tended to be efficiently biomagnified in the food web with a trophic magnification factor of 1.75; As, Cr, and Cu were biodiluted significantly, while Zn showed no biomagnification or biodilution trends. The dietary health risk assessment indicated the potential health risk of toxic trace metals for the local residents of long-term fish consumption. The present work highlights the accuracy and reliability of the novel CSIA-AAS+SIMM approach in the calculation of the trophic positions of freshwater organisms.


Assuntos
Mercúrio , Oligoelementos , Poluentes Químicos da Água , Animais , Organismos Aquáticos/metabolismo , Teorema de Bayes , China , Ecossistema , Monitoramento Ambiental/métodos , Cadeia Alimentar , Humanos , Lagos/química , Mercúrio/metabolismo , Reprodutibilidade dos Testes , Medição de Risco , Oligoelementos/metabolismo , Poluentes Químicos da Água/análise
8.
J Anim Ecol ; 91(9): 1736-1739, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36065143

RESUMO

Research Highlight: Li, X., Liu, T., Li, H., Geisen, S., Hu, F., & Liu, M. (2022). Management effects on soil nematode abundance differ among functional groups and land-use types at a global scale. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.13744. Despite the well-documented decline of aboveground species abundances as a result of land-use intensification, there has been little attention on the effects of human activities on belowground species abundances. Li et al. analyse nematode data, the most abundant animal on the planet, from across the globe to determine whether their abundances vary between managed and unmanaged habitats. The authors show that, unlike aboveground biodiversity, nematode abundance is higher in managed than unmanaged primary and secondary habitats. Furthermore, responses to land management vary between trophic groups and they do not appear to follow the general hypothesis that higher trophic levels are more vulnerable to human activity than those further down the food chain, except in urban habitats. Finally, Li et al. show that the relationships between environmental predictors and species abundance were weakened (and sometimes reversed) in managed habitats. Together, their results reveal how land-use management is impacting the trophic composition of soil nematode communities and their relationships with the environment, which has implications for ecosystem functioning.


Assuntos
Nematoides , Solo , Animais , Biodiversidade , Ecossistema , Cadeia Alimentar , Humanos , Nematoides/fisiologia
9.
Ecotoxicol Environ Saf ; 241: 113852, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36068768

RESUMO

Contamination of agro-ecosystems with heavy metals can affect the development and reproduction of insect natural enemies. This study reports a detailed Tandem Mass Tag based quantitative proteomic analysis of underlying mechanisms responsible for stress response of Cryptolaemus montrouzieri against heavy metals (cadmium (Cd) and lead (Pb)) transported across a multi-trophic food chain. A total of 6639 proteins were detected under Cd as well as Pb stress. In Pb versus the control cluster, 69 proteins (28 up-regulated and 41 down-regulated) were differentially expressed whereas 268 proteins were differentially expressed under Cd versus the control cluster, having 198 proteins up-regulated and 70 down-regulated proteins. The analysis of differentially expressed proteins showed that 27 proteins overlapped in both clusters representing the core proteome to Pb and Cd stress. The bioinformatics analysis demonstrated that these proteins were mapped to 57 and 99 pathways in Pb versus control and Cd versus control clusters, respectively. The functional classification by COG, GO and KEGG databases showed significant changes in protein expression by C. montrouzieri under Pb and Cd stress. The heavy metal stress (Pb and Cd) induced significant changes in expression of proteins like hexokinase (HK), succinyl-CoA, trypsin like proteins, cysteine proteases, cell division cycle proteins, and yellow gene proteins. The results provide detailed information on the protein expression levels of C. montrouzieri and will serve as basic information for future proteomic studies on heavy metal responses of insect predators within a multi-trophic food chain.


Assuntos
Besouros , Metais Pesados , Animais , Cádmio/metabolismo , Besouros/fisiologia , Ecossistema , Cadeia Alimentar , Insetos , Chumbo/metabolismo , Chumbo/toxicidade , Metais Pesados/metabolismo , Metais Pesados/toxicidade , Proteômica
10.
J Math Biol ; 85(4): 38, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36129551

RESUMO

Identifying early warning signs of sudden population changes and mechanisms leading to regime shifts are highly desirable in population biology. In this paper, a two-trophic ecosystem comprising of two species of predators, competing for their common prey, with explicit interference competition is considered. With proper rescaling, the model is portrayed as a singularly perturbed system with fast prey dynamics and slow dynamics of the predators. In a parameter regime near singular Hopf bifurcation, chaotic mixed-mode oscillations (MMOs), featuring concatenation of small and large amplitude oscillations are observed as long-lasting transients before the system approaches its asymptotic state. To analyze the dynamical cause that initiates a large amplitude oscillation in an MMO orbit, the model is reduced to a suitable normal form near the singular-Hopf point. The normal form possesses a separatrix surface that separates two different types of oscillations. A large amplitude oscillation is initiated if a trajectory moves from the "inner" to the "outer side" of this surface. A set of conditions on the normal form variables are obtained to determine whether a trajectory would exhibit another cycle of MMO dynamics before experiencing a regime shift (i.e. approaching its asymptotic state). These conditions serve as early warning signs for a sudden population shift as well as detect the onset of a regime shift in this ecological model.


Assuntos
Ecossistema , Comportamento Predatório , Animais , Cadeia Alimentar , Modelos Biológicos , Modelos Teóricos , Dinâmica Populacional
11.
Nature ; 609(7927): 535-540, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36071164

RESUMO

Ocean eddies are coherent, rotating features that can modulate pelagic ecosystems across many trophic levels. These mesoscale features, which are ubiquitous at mid-latitudes1, may increase productivity of nutrient-poor regions2,3, accumulate prey4 and modulate habitat conditions in the water column5. However, in nutrient-poor subtropical gyres-the largest marine biome-the role of eddies in modulating behaviour throughout the pelagic predator community remains unknown despite predictions for these gyres to expand6 and pelagic predators to become increasingly important for food security7. Using a large-scale fishery dataset in the North Pacific Subtropical Gyre, we show a pervasive pattern of increased pelagic predator catch inside anticyclonic eddies relative to cyclones and non-eddy areas. Our results indicate that increased mesopelagic prey abundance in anticyclone cores4,8 may be attracting diverse predators, forming ecological hotspots where these predators aggregate and exhibit increased abundance. In this energetically quiescent gyre, we expect that isolated mesoscale features (and the habitat conditions in them) exhibit primacy over peripheral submesoscale dynamics in structuring the foraging opportunities of pelagic predators. Our finding that eddies influence coupling of epi- to mesopelagic communities corroborates the growing evidence that deep scattering layer organisms are vital prey for a suite of commercially important predator species9 and, thus, provide valuable ecosystem services.


Assuntos
Ecossistema , Comportamento Predatório , Movimentos da Água , Água , Animais , Tempestades Ciclônicas , Conjuntos de Dados como Assunto , Pesqueiros , Cadeia Alimentar , Nutrientes/análise , Oceano Pacífico , Clima Tropical
12.
Science ; 377(6609): 918-919, 2022 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-36007050

RESUMO

Deep-learning tools can help to construct historical, modern-day, and future food webs.


Assuntos
Cadeia Alimentar , Animais , Aprendizado Profundo
13.
J Hazard Mater ; 440: 129715, 2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-35986943

RESUMO

This study investigated the effects of nanoplastics on marine organisms via trophic transfer in the food chain. We designed a three-step food chain comprising microalga (Dunaliella salina), small crustaceans (Artemia franciscana), and fish (small yellow croakers; Larimichthys polyactis) and evaluated the effects of trophic transfer in marine organisms, as well as verified the possibility of nanoplastic transfer to humans via trophic transfer. Using amine-modified nanopolystyrene (nPS-NH2) as a pollutant, we conducted both direct-exposure and trophic transfer experiments to determine how pollutants move through the food chain (D. salina → A. franciscana). Exposure of D. salina to nPS-NH2, which was adsorbed on its cell wall, resulted in transfer to A. franciscana with alteration of gut permeability. Additionally, assessment of the adverse effects of nPS-NH2 via a dietary pathway (three-step food chain) on the L. polyactis digestive system revealed that nanoplastics adsorbed to the cell wall of microalgae are gradually transferred to higher trophic level organisms, such as via food resources consumed by humans, inducing the inhibition of digestive enzyme activity (α-amylase). It indicates that human could eventually be exposed to nanoplastics and experience toxicity.


Assuntos
Microalgas , Nanopartículas , Perciformes , Poluentes Químicos da Água , Aminas , Animais , Organismos Aquáticos/metabolismo , Peixes/metabolismo , Cadeia Alimentar , Humanos , Microalgas/metabolismo , Microplásticos , Nanopartículas/metabolismo , Nanopartículas/toxicidade , Perciformes/metabolismo , Poluentes Químicos da Água/análise , alfa-Amilases/metabolismo
14.
Nat Commun ; 13(1): 4990, 2022 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-36008387

RESUMO

The ratio of predator-to-prey biomass is a key element of trophic structure that is typically investigated from a food chain perspective, ignoring channels of energy transfer (e.g. omnivory) that may govern community structure. Here, we address this shortcoming by characterising the biomass structure of 141 freshwater, marine and terrestrial food webs, spanning a broad gradient in community biomass. We test whether sub-linear scaling between predator and prey biomass (a potential signal of density-dependent processes) emerges within ecosystem types and across levels of biological organisation. We find a consistent, sub-linear scaling pattern whereby predator biomass scales with the total biomass of their prey with a near ¾-power exponent within food webs - i.e. more prey biomass supports proportionally less predator biomass. Across food webs, a similar sub-linear scaling pattern emerges between total predator biomass and the combined biomass of all prey within a food web. These general patterns in trophic structure are compatible with a systematic form of density dependence that holds among complex feeding interactions across levels of organization, irrespective of ecosystem type.


Assuntos
Ecossistema , Cadeia Alimentar , Animais , Biomassa , Água Doce , Comportamento Predatório
15.
Sci Rep ; 12(1): 13512, 2022 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-35933511

RESUMO

Phenological diversity in food resources prolongs foraging opportunities for consumers and buffers them against environmental disturbances. Such diversity is particularly important in forage fish such as Pacific herring (Clupea pallasii), which are foundational to coastal food webs and fisheries. While the importance of phenological diversity is well-known from contemporary studies, the extent to which different populations contribute to fisheries over long time scales is mostly unknown. In this study, we investigated the relative contributions of genetically and phenologically distinct herring populations to Indigenous Peoples' food systems over multiple centuries, using ancient DNA extracted from archaeological herring bones. These bones were excavated from two Coast Salish archaeological sites (Burton Acres Shell Midden and Bay Street Shell Midden) in the Puget Sound region, USA. Using genetic stock identification from seven nuclear DNA markers, we showed that catches at the two sites in central Puget Sound were dominated by January-February and March-April spawners, which are the contemporary spawning groups in the vicinity of the sites. However, May spawners were detected in the older Burton Acres assemblage (dated to 910-685 cal BP), and a mixed stock analysis indicated that catches at this site consisted of multiple populations. These results suggest that Coast Salish ancestors used a portfolio of herring populations and benefited from the ecological resource wave created by different spawning groups of herring. This study of ancient DNA allowed us to glimpse into Indigenous traditional food and management systems, and it enabled us to investigate long-term patterns of biodiversity in an ecologically important forage fish species.


Assuntos
DNA Antigo , Peixes , Animais , Pesqueiros , Peixes/genética , Cadeia Alimentar , Alimentos Marinhos
16.
Sci Rep ; 12(1): 13948, 2022 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-35977970

RESUMO

Food webs studies are intrinsically complex and time-consuming. Network data about trophic interaction across different large locations and ecosystems are scarce in comparison with general ecological data, especially if we consider terrestrial habitats. Here we present a complex network strategy to ease the gathering of the information by simplifying the collection of data with a taxonomic key. We test how well the topology of three different food webs retain their structure at the resolution of the nodes across distinct levels of simplification, and we estimate how community detection could be impacted by this strategy. The first level of simplification retains most of the general topological indices; betweenness and trophic levels seem to be consistent and robust even at the higher levels of simplification. This result suggests that generalisation and standardisation, as a good practice in food webs science, could benefit the community, both increasing the amount of open data available and the comparison among them, thus providing support especially for scientists that are new in this field and for exploratory analysis.


Assuntos
Ecossistema , Cadeia Alimentar
17.
Sci Rep ; 12(1): 14069, 2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-35982210

RESUMO

Domestic dogs are the most abundant carnivore globally and have demonstrable negative impacts to wildlife; yet, little evidence regarding their functional roles in natural food webs exists. Adding dogs to food webs may result in a net loss (via suppression of naturally occurring species), net gain (via mesopredator release), or no change (via functional replacement) to ecosystem function. Scavenging is a pivotal function in ecosystems, particularly those that are energetically supported by carrion. Dogs also scavenge on animal carcasses, but whether scavenging by dogs influences the structural and functional properties of food webs remains unclear. Here we used camera traps baited with carrion to test the effect of dogs on the composition and diversity of the vertebrate scavenger guild, as well as carrion detection and consumption rates. We conducted this work in sandy beach ecosystems, which rely on the import of marine organic matter (i.e. stranding of dead marine animals). Diversity of the scavenger community was similar on beaches without dogs. Dogs increased the time it took for carcasses to be detected and decreased the proportion of carrion consumed. This 'dog suppression effect' on scavenging was stronger for nocturnal mammalian scavengers, presumably being driven by indirect trait-mediated effects, which raises further questions about the broader ecological consequences of domestic dogs in natural systems.


Assuntos
Carnívoros , Cadeia Alimentar , Animais , Cães , Ecossistema , Peixes , Vertebrados
18.
J Environ Manage ; 319: 115488, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35982549

RESUMO

CONTEXT: Ecological Risk Assessments (ERAs) are important tools for supporting evidence-based decision making. However, most ERA frameworks rarely consider complex ecological feedbacks, which limit their capacity to evaluate risks at community and ecosystem levels of organisation. METHOD: We used qualitative mathematical modelling to add additional perspectives to previously conducted ERAs for the rehabilitation of the Ranger uranium mine (Northern Territory, Australia) and support an assessment of the cumulative risks from the mine site. Using expert elicitation workshops, separate qualitative models and scenarios were developed for aquatic and terrestrial systems. The models developed in the workshops were used to construct Bayes Nets that predicted whole-of-ecosystem outcomes after components were perturbed. RESULTS: The terrestrial model considered the effect of fire and weeds on established native vegetation that will be important for the successful rehabilitation of Ranger. It predicted that a combined intervention that suppresses both weeds and fire intensity gave similar response predictions as for weed control alone, except for lower levels of certainty to tall grasses and fire intensity in models with immature trees or tall grasses. However, this had ambiguous predictions for short grasses and forbs, and tall grasses in models representing mature vegetation. The aquatic model considered the effects of magnesium (Mg), a key solute in current and predicted mine runoff and groundwater egress, which is known to adversely affect many aquatic species. The aquatic models provided support that attached algae and phytoplankton assemblages are the key trophic base for food webs. It predicted that shifts in phytoplankton abundance arising from increase in Mg to receiving waters, may result in cascading effects through the food-chain. CONCLUSION: The qualitative modelling approach was flexible and capable of modelling both gradual (i.e. decadal) processes in the mine-site restoration and the comparatively more rapid (seasonal) processes of the aquatic ecosystem. The modelling also provides a useful decision tool for identifying important ecosystem sub-systems for further research efforts.


Assuntos
Ecossistema , Urânio , Teorema de Bayes , Cadeia Alimentar , Medição de Risco , Urânio/análise
19.
Sci Rep ; 12(1): 14668, 2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-36038623

RESUMO

Random matrix theory has been applied to food web stability for decades, implying elliptical eigenvalue spectra and that large food webs should be unstable. Here we allow feasible food webs to self-assemble within an evolutionary process, using simple Lotka-Volterra equations and several elementary interaction types. We show that, as complex food webs evolve under [Formula: see text] invasion attempts, the community matrix spectra become bi-modal, rather than falling onto elliptical geometries. Our results raise questions as to the applicability of random matrix theory to the analysis of food web steady states.


Assuntos
Ecossistema , Modelos Biológicos , Evolução Biológica , Cadeia Alimentar
20.
Environ Pollut ; 310: 119810, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35940481

RESUMO

Forest management can alter the mobilization of mercury (Hg) into headwater streams and its conversion to methylmercury (MeHg), the form that bioaccumulates in aquatic biota and biomagnifies through food webs. As headwater streams are important sources of organic materials and nutrients to larger systems, this connectivity may also increase MeHg in downstream biota through direct or indirect effects of forestry on water quality or food web structure. In this study, we collected water, seston, food sources (biofilm, leaves, organic matter), five macroinvertebrate taxa and fish (slimy sculpin; Cottus cognata) at 6 sites representing different stream orders (1-5) within three river basins with different total disturbances from forestry (both harvesting and silviculture). Methylmercury levels were highest in water and some food sources from the basin with moderate disturbance (greater clearcutting but less silviculture). Water, leaves, stoneflies and fish increased in MeHg or total Hg along the river continuum in the least disturbed basin, and there were some dissipative effects of forest management on these spatial patterns. Trophic level (δ15N) was a significant predictor of MeHg (and total Hg in fish) within food webs across all 18 sites, and biomagnification slopes were significantly lower in the basin with moderate total disturbance but not different in the other two basins. The elevated MeHg in lower trophic levels but its reduced trophic transfer in the basin with moderate disturbance was likely due to greater inputs of sediments and of dissolved organic carbon that is more humic, as these factors are known to both increase transport of Hg to streams and its uptake in primary producers but to also decrease MeHg bioaccumulation in consumers. Overall, these results suggest that the type of disturbance from forestry affects MeHg bioaccumulation and trophic transfer in stream food webs and some longitudinal patterns along a river continuum.


Assuntos
Mercúrio , Compostos de Metilmercúrio , Poluentes Químicos da Água , Animais , Bioacumulação , Monitoramento Ambiental , Peixes , Cadeia Alimentar , Florestas , Insetos
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