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Body length is an important parameter in morphological, ecological and behavioral studies of a species and contributes to the understanding of the body condition of individuals. This parameter is essential for conservation and management strategies by informing studies evaluating growth rates, physical maturity and classification of individuals into age groups, promoting better accuracy for the biological parameters of the species. The aim of this study was to identify predictors of body length for Amazonian manatees (Trichechus inunguis) using metric characters of osteological materials. Eleven linear measurements of skull, jaw, scapulae and humeri were collected from 41 Amazonian manatee skeletons of different age classes (calf, juvenile and adult). Data were analyzed by simple linear regression. The condylobasal length was the best predictor of body length for the species (R = 0.943), however, all bones evaluated showed at least one measurement with the capacity to predict body size (R2 > 0.9). Results of this study are useful for inferring body length of Amazonian manatees using bones deposited in museums and biological collections, expanding the informative potential of these materials. RESUMO O comprimento corporal é um importante parâmetro em estudos morfológicos, ecológicos e comportamentais de uma espécie e contribui para o entendimento da condição corporal de um indivíduo. Este parâmetro é essencial para estratégias de conservação e manejo, informando estudos que avaliam taxas de crescimento, maturidade física e classificação dos indivíduos em grupos de idade, promovendo uma melhor precisão aos parâmetros biológicos de uma espécie. O objetivo desse trabalho foi identificar preditores de comprimento corporal para o peixe-boi da Amazônia (Trichechus inunguis) utilizando caracteres métricos de material osteológico. Onze medidas lineares do crânio, mandíbula, escápula e úmero foram coletadas de 41 esqueletos de peixe-boi da Amazônia de diferentes classes de idade (filhote, juvenil e adulto). Os dados foram analisados por regressão linear simples. O comprimento côndilobasal foi o melhor preditor de comprimento corporal para a espécie (R = 0,943), entretanto, todos os ossos avaliados mostraram pelo menos um caractere com capacidade de predizer o comprimento corporal (R2 > 0,9). Os resultados deste estudo são úteis para inferir o comprimento corporal de peixes-boi da Amazônia a partir de ossos depositados em museus e coleções biológicas, expandindo o potencial informativo destes materiais.

P-glycoprotein (P-gp) induction and/or activation have been proposed as therapeutic strategies in intoxication scenarios, by reducing the intestinal absorption of xenobiotics, including drugs. Oxygenated xanthones (OXs) have been described as P-gp modulators and, therefore, the main goals of this study were to: (a) investigate the potential modulatory effect of six OXs on P-gp expression and activity in SW480 cells; (b) validate these cells for the screening/identification of P-gp inducers/activators; (c) explore the potential OXs-mediated protective effects against the cytotoxicity of mitoxantrone (MTX), a toxic P-gp substrate. Four OXs (OX2, OX4, OX5, and OX6) increased P-gp expression 24 h after exposure. However, a lack of correlation between P-gp expression and activity was observed for OX1 and OX4. In addition, after a short incubation with the P-gp fluorescent substrate, rhodamine 123, all the studied OXs, except OX3, efficient and immediately increased P-gp activity, suggesting their potential as P-gp activators. Despite these results, OXs failed to afford protection against MTX-induced cytotoxicity. Docking simulations performed in a human P-gp model revealed that the lack of protection may be explained by the different binding locations of OXs and MTX within the P-gp drug-binding pocket. In conclusion, the in vitro results confirmed OXs potential for P-gp induction and/or activation and suggested SW480 cells as a suitable in vitro model for these studies. However, P-gp activation did not protected SW480 cells against MTX cytotoxicity. In silico studies suggested the different binding locations as a limiting step in the P-gp-mediated efflux of its substrates under P-gp activation.

We assessed the feeding habits of the Amazonian manatee inhabiting blackwater (Negro River) and clearwater (Tapajos River) igapos (floodplains) using δ13C and δ15N of dentin and bone collagen from different ontogenetic classes (nursing calves, juveniles, and adults). Within an individual, the dentine δ13C and δ15N values did not vary with tooth position. Bones were more depleted in 13C and 15N compared to teeth, and the δ13C and δ15N in bone differed among classes. Food sources had δ13C values typical of algae, plants of C3 or C4 photosynthetic pathways. Mixing models showed that lactating females (inferred by isotopic values from nursing calves) had higher proportional consumption of C4 plants, while, for other adults, C3 plants were more frequent in the diet of manatees from both rivers. Juveniles had a mixed diet of C3 pants and C4 plants. We hypothesize the C4 plants signal of calves results from female movements to the floodplains of nearby whitewater rivers (varzeas), where C4 plants are abundant. Individuals from Tapajos may be more resident, as C3 plants and C4 plants are available during the flood pulse. Results demonstrate that manatee diets vary with ontogenetic classes and water typology. Preservation of habitats (igapo/varzea) is therefore required for the survival of Amazonian manatees.

Pesticide use is a major foundation of the agricultural intensification observed over the last few decades. As a result, soil contamination by pesticide residues has become an issue of increasing concern due to some pesticides' high soil persistence and toxicity to non-target species. In this study, the distribution of 76 pesticide residues was evaluated in 317 agricultural topsoil samples from across the European Union. The soils were collected in 2015 and originated from 11 EU Member States and 6 main cropping systems. Over 80% of the tested soils contained pesticide residues (25% of samples had 1 residue, 58% of samples had mixtures of two or more residues), in a total of 166 different pesticide combinations. Glyphosate and its metabolite AMPA, DDTs (DDT and its metabolites) and the broad-spectrum fungicides boscalid, epoxiconazole and tebuconazole were the compounds most frequently found in soil samples and the compounds found at the highest concentrations. These compounds occasionally exceeded their predicted environmental concentrations in soil but were below the respective toxic endpoints for standard in-soil organisms. Maximum individual pesticide content assessed in a soil sample was 2.05 mg kg−1 while maximum total pesticide content was 2.87 mg kg−1. This study reveals that the presence of mixtures of pesticide residues in soils are the rule rather than the exception, indicating that environmental risk assessment procedures should be adapted accordingly to minimize related risks to soil life and beyond. This information can be used to implement monitoring programs for pesticide residues in soil and to trigger toxicity assessments of mixtures of pesticide residues on a wider range of soil species in order to perform more comprehensive and accurate risk assessments.

Current farm systems rely on the use of Plant Protection Products (PPP) to secure high productivity and control threats to the quality of the crops. However, PPP use may have considerable impacts on human health and the environment. A study protocol is presented aiming to determine the occurrence and levels of PPP residues in plants (crops), animals (livestock), humans and other non-target species (ecosystem representatives) for exposure modelling and impact assessment. To achieve this, we designed a cross-sectional study to compare conventional and organic farm systems across Europe. Environmental and biological samples were/are being/will be collected during the 2021 growing season, at 10 case study sites in Europe covering a range of climate zones and crops. An additional study site in Argentina will inform the impact of PPP use on growing soybean which is an important European protein-source in animal feed. We will study the impact of PPP mixtures using an integrated risk assessment methodology. The fate of PPP in environmental media (soil, water and air) and in the homes of farmers will be monitored. This will be complemented by biomonitoring to estimate PPP uptake by humans and farm animals (cow, goat, sheep and chicken), and by collection of samples from non-target species (earthworms, fish, aquatic and terrestrial macroinvertebrates, bats, and farm cats). We will use data on PPP residues in environmental and biological matrices to estimate exposures by modelling. These exposure estimates together with health and toxicity data will be used to predict the impact of PPP use on environment, plant, animal and human health. The outcome of this study will then be integrated with socio-economic information leading to an overall assessment used to identify transition pathways towards more sustainable plant protection and inform decision makers, practitioners and other stakeholders regarding farming practices and land use policy. EEA Balcarce Fil: Silva, Vera. Wageningen University and Research. Soil Physics and Land Management Group; Países Bajos. Fil: Alaoui, Abdallah. University of Bern. Institute of Geography. Centre for Development and Environment; Suiza. Fil: Schlünssen, Vivi. Aarhus University. Department of Public Health; Dinamarca. National Research Centre for the Working Environment; Dinamarca. Fil: Vested, Anne. Aarhus University. Department of Public Health; Dinamarca. Fil: Graumans, Martien. Radboud Institute for Health Sciences; Países Bajos. Fil: Van Dael, Maurice. Radboud Institute for Health Sciences; Países Bajos. Fil: Trevisan, Marco. Università Cattolica del Sacro Cuore. Department for Sustainable Food Process; Italia. Fil: Suciu, Nicoleta. Università Cattolica del Sacro Cuore. Department for Sustainable Food Process; Italia. Fil: Mol, Hans. Wageningen University and Research. Wageningen Food Safety Research; Países Bajos. Fil: Beekmann, Karsten. Wageningen University and Research. Wageningen Food Safety Research; Países Bajos. Fil: Figueiredo, Daniel. Utrecht University. Institute for Risk Assessment Sciences; Países Bajos. Fil: Harkes, Paula. Wageningen University and Research. Soil Physics and Land Management Group; Países Bajos. Fil: Hofman, Jakub. Masaryk University. Faculty of Science. Research Centre for Toxic Compounds in the Environment; Republica Checa. Fil: Kandeler, Ellen. University of Hohenheim. Institute of Soil Science and Land Evaluation; Alemania. Fil: Abrantes, Nelson. University of Aveiro. Centre for Environmental and Marine Studies and Department of Environment and Planning; Portugal. Fil: Campos, Isabel. University of Aveiro. Centre for Environmental and Marine Studies and Department of Environment and Planning; Portugal. Fil: Martínez, María Ángeles. Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas; España. Fil: Pereira, Joana Luísa. Centre for Environmental and Marine Studies and Department of Environment and Planning; Portugal. Fil: Goossens, Dirk. Wageningen University and Research. Soil Physics and Land Management Group. Países Bajos. KU Leuven Department of Earth and Environmental Sciences; Belgica. Fil: Gandrass, Juergen. Institute of Coastal Environmental Chemistry; Alemania. Fil: Debler, Freya. Institute of Coastal Environmental Chemistry; Alemania. Fil: Huerta Lwanga, Esperanza. Wageningen University and Research. Soil Physics and Land Management Group; Países Bajos. Fil: Jonker, Marlot. Dutch Mammal Society; Países Bajos. Fil: Van Langevelde, Frank. Wageningen University and Research. Wildlife Ecology and Conservation Group; Países Bajos. Fil: Sorensen, Martin. Aarhus University. Department of Animal Science; Dinamarca. Fil: Wells, Jerry. Wageningen University and Research. Host-Microbe Interactomics, Animal Sciences Group; Países Bajos. Fil: Boekhorst, Jos. Wageningen University and Research. Host-Microbe Interactomics, Animal Sciences Group; Países Bajos. Fil: Huss, Anke. Utrecht University. Institute for Risk Assessment Sciences; Países Bajos. Fil: Mandrioli, Daniele. Ramazzini Institute. Cesare Maltoni Cancer Research Center; Italia. Fil: Sgargi, Daria. Ramazzini Institute. Cesare Maltoni Cancer Research Center; Italia. Fil: Nathanail, Paul. Land Quality Management; Reino Unido. Fil: Nathanail, Judith. Land Quality Management; Reino Unido. Fil: Tamm, Lucius. Research Institute of Organic Agriculture; Suiza. Fil: Fantke, Peter. Technical University of Denmark. Department of Technology, Management and Economics; Dinamarca. Fil: Mark, Jennifer. Research Institute of Organic Agriculture; Suiza. Fil: Grovermann, Christian. Research Institute of Organic Agriculture; Suiza. Fil: Larsen, Ana Frelih. Ecologic Institute; Alemania. Fil: Herb, Irina. Ecologic Institute; Alemania. Fil: Chivers, Charlotte Anne. University of Gloucestershire. Countryside and Community Research Institute; Reino Unido. Fil: Mills, Jane. University of Gloucestershire. Countryside and Community Research Institute; Reino Unido. Fil: Alcon, Francisco. Universidad Politécnica de Cartagena; España. Fil: Contreras, Josefina. Universidad Politécnica de Cartagena; España. Fil: Baldi, Isabelle. Bordeaux University. INSERM U1219; Francia. Fil: Pasković, Igor. Institute of Agriculture and Tourism, Department of Agriculture and Nutrition; Croacia. Fil: Matjaz, Glavan. University of Ljubljana. Biotechnical Faculty; Eslovenia. Fil: Norgaard, Trine. Aarhus University. Department of Agroecology; Dinamarca. Fil: Aparicio, Virginia Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Fil: Ritsema, Coen. Wageningen University and Research. Soil Physics and Land Management Group; Países Bajos. Fil: Geissen, Violette. University and Research. Soil Physics and Land Management Group; Países Bajos. Fil: Scheepers, Paul. Radboud Institute for Health Sciences; Países Bajos.

Considering that pesticides have been used in Europe for over 70 years, a system for monitoring pesticide residues in EU soils and their effects on soil health is long overdue. In an attempt to address this problem, we tested 340 EU agricultural topsoil samples for multiple pesticide residues. These samples originated from 4 representative EU case study sites (CSS), which covered 3 countries and four of the main EU crops: vegetable and orange production in Spain (S–V and S–O, respectively), grape production in Portugal (P-G), and potato production in the Netherlands (N–P). Soil samples were collected between 2015 and 2018 after harvest or before the start of the growing season, depending on the CSS. Conventional and organic farming results were compared in S–V, S–O and N–P. Soils from conventional farms presented mostly mixtures of pesticide residues, with a maximum of 16 residues/sample. Soils from organic farms had significantly fewer residues, with a maximum of 5 residues/sample. The residues with the highest frequency of detection and the highest content in soil were herbicides: glyphosate and its main metabolite AMPA (P-G, N–P, S–O), and pendimethalin (S–V). Total residue content in soil reached values of 0.8 mg kg−1 for S–V, 2 mg kg−1 for S–O and N–P, and 12 mg kg−1 for P-G. Organic soils presented 70–90% lower residue concentrations than the corresponding conventional soils. There is a severe knowledge gap concerning the effects of the accumulated and complex mixtures of pesticide residues found in soil on soil biota and soil health. Safety benchmarks should be defined and introduced into (soil) legislation as soon as possible. Furthermore, the process of transitioning to organic farming should take into consideration the residue mixtures at the conversion time and their residence time in soil.

The two Sotalia species (the marine S. guianensis and the freshwater S. fluviatilis) have only recently been recognized, and both face several conservation challenges. We investigated the existence of hybridization between the two species in their possible area of sympatry in the Amazon Estuary, in northern Brazil. A fast and cheap PCR-RFLP diagnostic method using nuclear DNA was developed to discriminate between the two species, while allowing the detection of hybrids. All samples that could be identified (N = 51) were identified as S. guianensis, and no hybrids were detected. Our results, coupled with previous mitochondrial data, suggest that S. fluviatilis is not present in the Amazon delta. Thus, sympatry with S. guianensis, if it does occur, may be restricted to upstream areas of the Amazon River.

This work relied on the use microcosms to evaluate the individual and the combined effects of different levels of copper sulfate (0.0, 0.013, 0.064 and 0.318 mg Cu L−1) – a fungicide commonly exceeding allowable thresholds in agricultural areas – and a range of water temperature increase scenarios (15, 20 and 25 °C) on freshwater species belonging to different functional groups. Hence, the growth inhibition of primary producers (the microalgae Raphidocelis subcapitata and the macrophyte Lemna minor), as well as the survival and feeding behavior of a shredder species (the Trichoptera Schizopelex sp.) were evaluated. The results revealed that copper was toxic to primary producers growth, as well as shredders growth and survival, being the growth of L. minor particularly affected. Higher water temperatures had generally enhanced the growth of primary producers under non-contaminated (microalgae and macrophytes) or low-contaminated (macrophytes) conditions. Despite the tendency for a more pronounced toxicity of copper under increasing water temperatures, a significant interaction between the two factors was only observed for microalgae. Since the test organisms represent relevant functional groups for sustaining freshwater systems functions, the present results may raise some concerns on the impacts caused by possible future climate change scenarios in aquatic habitats chronically exposed to the frequent or intensive use of the fungicide copper sulfate.

The spermatozoa from seven adult Amazon river dolphins (Inia geoffrensis, CETACEA: INIIDAE) were analyzed by light and electron microscopy. The spermatozoa showed an elongated ellipsoid shaped head and a long tail with a well distinguishable midpiece. The head spermatozoa have a smooth surface like other odontocetes examined, with the exception of the Delphinidae family. The mean dimensions of the spermatozoa were within the range already reported for other cetaceans. The spermatozoa midpiece, as in other cetaceans, showed a random pattern of mitochondria, different from that described for other mammals. Further studies of sperm morphology of a wider spectrum of cetacean families could help to better understand the reproductive biology of these animals and the intergeneric and intrageneric relationships among them, as well as, among other mammals. Anat Rec, 300:1519-1523, 2017. © 2017 Wiley Periodicals, Inc.

The number of wildfires has markedly increased in Mediterranean Europe, including in Portugal. Wildfires are environmentally concerning, not only due to the loss of biodiversity and forest area, but also as a consequence of environmental contamination by specific compounds including metals and polycyclic aromatic compounds (PAHs). These contaminants, mostly bound to ashes, can reach downstream water bodies, namely through surface runoff, being ultimately dispersed by vast areas and contacting with aquatic biota. Being toxicologically noteworthy, the potential toxic outcomes of the input of such chemicals across the aquatic compartment must be characterized. In this context, the present study used a biomarker-based approach to find early-warning signals of toxicity triggered by the exposure of the mosquitofish, Gambusia holbrooki, to affected aqueous runoff and stream water samples collected from a forest burnt area. The chemical analysis revealed concerning levels of metals and polycyclic aromatic hydrocarbons in both runoff and stream water samples. Biological responses elicited by the collected samples showed the occurrence of pro-oxidative modifications, specifically driven by enzymatic forms involved in the metabolism of glutathione. Despite these effects, no further signs of involvement of metals and PAHs were elicited in terms of neurotoxicity. The overall set of data implicates chemicals resulting from wildfires in clear deleterious effects in exposed fish. published

The potential value of protected areas for the conservation of cetaceans is widely recognized; however, few evaluation methods exist to assess their effectiveness. In this study, a modeling approach based on long-term mark-recapture/resight data was used to assess the effectiveness of a Brazilian reserve in protecting endangered Amazon River dolphins or boto (Inia geoffrensis), a species killed for use as fish bait. We built an annual discrete-time model with subdivisions based on hydrological periods and age classes. It included transition probabilities in and out of the reserve that were estimated utilizing multi-state mark-recapture models. To evaluate five reserve configurations, we re-estimated the transition probabilities to represent changes in the reserve boundaries. Model predictions showed that four scenarios, including one representing the existing boundaries, would be insufficient to protect the local boto population (no = 528) and a steep decline in abundance would occur in the next 50 years (0 ≤ n50 ≤ 108). However, one reserve configuration, encompassing both flooded forests and adjacent river habitats, and including beaches and channel/floodplain entrances, resulted in a nearly stable population in the same time frame (n50 = 515). These findings suggest that, with careful design and efficient management, protected areas could be an effective conservation tool for boto populations that exhibit site fidelity to Amazonian floodplains. With appropriate mark-recapture/resight data, the modeling framework employed could be extended to evaluate and design protected areas for populations of other species in other systems.

Wildfires, increasingly frequent and severe in the Mediterranean countries, can cause serious impacts on ecosystems. As a diffuse source of contaminants – namely inorganic elements (metals, metalloids and non-metallic elements) and polycyclic aromatic hydrocarbons (PAHs) – post-fire runoff may cause toxic effects on the aquatic biota. Despite the recognition of these likely impacts, this issue has been still largely neglected. This study explores the impacts of ash from wildfires on the freshwater clam Corbicula fluminea and the ability of this filter feeder to concentrate the contaminants associated with ash in post-fire runoff. The bio-concentration potential of the clam was assessed in a 7-day filtration experiment, using aqueous extract of ashes (AEA) to represent post-fire runoff. Despite the noticeable mortality of the clams exposed to the AEA (∼30% higher in AEA than in control after 7 days of exposure), there was a clear reduction on the concentration of almost all pyrolytic substances in the water linked to bio-filtration and bio-concentration activity. Along 7 days the clams operated decreases of more than 70% for some chemicals (Cu, Mn and Zn) while others were no longer detected in the water at the end of the experiment (Cr, NAP and PHE). The removal from water was accompanied by contaminants’ accumulation in clams’ soft tissues and, less extensively, in shells. Lower pollutant loads of filtered AEA translated into decreased toxicity of the matrix towards standard aquatic species (microalgae, macrophytes and cladocerans) confirming an improvement as well in the biological quality of the water through bio-filtration. Although post-fire loads can compromise C. fluminea survival, this study evidenced the potential of this invasive species to contribute to water quality improvement.

Deliberate killing for use as bait in a regional catfish (Calophysus macropterus) fishery is the primary threat affecting the survival of the Amazon river dolphin, or boto (Inia geoffrensis). Establishing and improving freshwater protected areas has been suggested as a possible course of action to protect the species. However, the ecology of the boto is poorly understood and more information is needed on the species’ habitat use and movement patterns to ensure that spatial protection initiatives meet conservation needs. In this study, mark-recapture/resight data collected in and near the Mamiraua Sustainable Development Reserve, a varzea in the Brazilian Amazon, was used to examine transition probabilities of botos between various habitat types. Our findings suggest that it is imperative that spatial protection initiatives focused on the boto take into account the importance of varzea habitat and bay systems for individuals in early life stages. Moreover, because botos frequently occupy the main rivers, particularly during the low water period, protecting areas of the main river waters adjacent to varzeas could aid in the protection of hunted populations.

Piperine has been associated with neuroprotective effects and monoamine oxidase (MAO) inhibition, thus being an attractive scaffold to develop new antiparkinsonian agents. Accordingly, we prepared a small library of piperine derivatives and screened the inhibitory activities towards human MAO isoforms (hMAO-A and hMAO-B). Structure-activity relationship (SAR) studies pointed out that the combination of α-cyano and benzyl ester groups increased both potency and selectivity towards hMAO-B. Kinetic experiments with compounds 7, 10 and 15 indicated a competitive hMAO-B inhibition mechanism. Compounds 15 and 16, at 10 μM, caused a small but significant decrease in P-gp efflux activity in Caco-2 cells. Compound 15 stands out as the most potent piperine-based hMAO-B inhibitor (IC50 = 47.4 nM), displaying favourable drug-like properties and a broad safety window. Compound 15 is thus a suitable candidate for lead optimization and the development of multitarget-directed ligands.

We monitored the underwater behavior of botos (Inia geoffrensis) using stereo acoustic data loggers to observe their local habitat use and its diel changes at the Mamiraua Sustainable Development Reserve, Brazil. A-tags were set at five sites in three different habitat types: Lake (low current), Channel (middle current), and Junction (junction of two channels). The presence index during nighttime was significantly greater than during daytime in the Lake and Junction. Underwater movement was estimated from the changing pattern (trajectory) of the relative angle of the sound source from A-tags. A staying-type trajectory was dominant in the Lake, although the prevalence of moving-type trajectory increased at night. More than 80% of detected trajectories were the staying type in the Junction, while moving-type trajectories dominated in the Channel. The frequency of click trains was greatest in the Lake, followed by the Junction and Channels. The average interpulse interval, which reflects the mean target distance of echolocation, was shortest in the Lake, followed by the Junction and Channel. These results suggest that the botos used the Lake as their primary habitat for active behaviors like foraging, especially at night, and the Junction as their primary habitat for relatively inactive behaviors at night.

Approval for glyphosate-based herbicides in the European Union (EU) is under intense debate due to concern about their effects on the environment and human health. The occurrence of glyphosate residues in European water bodies is rather well documented whereas only few, fragmented and outdated information is available for European soils. We provide the first large-scale assessment of distribution (occurrence and concentrations) of glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) in EU agricultural topsoils, and estimate their potential spreading by wind and water erosion. Glyphosate and/or AMPA were present in 45% of the topsoils collected, originating from eleven countries and six crop systems, with a maximum concentration of 2 mg kg− 1. Several glyphosate and AMPA hotspots were identified across the EU. Soil loss rates (obtained from recently derived European maps) were used to estimate the potential export of glyphosate and AMPA by wind and water erosion. The estimated exports, result of a conceptually simple model, clearly indicate that particulate transport can contribute to human and environmental exposure to herbicide residues. Residue threshold values in soils are urgently needed to define potential risks for soil health and off site effects related to export by wind and water erosion.

Toothed whales have evolved to live in extremely different habitats and yet they all rely strongly on echolocation for finding and catching prey. Such biosonar based foraging involves distinct phases of searching for, approaching, and capturing prey, where echolocating animals gradually adjust sonar output to actively shape the flow of sensory information. Measuring those outputs in absolute levels requires hydrophone arrays centred on the biosonar beam axis, but this has never been done for wild toothed whales approaching and capturing prey. Rather, field studies make the assumption that toothed whales will adjust their biosonar in the same manner to arrays as they will when approaching prey. To test this assumption, we recorded wild botos (Inia geoffrensis) as they approached and captured dead fish tethered to a hydrophone in front of a star-shaped seven-hydrophone array. We demonstrate that botos gradually decrease interclick intervals and output levels during prey approaches, using stronger adjustment magnitudes than extrapolated from previous boto array data. Prey interceptions are characterised by high click rates, but although botos buzz during prey capture, they do so at lower click rates than marine toothed whales, resulting in a much more gradual transition from approach phase to buzzing. We also demonstrate for the first time that wild toothed whales broaden biosonar beamwidth when closing in on prey, as it is also seen in captive toothed whales and in bats, thus resulting in a larger ensonified volume around the prey, likely aiding prey tracking by decreasing the risk of prey evading ensonification.

The Negro River currently has seven floating houses where tourists can feed and interact with botos, each with its own history of how these aggregations were formed. Some keepers say these groups are familial, even reporting individuals being born into the group. However, behavioral studies have shown that botos are solitary, only forming groups at feeding areas and during the mating season. In the present study we used 12 microsatellite and molecular sex markers to characterize relationships within and between two boto aggregations (ten and seven botos each) in the lower Negro River. Molecular sexing revealed that all botos sampled from both aggregations were males. This may be explained by habitat preference, as male botos are primarily found in the main channels of large rivers, whereas females prefer more protected areas, such as flooded forests and its channels and lakes. Most of the animals were unrelated within each aggregation, demonstrating that these aggregations are not normally formed due to kinship bonds, but are exclusively for feeding, as botos learn that these places provide easy access to food. This study provides important information that helps us understand how human interaction is affecting the social structure and behavior of these animals. © 2019 PeerJ Inc.. All rights reserved.

Obligate river dolphins occur only in the rivers of Asia and South America, where they are increasingly subject to damaging pressures such as habitat degradation, food competition and entanglement in fishing gear as human populations expand. The Amazon basin hosts two, very different, dolphins—the boto or Amazon river dolphin (Inia geoffrensis) and the smaller tucuxi (Sotalia fluviatilis). Both species have wide geographical ranges and were once considered to be relatively abundant. Their IUCN Red List conservation status of Data Deficient (DD), due to limited information on threats, ecology, population numbers and trends, did not initially cause alarm. However, the development of dolphin hunting to provide fish bait at around the beginning of this millennium broadly coincided with the onset of a widespread perception that numbers of both species were in decline. Consequently, the need for population trend data to inform conservation advice and measures became urgent. This paper presents a 22-year time series of standardised surveys for both dolphins within the Mamirauá Reserve, Amazonas State, Brazil. Analysis of these data show that both species are in steep decline, with their populations halving every 10 years (botos) and 9 years (tucuxis) at current rates. These results are consistent with published, independent information on survival rates of botos in this area, which demonstrated a substantial drop in annual survival, commencing at around the year 2000. Mamirauá is a protected area, and is subject to fewer environmental pressures than elsewhere in the region, so there is no reason to suspect that the decline in dolphins within the Reserve is more pronounced than outside it. If South America’s freshwater cetaceans are to avoid following their Asian counterparts on the path to a perilous conservation status, effective conservation measures are required immediately. Enforcement of existing fishery laws would greatly assist in achieving this. © 2018 F. da Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Conventional management of Mediterranean vineyards strongly contributes to land degradation. In Portugal, the use of integrated production has been encouraged by governmental subsidies because it is assumed to be a farm management system that protects the environment and favours agriculture sustainability. The purpose of this study is to assess the impact of minimum tillage and regulated fertilization practices, driven by integrated production, on runoff and associated sediment and nutrient exports (total phosphorous – TP, total nitrogen – TN and nitrates – NO3). A vineyard in the Bairrada wine region was instrumented with six runoff plots (80–122 m2). Plots were monitored on a weekly to bi-weekly basis (depending on the rainfall pattern), over two hydrological years (from October 2012 to September 2014). Results indicated that annual runoff coefficients ranged from 10% to 20%, sediment losses from 1.1 to 29.0 Mg ha−1 yr−1, TP exports from 0.4 to 6.5 kg ha−1 yr−1, TN exports from 0.2 to 20.0 kg ha−1 yr−1 and NO3 exports from 0.1 to 0.8 kg ha−1 yr−1. These results highlight the susceptibility of vineyards to land degradation and their role as a diffuse source of pollution. Rainfall strongly influenced runoff as well as sediment and nutrient concentrations, leading to relevant inter-annual and seasonal differences. Over the study period, about 60% of runoff and >85% of sediments and nutrients exported by runoff were recorded during winter. Management practices, namely inter-row tillage deeply influenced sediment exports, whereas fertilization, had a strong effect on nitrate exports. Although integrated production lead to lower runoff and nutrient exports than conventional viticulture, additional measures are needed to effectively prevent soil erosion and nutrient losses in Mediterranean vineyards.