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The ever-increasing level of marine pollution due to plastic debris is a globally recognized threat that needs effective actions of control and mitigation. Using marine organisms as bioindicators of plastic pollution can provide crucial information that would better integrate the spatial and temporal presence of plastic debris in the sea. Given the...
Citations
... Agricultural activities have been shown as the biggest threat to amphibians, which lead to habitat fragmentation and modification (Kacoliris et al., 2022). Amphibians require streams and wetlands in additional to terrestrial habitats for successful breeding and embryonic and larval development, which makes them more vulnerable to landscape change (Brodeur and Candioti, 2017). ...
Although the impacts of climate change on the yields of crops have been studied, how these changes will result in the eventual realized crop production through market feedbacks has received little attention. Using a combination of attainable yield predictions for wheat, rice, maize, soybean and sugarcane, computable general equilibrium and land rent models, we project market impacts and crop-specific land-use change up to 2100 and the resulting implications for carbon and biodiversity. The results show a general increase in crop prices in tropical regions and a decrease in sub-tropical and temperate regions. Land-use change driven by market feedbacks generally amplify the effects of climate change on yields. Wheat, maize and sugarcane are projected to experience the most expansion especially in Canada and Russia, which also present the highest potential for habitat conversion-driven carbon emissions. Conversely, Latin America presents the highest extinction potential for birds, mammals and amphibians due to cropland expansion. Climate change is likely to redistribute agricultural production, generating market-driven land-use feedback effects which could, counterintuitively, protect global biodiversity by shifting global food production towards less-biodiverse temperate regions while creating substantial restoration opportunities in the tropics.
... Environmental contamination is considered a driver of current amphibian population declines along with other factors (Brodeur and Vera Candioti 2017;Campbell Grant et al. 2016;Roelants et al. 2007;Stuart et al. 2004). As for most vertebrate groups, amphibians subjected to neonics involved exposure to chronic sublethal conditions rather than acute toxicity (Fonseca Peña, Natale, and Brodeur 2022). ...
The goal of the present study was to examine the effects of environmentally relevant concentrations of the neonicotinoid insecticides thiamethoxam and imidacloprid on the metamorphosis of the toad Rhinella arenarum. Tadpoles were exposed from stage 27 until completion of metamorphosis to concentrations of thiamethoxam ranging between 1.05 and 1050 µg/L and concentrations of imidacloprid varying between 3.4 and 3400 µg/L. The two neonicotinoids were found to act differently at the range of concentrations tested. Thiamethoxam did not markedly alter the final % tadpoles completing metamorphosis but extended by 6–20 days the time needed for tadpoles to complete metamorphosis. The extra number of days required to reach metamorphosis was concentration-dependent between 1.05 and 100.5 µg/L, and then stable at 20 days between 100.5 and 1005 µg/L. In contrast, imidacloprid did not significantly interfere with the overall time needed to complete metamorphosis but decreased success of metamorphosis at 3400 µg/L, the highest concentration tested. Both neonicotinoid concentrations did not markedly alter body size and weight of the newly metamorphosed toads. With a lowest observed effect concentration (LOEC) of 1.05 µg/L, thiamethoxam may be more likely to impact tadpole development in the wild compared to imidacloprid, which was without any apparent effect at concentrations up to 340 µg/L (no-observed effect concentration or NOEC). As the influence of thiamethoxam was triggered after tadpoles had reached Stage 39, when metamorphosis is strictly dependent upon thyroid hormones, this observed effect is attributed to result from actions of this neonicotinoid insecticide on the hypothalamic-pituitary-thyroid axis.
... This situation constitutes a risk for the species that inhabit these ecosystems, in particular anurans that have characteristics in their modes of life that make them prone to exposure and interaction with environmental pollutants (Agostini et al., 2013;Brodeur et al., 2011;Natale et al., 2018;Pérez-Iglesias et al., 2015). Furthermore, the low migratory capacity of anurans (Sinsch, 1990) makes them good indicators of the environment they live (Brodeur & Vera-Candioti, 2017;Blaustein & Wake, 1995;Guzy et al., 2012). ...
Introduction:
The frequent use of pesticides is currently considered a cause of environmental pollution due to the high rate of entry of these substances into agroecosystems. This constitutes a risk for the species that inhabit these ecosystems, in particular anurans whose characteristics make them prone to exposure to and interaction with environmental pollutants.
Objective:
To report the occurrence of abnormalities in larvae of the common toad Rhinella arenarum inhabiting ponds surrounded by agroecosystems.
Methods:
In two consecutive springs (2015 and 2016), reproductive events of common toads were monitored in temporary pond systems in agricultural and non-agricultural areas, located near the city of La Plata (Buenos Aires, Argentina). The physicochemical parameters of the ponds were measured, and the stage of each reproductive event was recorded, such as the numbers of adult toads, amplexus and clutches. In the laboratory, the larvae were measured and photographed, their stage of development was recorded, and their morphology was examined under a stereomicroscope. Representative samples (normal and abnormal) from each pond studied were processed for histopathological analysis.
Results:
In the field studies carried out on a population of R. arenarum collected in an agroecosystem, a lower number of reproductive adults and clutches were observed in relation to the population of a non-agricultural pond. A total of 1 910 larvae were collected: 529 and 1 381 larvae from ponds located in non-agricultural and agricultural areas, respectively. Larvae from the agroecosystem showed two types of abnormalities: severe tail flexure and abdominal bloating. In addition, five degrees of severity could be determined in relation to abdominal bloating.
Conclusions:
This work reports the high frequency and severity of abnormalities observed in the early stages of R. arenarum larvae living within an agroecosystem, providing evidence of the negative impact that agricultural activities cause on aquatic ecosystems surrounded by farming areas.
... Degradation of this kind extends beyond just the habitat itself to affect wildlife within the ecosystem. Amphibians are sensitive to environmental changes because of their reliance on both aquatic and terrestrial habitats, as well as their porous skin that absorbs potentially harmful substances from their environment (Brodeur & Candioti, 2017). While amphibians are not as sensitive to chemical changes as originally expected, these species are generally accepted and used as bioindicators, particularly in their egg and larval stages (Bridges et al., 2002;Brodeur & Candioti, 2017;Jansen & Healey, 2003;Kerby et al., 2009;Nowakowski et al., 2017). ...
... Amphibians are sensitive to environmental changes because of their reliance on both aquatic and terrestrial habitats, as well as their porous skin that absorbs potentially harmful substances from their environment (Brodeur & Candioti, 2017). While amphibians are not as sensitive to chemical changes as originally expected, these species are generally accepted and used as bioindicators, particularly in their egg and larval stages (Bridges et al., 2002;Brodeur & Candioti, 2017;Jansen & Healey, 2003;Kerby et al., 2009;Nowakowski et al., 2017). Amphibians rely on wetlands for reproduction with their early life stages taking place in water, while post-metamorphosis they generally live on land (Bridges et al., 2002;Brodeur & Candioti, 2017). ...
... While amphibians are not as sensitive to chemical changes as originally expected, these species are generally accepted and used as bioindicators, particularly in their egg and larval stages (Bridges et al., 2002;Brodeur & Candioti, 2017;Jansen & Healey, 2003;Kerby et al., 2009;Nowakowski et al., 2017). Amphibians rely on wetlands for reproduction with their early life stages taking place in water, while post-metamorphosis they generally live on land (Bridges et al., 2002;Brodeur & Candioti, 2017). Anuran movements and habitat use vary significantly across species and environments, and average post-breeding movements range from 38 m to 1810 m (Lemckert, 2004). ...
Cattle in wetlands impact water quality through waste excretion, which deposits excess nutrients, as well as decreasing the biomass and height of vegetation through trampling and herbivory. Amphibians are sensitive to these changes due to their porous skin and reliance on vegetated microhabitats. Previous studies examining the effect of cattle on amphibians in wetlands report conflicting results, exemplifying the need to avoid overgeneralizations and instead examine specific environments. In the Ñeembucú Wetland Complex in Paraguay, low-intensity cattle ranching is a common practice. This study seeks to understand how the presence of cattle in these operations impacts water chemistry and amphibian species richness, as well as determining which cattle effects (eutrophication, nutrient loading, and decreased vegetation height diversity) have the greatest impact on amphibian communities. We anticipated that increased cattle presence would negatively impact wetland condition, and consequentially lower amphibian species richness. Data was collected over seven weeks at Estancia Santa Ana, a low-intensity cattle ranch in Pilar, Paraguay. Cattle presence was measured through cow footprints and feces densities, while a vegetation survey and water quality testing (nitrate, phosphate, and dissolved oxygen) served as environmental metrics. Pitfall trapping was used to gather information on amphibian species richness and community composition. A Pearson parametric correlation test and Factor Analysis of Mixed Data in R were then used to understand the relationship between variables. Very few statistically relationships were found between variables, and those that existed showed a very weak correlation. This suggests that cow presence does not have as strong of an impact on water quality or amphibian species richness as expected. Terrestrial and aquatic vegetation were found to explain much of the variation among the data, which verifies the importance of amphibians’ microhabitats. While future research comparing generalist and specialist species in the area is necessary, these initial results suggest a hopeful future for collaboration on environmental efforts with low-intensity cattle ranchers.
KEYWORDS.
Amphibia; cattle ranching; livestock; vegetation structure; eutrophication
... The toxic load present in each of the specimens captured was estimated through the calculation of a pesticide toxicity index (PTI) as previously described (Nowell et al., 2014), but with some modifications for use with tissue residue values instead of water concentrations. The pesticide toxic load was then compared to the values obtained for a variety of body indices, and biochemical and histological parameters commonly employed as indicators of the physiological and bioenergetics status in frogs (Brodeur and Vera Candioti, 2017;Brodeur et al., 2011Brodeur et al., , 2020. Results obtained provide insights on the pesticide exposure of frogs from agricultural regions and, for the first time, associate the toxicity index of the mixture of pesticide present in the frogs to a number of biological effects. ...
Contamination with current-use pesticides is frequently mentioned as a key factor in global amphibian declines although a limited number of studies have examined the mixture of pesticides accumulated by free-living frogs. This study examined the presence of 46 different pesticide residues in the muscle and kidney tissues of two frog species living in close association with row crops in the Pampa region of Argentina: The terrestrial Leptodactylus latinasus and the semi-aquatic Leptodactylus latrans. A total of 20 different pesticides were identified in frog tissues; chlorpyrifos-methyl, pirimiphos-methyl and acetochlor being the most frequently detected molecules. Overall, one or more pesticide residues (up to 12 in a single frog) were detected in 40–57 % of L. latrans. L. latinasus was found to present more pesticide detections than L. latrans. Interestingly, frog sampled in a natural reserve where no pesticides are applied presented an equivalent frequency of detections as frogs living near a crop. In L. latrans, the calculation of a pesticide toxicity index (PTI) permitted to highlight the existence of a strong positive correlation between PTI and liver GSH contents of females whereas, in males, PTI was negatively correlated with the perimeter of testicular seminiferous tubules. Males also presented near significant negative correlations between PTI and both body condition and the scaled fat index. These results indicate that frogs inhabiting agricultural regions are exposed to a complex and diffuse contamination by pesticide mixtures which is likely responsible for a number of biological effects that may be relevant at the population level.
... The terrestrial, fossorial L. latinasus was selected as the test organism because it is easy to collect and breed in captivity (Pérez-Iglesias et al. 2016) and because its populations are not at risk as the species is classified as least concern (Vaira et al. 2012;IUCN 2020). In addition, L. latinasus has previously been recommended for biomonitoring pesticide contamination in the Pampa region (Brodeur and Vera Candioti 2017), being the most frequent species in Neotropical agroecosystems and in undisturbed areas (Agostini et al. 2016;Medina et al. 2016;Suárez et al. 2016), and has been previously employed in a number of ecotoxicological studies both in the field and in the laboratory (Brodeur et al. 2011;Guerra and Aráoz 2016;Pérez-Iglesias et al. 2016, 2020. However, to our knowledge, there are no studies reported in the literature on the effects of active ingredient or formulation of IMZT in adult frogs evaluated using multiple biomarkers. ...
Imazethapyr is an herbicide that is used in a variety of crops worldwide, including soybean and corn. The aim of the present study was to evaluate the biomarkers responses of adult Leptodactylus latinasus exposed to the formulation Pivot® H (10.59% imazethapyr) in the laboratory at concentrations and under conditions that simulate two potential field exposure scenarios: an immersion in field runoff (Scenario 1: 10 mg/L) and a direct exposure to the droplets emitted by spray noozles (Scenario 2: 1000 mg/L). In both scenarios, the experimental procedure involved completely immersing the frogs over a period of 15 s. Different endpoints were evaluated at several ecotoxicological levels 48 and 96 h after the herbicide exposure. These included individual (biometric indices and behavior alterations), histological (liver pigments and lesions), biochemical (catalase, glutathione system and cholinesterase activities) and genotoxic effects (micronuclei induction and nuclear abnormalities). Forty-eight hours after imazethapyr exposure, frogs submitted to Scenario 1 presented an inhibition of liver glutathione-S-transferase activity, whereas histological alterations and increased hepatic cholinesterase levels were observed in frogs exposed under Scenario 2. Ninety-six hours after exposure to the imazethapyr formulation, frogs from the Scenario 1 treatment presented a decrease in liver melanin and hemosiderin, increased hepatic catalase activity and micronuclei induction. For their part, frogs exposed to Scenario 2 presented a decrease in the hepatosomatic index, an increase in liver alterations, melanin reduction and micronuclei induction. The multivariate analysis enables correlations to be made between biomarkers of different organizational level in exposed anurans. Our result indicates that real exposure to imazethapyr formulations under field conditions may pose a risk to Leptodactylus latinasus populations living in the agroecosystems.
... Herbicides applied in agriculture can be leached into aquatic environments around agricultural areas, mainly during rainy periods (Botta et al., 2009;Islam et al., 2018). As many amphibians species are restricted to aquatic environments, they can be directly exposed to pesticides (Agostini et al., 2016;Suárez et al., 2016;Brodeur and Vera-Candioti, 2017;Ribeiro et al., 2017). Recent studies carried out in Brazil and Argentina have demonstrated the occurrence of abnormalities in amphibian species found close to agricultural environments, such as changes in development and genotoxic effects (Agostini et al., 2013;Sánchez-Domene et al., 2018;Borges et al., 2019;Agostini et al., 2020). ...
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Pesticide contamination is an important factor in the global decline of amphibians. The herbicides glyphosate and 2,4-D are the most applied worldwide. These herbicides are often found in surface waters close to agricultural areas. This study aims at evaluating the chronic effects caused by glyphosate + 2,4-D mixture in Boana faber and Leptodactylus latrans tadpoles. The combined solution of the glyphosate and 2,4-D, in 5 different concentrations, was applied for 168 hours. Herbicide mixtures did not affect the survival of the exposed tadpoles but growth and swimming activity were altered; besides causing several damages in the mouth and intestine. The erythrocytes showed micronuclei and other nuclear abnormalities. There is an ecological risk in the exposure of tadpoles of B. faber and L. latrans from the mixture of glyphosate + 2,4-D. Therefore, the approach used in this study provides important information on how commonly used pesticides can affect non-target organisms.
... Leptodactylus luctator also showed this preference. Rhinella fernandezae is a very plastic species that may colonize very heterogeneous habitats (Brodeur and Candioti, 2017), and the only significant selection was for those ponds related to soy crops in the Inland Pampa. We also identified the selection for ponds surrounding by soy crops in the case of O. americanus occurring in the Inland Pampas. ...
Agriculture has been identified as one of the largest contributors to the current global biodiversity crisis. Amphibians are declining worldwide, and the loss of habitat and water contamination related to agricultural land uses have been suggested as the main drivers of this phenomenon. In central Argentina, the Pampean Region combines the highest rates of grassland replacement of South America, the lowest percentage of protected areas of the country, and the lack of studies exploring diversity patterns of native amphibians occurring in agroecosystems. To fill these gaps, we surveyed anuran (frogs and toads) assemblages from 342 breeding ponds located in three ecological units from central Argentina (Rolling, Flooding, and Inland Pampas) during three breeding seasons (2015–2018). We aimed to evaluate the importance of breeding habitat characteristics (ponds) and the surrounding landscape features as drivers of anuran diversity occurring in agricultural landscapes under the primary land uses of the region (cattle grazing and soybean cropping). We tested for the effects of breeding habitat characteristics and landscape features on anuran richness, abundance, and individual species occurrence, using GLMM models and information-theoretic procedures. Results indicated that species richness and total abundances were differently influenced by the habitat and landscape features across the ecological units. Overall, vegetation cover of the ponds and land use were the most important variables influencing richness and anuran abundance. The positive influence of pond vegetation cover on anuran assemblages was registered for all the ecological units, while different patterns emerged when we analyzed the effects of land use surrounding the ponds. Land use expressed as the percentage of soy crop surrounding the ponds negatively affected richness and abundance of anurans of the Flooding Pampas, but the inverse relation was found for assemblages occurring in the Inland Pampas. Moreover, multiple competing models suggested a positive correlation between anuran diversity and land-use heterogeneity, and pond density. The differential responses of anuran assemblages among the ecological units can be related to a combination of several factors encompassing regional soil characteristics (i.e., soil texture), land-use intensity as well as requirements of anuran species. We discussed the particularities of each ecological unit in order to recognize those conservation efforts that will favor anuran diversity in these altered landscapes and further contribute to achieving agricultural sustainability.
... Several direct sublethal and lethal effects have been reported for larval and adult stages under laboratory (Agostini et al., 2010;Brodeur et al., 2014;Lajmanovich et al., 2015) and field conditions (Attademo et al., 2003;Lajmanovich et al., 2003;Campana et al., 2003;Agostini et al., 2009;Brodeur et al., 2011;Hayes et al., 2011;Lanctôt et al., 2014). Agrochemicals may also affect anurans indirectly through habitat resource modification, such as reduction of food and refuge (Sparling, 2002;Brodeur and Vera, 2017;Edge et al., 2020). However, almost all research on anuran effects has been focused either on one or the other impact factor (Sparling et al., 2003;Cushman, 2006). ...
Agricultural expansion and intensification has led globally to a rapid landscape structure change and high agrochemical use resulting in habitat loss and degraded environmental quality. Co-occurrence of landscape change and agrochemical contamination threatens biodiversity and might have interactive effects especially for organisms with complex life-cycles such as amphibians. We evaluated effects of landscape structure and agrochemical contamination at different spatial scales on anurans in Entre Rios, Argentina. We selected 35 independent stream headwaters along an agricultural expansion and intensification gradient. We conducted anuran call surveys from spring 2012 to summer 2013 and obtained detection-non detection data to estimate mean richness and focal species occupancy. We quantified forest area and riparian forest width at two spatial scales (sub-basin and local reach scale). We measured nutrients and pesticides in water and sediment. We evaluated anuran response to landscape and contamination variables using GLMs for richness and single season single-species occupancy models for focal species. Anuran diversity increased with forest area and riparian forest width, and decreased at sites with herbicide and nutrient contamination, particularly glyphosate; 2,4-D and nitrates. Also, most focal frog species responded mainly to basin forest and 2,4-D. Negative effects of agrochemical contamination on anuran diversity was mitigated in areas with larger basin forest cover. Agricultural management should ensure the reduction of herbicide and fertilizer use, the sparing of adequate forested habitat within drainage areas, and preservation of riparian forests around anuran breeding habitat to reduce and mitigate the negative effects of agrochemical contamination on anurans diversity in agroecosystems.
... Amphibians are good bioindicators of environmental quality because they show rapid responses to environmental stress (Halliday, 2000;Brodeur & Vera Candioti, 2017). In addition, they have permeable skin and eggs, making them vulnerable to aquatic contamination and infections. ...
... In addition, they have permeable skin and eggs, making them vulnerable to aquatic contamination and infections. As such, these animals are useful for monitoring changes in both the aquatic and terrestrial environments because they depend on the two environments to complete their life cycle (Brodeur & Vera Candioti, 2017). Amphibians are rapidly declining worldwide due to human-induced changes in the environment (Catenazzi, 2015;Alton & Franklin, 2017). ...
Background
Changes in land use trigger environmental changes that can lead to decreased biodiversity and species loss. The liver is an essential detoxification organ that reflects systemic physiological responses to environmental changes. Here, we tested whether contrasting land use patterns influence the amount of substances from the hepatic cellular catabolism and melanomacrophages (MMs) of five anuran species in the Brazilian Cerrado.
Methods
We collected the same five species of pond-dwelling frogs in one protected area and in an area with intense agricultural activity. We used routine histological and histochemical techniques to quantify the area occupied by lipofuscin, melanin, and hemosiderin in the liver of two frogs Leptodactylus fuscus , Physalaemus cuvieri , and three tree-frogs Dendropsophus minutus , Scinax fuscomarginatus , and Boana albopunctata . We classified land use types in a buffer around each pond based on satellite images. We then used a double-constrained Correspondence Analysis, a recently developed ecological method to relate functional traits to environmental variables, to test the effect of each land use type on the area of each liver pigment.
Results
There was an increase in the amount of melanin in environments with high proportion of agriculture, as well as variation in the amount of lipofuscin and hemosiderin. Liver pigments of P. cuvieri and B. albopunctata varied more strongly in response to land use types, suggesting they could be good indicator species. Therefore, the area of MMs in the liver and the metabolic products in their cytoplasm can be used as biomarkers of environmental changes in regions with intense agricultural activities. Our results add a new perspective to the influence of land use patterns on environmental health by highlighting the effect of environmental changes on internal morphological aspects of animals.
