Morphological, behavioral and genotoxic effects of glyphosate and 2,4-D mixture in tadpoles of two native species of South American amphibians.

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 h. 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.

Genotoxic effects of glyphosate on Physalaemus tadpoles.

Genotoxicity studies have revealed that pesticides bind to genetic material in non-target vertebrates, thereby impairing the genetic integrity of these animals. The main objective of this study was to determine the genotoxic damage in erythrocytes of two native South American amphibian Physalaemus cuvieri and Physalaemus gracilis, both species exposed to a glyphosate-based herbicide. We evaluated the presence of micronuclei (MN) and erythrocyte nuclear abnormalities (ENA) as biomarkers for potential genotoxic compounds. Tadpoles were exposed to doses permitted by Brazilian legislation and concentrations found naturally in Brazilian and Argentinian waters (500, 700 and 1000 µg/L). Glyphosate-based herbicide caused micronuclei formation and several types of erythrocyte nuclear abnormalities in both Physalaemus species. The total frequency of MN and ENA demonstrated the occurrence of cell damage at all tested concentrations. Glyphosate herbicide can be considered a genotoxic that may impact the genetic integrity of native populations of P. cuvieri and P. gracilis.

Can environmental concentrations of glyphosate affect survival and cause malformation in amphibians? Effects from a glyphosate-based herbicide on Physalaemus cuvieri and P. gracilis (Anura: Leptodactylidae).

Herbicides are the most common agrochemicals used in crops. Among them, glyphosate is the most widely applied in the world. Herbicides, especially organophosphates, have been shown to be hazardous to non-target species, including amphibians. The present study evaluated the acute and chronic effects of glyphosate-based herbicide (GBH), Roundup original® DI on tadpoles from two South American native species, Physalaemus cuvieri and P. gracilis. Spawnings were collected in the natural environment and maintained in the laboratory under controlled conditions. Acute and chronic toxicology trials began at stage 25 of Gosner (Herpetological 16:183-190, 1960). In an acute toxicity assay, seven GBH concentrations between 100 and 4500 µg a.e./L were tested over 96 h. For the chronic trials, tadpoles were subjected to both doses allowed by Brazilian legislation and to concentrations found in natural environment waters from Brazil and Argentina, between 65 and 1000 µg a.e/L over 14 days. Glyphosate had lethal effects on both studied species. Tadpoles showed shorter lengths and lower masses; that is, those that survived suffered chronic effects on growth and weight. The GBH maximum acceptable toxicant concentration for mortality and malformation was lower than the allowed level for Brazilian waters. The GBH tested in this study presented a high environmental and acute risk for the two studied species.

Acute and chronic toxicity of pesticides on tadpoles of Physalaemus cuvieri (Anura, Leptodactylidae).

Brazil is the largest consumer of pesticides in the world. However, knowledge on how these pesticides affect wildlife is scarce. Among the vertebrates, amphibians are particularly important in research to assess the impact of pesticides because of the correlation between pesticide and the decline of these species. This study aimed to evaluate the acute and chronic toxicity of commercial formulations of pesticides, i.e., atrazine (herbicide), cypermethrin (insecticide), and tebuconazole (fungicide) in Physalaemus cuvieri tadpoles. Eggs were collected in nature and cultivated under controlled conditions in the laboratory. Toxicity tests were carried out under standard conditions to determine the lethal concentration (LC50) after 96 h of exposure and to determine the effect of sublethal concentrations after 7 days. In addition, we performed swimming activity tests on tadpoles exposed to sublethal concentrations. The lethal concentration (LC50) was 19.69 mg/L for atrazine, 0.24 mg/L for cypermethrin and 0.98 mg/L for tebuconazole. In the acute test, atrazine showed lower toxicity than cypermethrin and tebuconazole for P. cuvieri. Swimming activity was affected at sublethal doses of atrazine and cypermethrin, but was not after exposure to tebuconazole. Cypermethrin was the insecticide that most altered the swimming activity of the individuals tested. The risk evaluation analysis indicated risks for tadpoles exposed to three tested pesticides, specially cypermethrin.

Anuros da Reserva Natural Salto Morato, Guaraqueçaba, Paraná, Brasil / Anurans of Reserva Natural Salto Morato, municipality of Guaraqueçaba, State of Paraná, southern Brazil

O objetivo do presente estudo é apresentar a lista de espécies de anfíbios da Reserva Natural Salto Morato (RNSM), uma reserva de Mata Atlântica no Estado do Paraná, sul do Brasil. O parque está localizado no litoral norte do Paraná, na divisa com o Estado de São Paulo. Nós amostramos ambientes lênticos e lóticos, bromélias e serrapilheira durante os meses de setembro de 2006 a março de 2007. Na RNSM foram registradas 42 espécies de anfíbios anuros, pertencentes a nove famílias, sendo uma espécie endêmica da área de estudo. Nós registramos 14 modos reprodutivos dos anuros na área de estudo. Na RNSM, 50% das espécies de anuros ocorreram em mais de 50% das amostragens, 26% das espécies foram registradas entre 25-50% das amostragens e 24% das espécies foram raras, ocorrendo em menos de 25% das amostragens. A RNSM até o presente momento é a área com a maior diversidade de anfíbios e de modos reprodutivos do Paraná. Esses fatores evidenciam a importância da RNSM para a conservação dos anfíbios.

Here we present a survey of amphibian species of the Reserva Natural Salto Morato (RNSM), an Atlantic rainforest reserve in Paraná, southern Brazil. We sampled lentic and lotic water bodies, phytotelmata and leaf litter from September 2006 to March 2007. We found 42 species from nine families, one of which is endemic to the study area. Additionally, we recorded 14 reproductive modes. In the RNSM, 50% of anuran species occur in more than 50% of samples, 26% of species occurred between 25 and 50% of samples, and 24% were rare, occurring in less than 25% of samples. The reserve holds the highest diversity of amphibians and reproductive modes in Paraná. Our results emphasize the importance of RNSM for amphibian conservation.

Ecologia e história natural de uma taxocenose de serpentes no Núcleo Santa Virgínia do Parque Estadual da Serra do Mar, no sudeste do Brasil / Ecology and natural history of a snake assemblage at Núcleo Santa Virgínia, Parque Estadual da Serra do Mar, southeastern Brazil

O objetivo deste estudo foi obter informações sobre a história natural e a ecologia de uma taxocenose de serpentes na Mata Atlântica do alto da Serra do Mar, no Núcleo Santa Virgínia do Parque Estadual da Serra do Mar, nordeste do Estado de São Paulo, Brasil. Os principais aspectos estudados foram riqueza, abundância relativa, padrões de atividade diária e sazonal, utilização do ambiente e dieta. Também são fornecidas informações adicionais sobre outros aspectos da história natural das espécies. Um total de 148 indivíduos, de 27 espécies, 19 gêneros e quatro famílias foi encontrado dentro dos limites do Núcleo Santa Virgínia. As espécies mais frequentemente encontradas foram Bothrops jararaca, Xenodon neuwiedii e Liophis atraventer. A maior parte das espécies é predominantemente diurna e terrícola. Dentre os fatores abióticos analisados para a área de estudo, o mais relacionado à abundância das serpentes foi a temperatura mínima, seguido da temperatura média e da pluviosidade. A maioria das espécies encontradas apresenta dieta concentrada em uma categoria de presa ou restrita a poucos tipos de itens alimentares. Aparentemente, anfíbios anuros são o principal recurso alimentar para as taxocenoses de serpentes da Mata Atlântica do alto da Serra do Mar. Os nossos resultados indicam que a estrutura da taxocenose de serpentes do Núcleo Santa Virgínia reflete principalmente as características ecológicas da linhagem mais representada na taxocenose.

The objective of this study was to describe the natural history and the ecology of a snake assemblage in the Atlantic rainforest, at Núcleo Santa Virgínia, Parque Estadual da Serra do Mar, located on the northeastem of the state of São Paulo, southeastern Brazil. We describe richness, relative abundance, daily and seasonal activity, and substrate use, besides additional aspects of the natural history of the snakes. A total of 148 individuals, of 27 species, 19 genera and four families, were found within the area of the Núcleo Santa Virgínia. Species that were sampled more frequently were Bothrops jararaca, Xenodon neuwiedii and Liophis atraventer. Among the abiotic factors analyzed, minimum temperature, followed by mean temperature and rainfall are apparently the most important in determining snake abundance and/or activity. Most species presented a diet concentrated on one prey category or restricted to a few major food items. Frogs seem to be the most important food resource for snake assemblages in the Atlantic rainforest on the top of Serra do Mar. Our results indicate that the structure of the Núcleo Santa Virgínia snake assemblage reflects mainly the ecological characteristics of each of the lineages that compose the assemblage.