Biomonitoring the impacts of pesticides used in extensive crops on adult anurans of the Pampa Region

Los efectos directos e indirectos de la exposición a plaguicidas usados en cultivos extensivos fueron evaluados en tres especies de anuros adultos (Leptodactylus latrans, Leptodactylus latinasus y Boana pulchella) de la región pampeana de Argentina. Los efectos indirectos fueron determinados caracterizando la disponibilidad y el consumo de alimentos, mientras que la determinación de biomarcadores, condición corporal e índices somáticos sirvió para evaluar efectos directos. Los parámetros analizados fueron comparados entre sitios con alta intensificación agrícola y un sitio de referencia localizado en un área geográfica protegida; antes y después de la aplicación de plaguicidas; y entre individuos con y sin presencia de plaguicidas en sus órganos. Los resultados mostraron que más del 40% de los ejemplares analizados presentaron residuos de plaguicidas en sus órganos. La presencia de plaguicidas en los órganos de los anfibios adultos se correlacionó con un menor consumo de alimento, menor condición corporal y alteraciones en biomarcadores en dos de las tres especies evaluadas. Este estudio demuestra que los anuros adultos están expuestos y acumulan plaguicidas en sus órganos generando efectos negativos directos e indirectos que podría afectar la salud de las especies expuestas en particular, y la de la biota en general.Direct and indirect effects of pesticides used in extensive crops were evaluated in three adult anuran species (Leptodactylus latrans, Leptodactylus latinasus and Boana pulchella) from the Pampean region of Argentina. Indirect effects were evaluated based on food availability and consumption, whereas biomarkers, body condition and somatic indices were determined to evaluate direct effects. Determined parameters were compared within an agricultural intensification gradient and with a reference site located in a protected area; before and after the application of pesticides; and between individuals with and without the presence of pesticides in their tissues. More than 40% of the frogs evaluated presented pesticide residues in their tissues. Pesticide presence in frogs was related to lower food consumption, lower body condition and biomarkers alterations in two of the three evaluated species. This study shows that anurans living in are exposed and accumulate pesticides in their tissues leading to direct and indirect negative effects that may impair their health.Fil: Damonte, María Jimena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Anuran responses to spatial patterns of agricultural landscapes in Argentina

Context: Amphibians are declining worldwide and land use change to agriculture is recognized as a leading cause. Argentina is undergoing an agriculturalization process with rapid changes in landscape structure. Objectives: We evaluated anuran response to landscape composition and configuration in two landscapes of east-central Argentina with different degrees of agriculturalization. We identified sensitive species and evaluated landscape influence on communities and individual species at two spatial scales. Methods: We compared anuran richness, frequency of occurrence, and activity between landscapes using call surveys data from 120 sampling points from 2007 to 2009. We evaluated anuran responses to landscape structure variables estimated within 250 and 500-m radius buffers using canonical correspondence analysis and multimodel inference from a set of candidate models. Results: Anuran richness was lower in the landscape with greater level of agriculturalization with reduced amount of forest cover and stream length. This pattern was driven by the lower occurrence and calling activity of seven out of the sixteen recorded species. Four species responded positively to the amount of forest cover and stream habitat. Three species responded positively to forest cohesion and negatively to rural housing. Two responded negatively to crop area and diversity of cover classes. Conclusions: Anurans within agricultural landscapes of east-central Argentina are responding to landscape structure. Responses varied depending on species and study scale. Life-history traits contribute to responses differences. Our study offers a better understanding of landscape effects on anurans and can be used for land management in other areas experiencing a similar agriculturalization process.Facultad de Ciencias ExactasCentro de Investigaciones del Medioambient

Biomonitoring the impacts of pesticides used in extensive crops on adult anurans of the Pampa Region

Los efectos directos e indirectos de la exposición a plaguicidas usados en cultivos extensivos fueron evaluados en tres especies de anuros adultos (Leptodactylus latrans, Leptodactylus latinasus y Boana pulchella) de la región pampeana de Argentina. Los efectos indirectos fueron determinados caracterizando la disponibilidad y el consumo de alimentos, mientras que la determinación de biomarcadores, condición corporal e índices somáticos sirvió para evaluar efectos directos. Los parámetros analizados fueron comparados entre sitios con alta intensificación agrícola y un sitio de referencia localizado en un área geográfica protegida; antes y después de la aplicación de plaguicidas; y entre individuos con y sin presencia de plaguicidas en sus órganos. Los resultados mostraron que más del 40% de los ejemplares analizados presentaron residuos de plaguicidas en sus órganos. La presencia de plaguicidas en los órganos de los anfibios adultos se correlacionó con un menor consumo de alimento, menor condición corporal y alteraciones en biomarcadores en dos de las tres especies evaluadas. Este estudio demuestra que los anuros adultos están expuestos y acumulan plaguicidas en sus órganos generando efectos negativos directos e indirectos que podría afectar la salud de las especies expuestas en particular, y la de la biota en general.Direct and indirect effects of pesticides used in extensive crops were evaluated in three adult anuran species (Leptodactylus latrans, Leptodactylus latinasus and Boana pulchella) from the Pampean region of Argentina. Indirect effects were evaluated based on food availability and consumption, whereas biomarkers, body condition and somatic indices were determined to evaluate direct effects. Determined parameters were compared within an agricultural intensification gradient and with a reference site located in a protected area; before and after the application of pesticides; and between individuals with and without the presence of pesticides in their tissues. More than 40% of the frogs evaluated presented pesticide residues in their tissues. Pesticide presence in frogs was related to lower food consumption, lower body condition and biomarkers alterations in two of the three evaluated species. This study shows that anurans living in are exposed and accumulate pesticides in their tissues leading to direct and indirect negative effects that may impair their health.Fil: Damonte, María Jimena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Conociendo a los árboles

Actividades que buscan que los chicos y las chicas interactúen con la naturaleza a partir de la observación de los árboles de su entorno. Observar, explorar, describir, preguntar, registrar, clasificar, relacionar, pero sobre todo hacer, son acciones que proponen el contacto con el mundo natural, analizar la diversidad biológica y comprender el medio ambiente que los rodea.Fil: Riera, Brenda. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: De Souza, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Solari, Laura María. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Medero, Laura Silvina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Damonte, María Jimena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentin

Frog body condition: Basic assumptions, comparison of methods and characterization of natural variability with field data from Leptodactylus Latrans

Body weight and snout-vent length (SVL) data of 3006 individual Leptodactylus latrans frogs collected over ten years in the Pampa Region of Argentina were analyzed to evaluate the best approach for expressing body condition and to characterize the natural variability of this parameter. Two different methods for expressing body condition were compared: the scaled mass index (SMI) and the residuals methods. Body weight of L. latrans was related to SVL through an allometric relationship described by the power function: Y = 0.00006 X3.11. The shape of the weight-length relationship was not affected by neither the sex of the animal nor its date or site of capture. A truly size-independent SMI value was more easily obtained when defining the scaling exponent through a non-linear regression of mass on length rather than when performing a standardized major axis regression of lnweight on lnlength. Overall, it was proved optimal to use a single scaling factor equal to 3.11 to compute SMI of all L. Latrans from the Pampa Region, irrespective of their gender and month or site of capture. Altogether, obtained results showed that SMI is a more performant indicator of body condition than residuals because it is less variable and it allows a better detection of effects. SMI and residuals condition factors deviated from each other in the extremities of L. latrans size range because scaling is not considered when calculating residuals. Body condition of females, males and juveniles was significantly lower in December/January compared to October/November and February/March. Moreover, juveniles consistently exhibited a lower body condition compared to both males and females. Based on the natural inter- and intra-annual variability observed for L. latrans SMI values, it should be possible to detect a 10% difference in SMI in an intra-annual study by sampling 14 to 17 frogs per group, whereas a 15% difference in SMI could be detected in an inter-annual study by sampling 23–29 animals per site. These numbers show that alterations of body condition should be straightforwardly identifiable in field studies with L. latrans when using SMI. The determination of SMI body condition factor during amphibian monitoring programs could be of great value, as it would provide information on amphibian health together with population abundance numbers.Fil: Brodeur, Julie Céline. Consejo de Investigaciones Científicas y Técnicas (CONICET); Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos. ArgentinaFil: Damonte, María Jimena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos. ArgentinaFil: Vera Candioti, Josefina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros. Agencia De Extensión Rural Venado Tuerto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. ArgentinaFil: Poliserpi, María Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina.Fil: D'Andrea, María Florencia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Bahl, María Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Argentina

Frog somatic indices: Importance of considering allometric scaling, relation with body condition and seasonal variation in the frog Leptodactylus latrans

Snout-vent length (SVL) and liver, gonad, fat bodies and carcass weight data from 661 individual Leptodactylus latrans frogs collected over ten years in the Pampa Region of Argentina were analyzed to evaluate the best approach for expressing the corresponding somatic indices. The seasonal variation of these indices and their respective correlation with body condition was also examined. Results obtained demonstrated that the weight of all examined tissues and organs vary in an allometric manner in function of SVL, which implies that scaled somatic indices should be employed in this species. The study also highlights the fact that size-independent somatic indices are more easily obtained if the scaling exponent is defined through a non-linear regression of mass on length rather than by performing a standardized major axis regression of lnweight on lnlength. In the case of liver, fat and carcass, the non-linear regression curves were not statistically different amongst sexes and so a single relationship was described for both males and females L. latrans. Logically, the relationships between SVL and male and female gonad weight varied on distinct scale, and so it was necessary to analyze ovaries and testis separately. Scaling factors equal to 5.03, 3.11 and 2.75 were calculated to respectively estimate fat (SFI), liver (SLI) and carcass (SCI) scaled indices of L. latrans. In the case of the scaled gonadal index (SGI), scaling factors equal to 3.81 and 6.49 were used to calculate male and female indices. In both sexes, the seasonal variation in SFI and SGI was perfectly opposite, SGI being at its maximum in the spring when SFI was near zero, and reaching its lowest values in February-March when SFI increased. The amplitude of these changes was, nevertheless greater in females, representing a 4–5 times order of variation, in contrast to a 2–3 times order of change in males. In both sexes, SLI exhibited a 30% drop from October to December, although this loss was completely recovered in the second half of the summer (December to March). SLI was the somatic index that best correlated with the 14–18% natural variation in body condition that was observed over the spring-summer season. Nevertheless, carcass-related energy reserves were also of significant importance for frog metabolism as SCI varied very closely with body condition, explaining 75–80% of is variation. Results obtained illustrate the fact that no single somatic index can solely illustrate body condition because of the intricate relationship existing between SGI and SFI, and the importance of carcass-related energy reserves. In view of all the above, body condition comes out as the ideal monitoring endpoint for acquiring information on frog energy status.Instituto de Recursos BiológicosFil: Brodeur, Julie Céline. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos. Argentina. Consejo de Investigaciones Científicas y Técnicas; Argentina.Fil: Vera Candioti, Josefina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros. Agencia De Extensión Rural Venado Tuerto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. ArgentinaFil: Damonte, María Jimena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos. ArgentinaFil: Bahl, María Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Argentina.Fil: Poliserpi, María Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina.Fil: D'Andrea, María Florencia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Concentration of current-use pesticides in frogs from the Pampa region and correlation of a mixture toxicity index with 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.EEA PergaminoFil: Brodeur, Julie Céline. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Brodeur, Julie Céline. Consejo de Investigaciones Científicas y Técnicas; ArgentinaFil: Damonte, María Jimena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Rojas, Dante Emanuel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; ArgentinaFil: Cristos, Diego Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; ArgentinaFil: Vargas, Claudia. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Microbiología y Parasitología Médica; ArgentinaFil: Poliserpi, Maria Belen. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Andriulo, Adrián. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Departamento de Laboratorio de Suelo; Argentin

Accumulation of current-use pesticides, cholinesterase inhibition and reduced body condition in juvenile one-sided livebearer fish (Jenynsia multidentata) from the agricultural Pampa region of Argentina

The aim of this study was to characterize the level and nature of the pesticide contamination received by one-sided livebearer fish (Jenynsia multidentata) from a watercourse situated within the main agricultural region of Argentina, and to assess the effects of this contamination on fish health. Juvenile onesided livebearer fish (Jenynsia multidentata) were collected in December 2011 and March 2012 from three sites along the Pergamino River. Pesticide contamination was characterized by extracting whole fish and analytically determining thirty different pesticide molecules. The biomarkers catalase, glutathione-S-transferase, and cholinesterases were assessed. Body condition was calculated as an estimate of the amount of energy reserves possessed by the fish. Seventeen different pesticides were detected in fish tissues with 81% of captured animals containing at least one pesticide molecule. The pyrethroid insecticides fenvalerate and bifenthrin were most frequently detected, being respectively found in 41.8 and 36.4% of samples tested. Highly toxic dichlorvos and pirimiphos-methyl were detected. Differential levels of contamination could not be established amongst sites but were observed within sites amongst the two sampling dates. The months when pesticide residues were most abundant from in Site A and B corresponded to the months when body condition was at its lowest in the two sites. The inhibition of Che activity in March when body condition was reduced also points to a role of insecticide contamination in the reduction of body condition. These findings provide strong new evidence that current-used agricultural pesticides can accumulate in wild fish and impact their health and energetics.EEA PergaminoFil: Brodeur, Celine Marie Julie. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Bilológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Sanchez, Marisol. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Bilológicos. Centro de Investigaciónes de Recusrsos Naturales (CIRN); Argentina.Fil: Castro, Luciana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Bilológicos. Centro de Investigaciónes de Recusrsos Naturales (CIRN); Argentina.Fil: Rojas, Dante Emanuel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos. Centro de Investigación de Agroindustria (CIA); Argentina.Fil: Cristos, Diego. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos. Centro de Investigación de Agroindustria (CIA); Argentina.Fil: Damonte, María Jimena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Bilológicos. Centro de Investigaciónes de Recusrsos Naturales (CIRN); Argentina.Fil: Poliserpi, María Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Bilológicos. Centro de Investigaciónes de Recusrsos Naturales (CIRN); Argentina.Fil: D'Andrea, María Florencia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Bilológicos. Centro de Investigaciónes de Recusrsos Naturales (CIRN); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Andriulo, Adrián Enrique. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Departamento Laboratorio Suelos; Argentina