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

Formulated Beta-Cyfluthrin Shows Wide Divergence in Toxicity among Bird Species

It is generally assumed that the toxicity of pyrethroid insecticides to birds is negligible, though few species have been tested. The oral acute toxicity of formulated beta-cyfluthrin was determined for canaries (Serinus sp.), shiny cowbirds (Molothrus bonariensis), and eared doves (Zenaida auriculata). Single doses were administered to adults by gavage. Approximate lethal doses 50 (LD(50)) and their confidence intervals were determined by approximate D-optimal design. Canaries were found to be substantially more sensitive to formulated beta-cyfluthrin (LD(50) = (170 ± 41) mg/kg) than the other two species tested (LD(50) = (2234 ± 544) mg/kg and LD(50) = (2271 ± 433) mg/kg, resp.). The LD(50) obtained for canaries was also considerably lower than typical toxicity values available in the literature for pyrethroids. This study emphasizes the need for testing a broader range of species with potentially toxic insecticides, using modern up and down test designs with minimal numbers of birds

Mean occupancy (ψ^ ±SD, 95% BCI) for the complete study area during 2003–2012, in the regional bird monitoring program in Argentina for Non Passeriformes species.

<p>(a) Raptors; (b) ground omnivores and herbivores; (c) ground granivores. For details of species names and guilds, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130874#pone.0130874.s019" target="_blank">S1 Table</a>.</p

Leg streamers for marking Chestnut-capped Blackbirds <i>Agelaius ruficapillus</i> in Argentina

Se condujeron estudios de campo y cautividad para evaluar el uso de las banda plásticas de colores en estudios de comportamiento del Varillero Congo (<i>Agelaius ruficapillus</i>) en una colonia reproductiva y en sitios de alimentación vecinos a la misma. En la colonia, las observaciones desde sitios ocultos muestran la utilidad del uso de las banda numeradas para la colección de datos sobre el comportamiento de los indiviudos. En los campos de arroz, si bien los números no se pudieron observar, se pudo delinear la distribución de los miembros marcados en la colonia. Se investigaron en condiciones de laboratorio y jaula, dos métodos de adhesión y dos de tipo de tintas para marcado de las banda

Land use and land cover proportion in the area of regional bird monitoring program in Pampas and Espinal ecoregions in Argentina.

<p>Land use of (a) soybean and land cover of (b) native forests for (1) 2006 and (2) 2012 is represented in percentage coverage in each site.</p

Native forest coefficients in the logit scale (β^ ±SD, 95% BCI) on logit occupancy (logit ψ^) of each bird species in the regional bird monitoring program in Argentina, 2003–2012.

<p>(a) Raptors; (b) ground omnivores and herbivores; (c) ground granivores; (d) other granivores; (e) insectivores mostly associated with folliage; (f) other insectivores. For details of species names and guilds, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130874#pone.0130874.s019" target="_blank">S1 Table</a>.</p