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

Unusual behaviour of the spot-winged falconet Spiziapteryx circumcinctus

Volume: 16Start Page: 25End Page: 2

Biological and ethological notes on Falco peregrinus cassini in central Argentina

Volume: 18Start Page: 123End Page: 13

Temporal and Spatial Activity Patterns of Three Species in the Leptodactylus fuscus Group (Amphibia, Leptodactylidae)

Space and time are two of the main dimensions of the ecological niche. Because of their high dependence upon aquatic environments during breeding activity, anuran assemblages are interesting models for studying inter-populational relationships. The overlap in habitat use could be particularly high, especially for seasonal species and among taxa that share a common phylogenetic history. Three species of the Leptodactylus fuscus group occur in a semi-permanent pond at Cerro Verde (Rocha, Uruguay): L. latinasus, L. mystacinus and L. gracilis. The aim of this work was to describe the spatial and temporal calling patterns of the three species and the effects of environmental conditions upon them on a daily scale. Their relative abundance was quantified over four weeks (December 2004-January 2005) during the first half of the night along a transect using acoustic surveys. Nestedness, segregation, Jaccard's index and association analysis were calculated, revealing a nested pattern with low overlap between species in the occupation of microhabitats. On the temporal axis, the calling behavior of the species seems to be better described by the time of night than by temperature, humidity, or atmospheric pressure. These analyses also showed a non-linear association of activity with time of night, indicating that higher activity occurs at different hours for each species

O status taxonômico de Hyla cochranae Mertens e recaracterização de Aplastodiscus A. Lutz (Anura, Hylidae) The taxonomic status of the Hyla cochranae Mertens and recharacterization of Aplastodiscus A. Lutz (Anura, Hylidae)

<abstract language="eng">Hyla cochranae Mertens, 1952 is revalidated and the description of the tadpole and vocalization is provided. Based on external morphology, the genus Aplastodiscus A. Lutz, 1950 is recharacterized and a redescription of A. perviridis A. Lutz, 1950 is given. New data on geographical distribution and biology of both species are provided