Activity and reproductive patterns of lizards in the Chaco of Argentina

We studied the activity and breeding pattern of dominant lizard species in the Arid Chaco, the southernmost subregion of the Chaco ecoregion (Chancaní Reserve, Córdoba province, Argentina). Lizards were captured with pitfall traps over a 4-year period. In total, 1449 individuals belonging to 11 of the 12 lizard species recorded in the area were trapped. Of these, we selected six species for a detailed analysis: Teius teyou and Stenocercus doellojuradoi accounted for 63% of the captures, Tropidurus etheridgei, Liolaemus chacoensis and Homonota fasciata accounted for 32%, and 5% comprised Leiosaurus paronae and the remaining five species. All the studied species were active during the warm–rainy season (September to March). Monthly lizard captures were highly correlated with monthly mean temperature and rainfall. No captures occurred during the remaining months of the year. All reproductive tactics known for the Chaco lizards were observed in Chancaní, including single clutch in a short breeding season in summer or autumn, as well as an extended breeding season with multiple clutches. Stenocercus doellojuradoi and L. paronae showed a singular reproductive timing, suggesting the occurrence of egg retention. Compared with sub-tropical Chaco sites, the Arid Chaco only differs in the lack of winter activity, resulting from the lower temperature and rainfall regime of our study site.Fil: Pelegrin, Nicolas. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; ArgentinaFil: Bucher, Enrique Hugo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; Argentin

La cotorra como especie invasora : el caso de las pampas

Fil: Bucher, Enrique H.. Facultad de Ciencias Exactas, Físicas y Naturales. Universidad Nacional de Córdoba; ArgentinaFil: Aramburú, Rosana Mariel. División Zoología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Nesting habitat of the Tucuman Parrot Amazona tucumana in an old-growth cloud-forest of Argentina

Tucuman Parrot Amazona tucumana breeds in the cloud-forest of south-eastern Bolivia and north-western Argentina (or Southern Yungas forest). We studied the nesting requirements of the Tucuman Parrot and assessed cavity availability, reuse, and spatial pattern of nests in El Rey National Park-one of the last mature, undisturbed areas of the Southern Yungas forest. We recorded 44 nesting attempts in seven tree species, with most nests (95%) being located in live canopy trees > 60 cm DBH. Most parrot nest-cavities occurred in Blepharocalix salicifolius (60%) and cavities in this species were selected significantly more than expected based on availability. Nests were shallower and higher than nests of other Amazona species. For all years combined, mean nest density of Tucuman Parrot was 0.24 ± 0.04 nest ha-1 and the distance to the nearest active nest was significantly greater than the distance between all trees used as nests. Nesting pairs of Tucuman Parrot were separated by 144.1 ± 152.8 m, while potential nest-trees were 66.0 ± 55.4 m apart. Density of suitable cavities for nesting was 4.6 cavities ha-1. Approximately 16 suitable cavities were available for each breeding pair (0.24 breeding pair ha-1 and four suitable cavities ha-1) and 5% of the suitable cavities available were occupied, suggesting that suitable cavities are not a limiting resource. However, due to the territorial behaviour of breeding pairs, some of these cavities are unavailable to other breeding pairs. The spatial requirements of Tucuman Parrot for nesting could limit management actions intended to increase the density of nesting pairs.Fil: Rivera, Luis. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Cátedra de Desarrollo Sustentable y Biodiversidad; ArgentinaFil: Politi, Natalia. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Cátedra de Desarrollo Sustentable y Biodiversidad; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bucher, Enrique Hugo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Ecología de la fauna chaqueña. Una revisión.

The present status of knowledge about the Chaco fauna is reviewed. The main points considered inelude: The environment. Regional división. The fauna: mammals, birds, reptiles, anurans and invertebrates. Pattems of species diversity. Adaptations of the Chaco animáis. Key processes. The following relevant processes are considered in detail: edaphic inñuence of ants, termites and mammals; decomposers and reducers; pattems of herbivory, particularly the importance of leaf-cutting ants as primary consumers; and the impact of human activity on the Chaco fauna. The present status of knowledge about the Chaco fauna is reviewed. The main points considered inelude: The environment. Regional división. The fauna: mammals, birds, reptiles, anurans and invertebrates. Pattems of species diversity. Adaptations of the Chaco animáis. Key processes. The following relevant processes are considered in detail: edaphic inñuence of ants, termites and mammals; decomposers and reducers; pattems of herbivory, particularly the importance of leaf-cutting ants as primary consumers; and the impact of human activity on the Chaco fauna.&nbsp

Using stable isotopes to determine migratory connectivity in birds: extent and limitations

La necesidad de determinar la conectividad migratoria en diversas especies de aves ha generado el surgimiento de numerosas técnicas de marcado para determinar el origen geográfico de individuos. El uso de la composición de isótopos estables en tejidos animales es una de las técnicas que más se desarrollaron en los últimos tiempos. Su uso se basa, primero, en que los valores isotópicos de diferentes elementos químicos varían espacialmente debido a procesos naturales y de origen humano. Segundo, en que un individuo, al alimentarse, asimila y eventualmente refleja en sus tejidos la composición isotópica del sitio donde se está alimentando. El tejido más utilizado en este tipo de análisis es el de las plumas remeras, ya que, al crecer, asimilan la composición isotópica del alimento, y luego permanecen metabolicamente inactivas hasta el próximo evento de muda. Aunque esta técnica ha sido exitosamente aplicada en distintas especies de aves, la variabilidad observada entre individuos limita de cierta forma su precisión. Esta variabilidad puede ser producto de diferentes procesos que afectan el cambio isotópico entre la dieta y los tejidos de la especie de interés, de desplazamientos durante el periodo de muda o de variaciones en la línea de base isotópica (cambios en los valores isotópicos de hidrógeno en las precipitaciones). Conocer y entender las fuentes de error puede ayudar a diseñar mejores estudios que minimicen la variabilidad y a desarrollar mejores modelos predictivos para determinar el origen geográfico de un individuo.The need to unravel migratory connectivity in different bird species has generated the development of several techniques to determine the geographical origin of individuals. Using the stable isotopes composition of animal tissues is one of the emerging techniques that had the greatest development. The principles of the technique are, first, that there is a geographical pattern in stable isotopes values, as a result of natural and anthropogenic processes, and, second, that stable isotopes are assimilated when an organism eats, and eventually they become fixed in animal tissues, in proportions related to the natural abundance in the environment. The most commonly used tissue is from flight feathers, since they incorporate the stable isotope composition of the food and, once moult is finished, they stay metabolically inactive until they are replaced. Although this technique has been applied with success in several species, variability found within birds from the same origin limits its potential accuracy. This variability could be the result of different processes affecting the isotopic change between food and tissues of the target species, winter movements, or baseline changes through time (temporal changes in the hydrogen isotopic values in precipitation). A better understanding of the sources of error would help to design better studies in order to minimize variability and to develop better models to determine the geographic origin of individual birds

Comunidades de aves acuáticas de la laguna Mar Chiquita (Córdoba, Argentina)

Mar Chiquita is a large inland brackish water body of about 2,000 km2, with a salinity of around 100 °/oo. Its aquatic bird communities were studied throughout a year in three study areas, representative of the main habitat types found in the región. We collected information on species composition and abundance, as well as foraging behaviour, feeding site utilization and stomach contents. In total we recorded 55 species. The richest community (both in number o f species and individuals) was found around the Rio Segundo estuary, while the less diverse corresponde to saline ponds near the coast. Summer migrant species (long range neartic migrants) included nine species and accounted for the 21% of the observed birds. Winter visitors included five species and made up 1% of bird numbers. Ecological guilds species composition and patterns of resource utilization are analyzed. They closely resemble those of marine estuarine and intertidal conditions. At present, the main adverse factors for the preservation of the local aviiauna are linked with planned stream regime modifications through dam building, and contamination due to industrialdevelopment along tributary rivers.Mar Chiquita is a large inland brackish water body of about 2,000 km2, with a salinity of around 100 °/oo. Its aquatic bird communities were studied throughout a year in three study areas, representative of the main habitat types found in the región. We collected information on species composition and abundance, as well as foraging behaviour, feeding site utilization and stomach contents. In total we recorded 55 species. The richest community (both in number o f species and individuals) was found around the Rio Segundo estuary, while the less diverse corresponde to saline ponds near the coast. Summer migrant species (long range neartic migrants) included nine species and accounted for the 21% of the observed birds. Winter visitors included five species and made up 1% of bird numbers. Ecological guilds species composition and patterns of resource utilization are analyzed. They closely resemble those of marine estuarine and intertidal conditions. At present, the main adverse factors for the preservation of the local aviiauna are linked with planned stream regime modifications through dam building, and contamination due to industrialdevelopment along tributary rivers

Genetic evidence of extra-pair paternity and intraspecific brood parasitism in the monk parakeet

Introduction: The monk parakeet (Myiopsitta monachus) is a widespread invasive species native to southern South America that has become established in many regions of the world. Monk parakeets breed in a large, fully enclosed structure built from twigs, which consist of one to many individual brooding chambers. The species has been considered to be socially and genetically monogamous. However, genetic relatedness of adults to juveniles in the native area was found to be lower than expected for monogamy. To assess the significance of this discrepancy, we examined individual and population genetic patterns of microsatellite loci at two sites in Córdoba province, Argentina. Results: We sampled 154 nestlings and 42 adults in Córdoba, Argentina. Mean value of pairwise relatedness of nestlings within chambers was about 0.40. Contrarily, relatedness of nestlings between chambers was close to zero. We found a considerable degree of variation in nestling pairwise relatedness and parentage within chambers, including chambers with combinations of unrelated, half-sib, and full-sib nestlings. The proportion of sibling relatedness indicated monogamy in 47% and extra pair-paternity in 40% of the chambers. We also found intra-brood parasitism in 3% of the chambers. Conclusions: Our results indicate that the monk parakeet is sexually polygamous in its native range in Argentina, which is consistent with the observed mean value of relatedness of adults to juveniles of about 0.4. We also confirm the existence of intra-brood parasitism. High density of monk parakeets may favor occurrence of extra-pair paternity and intra-brood parasitism in the native sites.Fil: Martinez, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentina;Fil: de Aranzamendi, Maria Carla. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina;Fil: Masello, Juan Francisco. Max Planck Institute for Ornithology; Alemania; Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina;Fil: Bucher, Enrique Hugo. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina

La cotorra como especie invasora: el caso de las pampas

¿Cómo se explica que la cotorra (Myiopsitta monachus), que vivía en la Argentina principalmente en zonas boscosas y semiáridas, haya invadido espontáneamente el pastizal pampeano y aparecido también en pueblos y hasta en grandes ciudades?Facultad de Ciencias Naturales y Muse

La fauna de serpientes de la provincia de Córdoba, Argentina: I. Lista y distribución

We have reeorded 24 species occurring in the province's territory (29" to 35" S; 61" to 65" W), including one (Tomodon ocellatus) not mentioned previously. The list and distribution maps are based on 3 966 specimens sent to the Serpentarium of the Centre for Applied Zoology at Córdoba between 1973 and 1981.We have reeorded 24 species occurring in the province's territory (29" to 35" S; 61" to 65" W), including one (Tomodon ocellatus) not mentioned previously. The list and distribution maps are based on 3 966 specimens sent to the Serpentarium of the Centre for Applied Zoology at Córdoba between 1973 and 1981