Evaluation of the territorial behaviour of four species of sparrows in the central Monte desert

El comportamiento territorial en aves es común pero en pocos trabajos se busca entender qué es lo que las aves defienden en sus territorios. Se estudió el comportamiento territorial intra e interespecífico entre cuatro especies de aves granívoras en la porción central del desierto del Monte durante dos años consecutivos, a fin de evaluar un posible escenario de interacciones y la plasticidad del comportamiento. Se realizaron experimentos de "playback" con la Monterita Canela (Poospiza ornata), la Monterita de Collar (Poospiza torquata), el Chingolo (Zonotrichia capensis) y el Pepitero Chico (Saltatricula multicolor). Todas las especies mostraron territorialidad frente a conespecíficos, la cual tendió a ser menos agresiva el año de mejores condiciones ambientales (más precipitaciones y mayor abundancia de alimento). No hubo respuesta territorial entre especies del mismo gremio de alimentación, pero sí una respuesta asimétrica entre las especies que usan los mismos sitios de nidificación. La Monterita Canela mostró un comportamiento agresivo frente a la Monterita de Collar durante la temporada reproductiva en la que la densidad de la primera especie fue alta. Los resultados y la evidencia previa sugieren que la territorialidad en las aves granívoras en el Monte central está más relacio­nada con la defensa de recursos reproductivos y que los conflictos por el alimento son menos importantes. Además, los resultados mostraron que las aves podrían responder de manera diferente frente a conespecíficos y heterospecíficos dependiendo de su propia abundancia y de las condiciones ambientales.Territorial behaviour in birds is common, but very few studies have attempted to understand what are birds defending in their territories. We evaluated intra and interspecific territorial behaviour among four species of sparrows in the central Monte desert during two consecutive years, in order to assess possible interactions and plasticity in their behaviour. We performed playback experiments on the Cinnamon Warbling-Finch (Poospiza ornata), the Ringed Warbling-Finch (Poospiza torquata), the Rufous-collared Sparrow (Zonotrichia capensis), and the Many-coloured Chaco-Finch (Saltatricula multicolor). Every species showed conspecific territoriality, which tended to be weaker during the year of better environmental conditions (wetter and with higher food abundance). We also found a lack of territorial response among the species within the same feeding guild. However, we observed an asymmetric response between the species that use similar nest sites. The Cinnamon Warbling-Finch showed aggression towards the Ringed Warbling-Finch, and this occurred only during the year when the abundance of the former species was high. Our results and previous evidence suggest that territoriality in central Monte desert sparrows is most likely to be driven by defence of reproductive resources, and conflicts over food would be less important. Our results also hint that birds may respond different to both heterospecifics and conspecifics based both on their own abundance and on environmental conditions.Fil: Sagario, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Grupo de Investigación en Ecologia de Comunidades del Desierto; ArgentinaFil: Cueto, Victor. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Grupo de Investigación en Ecologia de Comunidades del Desierto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Estabilidad territorial durante la época reproductiva de aves granívoras residentes en el desierto del Monte central, Argentina

Fil: Sagario, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Cueto, Victor. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagonica. Universidad Nacional de la Patagonia "san Juan Bosco". Facultad de Cs.naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagonica; Argentin

SEASONAL CHANGES IN BIRD ASSEMBLAGES OF A FOREST-STEPPE ECOTONE IN NORTH PATAGONIA

Abstract ∙ We studied seasonal variation in a community of birds inhabiting a forest–steppe ecotone of north Patagonia. We analyzed changes in species richness, species composition and total abundance, and, at the species level, we evaluated differences in breeding and molting seasonality. The bird assemblage showed a low seasonal variation in richness and total abundance, but a great change in species composition between spring–summer and fall–winter. The change in species composition did not lead to changes in richness and total abundance, due to the presence of abundant species that visit the area in different seasons. At the species level, resident birds and short distance migrants tended to begin breeding earlier than long distance migrants, and those bird species began to molt body and flight feathers after breeding. Therefore, we found a low overlap between these two energetically demanding activities. Elaenia albiceps, the only long-distance migrant species, did not molt body and flight feathers in our study area. Our results highlight the importance of bird movements in response to seasonal variations in the availability of resources, which promote migration or local displacements of birds. Resumen ∙ Cambios estacionales en los ensambles de aves en un ecotono bosque–estepa del norte de Patagonia Estudiamos las variaciones estacionales en una comunidad de aves que habitan el ecotono bosque-estepa del norte de Patagonia. Analizamos los cambios en la riqueza de especies, la composición de especies y la abundancia total, y a nivel de las especies, evaluamos las diferencias en la estacionalidad reproductiva y de muda. El ensamble de aves mostró pocas variaciones estacionales en la riqueza y abundancia total, pero un notable cambio en la composición de especies entre la primavera–verano y el otoño–invierno. El cambio en la composición de especies no promovió variaciones estacionales en la riqueza y la abundancia total, debido a la presencia de especies abundantes que visitan el área en las diferentes estaciones. A nivel de las especies, las aves residentes y migrantes de corta distancia tendieron a comenzar la reproducción antes que las migrantes de larga distancia, y aquellas especies de aves comenzaron la muda de plumas del cuerpo y del ala al finalizar la reproducción. Por lo cual encontramos una baja superposición de estas dos demandantes actividades. Elaenia albiceps, la única especie migradora de larga distancia, no presentó muda corporal o del plumaje de vuelo en nuestra área de estudio. Nuestros resultados remarcan la importancia del movimiento de las aves en respuesta a las variaciones en la disponibilidad de recursos, que promueven la migración o el desplazamiento local de las aves

Regularized regressions for parametric models based on separated representations

Regressions created from experimental or simulated data enable the construction of metamodels, widely used in a variety of engineering applications. Many engineering problems involve multi-parametric physics whose corresponding multi-parametric solutions can be viewed as a sort of computational vademecum that, once computed offline, can be then used in a variety of real-time engineering applications including optimization, inverse analysis, uncertainty propagation or simulation based control. Sometimes, these multi-parametric problems can be solved by using advanced model order reduction—MOR-techniques. However, solving these multi-parametric problems can be very costly. In that case, one possibility consists in solving the problem for a sample of the parametric values and creating a regression from all the computed solutions. The solution for any choice of the parameters is then inferred from the prediction of the regression model. However, addressing high-dimensionality at the low data limit, ensuring accuracy and avoiding overfitting constitutes a difficult challenge. The present paper aims at proposing and discussing different advanced regressions based on the proper generalized decomposition (PGD) enabling the just referred features. In particular, new PGD strategies are developed adding different regularizations to the s-PGD method. In addition, the ANOVA-based PGD is proposed to ally them

Do animal-plant interactions influence the spatial distribution of Aristotelia chilensis shrubs in temperate forests of southern South America?

Seed dispersal constrains the environmental heterogeneity to which a plant species is exposed through its life. Behavior of seed dispersers and seed predators could be influenced by food availability and vegetation cover. Consequently, recruitment probabilities are heterogeneous in space and time, and “regeneration windows” may appear. Aristotelia chilensis is the most abundant fleshy-fruited shrub in the temperate forest of southern South America (TFSA). TFSA exhibits an environmental patchiness that could influence fruit abundance and animal behavior. Our objective was to determine the regeneration windows of A. chilensis, and to detect how forest structure and animal behavior could affect the spatial distribution of this species. We characterized forest structure in two plots that included mature forest, young forest, and open areas. We assessed the spatio-temporal distribution of A. chilensis fruits and studied fruit removal by animals. Also, we experimentally evaluated germination and post-dispersal seed predation. We developed a conceptual model to relate A. chilensis recruitment with forest successional stages. The fruiting individuals of this shrub were mostly located in fire-opened areas or forest gaps, and the seed rain generated by the migratory bird Elaenia albiceps was denser in these areas. In contrast, seed predation by rodents was higher in closed, young forest areas. A. chilensis recruitment follows a nucleation dynamic around fruiting females. Concerning forest succession, A. chilensis recruitment was higher near re-sprouting females in open areas, and lowest in young forests, where fruiting process was hindered by light constraints. When forests mature, new nucleation processes start around females surviving in gaps. We conclude that areas opened by disturbances provide a regeneration window for A. chilensis shrubs.Fil: Bravo, Susana Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónicas; ArgentinaFil: Cueto, Victor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónicas; ArgentinaFil: Amico, Guillermo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; Argentin

Modeling systems from partial observations

Modeling systems from collected data faces two main difficulties: the first one concerns the choice of measurable variables that will define the learnt model features, which should be the ones concerned by the addressed physics, optimally neither more nor less than the essential ones. The second one is linked to accessibility to data since, generally, only limited parts of the system are accessible to perform measurements. This work revisits some aspects related to the observation, description, and modeling of systems that are only partially accessible and shows that a model can be defined when the loading in unresolved degrees of freedom remains unaltered in the different experiments

Follow the Rain? Environmental Drivers of Tyrannus Migration across the New World

Predictable seasonal changes in resources are thought to drive the timing of annual animal migrations; however, we currently understand little about which environmental cues or resources are tracked by different migratory bird species across the planet. Understanding which environmental cues or resources birds track in multiple migratory systems is a prerequisite to developing generalizable conservation plans for migratory birds in a changing global environment. Within the New World, climatic differences experienced by Nearctic–Neotropical migratory (NNM; i.e. breed in North America and spend the nonbreeding period in the Neotropics) and Neotropical austral migratory (NAM; i.e. breed and spend the nonbreeding period wholly within South America) bird species suggest that their migratory strategies may be shaped by unique selective pressures. We used data gathered from individuals fitted with light-level geolocators to build species distribution models (SDMs) to test which environmental factors drive the migratory strategies of species in each system. To do so, we evaluated whether temperature, precipitation, and primary productivity (NDVI) were related to the seasonal distributions of an NNM (Eastern Kingbird [Tyrannus tyrannus]) and NAM species (Fork-tailed Flycatcher [T. savana]). Both Eastern Kingbird and Fork-tailed Flycatcher locations were positively correlated with high precipitation during their nonbreeding seasons. Eastern Kingbird locations were positively correlated with both NDVI and temperature during their breeding season and both pre- and post-breeding migrations. Fork-tailed Flycatcher locations were positively correlated with both temperature and precipitation during both migrations, but only temperature during the breeding season. The value of extending the application of geolocator data, such as in SDMs, is underscored by the finding that precipitation was such an important predictor of the nonbreeding distributions of both types of migrants, as it remains unclear how global climate change will affect wet–dry cycles in the tropics

Learning data-driven reduced elastic and inelastic models of spot-welded patches

Solving mechanical problems in large structures with rich localized behaviors remains a challenging issue despite the enormous advances in numerical procedures and computational performance. In particular, these localized behaviors need for extremely fine descriptions, and this has an associated impact in the number of degrees of freedom from one side, and the decrease of the time step employed in usual explicit time integrations, whose stability scales with the size of the smallest element involved in the mesh. In the present work we propose a data-driven technique for learning the rich behavior of a local patch and integrate it into a standard coarser description at the structure level. Thus, localized behaviors impact the global structural response without needing an explicit description of that fine scale behaviors