Sex morphs and invasiveness of a fleshy-fruited tree in natural grasslands from Argentina

Invasiveness has usually been studied as a species-level attribute; nevertheless, phenotypic differences between individuals in a population can lead to significant variations in colonization ability. In this paper, we analyse the potential effects of sex morphs of Prunus mahaleb, a gynodioecius fleshy-fruited tree, on its invasiveness in natural grasslands in the southern Argentine Pampas. We assessed the abundance of both hermaphrodite and female plants and compared their fecundity, propagule size and germination response. We found that the females were less abundant in the invasive populations studied, apparently since the beginning of the colonization. However, our results demonstrated that at the present time females do not show any fecundity reduction, which clearly shows that P. mahaleb has established an effective interaction with generalist pollinators which compensates for the apparent disadvantage of females. Fruit set showed a wider range of variability over time in the females than in the hermaphrodites, which could be the consequence of greater susceptibility to changes in the activity of pollinators. We found no evidence of a female benefit due to reallocation of resources or better outcrossed progeny considering propagule size and germination. We discuss the relative importance of sex morphs and interactions at different stages of the invasion process.Fil: Amodeo, Martín Raúl. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Seedling emergence and survival of invasive pines in Argentinian mountain grasslands

Natural regeneration is a critical step for the dispersal of alien plants and the establishment of new invasive foci. The adequate timing and location of germination, as well as the survival of the seedlings, have direct effects on the recruitment of the population, and are expected to depend on habitat characteristics. Understanding the dynamics of these processes, and their variations according to the landscape at different scales, can be particularly important to design and implement control strategies. In this article, we evaluate differences in seedling emergence and establishment of Pinus halepensis in highland grasslands of the Argentine pampas, according to altitude, orientation of the slope and vegetation cover. Our results showed spatial variation on the rate of seedling emergence, with topography as a determining factor, possibly due to a facilitating effect on the slopes with higher incident solar radiation (NE at the study site). Slope exposition, on the contrary, seemed to have the opposite effect on the survival of seedlings. Once established, seedlings also survived better in sites with less solar exposure, probably due to protection from high evapotranspiration during the summer. These results could explain variations in the invasive performance of the species and guide management actions aimed at preventing its further expansion in the study area and in other habitats with similar characteristics.Fil: Brancatelli, Gabriela Ivanna Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; ArgentinaFil: Amodeo, Martín Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; ArgentinaFil: Zalba, Sergio Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentin

Fungal biomass estimation in soils from southwestern Buenos Aires province (Argentina) using calcofluor white stain

Los microorganismos del suelo son vitales para el correcto funcionamiento de los ecosistemas, principalmente por su rol en el ciclado de nutrientes. La intensificación del uso del suelo y las prácticas agrícolas alteran negativamente la actividad microbiana. La biomasa fúngica es uno de los parámetros más utilizados para estudiar el impacto de las actividades agrícolas en la estructura y funcionamiento del suelo. El objetivo del presente trabajo fue estimar la biomasa fúngica en un suelo del sudoeste bonaerense con el fin de obtener valores de referencia que permitan usar este parámetro como un indicador de cambios en el ecosistema y por otro lado, demostrar que la metodología empleada es sensible a las variaciones en las condiciones climáticas. Se colectaron muestras de suelos durante dos años consecutivos. Se prepararon frotis de suelo y se tiñeron con soluciones de distintas concentraciones de blanco de calcoflúor y luego se estimó la biomasa fúngica observando los frotis con microscopio de epifluorescencia. Los valores de biomasa fúngica estimados variaron entre 2,23 y 26,89 µg Cfúngico/g de suelo y estuvieron dentro del rango esperable para el tipo de suelo estudiado. La biomasa fúngica mostró una relación positiva con la temperatura y las precipitaciones. La metodología empleada resultó ser confiable, repetible, y sensible a cambios en las condiciones climáticas. Los resultados podrían usarse como valores de referencia para estudiar en la biomasa fúngica de suelos bajo distintas condiciones y emplearse como indicadores del impacto de las distintas prácticas agrícolas sobre el ecosistema.Soil microorganisms are vital for ecosystem functioning because of the role they play in soil nutrient cycling. Agricultural practices and the intensification of land use have a negative effect on microbial activities and fungal biomass has been widely used as an indicator of soil health. The aim of this study was to analyze fungal biomass in soils from southwestern Buenos Aires province using direct fluorescent staining and to contribute to its use as an indicator of environmental changes in the ecosystem as well as to define its sensitivity to weather conditions. Soil samples were collected during two consecutive years. Soil smears were prepared and stained with two different concentrations of calcofluor, and the fungal biomass was estimated under an epifluorescence microscope. Soil fungal biomass varied between 2.23 and 26.89 μg fungal C/g soil, being these values in the range expected for the studied soil type. The fungal biomass was positively related to temperature and precipitations. The methodology used was reliable, standardized and sensitive to weather conditions. The results of this study contribute information to evaluate fungal biomass in different soil types and support its use as an indicator of soil health for analyzing the impact of different agricultural practices.Fil: Vazquez, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Amodeo, Martín Raúl. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia. Grupo de Estudios en Conservacion y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bianchinotti, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; Argentin

Assessment of surf zone zooplankton dynamics in a Southwestern Atlantic sandy beach: Seasonal cycle and tidal height influence

Surf zones of sandy beaches are poorly studied in comparison to estuarine and continental shelf waters, specifically because of the difficulties experienced in sampling in high-energy environments. The zooplankton of these areas, therefore, has received less attention than that in other coastal systems. The aim of this study was to investigate the seasonal patterns and tidal height effects (high tide/low tide) on the surf zooplankton community in a temperate Southwestern Atlantic sandy beach. We also aimed to evaluate the influence of some environmental variables (water temperature, salinity, chlorophyll-a, suspended particulate matter and particulate organic carbon) on the community structure and to compare the surf community to nearby coastal zone (<to 50 m). Sampling was carried out from September 2009 to November 2010, with a monthly frequency during autumn-winter and bi-monthly during spring-summer.Fil: Menendez, Maria Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Baleani, Carla Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Amodeo, Martín Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Acha, Eduardo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; ArgentinaFil: Piccolo, Maria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Teorías sobre el origen de la música como un rasgo adaptativo

Throughout human history, people have developed the faculty to appreciate and create music. Musical thinking implies the development of cognitive and emotional faculties by complex neural processes. How could such a complex behavior as music be originated by evolution? This article reviews the main evolutionary approaches that have been proposed to explain this process. The main hypotheses state that music has emerged from adaptive processes such as communication and emotional coordination between mother and infant, the conformation of large cohesive groups, mate selection or the development of cognitive and emotional flexibility through play. Natural selection could have enabled the establishment of this faculty, whereas cultural evolution and gene-culture interaction could have led to the establishment of music as we know it.A lo largo de la historia evolutiva del humano, surgió una facultad que actualmente y a nivel universal nos permite apreciar y crear música. El pensamiento musical implica un desarrollo de las facultades cognitivas y emocionales de un individuo a través de procesos mentales complejos. ¿Cómo pudo originarse un comportamiento así en el curso de la evolución? Este trabajo propone revisar los principales abordajes que, desde una perspectiva ecológica evolutiva, intentan dar explicación a este proceso. Las principales hipótesis proponen que sus raíces se hallan en actividades de importancia adaptativa tales como la comunicación y coordinación emocional entre madres y bebés, la formación de grandes grupos cohesivos, la atracción de pareja o el desarrollo de flexibilidad cognitiva y emocional a través del juego. La selección natural habría permitido el establecimiento de esta facultad, mientras que la evolución cultural y la interacción gen-cultura habrían dado lugar a la música actual

Teorías sobre el origen de la música como un rasgo adaptativo

Throughout human history, people have developed the faculty to appreciate and create music. Musical thinking implies the development of cognitive and emotional faculties by complex neural processes. How could such a complex behavior as music be originated by evolution? This article reviews the main evolutionary approaches that have been proposed to explain this process. The main hypotheses state that music has emerged from adaptive processes such as communication and emotional coordination between mother and infant, the conformation of large cohesive groups, mate selection or the development of cognitive and emotional flexibility through play. Natural selection could have enabled the establishment of this faculty, whereas cultural evolution and gene-culture interaction could have led to the establishment of music as we know it.A lo largo de la historia evolutiva del humano, surgió una facultad que actualmente y a nivel universal nos permite apreciar y crear música. El pensamiento musical implica un desarrollo de las facultades cognitivas y emocionales de un individuo a través de procesos mentales complejos. ¿Cómo pudo originarse un comportamiento así en el curso de la evolución? Este trabajo propone revisar los principales abordajes que, desde una perspectiva ecológica evolutiva, intentan dar explicación a este proceso. Las principales hipótesis proponen que sus raíces se hallan en actividades de importancia adaptativa tales como la comunicación y coordinación emocional entre madres y bebés, la formación de grandes grupos cohesivos, la atracción de pareja o el desarrollo de flexibilidad cognitiva y emocional a través del juego. La selección natural habría permitido el establecimiento de esta facultad, mientras que la evolución cultural y la interacción gen-cultura habrían dado lugar a la música actual

The origins of music as an adaptive trait in humans

Throughout human history, people have developed the faculty to appreciate and create music. Musical thinking implies the development of cognitive and emotional faculties by complex neural processes. How could such a complex behavior as music be originated by evolution? This article reviews the main evolutionary approaches that have been proposed to explain this process. The main hypotheses state that music has emerged from adaptive processes such as communication and emotional coordination between mother and infant, the conformation of large cohesive groups, mate selection or the development of cognitive and emotional flexibility through play. Natural selection could have enabled the establishment of this faculty, whereas cultural evolution and gene-culture interaction could have led to the establishment of music as we know it

Site-specific reproductive performance of an invasive fleshy-fruited tree in remnant grasslands of the Argentinean Pampas

Prunus mahaleb (Saint Lucie´s cherry) is a fleshy-fruited small rosaceous tree, native to the Mediterranean region that has been extensively used as a rootstock species for commercial orchard trees. It has been widely introduced in several countries, becoming invasive in many regions, including the Pampas region of southern Argentina. We studied the reproductive performance of trees spontaneously growing in natural grasslands inside a protected area, estimating age at first reproduction and analysing changes in fruit production, age, canopy volume and basal stem diameter associated with different soil types: rock crevices on hillsides, deep soils in valleys and deep soils in stream-side habitats. Fruit production starts at the age of 3?6 years, and it can be abundant, even for young plants. We found evidence that fecundity is related to plant size, and that the age at which individuals reach a particular size and begin fruiting differs depending on the soil type where they grow. Trees in the study area show an order of magnitude increase in fruit production on reaching ages from 7 to 10 years for plants growing in deep soils at stream-side habitats and 13?16 years for plants growing in rock crevices. Invasive trees should be felled before they reach a basal stem diameter of c. 9 cm to avoid this increase in propagule pressure. Considering that the age at which this stage is reached depends on soil type, the streams could act as dispersal corridors for the spread and invasion of this species.Fil: Zalba, Sergio Martin. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia. Grupo de Estudios en Conservacion y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Amodeo, Martín Raúl. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia. Grupo de Estudios en Conservacion y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Wild cherries invading natural grasslands: unraveling colonization history from population structure and spatial patterns

Invasive success of many fleshy-fruited plants has been linked to opportunistic interactions with generalist frugivores. Prunus mahaleb is a small tree, producing large quantities of little, bright black, sugary drupes that are consumed by vertebrates. It is native to the Mediterranean region but has become invasive in several countries. This study was carried out at a nature reserve including remnant mountain grasslands of high conservation value in the southern Argentine Pampas. Our aim is to reconstruct the colonization history of invading populations proposing a generalized model to describe the invasion process: colonization events result in the establishment of a founder tree followed by a lag phase until it reaches massive seed production and enables an increase in local recruitment and plant density. To test this hypothesis, we analyzed population age structures and contrasted them with those predicted using a Leslie matrix growth model. We found that matrix model predictions fit well to actual age structures. Our results reveal the existence of an 8-18-year lag period between the establishment of the founder tree and local effective recruitment. The end of this lag coincides with an abrupt increase in individual fruit production that may have a strong effect on bird attraction and successful seed dispersal. This lag phase represents an opportunity for preventing further spread of P. mahaleb. Early detection and rapid eradication of new invasion focuses should be targeted as a principal aim of an effective control strategy.Fil: Amodeo, Martín Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia. Grupo de Estudios en Conservacion y Manejo; ArgentinaFil: Zalba, Sergio Martin. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia. Grupo de Estudios en Conservacion y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Generalist dispersers promote germination of an alien fleshy-fruited tree invading natural grasslands.

Plants with animal-dispersed fruits seem to overcome the barriers that limit their spread into new habitats more easily than other invasive plants and, at the same time, they pose special difficulties for containment, control or eradication. The effects of animals on plant propagules can be very diverse, with positive, neutral or negative consequences for germination and recruitment. Moreover, the environmental conditions where the seeds are deposited and where the post-dispersal processes take place can be crucial for their fate. Prunus mahaleb is a fleshy-fruited tree invading natural grasslands in the Argentine Pampas. In this study, we analyzed the importance of pulp removal, endocarp scarification and the effects of vectors on its germination response, by means of germination experiments both in the laboratory and under semi-natural conditions. Our laboratory results demonstrated that endocarp scarification enhances germination and suggests that vestiges of pulp on the stones have inhibitory effects. Frugivores exert a variety of effects on germination responses and this variation can be explained by their differing influence on pulp removal and endocarp scarification. Most frugivores produced a positive effect on germination under laboratory conditions, in comparison to intact fruits and hand-peeled stones. We observed different degrees of pulp removal from the surface of the stones by the dispersers which was directly correlated to the germination response. On the other hand, all the treatments showed high germination responses under semi-natural conditions suggesting that post-dispersal processes, like seed burial, and the exposure to natural conditions might exert a positive effect on germination response, attenuating the plant's dependence on the dispersers' gut treatment. Our results highlight the need to consider the whole seed dispersal process and the value of combining laboratory and field tests