Seasonal patterns of the insect community structure in urban rain pools of temperate Argentina

Temporary aquatic environments are widespread in the world, and although there are considerable regional differences in their type and method of formation they have many physical, chemical and biological properties in common. With the aim to increase knowledge of urban temporary pool fauna, the objectives of this work were to assess the seasonal patterns of species composition, richness, and diversity of the aquatic insect community inhabiting rain pools in urban temperate Argentina, and to identify the environmental variables associated to these patterns. Four temporary pools of an urban green space in Buenos Aires City were studied throughout a 1-year period. Eleven flood cycles with very varied hydroperiods and dry periods, mainly associated with rainfall, were identified. Insect species richness in these temporary urban pools, 86 taxa were documented, was found to be within the range reported for wild temporary water bodies of other regions of the world. The present results provide evidence for the existence of a clear link between habitat and community variability. Hydroperiod and seasonality were the main environmental factors involved in structuring the insect communities of the studied water bodies. Urban pools in green spaces have the potential to act to its dwellers like corridors through the urban matrix. Taking into account these characteristics and their accessibility, urban temporary pools can be considered as promising habitats for the study of ecological processes involving the insect community.Fil: Fontanarrosa, María Soledad. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Collantes, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Bachmann, Axel Oscar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Botanical composition of sheep diet in two contrasting environments at Tierra del Fuego steppe (Argentina)

The botanical composition of the diet of sheep in two contrasting environments of the fueguian steppe was compared by means of a microscopic analysis of feces, during the spring and summer 2006. In both areas of study, grasses showed to be the most important group in the diet of both locations and of both seasons, followed by native dicotyledonous. In addition, it was found that in the abandoned pasture of Cullen ranch, the intake of Hieracium pilosella, an invasive species, is high. Management strategies should be targeted to the conservation of grasses which are the life forms that are most susceptible to over grazing disturbance. Besides, these results contribute to the stage of advancement of the invasive species H. pilosella in the fueguian steppe and to the knowledge of the incorporation of this species in the diet of livestock, and possibly in the diets of native herbivores.Fil: Fernández Pepi, María Gabriela. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal. Cátedra de Nutrición Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arriaga, Mirta Olga. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Stampacchio, Monica Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Collantes, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Experiencias de largo plazo para el manejo de una hierba invasora de pastizales: El caso de Hieracium pilosella L. en la Estepa Fueguina

Las experiencias de largo plazo son poco frecuentes en los estudios sobre manejo de especies invasoras y resultan claves para comprender la efectividad de los controles. En este trabajo, revisitamos un experimento instalado hace más de siete años, para evaluar diferentes alternativas de control (inter-siembra de pasturas, fertilizaciones y aplicación de herbicidas selectivos y no selectivos) bajo dos condiciones de pastoreo (con y sin pastoreo) en pastizales de Tierra del Fuego invadidos por la maleza exótica Hieracium pilosella L. (velosilla, Asteraceae). Con el fin de evaluar los efectos de los tratamientos aplicados hace siete años, se midió la cobertura de la especie invasora, de las formas de vida dominantes y del suelo desnudo. Los efectos de la fertilización dependieron de las condiciones de pastoreo; la cobertura de H. pilosella luego de siete años disminuyó en más de un 82% y fue reemplazada por otras hierbas (mayormente especies naturalizadas y de valor forrajero) en las parcelas fertilizadas y sin pastoreo doméstico, mientras que no hubo cambios en las parcelas fertilizadas y pastoreadas. Por otro lado, ambos herbicidas (selectivos y no selectivos) redujeron la cobertura de H. pilosella en ca. 90% luego de siete años, independientemente del pastoreo. Sin embargo, la aplicación del herbicida no selectivo determinó un aumento de la cobertura de suelo desnudo de hasta un 15%. Con la aplicación del herbicida selectivo, por el contrario, la cobertura de graminoides aumentó hasta casi un 60% y la cobertura de suelo descubierto se mantuvo por debajo del 2%. Estos resultados permiten sugerir que una estrategia de control basada en la aplicación local de herbicidas selectivos y/o fertilizaciones con exclusiones temporarias del ganado ovino reduce la cobertura de la maleza invasora a escala local y a mediano plazo.Long-term experiences are generally rare in studies on management of invasive species, and they are the key to understand the effectiveness of controls. In this work, we revisited a field experiment set seven years ago to evaluate the effects of four control measures (pasture sown + fertilizer, fertilizer and selective/non-selective herbicide applications) under two different grazing conditions (grazed and ungrazed) in rangelands from northern grasslands of Tierra del Fuego Island in Southern Patagonia (Argentina) invaded by the exotic weed Hieracium pilosella L. (mouse-ear hawkweed, Asteraceae). To evaluate the effects of the treatments applied seven years ago, we measured the cover of the invasive species, the dominant growth forms, and bare soil. The effects of fertilization depended on the grazing conditions; H. pilosella cover decreased by more than 82% and it was replaced by naturalized herbs with high forage value in the ungrazed-fertilized plots, while it exhibited no decrease in the grazed-fertilized plots after seven years since the application. Both herbicides (selective and non-selective) reduced H. pilosella cover by ca. 90% independently of grazing. However, the non-selective herbicide application resulted in an increase in bare soil cover (15%) independently of grazing. In contrast, the selective broadleaf herbicide application increased the graminoids cover up to a 60% and the bare soil cover was below the 2%. According with the results, we suggest a control strategy based on the local application of selective herbicides and/or fertilizers in conjunction with a transient ban on sheep grazing because it is able to reduce the invader’s cover at midterm and local scaleEEA San LuisFil: Cipriotti, Pablo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; ArgentinaFil: Collantes, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales. Laboratorio de Ecología de Pastizales; ArgentinaFil: Escartin, Celina Andrea. Universidad Maimónides. Departamento de Ecología y Ciencias Ambientales; ArgentinaFil: Cabeza, S.. Estancia Guazu-cue; ArgentinaFil: Rauber, Ruth Bibiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Braun, Karen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales. Laboratorio de Ecología de Pastizales; Argentin

Anti-Spike antibodies 3 months after SARS-CoV-2 mRNA vaccine booster dose in patients on hemodialysis: the prospective SENCOVAC study

Background: Patients on hemodialysis are at high-risk for complications derived from coronavirus disease 2019 (COVID-19). The present analysis evaluated the impact of a booster vaccine dose and breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections on humoral immunity 3 months after the booster dose. Methods: This is a multicentric and prospective study assessing immunoglobulin G anti-Spike antibodies 6 and 9 months after initial SARS-CoV-2 vaccination in patients on hemodialysis that had also received a booster dose before the 6-month assessment (early booster) or between the 6- and 9-month assessments (late booster). The impact of breakthrough infections, type of vaccine, time from the booster and clinical variables were assessed. Results: A total of 711 patients [67% male, median age (range) 67 (20-89) years] were included. Of these, 545 (77%) received an early booster and the rest a late booster. At 6 months, 64 (9%) patients had negative anti-Spike antibody titers (3% of early booster and 29% of late booster patients, P =. 001). At 9 months, 91% of patients with 6-month negative response had seroconverted and there were no differences in residual prevalence of negative humoral response between early and late booster patients (0.9% vs 0.6%, P =. 693). During follow-up, 35 patients (5%) developed breakthrough SARS-CoV-2 infection. Antibody titers at 9 months were independently associated with mRNA-1273 booster (P =. 001), lower time from booster (P =. 043) and past breakthrough SARS-CoV-2 infection (P <. 001). Conclusions: In hemodialysis patients, higher titers of anti-Spike antibodies at 9 months were associated with mRNA-1273 booster, lower time from booster and past breakthrough SARS-CoV-2 infectionThe present project has been supported by Fresenius Medical Care, Diaverum, Vifor Pharma, Vircell, Fundación Renal Iñigo Álvarez de Toledo and ISCIII FEDER funds RICORS2040 (RD21/0005

Investigación joven con perspectiva de género III

Actas del III Congreso Internacional de Estudios de Género, Perspectivas y Retos de Futuro: Jóvenes Investigadores (Getafe, 13 - 15 de junio de 2018) organizado por el Instituto Universitario de Estudios de Género de la Universidad Carlos III de Madrid

Environmental effects on grass-endophyte associations in the harsh conditions of south Patagonia

Cool-season grasses are frequently infected by Neotyphodium endophytes and this association is often considered as a mutualistic symbiosis. We examined the incidence of Neotyphodium in populations of Bromus setifolius, Phleum alpinum and Poa spiciformis, native and wide-spread grasses from south Patagonia, Argentina. The incidence of 36 populations of Bromus setifolius was studied in association with climatic and soil variables. 31 populations of Ph. alpinum were sampled in five different plant communities. Seventeen populations of P. spiciformis were sampled in three different plant communities. The association between incidence and climatic variables in Ph. alpinum and between incidence and soil fertility in P. spiciformis was investigated. In B. setifolius endophyte incidence was positively correlated with annual average rainfall contrary to the results found in Ph. alpinum. All the populations of P. spiciformis were infected by endophytes and the incidence was associated with plant community. The Neotyphodium-grass interaction is variable in natural populations, supporting the increasing evidence that the Neotyphodium-host interaction depends, in many cases, on the environmental conditions. Field observations suggest that in detrimental low growth conditions the association is not favoured, leading to a decrease in the endophyte frequency of infection or even to the complete loss of the association.Fil: Novas, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Collantes, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: Cabral, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentin

Plant functional traits, herbivore selectivity and response to sheep grazing in Patagonian steppe grasslands

1. In some ecosystems there is a positive feedback between forage quality and grazing intensity. This involves three components of plant tolerance to grazing: functional traits, herbivore selectivity and response to grazing. We analysed the relationships between these components at species and community levels in Patagonian steppe grasslands. 2. We measured plant functional traits [height, specific leaf area (SLA) and foliar toughness] and estimated sheep selectivity and grazing response indices for 35 plant species. Sheep selectivity indices were obtained from microhistological and species availability data, and grazing response indices from species abundances in sites with contrasting grazing intensities. We performed correlations and multiple regressions among the three types of variables across the pool of 35 species. 3. To analyse data at the community level, we computed weighted averages of traits and sheep selectivity indices for 34 floristic samples taken from each side of 17 fence lines with contrasting grazing intensities. Correlations between mean trait values and sheep selectivity across the 34 samples, and paired comparisons of those variables between sides of the fences, were performed. 4. Taller plants had leaves with lower SLA and/or higher toughness. Short species of intermediate toughness were selected more often by sheep, while SLA was not related to sheep selectivity. Short species with high SLA increased with grazing, while toughness and sheep selectivity were unrelated to grazing response. 5. At the community level, short swards with high average SLA had high selectivity indices and were more abundant on the most intensively grazed sides of fence lines. Leaf toughness was unrelated to other traits or to sheep selectivity, and showed no significant response to grazing. 6. Synthesis and applications. Intensive grazing can increase the forage value of grasslands by the creation of lawns dominated by tolerant species. However, results from this study showed that some plant species that were avoided by grazers also increased, indicating a potential risk of a shift in composition of grazing lawns towards states of low forage value. This suggests that periodic resting of lawns could be a good management strategy to favour palatable species, thereby minimizing the risk of undesirable shifts in the overall species composition.Fil: Cingolani, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Posse Beaulieu, Gabriela. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; ArgentinaFil: Collantes, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentin

Local and intermediated-intensity soil disturbances increase the colonization and expansion dynamics of an invasive plant in Southern Patagonian rangelands

Disturbances are important drivers in natural ecosystems, affecting the vegetation structure and functioning. Invasions of exotic plant species are often associated to disturbances in a complex manner, because they depend on the type, intensity,spatial and temporal arrangement of disturbances, and the particular abiotic and biotic context. Field studies that evaluate the dynamics of plant invasions under different disturbance regimes have a great importance for the understanding of the disturbance effects on invasion spread. In this work we evaluated, through a field manipulative experiment, the early colonization and expansion dynamics of an aggressive invader of grasslands, Hieracium pilosella L., under two disturbance types. We used a split-plot experiment by crossing three levels for a local, sporadic, of increasing intensity disturbance [i.e., 1- undisturbed, 2- vegetation mowing, and 3- ploughing], within two levels for an extensive and chronic disturbance (i.e., grazed and ungrazed). In the range of intensities of disturbance evaluated, the intermediate intensity (i.e., mowing) accelerated the colonization when it is grazed and the expansion of H. pilosella in ungrazed condition. In contrast, lower and higher intensity disturbances, such as ungrazed and ploughing treatments decelerated both invasion processes. Changes in resource availability, interspecific competition and particular characteristics of the invader, i.e., high light requirements, prostrate growth and the presence of stolons, could explain these early invasion patterns.Fil: Rauber, Ruth Bibiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Corrientes. Estación Experimental Agropecuaria Mercedes; ArgentinaFil: Cipriotti, Pablo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; ArgentinaFil: Collantes, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentin

Aquatic Insect Assemblages of Man-made Permanent Ponds, Buenos Aires City, Argentina

Freshwater habitats are important elements within urban green space, and they are endangered by various types of human activity. With the aim to increase the knowledge about species biodiversity in urban ecosystems, we characterized the assemblages of aquatic insects in four man-made permanent ponds in Buenos Aires city (Argentina) during a one year period. The species richness recorded was 32. The most abundant taxa in three ponds were Sigara spp. (Hemiptera) and Chironominae (Diptera), in the other pond were Sigara and Caenis (Ephemeroptera). The removal of aquatic vegetation from the study ponds may affect both the establishment and permanence of the insect community. Swimmers were the dominant group in the studied sites, followed by burrowers and sprawlers, only a few strictly climbers were collected. Accordingly, all the ponds were dominated by collectors (principally gatherers), secondarily by predators and only few shredders were detected, which was much affected by the extraction of macrophytes. Non-parametric abundance indexes estimated a number of species very close to the observed number in each site. Conversely, the incidence indexes estimated more species because there were many more taxa presented only in one sample than those represented by few individual in a sample. The present study contributes with some knowledge that can improve the management of these aquatic urban habitats. Considering that macrophytes affect animal assemblages due to their role as physical structures that increase the complexity or heterogeneity of habitats, they should not be removed by authorities in order to promote biodiversity.Fil: Fontanarrosa, María Soledad. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Limnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Collantes, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; ArgentinaFil: Bachmann, Axel Oscar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biologia Experimental. Laboratorio de Entomologia; Argentin

Pastoreo intensivo controlado, pisoteo y agregado de nutrientes mejoran la cobertura de gramíneas en los pastizales degradados de Tierra del Fuego (Argentina)

Se estudió el efecto del régimen de pastoreo en la estepa magallánica de Tierra del Fuego, donde los pastizales degradados habían sido sometidos a pastoreo extensivo durante los últimos 60 años. El objetivo fue determinar si con una serie de tratamientos se podría realizar una transición desde un pastizal degradado y dominado por arbustos postrados (Empetrum rubrum) de muy mala calidad forrajera, a una cubierta de mejor calidad de forraje. Se utilizaron tratamientos de fertilización con N y P, compactación por animales y compactación por medios artificiales para medir cambios en propiedades del suelo y vegetación. El pH del suelo y la diversidad de especies aumentaron (P ≤ 0.05) con: pastoreo intensivo, fertilización y la combinación de fertilización más pisoteo artificial. El aumento de pH suelo se correlacionó con una mayor cobertura de gramíneas, mientras que el pastoreo extensivo disminuyó el pH y aumentó la cobertura de arbustos postrados. Después de cuatro años, la cubierta de gramíneas fue la más baja en zonas sometidas a pastoreo extensivo (P ≤ 0,05), mientras que en zonas donde se excluyeron los animales o bien pastaban intensamente con y sin la aplicación de fertilizantes la cobertura de gramíneas se incrementó. En las áreas intensamente pastoreadas y fertilizadas, las gramíneas cubrieron más del doble del terreno (67,0%) que en otros tratamientos, y fue además ocho veces mayor respecto a las zonas pastoreadas extensivamente (8,4%). Estos resultados contribuyen al diseño de sistemas de restauración de estos pastizales degradados.Agrazing experiment was conducted in the Magellanic steppe of Tierra del Fuego (Argentina) where degraded grassland had been subjected to extensive grazing for the last 60 years. The objective was to determine whether a series of treatments would effect a transition from that degraded grassland dominated by Empetrum rubrum of very poor forage quality into a richer, higher-quality cover. Nitrogen and phosphorus fertilizers and soil compaction by animals or artificial means were applied to restore certain ecological processes characteristic of an optimal grassland state —e. g., raising the soil pH and increasing nutrient availability and grass cover. Soil pH and species diversity increased (P ≤ 0.05) with intensive grazing, fertilization, or fertilization plus artificial trampling. Increased soil pH was associated with greater grass cover, while extensive grazing resulted in a decreased pH and a cover of prostrate cushion shrubs. After four years, the grass cover was the lowest in extensively grazed areas, but increased (P ≤ 0.05)in areas where animals were excluded or else grazed intensively with and without fertilizer application. Grass cover in the intensively fertilized areas was more than double (at 67.0 %) that of other locations and was eight times greater than in areas that were extensively grazed (at 8.4 %). These findings contribute to the design of restoration systems for these degraded grasslands.Fil: Mendoza, Rodolfo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Collantes, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: de Anchorena, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin