Ganadería en humedales: Respuestas de la vegetación a la exclusión del pastoreo en tres tipos de ambientes en un paisaje del Delta del Paraná

Los herbívoros pueden influir profundamente sobre la estructura y funcionamiento de los ecosistemas, impactando tanto sobre el ambiente físico como sobre las comunidades vegetales y animales. Se estudió la respuesta de la vegetación luego de la exclusión del pastoreo por ganado doméstico, antes y después de una inundación prolongada, analizando la composición florística, la diversidad y la dinámica de la biomasa aérea verde en tres tipos de ambientes localizadas en distintas porciones de un gradiente topográfico (albardón, media loma alta y media loma baja) de un paisaje de humedales en el Delta del río Paraná. El pastoreo produjo un efecto sobre los parámetros de las comunidades estudiadas mientras que con la exclusión se observó una tendencia a la recuperación de la fisonomía de los ambientes originales. Asimismo los datos del período post inundación muestran que el pastoreo junto a este evento tuvieron un efecto negativo sinérgico que afectó el incremento de la biomasa de la especie dominante (Hymenachne pernambucense) y de alto valor forrajero para la media loma baja y provocó la disminución de la diversidad para las otras coberturas. Las diferencias en la biomasa viva estuvieron influenciadas tanto por la dinámica de las propias comunidades como por la herbivoría de especies palatables. Los datos generados en este trabajo son de gran valor considerando que aún no existen registros para la región y son poco los antecedentes en humedales fluviales. Además, estos resultados conjuntamente con los que se continuaron realizando a partir del año 2011 generarán una importante base de información de utilidad para establecer pautas de manejo que contribuyan al establecimiento de un sistema ganadero sustentable para la región.Herbivores may profoundly influence on structure and functioning of ecosystems impacting on physical environment and plants and animals communities. The effect of livestock grazing, by exclusion, on floristic composition, diversity and aboveground biomass dynamic were studied on three environments located in different portions of topographical gradient (levee, high mid-slope and down mid-slope) in a wetland of the Paraná river Delta. In addition, these systems were analyzed for pre and post flood period. Cattle grazing had an effect on studied communities and biomass, while with exclusion was observed, despite the short period, a tendency to recover the features of the original environments. Also the post flood period data show that grazing next to this event had a negative synergistic effect that influenced on the growth of the dominant specie (Hymenachne pernambucense) with high forage value in down mid-slope and caused the decrease of diversity for the others coverages. The differences in green biomass were influenced by the dynamics of communities than the herbivory of palatable species. The data generated in this work are great value considering that yet there are no records for this region and the background in riverine wetlands are few. In addition along with the work we are performing. Furthermore, these results together with those who continued to perform from the year2011 will generate an important base of information useful for generating management guidelines that contribute to the establishment of a sustainable livestock system for the region.Fil: Magnano, Andrea Laura. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. Laboratorio de Biodiversidad, Limnología y Conservación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vicari, Ricardo Luis. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Regional; ArgentinaFil: Astrada, Elizabeth Nora. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. Laboratorio de Biodiversidad, Limnología y Conservación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Quintana, Ruben Dario. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. Laboratorio de Biodiversidad, Limnología y Conservación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Carbon budget alteration due to landcover-landuse change in wetlands. The case of afforestation in the Lower Delta of the Paraná River marshes (Argentina)

The objective of this work was to analyze the effects on carbon budget caused by the replacement of freshwater marshes by salicaceae plantations at ecosystem and regional scales, in the Lower Delta of the Paraná River in Argentina. Biomass and NAPP were estimated for one of the main species planted in the delta, Salix babylonica var sacramenta and for the dominant species of the marshes that are most widespread in the study area, Scirpus giganteus and Schoenoplectus californicus. Soil organic carbon was also estimated. Afforestation and marshes were mapped based on the digital classification of Landsat imagery. Aboveground biomass stored by afforestation is higher than by marshes (113.4 Mg ha-1 vs. around 10 Mg ha-1). Nevertheless, soil organic matter accumulation is ten-fold higher in the marshes. A great amount of carbon is released to the atmosphere when marshes are converted to forest due to change from wetland to terrestrial condition  .Fil: Vicari, Ricardo Luis. Universidad de Buenos Aires; ArgentinaFil: Kandus, Patricia. Universidad de Buenos Aires; ArgentinaFil: Pratolongo, Paula Daniela. 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 de Buenos Aires; ArgentinaFil: Burghi, Mariana. Universidad de Buenos Aires; Argentin

Tiller dynamic and production on a SW Atlantic Spartina alterniflora marsh

We used non-destructive methods to study the bi-monthly changes in standing stock, turnover, and net aerial primary productivity (NAPP) of Spartina alterniflora in the Bahı ́ a Blanca Estuary, Argentina, from 2005 to 2007. Tillers were tagged and counted bimonthly and a weight:height relationship developed for the live and dead stems in a regularly flooded zone (low marsh, LM) and an irregularly flooded one (high marsh, HM). The annual tiller natality in year one compared to year two decreased from 440 68 to 220 58 new individuals m –2 yr –1 in the HM and from 500 103 to 280 97 new individuals m –2 yr –1 in the LM ( m 1 SE). Tiller mortality averaged 670 70 individuals m –2 yr –1 . Living biomass was present throughout the year in both the sites, but flowering occurred only at the HM where it began in December. The live biomass in the LM was significantly greater than in the HM in the first year, but decreased in the second year from 455 66 to 266 31 g m –2 in the HM and from 572 76 to 277 78 g m –2 in the LM ( m 1 SE). The highest levels of standing dead material were in the HM (55%) and the lowest in the LM (24%). The average total (live þ dead) aboveground biomass in the HM was significantly greater than in the LM in the first year, but decreased in the second year from 1033 120 to 556 33 g m –2 , and in the LM from 679 57 to 355 61 g m –2 ( m 1 SE). The annual NAPP, calculated as the sum of positive growth in individual tillers between intervals, showed no significant differences between years and sites, and averaged 628 94 g m –2 yr –1 ( m 1 SE). The dead biomass output (DBO), calculated as the sum of negative increments in NAPP between sampling intervals, was 956 121 g –2 yr –1 , and was not statistically different between sites. The productivity at this site is not different from that estimated for other marshes, when similar methods are used. The production at this site, however, may be limited by high salinity levels, and the differences observed between years related to climate changes between years, e.g., the 2006–2007 was an ENSO period.Fil: Gonzalez Trilla, Gabriela Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Regional; ArgentinaFil: Kandus, Patricia. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Regional; ArgentinaFil: Negrin, Vanesa Lorena. 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: Vicari, Ricardo Luis. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Regional; ArgentinaFil: Marcovecchio, Jorge Eduardo. 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

Net Primary productivity of Spartina densiflora brong in a SW atlantic coastal salt marsh

Abstract. Coastal marshes are known as organic matter producers. The goal of this work is to study tiller demography, standing biomass, and net aerial primary productivity (NAPP) in a Spartina densiflora coastal wetland, using a method applied to permanent sample plots located at two sites differing in topographic location, a regularly flooded zone [relative low marsh (LM)] and an irregularly flooded one [relative high marsh (HM)]. Measurements were made every 2 months during the 2005–2007 period. The annual NAPP was estimated to be 2,599±705 gDW m−2year−1 for the HM and 2,181± 605 gDW m−2year−1 and 602±154 gDW m−2year−1 for the first and second period of the LM populations, respectively, showing a seasonal pattern reaching maximum values in summer. The reduced NAPP values of the LM sites in the second year was associated with an extremely high precipitation period related to the 2007–2008 El Niño event.Fil: Gonzalez Trilla, Gabriela Liliana. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Regional; ArgentinaFil: de Marco, Silvia Graciela. Universidad Nacional de Mar del Plata; ArgentinaFil: Marcovecchio, Jorge Eduardo. 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: Vicari, Ricardo Luis. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Regional; ArgentinaFil: Kandus, Patricia. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Regional; Argentin

Natural triploidy in Rhamdia quelen identified by cytogenetic monitoring in Iguaçu basin, southern Brazil

The freshwater silver catfish from the genus Rhamdia belongs to a group of neotropical fish with wide distribution throughout Central and South America. The results obtained in the F1 generation of native specimens of this species bred in captivity using molecular cytogenetic tools revealed a high number of triploid specimens (46.8%) in the samples analyzed. The use of double fluorescent in situ hybridization (double-FISH) with 18S and 5S rDNA probes allowed highlighting the location of ribosomal sites with independent activity. This chromosome marker allowed the identification of triploid nuclei, in which three markers were visualized, in contrast to diploid fish, which only exhibited two fluorescent signals. As triploid specimens exhibit either total or partial gonad sterility, the present study demonstrates the importance of cytogenetic monitoring in restocking programs aimed at genetic conservation. © 2011 Springer Science+Business Media B.V

Post-anaesthesia pulmonary complications after use of muscle relaxants (POPULAR): a multicentre, prospective observational study

Background Results from retrospective studies suggest that use of neuromuscular blocking agents during general anaesthesia might be linked to postoperative pulmonary complications. We therefore aimed to assess whether the use of neuromuscular blocking agents is associated with postoperative pulmonary complications. Methods We did a multicentre, prospective observational cohort study. Patients were recruited from 211 hospitals in 28 European countries. We included patients (aged ≥18 years) who received general anaesthesia for any in-hospital procedure except cardiac surgery. Patient characteristics, surgical and anaesthetic details, and chart review at discharge were prospectively collected over 2 weeks. Additionally, each patient underwent postoperative physical examination within 3 days of surgery to check for adverse pulmonary events. The study outcome was the incidence of postoperative pulmonary complications from the end of surgery up to postoperative day 28. Logistic regression analyses were adjusted for surgical factors and patients’ preoperative physical status, providing adjusted odds ratios (ORadj) and adjusted absolute risk reduction (ARRadj). This study is registered with ClinicalTrials.gov, number NCT01865513. Findings Between June 16, 2014, and April 29, 2015, data from 22803 patients were collected. The use of neuromuscular blocking agents was associated with an increased incidence of postoperative pulmonary complications in patients who had undergone general anaesthesia (1658 [7·6%] of 21694); ORadj 1·86, 95% CI 1·53–2·26; ARRadj –4·4%, 95% CI –5·5 to –3·2). Only 2·3% of high-risk surgical patients and those with adverse respiratory profiles were anaesthetised without neuromuscular blocking agents. The use of neuromuscular monitoring (ORadj 1·31, 95% CI 1·15–1·49; ARRadj –2·6%, 95% CI –3·9 to –1·4) and the administration of reversal agents (1·23, 1·07–1·41; –1·9%, –3·2 to –0·7) were not associated with a decreased risk of postoperative pulmonary complications. Neither the choice of sugammadex instead of neostigmine for reversal (ORadj 1·03, 95% CI 0·85–1·25; ARRadj –0·3%, 95% CI –2·4 to 1·5) nor extubation at a train-of-four ratio of 0·9 or more (1·03, 0·82–1·31; –0·4%, –3·5 to 2·2) was associated with better pulmonary outcomes. Interpretation We showed that the use of neuromuscular blocking drugs in general anaesthesia is associated with an increased risk of postoperative pulmonary complications. Anaesthetists must balance the potential benefits of neuromuscular blockade against the increased risk of postoperative pulmonary complications

The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis

© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine

Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London