Arbuscular mycorrhizae reduce the response of important plant functional traits to drought and salinity. A meta-analysis study.

We aimed at exploring the plant functional traits whose responses to drought or salinity are altered by the presence of arbuscular mycorrhiza (AM). We performed a meta-analysis across 114 articles spanning 110 plant species or cultivars. We quantified the size effect of AM symbiosis on the stress response of several functional traits, using linear mixed model analysis (LMM). Correlation analysis between functional traits and total biomass responses to stresses were also performed through LMM. The literature search and further selection yielded seven functional traits, extracted from 114 laboratory studies, including 888 observations and 110 plant species/cultivars. Evidence for significant effects of predictor variables (type of stress, AM symbiosis and/or their interaction) on functional trait response were found for leaf area ratio (LAR), root mass fraction (RMF) and root-shoot (R:S) ratio. Our results provided evidence to accept the hypothesis that AM fungal inoculation may reduce the stress response of these plant functional traits by decreasing its magnitude. We also found a weak correlation between stress responses of these traits and total biomass variation. Although our literature search and data collection were intensive and our results robust, the scope of our conclusions is limited by the agronomical bias of plant species targeted by the meta-analysis. Further knowledge on non-cultivable plant species and better understanding of the mechanisms ruling resources allocation in plants would allow more generalised conclusions.

Modelling relative abundance of Oligoryzomys flavescens, an Orthohantavirus reservoir, in an endemic hantavirus pulmonary syndrome zone.

Hantavirus pulmonary syndrome (HPS) is a zoonotic emerging infectious disease caused by New World orthohantaviruses (family Hantaviridae) hosted by rodents of the family Cricetidae. In Argentina, one of its main hosts is the sigmodontine rodent Oligoryzomys flavescens, a widely distributed mouse of the Pampas, Delta and Espinal ecoregions of central-east Argentina. Because the abundance of the reservoir and its proportion in the rodent community affects both virus prevalence and human exposure risk, its estimation throughout its known geographical distribution is of key importance for the design of public health strategies to prevent HPS. The aim of this study was therefore to model the relative abundance of O. flavescens in most of the Pampas ecoregion within Buenos Aires Province, Argentina, where hantavirus pulmonary syndrome is endemic. To do this we used owl-pellet samples collected between 2006 and 2008 from 51 sites distributed throughout most of Buenos Aires province. Mammalian prey in each pellet was identified to the lowest possible taxonomic level by examination of the skulls, dentaries and molars. We modelled the frequency of O. flavescens found in each sample as a function of climatic, environmental, and topographic data of each site. The two best models were applied to a Geo referential Information System to build maps of estimated frequency (as a proxy of relative abundance) within Buenos Aires province. Estimated relative abundance of O. flavescens in Buenos Aires province was significantly associated with annual mean temperature, annual precipitation and presence of freshwater bodies, and varied among sub-regions, with the Inland and Rolling Pampas being the regions with highest frequencies. Knowing in which areas O. flavescens abundance is expected to be higher can be used to concentrate limited sanitary efforts in those areas that are most needed in order to reduce transmission and increase detection.

Spatial arrangement of silo bags is key to mitigate damage by wildlife.

BACKGROUND: Silo bag is a major harvest storage option in many countries worldwide. Wildlife interacts with this new element in the rural landscape. As a result, wildlife activity could generate breaks in silo bag lining, causing losses to the stored content. The aim of this study was to analyze the damage in silo bags by large hairy armadillos (Chaetophractus villosus) according to different spatial arrangements of silo bags, in order to propose a management strategy to reduce the damage. Our prediction was that silo bags arranged in a cluster would have less damage by large hairy armadillos than bags arranged in a row or than single (isolated) bags at a certain plot. In addition, we expected that in a cluster the exposed outside of the bags would show increased damage compared to the inside of the cluster. RESULTS: We measured 294 silo bags. Damage intensity (number of breaks/100 m silo bag perimeter) in silo bags arranged in a cluster was 72% lower than in bags arranged in a row (P = 0.03), and 77% lower than in single bags (P = 0.001). Moreover, we detected that damage intensity inside was 75% lower than outside of a cluster (P = 0.001). CONCLUSION: We propose grouping in a cluster of parallel bags instead of installing them in a row or isolated bags at plot as a strategy that could be adopted and implemented by farmers in order to reduce the damage by large hairy armadillos, the most harmful wildlife species to silo bags in Argentina. © 2021 Society of Chemical Industry.

The seasonal role of field characteristics on seed-eating bird abundances in agricultural landscapes.

In temperate agroecosystems, avian responses in abundance and distribution to landscape attributes may be exacerbated by the coupling of natural seasons and farming practices. We assessed the seasonal roles of field type, field use in the surroundings, and distance from a field to the nearest woodlot on the abundance of seed-eating birds in a 225,000 km2 study area in the Pampas of central Argentina. During spring-summer and autumn of 2011-2013, we randomly selected 392 fields and used transect samples to collect data on abundance and presence of seed-eating bird species. We recorded a total of 11,579 individuals belonging to 15 seed-eating bird species. We used generalized lineal mixed models to relate bird abundance to field type, field use in the surroundings, and distance to the nearest woodlot. In spring-summer (breeding season) most bird responses were associated with their nesting requirements. Species that build their nests in trees, such as eared doves Zenaida auriculata, picazuro pigeons Patagioenas picazuro, and monk parakeets Myiopsitta monachus, were more abundant in fields closer to woodlots, whereas grassland yellow-finches Sicalis luteola, which nest at areas with tall grasses, were more abundant in fields with livestock use patches in the field surroundings. In autumn (non-breeding season), most bird responses were associated with foraging and refuge needs. The high abundance of eared doves in crop stubbles and the association of pigeons at field surroundings dominated by croplands or at crop stubbles surrounded by livestock use fields revealed the intimate association of these species to sites with high availability of food resources. In addition, both picazuro pigeons and spot-winged pigeons Patagioenas maculosa were associated with woodlots, which provide suitable roosting sites. Our results show that in temperate agroecosystems, the relationships between field characteristics and seed-eating bird abundances vary with season.

Prevalence of infection with hantavirus in rodent populations of central Argentina.

We studied hantavirus seroprevalence and virus variability in rodent populations in Diego Gaynor, northwest of Buenos Aires province, Argentina. Rodent samplings were conducted in railroads and cropfield borders in March and July 1999, September and December 2000, and March 2001. Antibody detection was performed by an enzyme link immunosorbent assay (ELISA), using the recombinant nucleoprotein of Andes (AND) virus as antigen. Tissue samples were taken from positive antibody individuals in order to confirm the presence of hantavirus genomic material and to identify virus genotypes. Akodon azarae was the most abundant species, followed by Oligoryzomys flavescens, while Calomys laucha and C. musculinus were rarely caught. We found a rate of seroprevalence of 9.3% for a total sample of 291 A. azarae and 13.5% for 37 O. flavescens. After molecular analyses of hantavirus, we confirmed the presence of hantavirus genomic material in 16 individuals with ELISA (+) results and two individuals with ELISA (-). Four amplimers for each species were sequenced and compared to the corresponding sequences of representative hantaviruses. We identified the AND Cent Lec from three O. flavescens, and the Pergamino virus from four A. azarae and from one O. flavescens. A. azarae males had higher seroprevalence than females, and heavier individuals showed higher seroprevalence than lighter ones. We did not find seroprevalence differences according to sex in O. flavescens, although this result may have been produced by the low sample size. The lowest seroprevalence was found in a period of high rodent density, when juveniles prevailed in the population. We found higher seroprevalences than those detected in previous studies for other localities of central Argentina where cases of hantavirus pulmonary syndrome (HPS) have been reported. The presence of AND Cent Lec virus in rodent populations of the study area, which is responsible of HPS cases in central Argentina, suggests that human populations are at risk of HPS disease, although there were not reported cases of this disease until today.

Prevalence of infection with hantavirus in rodent populations of central Argentina

We studied hantavirus seroprevalence and virus variability in rodent populations in Diego Gaynor, northwest of Buenos Aires province, Argentina. Rodent samplings were conducted in railroads and cropfield borders in March and July 1999, September and December 2000, and March 2001. Antibody detection was performed by an enzyme link immunosorbent assay (ELISA), using the recombinant nucleoprotein of Andes (AND) virus as antigen. Tissue samples were taken from positive antibody individuals in order to confirm the presence of hantavirus genomic material and to identify virus genotypes. Akodon azarae was the most abundant species, followed by Oligoryzomys flavescens, while Calomys laucha and C. musculinus were rarely caught. We found a rate of seroprevalence of 9.3 percent for a total sample of 291 A. azarae and 13.5 percent for 37 O. flavescens. After molecular analyses of hantavirus, we confirmed the presence of hantavirus genomic material in 16 individuals with ELISA (+) results and two individuals with ELISA (-). Four amplimers for each species were sequenced and compared to the corresponding sequences of representative hantaviruses. We identified the AND Cent Lec from three O. flavescens, and the Pergamino virus from four A. azarae and from one O. flavescens. A. azarae males had higher seroprevalence than females, and heavier individuals showed higher seroprevalence than lighter ones. We did not find seroprevalence differences according to sex in O. flavescens, although this result may have been produced by the low sample size. The lowest seroprevalence was found in a period of high rodent density, when juveniles prevailed in the population. We found higher seroprevalences than those detected in previous studies for other localities of central Argentina where cases of hantavirus pulmonary syndrome (HPS) have been reported. The presence of AND Cent Lec virus in rodent populations of the study area, which is responsible of HPS cases in central Argentina, suggests that human populations are at risk of HPS disease, although there were not reported cases of this disease until today

Servicios ecosistémicos: un puente entre la ecología y la economía

Este trabajo introduce al campo interdisciplinario de la economía ecológica, en el cual se procura desarrollar técnicas y conocimientos en pos de un mundo que sea a la vez económica y ecológicamente sustentable. En particular se presenta el concepto de servicio ecosistémico, con que se denota a cualquier función o proceso ecológico que sea percibido como beneficioso por la sociedad, como la producción de alimentos y materias primas, la contribución a la regulación del clima, la purificación del agua y del aire, el control natural de la erosión y las inundaciones, etc. Estimaciones preliminares indican que la valuación económica de los servicios ecosistémicos que provee nuestro planeta rondaría los 33 trillones de dólares anuales, superando holgadamente el producto bruto de la economía mundial. El debate sobre la necesidad de proteger la provisión de los servicios ecosistémicos se encamina a convertirse en uno de los temas de mayor prioridad en la agenda política internacional

Servicios ecosistémicos: un puente entre la ecología y la economía

Este trabajo introduce al campo interdisciplinario de la economía ecológica, en el cual se procura desarrollar técnicas y conocimientos en pos de un mundo que sea a la vez económica y ecológicamente sustentable. En particular se presenta el concepto de servicio ecosistémico, con que se denota a cualquier función o proceso ecológico que sea percibido como beneficioso por la sociedad, como la producción de alimentos y materias primas, la contribución a la regulación del clima, la purificación del agua y del aire, el control natural de la erosión y las inundaciones, etc. Estimaciones preliminares indican que la valuación económica de los servicios ecosistémicos que provee nuestro planeta rondaría los 33 trillones de dólares anuales, superando holgadamente el producto bruto de la economía mundial. El debate sobre la necesidad de proteger la provisión de los servicios ecosistémicos se encamina a convertirse en uno de los temas de mayor prioridad en la agenda política internacional

Restauracion ecologica

La practica de la restauracion ecologica es relativamente joven, gran parte de la literatura ligada al tema se ocupa de debatir acerca del verdadero significado de la restauracion ecologica, lo que revela por un lado,la necesidad de evaluar y reformular las definiciones en funcion de la experiencia acumulada, pero tambien la urgencia por conseguir una cierta estabilidad en los terminos de referencia que se debieran emplear

Restauracion ecologica

La practica de la restauracion ecologica es relativamente joven, gran parte de la literatura ligada al tema se ocupa de debatir acerca del verdadero significado de la restauracion ecologica, lo que revela por un lado,la necesidad de evaluar y reformular las definiciones en funcion de la experiencia acumulada, pero tambien la urgencia por conseguir una cierta estabilidad en los terminos de referencia que se debieran emplear