Short-term effects of nitrogen deposition on soil microbial biomass in Calluna heathlands NW Spain: critical loads

[EN] We evaluate the short-term effects of different N deposition loads on nutrient dynamic of soil microbial biomass in Cantabrian heathlands. A surplus of 10 kg N ha-1 yr-1 above N background deposition was required to increase soil microbial biomass N content in old Calluna heathlands, while a surplus of 20 kg N ha-1 yr-1 was required in young ones. The increase of atmospheric N deposition showed no change in soil microbial biomass C content. This caused a decrease in C:N ratio with the highest N deposition loads, being linked to a bacterial biomass dominance against fungal dominanceS

Landscape Implications of Contemporary Abandonment of Extensive Sheep Grazing in a Globally Important Agricultural Heritage System

[EN], In Southern Europe, the abandonment of the traditional transhumant system where sheep graze lowland areas during winter and distant mountain systems during summer has led to an important cultural loss and still poorly understood ecological consequences. We investigate the landscape-scale implications of contemporary sheep grazing patterns in a Globally Important Agricultural Heritage System (GIAHS). Our analysis showed a heterogeneous use of mountain grazing areas between 1990 and 2020. The areas most used by sheep had more abundance of pasture, fewer forests, and structurally different landscapes than those that had been fully abandoned by sheep. Likewise, we have detected decreasing trends in landscape diversity in those areas not used by sheep over the study period, whereas landscape heterogeneity is maintained in those areas grazed by sheep. Our study constitutes an original analysis of landscape patterns and shifts in relation to extensive sheep grazing by using novel approaches that combine interviews, updated satellite time series, and state-of-the-art landscape analysis techniques. Likewise, our results constitute a benchmark as they inform on the importance of preserving extensive sheep grazing if we aim to maintain the cultural heritage, and traditional diverse landscape and the semi-natural grasslands in the Mountains of León.SIEuropean Union Next-Generation EU fundsCESEFORMAP

Plant and vegetation functional responses to cumulative high nitrogen deposition in rear-edge heathlands

P. 980-990Elevated atmospheric nitrogen (N) deposition is a major driver of change, altering the structure/functioning of nutrient-poor Calluna vulgaris-heathlands over Europe. These effects amply proven for north-western/central heathlands may, however, vary across the ecosystem's distribution, especially at the range limits, as heathlands are highly vulnerable to land-use changes combined with present climate change. This is an often overlooked and greatly understudied aspect of the ecology of heathlands facing global change. We investigated the effects of five N-fertilisation treatments simulating a range of N deposition rates (0, 10, 20, and 50 kg N ha−1 yr−1 for 1 year; and 56 kg N ha−1 yr−1 for 9 years) on the Calluna-plants, the plant functional groups, species composition and richness of two life-cycle stages (building/young- and mature-phase) of Calluna-heathlands at their rear-edge limit. Our findings revealed a dose-related response of the shoot length and number of flowers of young and mature Calluna-plants to the addition of N, adhering to the findings from other heathland locations. However, cumulative high-N loading reduced the annual growth and flowering of young plants, showing early signs of N saturation. The different plant functional groups showed contrasting responses to the cumulative addition of N: annual/perennial forbs and annual graminoids increased with quite low values; perennial graminoids were rather abundant in young heathlands but only slightly augmented in mature ones; while bryophytes and lichens strongly declined at the two heathland life-cycle stages. Meanwhile there were no significant N-driven changes in plant species composition and richness. Our results demonstrated that Calluna-heathlands at their low-latitude distribution limit are moderately resistant to cumulative high-N loading. As north-western/central European heathlands under high-N inputs broadly experienced the loss of plant diversity and pronounced changes in plant species dominance, rear-edge locations may be of critical importance to unravel the mechanisms of heathland resilience to future global change.S

Fuel build-up promotes an increase in fire severity of reburned areas in fire-prone ecosystems of the western Mediterranean Basin

​​​​​​​Fire Ecology is the official journal of the Association for Fire Ecology[EN] Background Fire‑vegetation feedbacks can modulate the global change effects conducive to extreme fire behavior and high fire severity of subsequent wildfires in reburn areas by altering the composition, flammability traits, and spatial arrangement of fuels. Repeated, high‑severity wildfires at short return intervals may trigger long‑term vegetation state transitions. However, empirical evidence about these feedbacks is absent in fire‑prone ecosystems of the west‑ern Mediterranean Basin, where the response of fire activity has been enhanced by contemporary socioeconomic and land‑use changes. Here, we evaluated whether fire severity differs between initial burns and subsequent wild‑fires in reburn areas (fire‑free periods = 10–15 years) of maritime pine and Aleppo pine forests, holm oak woodlands, and shrublands in the western Mediterranean Basin, and whether there is a relationship between the severity of such interactive wildfire disturbances. We also tested how the type of ecosystem and changes in vegetation structure after the initial wildfires influence these relationships. We leveraged Landsat‑based fire severity estimates for initial and last wildfires using the Relativized Burn Ratio (RBR) and Light Detection and Ranging (LiDAR) data acquired before the last wildfire. Results Fire severity of the last wildfire was significantly higher than that of the initial wildfire for each dominant ecosystem type in reburn areas. These differences were very pronounced in maritime pine forests and shrublands. For consistency, the same patterns were evidenced for the fire severity in reburn and first‑entry areas of the last wild‑fire for each dominant ecosystem type. Fire severity of the last wildfire in forests and woodlands (particularly maritime pine‑dominated) raised with increasing severity of the previous wildfire to a greater extent than in shrublands. Pre‑fire fuel density in the lower vegetation strata (up to 4 m high in maritime and Aleppo pine forests, as well as in shrub‑lands, and up to 2 m high in holm oak forests) was significantly higher in reburn than in first‑entry areas of the last wildfire. Conclusions Our results suggest that land managers should promote more fire‑resistant landscapes to high fire severity by minimizing fuel build‑up and thus fire hazard through pre‑fire fuel reduction treatments such as pre‑scribed burning[ES] Antecedentes La retroalimentación entre el fuego y la vegetación puede modular los efectos del cambio global que conducen al comportamiento extremo del fuego y a una alta severidad de fuegos subsiguientes en áreas de interacción entre incendios. Esto se puede producir mediante alteraciones en la composición, características de inflamabilidad, y la disposición espacial del combustible. Los incendios repetidos, de alta severidad en intervalos de tiempo cortos, pueden producir transiciones a largo plazo sobre el estado de la vegetación. Sin embargo, la evidencia empírica sobre estas retroalimentaciones está ausente en los ecosistemas propensos al fuego en la cuenca oeste del Mediterráneo, donde la respuesta a la actividad del fuego ha aumentado por las actividades socioeconómicas y el cambio en los usos del suelo. En este trabajo, evaluamos si la severidad del fuego difiere entre incendios iniciales y subsiguientes en áreas con fuegos recurrentes (período libre de incendios de 10–15 años), en bosques de pino marítimo y pino de Alepo, en bosques de encinas y en matorrales de la cuenca oeste del Mediterráneo, y si existe una relación entre la severidad de estas perturbaciones interactivas. Testeamos asimismo cómo el tipo de ecosistema y cambios en la estructura de la vegetación después de los incendios iniciales influencian esas relaciones. Potenciamos las estimaciones de severidad basadas en LANDSAT para los incendios iniciales y finales, usando el Ratio Relativo a de Quema (Relativized Burn Ratio o RBR en inglés), y datos LIDAR adquiridos antes del último incendio. Resultados La severidad del último incendio fue significativamente más alta que la del fuego inicial para cada tipo de ecosistema dominante en áreas de interacción de incendios. Estas diferencias fueron muy pronunciadas en bosques de pino marítimo y en matorrales. Consistentemente, los mismos patrones fueron evidenciados para la severidad de los incendios en áreas de interacción de incendios y en aquellas en que el fuego entró por vez primera durante el último incendio para cada tipo de ecosistema. La severidad del último incendio en bosques (particularmente los dominados por pino marítimo) aumentó con una la severidad del incendio anterior en mayor grado que en matorrales. La densidad del combustible preincendio en los estratos de vegetación bajos (hasta 4 m de altura en bosques de pino marítimo y de Alepo, como también en matorrales, y hasta 2 m de altura en bosques de encinas), fueron también significativamente más altos en las zonas de interacción de incendios que en la primera entrada del fuego durante el último incendio. Conclusiones Nuestros resultados sugieren que los gestores del territorio deben promover paisajes más resistentes a la alta severidad, minimizando el aumento de la carga de combustible y por lo tanto el riesgo de incendio, mediante tratamientos de reducción del combustible, como por ejemplo quemas prescriptasSIThis study was fnancially supported by the Spanish Ministry of Science and Innovation in the framework of LANDSUSFIRE project (PID2022-139156OBC21) within the National Program for the Promotion of Scientifc-Technical Research (2021-2023), and with Next-Generation Funds of the European Union (EU) in the framework of the FIREMAP project (TED2021-130925B-I00); by the Regional Government of Castile and León in the framework of the IA-FIREXTCyL project (LE081P23); and by the Portuguese Foundation for Science and Technology in the frame of project UIDB/04033/2020. José Manuel Fernández-Guisuraga was supported by a Ramón Areces Foundation postdoctoral fellowshi

Actions of the entreprise’s social responsibility.Does it attract, retain and motivate theintellectual capital of the company?

[Resumo] Este artigo establece, a través dunha investigación de campo, a importancia da implantación da responsabilidade social nas empresas co fin de estas reteren o seu capital intelectual. A fugade cerebros e a retención do talento é arestora un tema de actualidade que preocupa as grandes entidades, as cales intentan motivar, atraer e reter o seu know how para lograren desta forma posicionarse como líderes no seu sector ou nicho de mercado. Para isto, implementan dentro das súas políticas a responsabilidade social empresarial, con accións que varían en función da xeración a que pertence o seu cadro de persoal e que se relacionan neste estudo.[Abstract] This article establishes the importance of the implantation of the enterprise social responsibility in the companies to retain its intellectual capital through a field research. The brain drain and the retention of talent, are very current subjects and a concern for the big companies, that try to motivate, to attract and to retain its know how and thus to position themselves as the leader sin its sector or niche of market. For this reason, they implement enterprise social responsibility within their policies, with actions that vary based on the generation to which their group belongs and that is related in this study

The PointGroupNRG code for numerical renormalization group calculations with discrete point-group symmetries

The numerical renormalization group (NRG) has been widely used as a magnetic impurity solver since the pioneering works by Wilson. Over the past decades, a significant attention has been focused on the application of symmetries in order to reduce the computational cost of the calculations and to improve their accuracy. In particular, a notable progress has been made in implementing continuous symmetries such as $SO(3)$, useful for studying impurities in an isotropic medium, or $SU(N)$, which is applicable to a wide range of systems. In this work, we focus on the application of discrete point group symmetries, which are particularly relevant for impurity systems in metals where crystal field effects are important. With this aim, we have developed an original NRG code written in the Julia language, PointGroupNRG, where we have implemented crystal point-group symmetries for the Anderson impurity model, as well as the continuous spin and charge symmetries. Among other results, we demonstrate the advantage of our procedure by performing thermodynamic calculations for an impurity system with two orbitals of $E_g$ symmetry and two channels. We compare the results with those obtained for an approximate equivalent model with continuous orbital symmetry.Comment: 17 pages, 1 figur

Fertilization of maize with compost from cattle manure supplemented with additional mineral nutrients

[EN] An alternative approach for cattle manure management on intensive livestock farms is the composting process. An industrial-scale composting plant has been set up in northwest Spain for producing compost from cattle manure. Manure composting involved an increase in pH, electrical conductivity (EC), cation exchange capacity (CEC) and NO3--N concentration, and a decrease in temperature, moisture content, organic matter (OM) content, NH4+-N concentration and C/N ratio. Cu, Zn and Ni concentrations increased due to the reduction of pile weight during the composting process. The resulting compost was applied to a field to study the viability of applying this compost combined with a nitrogen mineral fertilizer as a replacement for the mineral fertilization conventionally used for maize (Zea mays L.). The thermophilic phase of the composting process was very prolonged in the time, which may have slowed down the decomposition of the organic matter and reduced the nitrification process, leading to an over-short maturation phase. The humification and respirometric indexes, however, determined immediately after compost application to the soil, showed it to be stable. Compost application did not decrease the grain yield. A year later, soil pH, OM content and CEC were higher with the compost treatment. Total P, K, Ca and Na concentrations in compost-amended plots were higher than in mineral-fertilized ones, and no significant differences between treatments were found in soil concentrations of NH4+-N, NO3--N, available P, Mg and B. Compost caused no heavy metal pollution into the soil. Therefore, this compost would be a good substitute for the mineral fertilizers generally used for basal dressing in maize growingS

The footprint of large wildfires on the multifunctionality of fire-prone pine ecosystems is driven by the interaction of fire regime attributes

[EN], Background Mediterranean ecosystems dominated by Pinus pinaster Ait. (maritime pine) are subject to a shift from fuel-limited to drought-driven fire regimes, characterized by an increasing wildfire extent, recurrence, and severity. Previous studies have not addressed the interacting effects of fire recurrence and severity on the ecosystem multifunctionality (EMF) of maritime pine forests, although complex relationships between such fire regime attributes are expected. Here, we evaluated the medium-term effects of fire recurrence and severity on the EMF response of unmanaged, native pine ecosystems dominated by Pinus pinaster in the western Mediterranean Basin. We considered four key ecosystem functions computed from functional indicators (carbon regulation, decomposition, soil fertility, and plant production), which were pooled into an EMF construct. The fire regime effects on the trade-offs and synergies between the considered ecosystem functions were also analyzed. Results Multiple ecosystem functions responded differentially to fire recurrence and severity. Fire recurrence had a strong effect on soil fertility, decomposition, and plant production functions. No significant effects of fire severity on any of the individual functions were detected. However, both fire regime attributes interacted to determine soil fertility and decomposition functions, suggesting that their performance is only impaired by fire severity when fire recurrence is low. The differing responses to the fire regime attributes among ecosystem functions fostered a significant EMF response to fire severity and its interaction with fire recurrence, indicating that the effect of fire severity on EMF was stronger under low fire recurrence scenarios, even when relationships between individual functions and fire severity were weak. Fire recurrence caused significant trade-offs between functions to emerge. However, these trade-offs were not strong enough to differ significantly from the intrinsic trade-offs (i.e., regardless of the fire regime) of maritime pine ecosystems. Conclusions Our results indicated the need to use an integrative approach to assess the response of ecosystem functioning to the fire regime in maritime pine ecosystems. Adaptive management responses are necessary towards the minimization of repeated burnings and the reduction of the fuel load in unmanaged maritime pine stands of the western Mediterranean Basin with similar characteristics to those analyzed in this study.[ES], Antecedentes Los ecosistemas mediterráneos dominados por pino marítimo (Pinus pinaster Ait.) están sujetos a cambios en regímenes de fuego limitados por el combustible hacia regímenes conducidos por la sequía, y caracterizados por un incremento en la extensión, recurrencia y severidad de los incendios. Estudios previos no han abordado los efectos interactivos de la recurrencia y severidad del fuego en la multifuncionalidad de los ecosistemas (EMF) en bosques de pino marítimo, aunque cabe esperar relaciones complejas entre estos atributos del regimen de fuego. En este trabajo, evaluamos los efectos a medio plazo de la recurrencia y severidad en la respuesta de la multifuncionalidad de los ecosistemas (EMF) de bosques nativos dominados por pino marítimo no gestionados en la cuenca Mediterránea occidental. Consideramos cuatro funciones clave calculadas a partir de indicadores funcionales (regulación del carbono, descomposición, fertilidad del suelo, y producción egetal) los cuales fueron agrupados en un constructo EMF. Los efectos del régimen de fuego sobre las sinergias y contrapartidas entre las funciones ecosistémicas también fueron analizados. Resultados Múltiples funciones ecosistémicas respondieron diferencialmente a la recurrencia y severidad. La recurrencia del fuego tuvo un efecto muy fuerte en la fertilidad del suelo, en la descomposición y en las funciones de producción. Ningún efecto significativo de la severidad del fuego fue detectado en ninguna de las funciones individuales. Sin embargo, los atributos de ambos regímenes de fuego interactuaron para determinar las funciones de fertilidad y descomposición, sugiriendo que su rendimiento es afectado por la severidad solo cuando la recurrencia del fuego es baja. Las diferentes respuestas a los atributos de los regímenes de fuego entre las funciones ecosistémicas promueven una respuesta significativa de la EMF a la severidad del fuego y su interacción con la recurrencia, indicando que el efecto de la severidad sobre la EMF fue más fuerte bajo escenarios de baja recurrencia, aun cuando las relaciones entre funciones individuales y la severidad fueran débiles. La recurrencia del fuego causó la aparición de ontrapartidas significativas entre funciones. Obviamente, estas contrapartidas no fueron lo suficientemente fuertes para diferir significativamente de aquellas intrínsecas (i.e., independientemente del régimen de fuego) en los ecosistemas de pino marítimo. Conclusiones Nuestros resultados indican la necesidad de usar una aproximación integrada para determinar la respuesta del funcionamiento al régimen de fuego en ecosistemas de pino marítimo. Respuestas de manejo adaptativo son necesarias para la minimización de quemas repetidas y la reducción de la carga de combustible en rodales de pino marítimo no gestionados en la cuenca Mediterránea, con características similares a aquellos analizados en este estudio.SIAEIBritish Ecological SocietyPortuguese Foundation for Science and Technolog

The role of prescribed fire in the provision of regulating ecosystem services of Spanish heathlands

[EN] We provide a synthesis of evidence of the effects of burning and N deposition on the provision of regulating ecosystem services of Cantabrian heathlands (NW Spain). We quantified carbon sequestration in litter, above and belowground biomass, root and soil compartments in heathlands after burning and burning plus N fertilizationS