Análisis de la diversidad de los sistemas de producción agrícolas: un caso de estudio en el suroeste de Francia

The huge changes in agricultural activities, which may be amplified by the forthcoming Common Agriculture Policy reform, call the future of crop-livestock systems into question and hence the impact of these changes on landscapes and biodiversity. We analyzed relationships between agriculture, landscape and biodiversity in south-western France. The study area covered about 4000 ha and included four villages. We conducted a survey of 56 farms. Multivariate analysis (multiple factor analysis and cluster analysis) were used to analyze relationships between 25 variables and to build a typology. The type of farming (beef and/or dairy cattle, cash crops), size (area and workforce) and cultivation practices, among others, were revealed as differentiating factors of farms. Six farming types were identified (1) hillside mixed crop-livestock farms, (2) large ‘corporate’ farms, (3) extensive cattle farms, (4) large intensive farms on the valley sides, (5) small multiple-job holdings, and (6) ‘hobby’ farms. The diversity of farming systems revealed the variable impact of the main drivers of change affecting agricultural development, particularly the enlargement and modernization of farms along with the demography of agricultural holdings.Los enormes cambios experimentados en las actividades agrícolas en Europa, que podrían ser amplificados por la próxima reforma de la política agrícola común de Europa, cuestionan el futuro de los sistemas agropecuarios y, por tanto, el impacto de estos cambios en el paisaje y en la biodiversidad. Para ello, se estudiaron las relaciones entre la agricultura, el paisaje y la biodiversidad en el suroeste de Francia (Cerros de Gascuña). El área de estudio cubre aproximadamente 4000 ha e incluye cuatro municipios. Los datos relacionados con las actividades agrícolas provienen de encuestas realizadas en 56 explotaciones. Para estudiar las relaciones entre 25 variables, se utilizaron análisis multivariados (análisis factorial múltiple y análisis de conglomerados) y se elaboró una tipología. Los factores de diferenciación identificados, entre otros, son: el tipo de producción (ganado de carne y/o lechero, cultivos herbáceos), tamaño (superficie y mano de obra) y prácticas de cultivo. Se distinguieron seis tipos de explotaciones: (1) explotaciones de ladera que combinan agricultura y ganadería, (2) grandes explotaciones corporativas, (3) explotaciones ganaderas extensivas, (4) grandes explotaciones intensivas en valles, (5) pequeñas fincas explotadas a tiempo parcial, y (6) explotaciones para ocio. La diversidad de los sistemas de producción reveló el impacto variable de las principales fuerzas de cambio que afectan al desarrollo de la agricultura, en particular a la ampliación y modernización de las explotaciones, junto con la demografía de la población agrícola

Modelling and simulating change in reforesting mountain landscapes using a social-ecological framework

Natural reforestation of European mountain landscapes raises major environmental and societal issues. With local stakeholders in the Pyrenees National Park area (France), we studied agricultural landscape colonisation by ash (Fraxinus excelsior) to enlighten its impacts on biodiversity and other landscape functions of importance for the valley socio-economics. The study comprised an integrated assessment of land-use and land-cover change (LUCC) since the 1950s, and a scenario analysis of alternative future policy. We combined knowledge and methods from landscape ecology, land change and agricultural sciences, and a set of coordinated field studies to capture interactions and feedback in the local landscape/land-use system. Our results elicited the hierarchically-nested relationships between social and ecological processes. Agricultural change played a preeminent role in the spatial and temporal patterns of LUCC. Landscape colonisation by ash at the parcel level of organisation was merely controlled by grassland management, and in fact depended on the farmer's land management at the whole-farm level. LUCC patterns at the landscape level depended to a great extent on interactions between farm household behaviours and the spatial arrangement of landholdings within the landscape mosaic. Our results stressed the need to represent the local SES function at a fine scale to adequately capture scenarios of change in landscape functions. These findings orientated our modelling choices in the building an agent-based model for LUCC simulation (SMASH - Spatialized Multi-Agent System of landscape colonization by ASH). We discuss our method and results with reference to topical issues in interdisciplinary research into the sustainability of multifunctional landscapes

Developmental axon degeneration requires trpv1-dependent Ca 2+ influx

Development of the nervous system relies on a balance between axon and dendrite growth and subsequent pruning and degeneration. The developmental degeneration of dorsal root ganglion (DRG) sensory axons has been well studied in part because it can be readily modeled by removing the trophic support by nerve growth factor (NGF) in vitro. We have recently reported that axonal fragmentation induced by NGF withdrawal is dependent on Ca2+, and here, we address the mechanism of Ca2+ entry required for developmental axon degeneration of mouse embryonic DRG neurons. Our results show that the transient receptor potential vanilloid family member 1 (TRPV1) cation channel plays a critical role mediating Ca2+ influx in DRG axons withdrawn from NGF. We further demonstrate that TRPV1 activation is dependent on reactive oxygen species (ROS) generation that is driven through protein kinase C (PKC) and NADPH oxidase (NOX)-dependent pathways that become active upon NGF withdrawal. These findings demonstrate novel mechanistic links between NGF deprivation, PKC activation, ROS generation, and TRPV1-dependent Ca2+ influx in sensory axon degeneration.Fil: Johnstone, Aaron D.. University of British Columbia; Canadá. McGill University; CanadáFil: de Léon, Andrés. University of British Columbia; Canadá. McGill University; CanadáFil: Unsain, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Gibon, Julien. University of British Columbia; CanadáFil: Barker, Philip A.. University of British Columbia; Canad

Agricultural land-use change and ash (Fraxinus excelsior L.) colonization in Pyrenean landscapes: an interdisciplinary case study

 ONLINE FIRSTInternational audienceChanges in agricultural land use are responsible for significant modifications in mountain landscapes. This study is part of an interdisciplinary research on the processes and consequences of spontaneous afforestation of Pyrenean landscapes by ash, and the possibilities for its management. We address the relationships between vegetation dynamics and land-use change from the combination of an agricultural study of change in farm management and an ecological study of grassland colonization by ash. In the framework of a village case study, we characterized parcels management and land-use histories, and analyzed the dynamics of the composition of grassland vegetation communities. From a joint analysis of the results obtained in each discipline, we discuss the limitations and comple-mentarities of the two approaches for the interdisciplinary assessment of the afforestation process

LIVESTOCK FARMING SYSTEMS RESEARCH IN EUROPEAND ITS POTENTIAL CONTRIBUTION FOR MANAGING FOR SUSTAINABILITY IN LIVESTOCK FARMING

International audienc

Stress-Induced GSK3 Regulates the Redox Stress Response by Phosphorylating Glucose-6-Phosphate Dehydrogenase in Arabidopsis.

Diverse stresses such as high salt conditions cause an increase in reactive oxygen species (ROS), necessitating a redox stress response. However, little is known about the signaling pathways that regulate the antioxidant system to counteract oxidative stress. Here, we show that a Glycogen Synthase Kinase3 from Arabidopsis thaliana (ASKα) regulates stress tolerance by activating Glc-6-phosphate dehydrogenase (G6PD), which is essential for maintaining the cellular redox balance. Loss of stress-activated ASKα leads to reduced G6PD activity, elevated levels of ROS, and enhanced sensitivity to salt stress. Conversely, plants overexpressing ASKα have increased G6PD activity and low levels of ROS in response to stress and are more tolerant to salt stress. ASKα stimulates the activity of a specific cytosolic G6PD isoform by phosphorylating the evolutionarily conserved Thr-467, which is implicated in cosubstrate binding. Our results reveal a novel mechanism of G6PD adaptive regulation that is critical for the cellular stress response