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Livestock production in drylands requires consideration of the ecological applications of ecohydrological redistribution of water. Intensive cattle trampling and the associated increase of surface runoff are common concerns for rangeland productivity and sustainability. Here, we highlight a regional livestock production system in which cattle trails and trampling surrounding an artificial impoundment are purposely managed to enhance redistribution and availability of water for cattle drinking. Based on literature synthesis and field measurements, we first describe cattle production systems and surface water redistribution in the Dry Chaco rangelands of South America, and then develop a conceptual framework to synthesize the ecohydrological impacts of livestock production on these ecosystems. Critical to this framework is the pioshere-an degraded overgrazed and overtrampled area where vegetation has difficulties to grow, usually close to the water points. The Dry Chaco rangelands have three key distinctive characteristics associated with the flat sedimentary environment lacking fresh groundwater and the very extensive ranching conditions: (i) cattle drinking water is provided by artificial impoundments filled by runoff, (ii) heavy trampling around the impoundment and its adjacent areas generates a piosphere that favors runoff towards the impoundment, and (iii) the impoundment, piosphere, and extensive forage areas are hydrologically connected with a network of cattle trails. We propose an ecohydrological framework where cattle transit and trampling alter the natural water circulation of these ecosystems, affecting small fractions of the landscape through increased runoff (compaction in piosphere and trails), surface connectivity (convergence of trails to piosphere to impoundment) and ponding (compaction of the impoundment floor) that operate together making water harvesting and storage possible. These effects have likely generated a positive water feedback on the expansion of livestock in the region with a relatively low impact on forage production. We highlight the role of livestock transit as a geomorphological agent capable of reshaping the hydrology of flat sedimentary rangelands in ways that can be managed positively for sustainable ranching systems. We suggest that the Dry Chaco offers an alternative paradigm for rangelands in which cattle trampling may contribute to sustainable seminatural production systems with implications for other dry and flat rangelands of the world.

Surface soil moisture (SSM) dry-downs have been employed to compare independent data sources on the dynamics of water in soils, including such remote sensing, land surface models and in-situ measurements, which are often difficult to contrast with standard methodologies. The soil drying approach summarizes the soil response to climate as well as surface conditions during a dry period. In this work it is estimated as the SSM e-folding decay, named as dry-down time scale. This is the first assessment over eastern Cordoba, Argentina, a region with a very high cultivated land fraction that was subject of important agricultural changes in the last decades. SMOS SSM product (derived from microwave measurements at L band) is validated with in-situ SSM measurements provided by the National Commission for Space Activities during 2012–2018. Both products agree in showing that the austral spring season has the largest number of dry-down events for the whole period. The dry-down time scale sensitivity to the chosen detection method as well as the data sampling frequency is larger in summer than in spring. A faster soil drying in SMOS than in In-situ SSM is found, likely as a consequence of the shallower sensing depth of the first. This dependency seems to be more important than the temporal sampling frequency in the SSM data.

The study of the spatio-temporal dynamics of surface soil moisture (SSM) drydowns integrates the soil response to climatic conditions, drainage and land cover and is key to advances in our knowledg...

Pine tree invasions threaten many natural ecosystems of the Southern Hemisphere, modifying their structure and functioning through shifts in fire regimes, water balance, and biodiversity. The magnitude of such impacts depends on how much of the landscape has been invaded, thus a better understanding of the dispersal ability of pines and predictions of their future invasions are needed. Here we depict the spatio-temporal patterns of Pinus elliottii and Pinus taeda invading a new environment away from planted plots (i.e., invasion front), and discuss the underlying mechanisms that lead to a very concerning, yet poorly documented, pine invasion in central Argentina. Combining high-resolution imagery, allometric field data, and dendrochronology, we reconstructed the pine invasion into mountain grasslands from its onset in 1990. We found that even though the maximum density of invading pines (80 trees ha−1) was very low compared to adjacent plantation (1000 trees ha−1), density decreases exponentially with distance from the plantation edge. Remarkably, invading pines were found throughout the sampling plots showing high dispersal capacity, with no differences in age with increasing distance. The observed low density and spatially widespread exotic pine establishment, create a stealth type of invasion that is difficult to perceive in its early stages and challenging to manage once large areas are compromised. As invasion continues, long-distance dispersal will possibly become a major agent of landscape transformation and may lead to large pine-dominated neo-ecosystems, such as the savanna-like formation described here that replaced native grasslands in only three decades.

El reemplazo de pastizales por forestaciones es uno de los cambios mas extremos en el uso del suelo por su impacto en el suelo y en el funcionamiento de la vegetacion. En los ecosistemas de llanuras, este cambio genero, en muchos casos, alteraciones quimicas en los suelos como salinizacion, sodificacion y alcalinizacion/acidificacion. Si bien los procesos hidricos, quimicos y biologicos que tienen lugar fueron extensamente caracterizados, debido al acoplamiento entre estos procesos y su no-linealidad, la tarea de cuantificarlos es dificil y, hasta el momento, no existen estudios que los hayan evaluado. El presente trabajo intenta caracterizar, mediante la modelacion del transporte reactivo, los procesos fisico-quimicos que tienen lugar en un pastizal forestado con Eucalyptus camaldulensis en la Pampa Deprimida (Castelli, provincia de Buenos Aires). Para ello, se utilizo informacion hidrologica y quimica (agua, suelo y plantas). El modelo numerico simula los flujos de agua y las potenciales reacciones quimicas en el contexto de reproducir 1) las alteraciones hidrologicas que causa la forestacion y por 2) la intrusion de agua salina profunda, 3) la absorcion y la exudacion de nutrientes por las raices, y 4) la respiracion y el reciclaje de solutos. Los resultados de la modelacion sugieren que factores como la composicion quimica de la napa freatica, el intercambio cationico de los materiales del suelo con la solucion del suelo, la precipitacion/disolucion de minerales y la interaccion con la rizosfera (toma/exclusion/exudacion de solutos) son los mecanismos dominantes que controlarian la direccion del cambio quimico en el suelo (acidificacion vs. alcalinizacion). Este cambio muestra contrastes marcados en distancias cortas (250 m) desde el pastizal, pasando por el margen, hasta el centro del sector forestado. Finalmente, la intensidad y la direccion de los cambios, y la transformacion del suelo dependera tanto del nuevo ecosistema que los humanos imponen como de la naturaleza quimica e hidrologica del sitio. https://doi.org/10.25260/EA.19.29.3.0.896

Rainwater harvesting and associated storage is essential for cattle ranching in the drylands of Argentina and elsewhere. This is the first study to attempt to quantify the hydrological inflows and losses from rainwater harvesting impoundments. To address the direct effect of cattle within impoundments, a typical cattle-affected impoundment was instrumented and compared with that of a similar impoundment but without cattle access. Analysis of the storage dynamics with reference to the controlling variables demonstrated the highly episodic nature of the generation of infiltrationexcess overland flow that recharged the impoundments. The impoundments experienced 43 and 35% of storage loss to open-water-evaporation for the cattle-affected and control impoundments, respectively. Critically, the cattle-effected impoundment lost only 15% of storage to leakage (after cattle consumption was taken into account), while the control lost 65% of its water to basal leakage. Indeed systems modelling of the rainfall-storage dynamics showed that the cattle-affected impoundment, despite consumption by 300 cows, maintained water in the impoundment (per a unit input of rainfall) for longer than the control (a 65- versus 25-day residence time). These results highlight the unintended beneficial effect of cattle trampling on the floor of the impoundment reducing leakage losses. Fil: Magliano, Patricio Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Mindham, David. Lancaster University. ; Reino Unido Fil: Tych, Wlodek. Lancaster University. ; Reino Unido Fil: Murray, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Instituto Nacional de Tecnología Agropecuaria; Argentina Fil: Nosetto, Marcelo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidad Nacional de Entre Ríos; Argentina Fil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Niborski, Marcos Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Rufino, Mariana C.. Lancaster University. ; Reino Unido Fil: Chappell, Nick A.. Lancaster University. ; Reino Unido

Pines (Pinus spp.) rely on co-introduced ectomycorrhizal (EM) fungi to invade native ecosystems in the Southern Hemisphere. Although co-invasive EM fungal communities are expected to be poor in species, long-term successional trajectories and the persistence of dispersal limitations are not well understood. We sampled the roots and surrounding soil of Pinus elliottii and P. taeda trees invading mountain grasslands of Argentina. We also sampled the EM fungal spore bank in grassland soil near (~150 m) and far (~850 m) from original pine plantations. We found an impressive total of 47 different co-invasive EM fungal OTUs. Differential dispersal capacities among EM fungi were detected in the spore bank of grassland soil, but not under mature invading pines. After thirty years of invasion, the age but not the degree of spatial isolation of pine individuals affected the EM fungal composition. We showed that invading pines can host a highly diverse EM fungal community and although dispersal limitations can be important during the colonization of non-invaded sites, they can be overcome in the life-span of pines, allowing EM succession to continue. These results enhance our understanding of the spatial structure and dispersal dynamics of EM fungi during pine invasions.

Despite the importance of long-term atmospheric deposition of ions for vegetation productivity and biogeochemistry, southern South America lacks long-term deposition records. We report a 6-year-long record of atmospheric deposition measurements of Mg2+, Ca2+, Na+, K+, Cl−, SO42−, NO3− and NH4+ in the plains of southern South America, which encompass one of the most important agricultural basins and urban clusters of the continent. After establishing a deposition measurement network across four sites in Argentina and Uruguay, we collected bulk atmospheric deposition monthly form January 2007 through December 2012 in an east–west transect of 700 km. Spatial changes in the sea-salt component of atmospheric deposition were primarily associated with proximity to the sea—as observed in other regions of the world—whereas non-sea-salt components of atmospheric deposition of terrestrial origin were primarily associated with the size of the human population surrounding collection sites. Atmospheric deposition showed a strong interannual variability (CV 50%) mainly associated with variations in the non-sea salt components of terrestrial origin and were within observed values for other relatively unpolluted sites of South America and globally. However, atmospheric deposition appears to be increasing in the region, particularly for SO42− and other ions around Buenos Aires, Argentina, which may represent an early warning of increased air pollution in the area. Average annual regional deposition of sulfate (SO42−) was 12.7 kg S hectare−1 and nitrate (NO3−) was 9.2 kg N hectare−1. Weighted average concentrations of base cations (sum of Mg2+, Ca2+, Na+ and K+) was 0.27 mg L−1, and weighted average concentrations of SO42−, NO3− and NH4+ were 0.094, 0.018 and 0.046 mg L−1, respectively. Our work highlights the need for long-term networks recording atmospheric deposition in the region, increasing knowledge of nutrient cycling and establishing a baseline for future atmospheric pollution measurements.

Las sociedades humanas que habitaron las zonas áridas y semiáridas de todo el planeta han tenido en elpasado, igual que en la actualidad, al agua como unrecurso crítico en su toma de decisiones. Desde lasciencias humanas y naturales se han hecho aportespara comprender los patrones de uso del espacio deestos grupos y el manejo (en un sentido amplísimodel término, desde lo estrictamente económico a losimbólico) que tuvieron del recurso hídrico. En estetrabajo buscamos entender el uso del espacio y lamovilidad de los grupos humanos que habitaron unsector de la Diagonal Árida Sudamericana ubicadoen el centro de Argentina, desde la interface de lasciencias geológicas, hidrológicas y ecológicas. El áreade estudio fue conocida como ?Las Travesías? desdeel tiempo de contacto hispano-indígena debido a lasdificultades que imponían para atravesarla, la carencia de agua y el bajo poblamiento. Esta noción europea del paisaje resulta inapropiada a la luz de lasevidencias arqueológicas de pueblos originarios enel territorio desde hace ca. 8000 años AP, que indicarían la presencia de recursos hídricos previamentesubestimados. Combinando el análisis geomorfológico e hidrológico de los paisajes de dunas prevalentesen gran parte de Las Travesías con las evidenciasarqueológicas y etnográficas existentes, proponemosun modelo de ocupación del espacio de la región conmayor déficit hídrico de Sudamérica, en el que estospaisajes funcionaron como eco-refugios. Estos sistemas de dunas suelen albergar aguas subterráneas debajo contenido de sales y poca profundidad, graciasal alto drenaje del sustrato arenoso que permite queuna fracción apreciable de las lluvias, aun en climasáridos, escape de la evapotranspiración y recargue elacuífero freático. Evidencia actual y etnográfica sugiere que la ocupación y disturbio persistente de estossistemas de dunas aumenta su capacidad de proveeragua al deteriorar la cubierta vegetal y así (i) restringir la evapotranspiración y aumentar la recarga y (ii)deprimir zonas del terreno por erosión, acortando laprofundidad al manto freático. Un conjunto relativamente limitado pero eficiente de estrategias para lacosecha de agua, sumado a una movilidad estacionaly el conocimiento profundo del espacio, se planteancomo estrategias que permitieron no solo la exploración y colonización inicial de Las Travesías sino, posteriormente también, su ocupación definitiva. Both in the past as in the present, the native peoples who inhabited the arid and semi-arid zones of the entire planet have had water as a critical resource in their decision-making. From the human and natural sciences, contributions have been made to understand the patterns of the use of space of these groups and the management (in a very broad sense of the term, from the strictly economic to the symbolic one) of the water resource. The aim of this work is to understand the use of space and mobility of the human groups that inhabited a sector of the Arid South American Diagonal, located in the center of Argentina, from the interface of the geological, hydrological, and ecological sciences. The study area was known as “Las Travesías” from the time of the Hispanic-Indigenous contact due to the difficulties of crossing it, because of the lack of water and the low population. This European notion of the landscape is inappropriate in the light of the archaeological evidence of indigenous peoples in the territory since ca. 8000 years BP. These occupations suggest the presence of previously underestimated water resources. Combining the geomorphological and hydrological analyses of the dune landscapes, prevalent in a large part of Las Travesías, with the existing archaeological and ethnographic evidences, we propose a model of space occupation with greatest water deficit in South America and, in which, these landscapes have functioned as eco-shelters. These systems of dunes tend to hold groundwater with low salt content and shallowness due to the high drainage of the sandy substrate that allows a considerable fraction of the rains, even in arid climates, escape evapotranspiration and recharge the phreatic aquifer. Modern and ethnographic evidence suggests that the persistent occupation and disturbance of these dune systems increases their ability to provide water by damaging the vegetation cover, restricting evapotranspiration, increasing recharge, and depressing areas of the land by erosion, shortening the depth to the water table. A relatively small but efficient set of strategies for harvesting water, together with seasonal mobility and a deep knowledge of the space, are proposed as the strategies that allowed not only the exploration and initial colonization of Las Travesías but also the definitive occupation of this space. Fil: Heider, Guillermo. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis; Argentina Fil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Tripaldi, Alfonsina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina

Soils hold the largest pool of organic carbon (C) on Earth; yet, soil organic carbon (SOC) reservoirs are not well represented in climate change mitigation strategies because our database for ecosystems where human impacts are minimal is still fragmentary. Here, we provide a tool for generating a global baseline of SOC stocks. We used partial least square (PLS) regression and available geographic datasets that describe SOC, climate, organisms, relief, parent material and time. The accuracy of the model was determined by the root mean square deviation (RMSD) of predicted SOC against 100 independent measurements. The best predictors were related to primary productivity, climate, topography, biome classification, and soil type. The largest C stocks for the top 1 m were found in boreal forests (254 ± 14.3 t ha−1) and tundra (310 ± 15.3 t ha−1). Deserts had the lowest C stocks (53.2 ± 6.3 t ha−1) and statistically similar C stocks were found for temperate and Mediterranean forests (142 - 221 t ha−1), tropical and subtropical forests (94 - 143 t ha−1) and grasslands (99-104 t ha−1). Solar radiation, evapotranspiration, and annual mean temperature were negatively correlated with SOC, whereas soil water content was positively correlated with SOC. Our model explained 49% of SOC variability, with RMSD (0.68) representing approximately 14% of observed C stock variance, overestimating extremely low and underestimating extremely high stocks, respectively. Our baseline PLS predictions of SOC stocks can be used for estimating the maximum amount of C that may be sequestered in soils across biomes. Fil: Duarte-Guardia, Sandra. Universidad Nacional de la Patagonia Austral; Argentina Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional.patagonia Sur. Estacion Experimental Agropecuaria Santa Cruz. Agencia de Extension Rural Rio Gallegos.; Argentina Fil: Amelung, Wulf. Universitat Bonn; Alemania Fil: Sheil, Douglas. Norwegian University of Life Sciences. Faculty of Environmental Sciences and Natural Resource Management; Noruega. Center for International Forestry Research (CIFOR); Indonesia Fil: Laffan, Shawn W.. Center for International Forestry Research (CIFOR); Indonesia Fil: Borchard, Nils. Agrosphere Institute (IBG-3); Alemania. Center for International Forestry Research (CIFOR); Indonesia. Ruhr-University Bochum. Institute of Geography; Alemania. Institute Finland. Plant Production, Natural Resources; Finlandia Fil: Bird, Michael I.. James Cook University; Australia Fil: Dieleman, Wouter. James Cook University; Australia Fil: Pepper, David A.. University of New South Wales; Australia. University of Canberra. Institute for Applied Ecology,; Australia Fil: Zutta, Brian. Ministerio del Ambiente; Perú Fil: Jobbagy, Esteban. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Silva, Lucas C. R.. State University of Oregon; Estados Unidos Fil: Bonser, Stephen P.. University of New South Wales; Australia Fil: Ladd, Brenton. University of New South Wales; Australia Fil: Berhongaray, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Piñeiro, Gervasio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de la República; Uruguay Fil: Martinez, Maria-Jose. Universidad Científica del Sur. Escuela de Agroforestería; Perú Fil: Cowie, Annette L.. University of New England. School of Environmental and Rural Science; Australia Fil: Ladd, Brenton. Universidad Científica del Sur. Escuela de Agroforestería; Perú

An improved understanding of the drivers controlling infiltration patterns in semiarid regions is of key importance, as they have important implications for ecosystem productivity, retention of resources and the restoration of degraded areas. The infiltration depth variability (ΔInf) in vegetation patches at the hillslope scale can be driven by different factors along the hillslope. Here we investigate the effects of vegetation and terrain attributes under hypothesis that these attributes exert a major control in ΔInf within the patches. We characterise the ΔInf within vegetation patches at a semiarid hillslope located at the Jornada Experimental Range at dry antecedent conditions preceding two winter frontal rainfall events. We measured these events that are typical during winter conditions, and are characterised by low intensity (0.67 and 4.48 mm h −1 ) and a total rainfall of 10.4 and 4.6 mm. High precision geo-referenced wetting front depth measurements were taken at various locations within the vegetation patches using differential GPS. Vegetation and terrain attributes were analysed to explain the ΔInf among the vegetation patches. The infiltration depths in the periphery of the patches were in general considerably deeper than those in the centre. The observations suggest that the upslope margin of the patches received additional water in the form of runon from upslope adjacent bare soil. Patch orientation with regard to the slope dictated the effect of the rest of the patch attributes and the distance to the hillslope crest on ΔInf. We found that primarily patch orientation, followed by shape and size modulate lateral surface water transport through their effects on overland flow paths and water retention; something that would be obscured under more simplistic characterisations based on bare versus uniform vegetated soil discrimination. Fil: Rossi, María Julieta. University of Sydney; Australia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina. Universidad de Newcastle; Australia Fil: Ares, Jorge Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina Fil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Vivoni, E. R.. Arizona State University; Estados Unidos Fil: Vervoort, R. W.. University of Sydney; Australia Fil: Schreiner McGraw, A. P.. Arizona State University; Estados Unidos Fil: Saco, P. M.. Universidad de Newcastle; Australia

Diets link human health with environmental sustainability, offering promising pressure points to enhance the sustainability of food systems. We investigated the health, environmental, and economic dimensions of the current diet in Argentina and the possible effects of six dietary change scenarios on nutrient adequacy, dietary quality, food expenditure, and six environmental impact categories (i.e., GHG emissions, total land occupation, cropland use, fossil energy use, freshwater consumption, and the emission of eutrophying pollutants). Current dietary patterns are unhealthy, unsustainable, and relatively expensive, and all things being equal, an increase in income levels would not alter the health dimension, but increase environmental impacts by 33–38%, and costs by 38%. Compared to the prevailing diet, the six healthier diet alternatives could improve health with an expenditure between + 27% (National Dietary Guidelines) to -5% (vegan diet) of the current diet. These dietary changes could result in trade-offs between different environmental impacts. Plant-based diets showed the lowest overall environmental impact, with GHG emissions and land occupation reduced by up to 79% and 88%, respectively, without significant changes in cropland demand. However, fossil energy use and freshwater consumption could increase by up to 101% and 220%, respectively. The emission of eutrophying pollutants could increase by up to 54% for all healthy diet scenarios, except for the vegan one (18% decrease). We conclude that the health and environmental crisis that Argentina (and other developing countries) currently face could be mitigated by adopting healthy diets (particularly plant-based), bringing in the process benefits to both people and nature. Supplementary Information The online version contains supplementary material available at 10.1007/s11625-021-01087-7.

Over the last decades, the rapid replacement of native forests by crops and pastures in the Argentinean semiarid Chaco plains has triggered unprecedented groundwater level raises resulting from deep drainage increases, leading to the first massive waterlogging event on records (~25,000 Ha flooded in 2015 near Bandera, one of the most cultivated clusters of the Chaco). In this paper, we link this episode to the ongoing deforestation and cropping scheme shifts through the combined analysis of remote sensing data, agricultural surveys, local farmer information and hydrologic modelling. From 2000 to 2015, the agricultural area of Bandera increased from 21% to 50%, mostly at the expense of dry forests. In this period, agriculture migrated from more intensive (i.e., double-cropping) to more water-conservative (i.e., late-summer single crops) schemes as a general strategy to reduce drought risks. These changes reduced regional evapotranspiration and increased the intensity of deep drainage in wet years. Contrasting cropping schemes displayed significant evapotranspiration differences, but all of them experienced substantial drainage losses (~100–200 mm) during the wettest year (2014/2015), suggesting that cropping adjustments have a limited capacity to halt the generation of water excesses. Nearly 50% of the cropped area in Bandera could not be sown or harvested following the groundwater recharge event of 2014/2015. In the ongoing context of shallow and rising water tables, the introduction of novel cropping schemes that include deep-rooted perennials, to promote transpirative groundwater discharge, seems crucial to avoid the recurrence of water excesses and their associated dryland salinity risk in the region. Fil: Giménez, Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Mercau, Jorge Luis. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria San Luis. Agencia de Extensión Rural San Luis; Argentina Fil: Bert, Federico Esteban. Universidad de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Kuppel, Sylvain. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centre National de la Recherche Scientifique; Francia. University of Aberdeen; Reino Unido Fil: Baldi, Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Geología; Argentina Fil: Houspanossian, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Geología; Argentina Fil: Magliano, Patricio Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina Fil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina

Fil: Villarino, Sebastian Horacio. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Laboratorio de Agroecologia; Argentina

Our understanding of the mechanisms routing precipitation inputs to evapotranspiration and streamflow in catchments is still very fragmented, particularly in the case of saturated flows. Here we explore five mechanisms by which plants and streams compete with each other for water, based on multiple scales of observations in a flat semiarid sedimentary catchment of central Argentina subject to abrupt hydrological transformations. Since the 80s, the “El Morro” catchment (1334 km2, -33.64°, -65.36°) experienced a fast expansion of crops over native forests and grasslands, rapid water table level rises (~0.3 m y-1), spontaneous expansion of wetlands and permanent streams by groundwater sapping. Based on episodic and continuous groundwater level, stream flow, and remote sensing data we show that plants not only take away water from streams by drying the unsaturated zone (mechanism 1), but by tapping the saturated zone in the expanding waterlogged environments (mechanism 2) and in the upland environments that remain uncultivated and display increasing tree cover (mechanism 3). Conversely, streams take away water from plants through pulsed bed-deepening and water table depression (mechanism 4), and riparian and wetland zones burying with fresh sediments (mechanism 5). While earlier work established widespread support for mechanisms 1 preventing stream formation, diurnal and seasonal fluctuations of water table levels and base streamflow records in this study proved the importance of mechanisms 2 and 3 under the current high-water table conditions. These data together with remotely-sensed greenness showed a growing but localized relevance of mechanism 4 and 5 as the stream network developed. The distinction of recharge- vs. topography-controlled groundwater systems is useful to organize the interplay of these concurrent mechanisms. Findings point to the unsaturated-saturated contact zone as a crucial and dynamic hub for water partition and for ecological, geomorphological, and hydrological knowledge integration.

International agreements aim to conserve 17% of Earth's land area by 2020 but include no area-based conservation targets within the working landscapes that support human needs through farming, ranching, and forestry. Through a review of country-level legislation, we found that just 38% of countries have minimum area requirements for conserving native habitats within working landscapes. We argue for increasing native habitats to at least 20% of working landscape area where it is below this minimum. Such target has benefits for food security, nature's contributions to people, and the connectivity and effectiveness of protected area networks in biomes in which protected areas are underrepresented. We also argue for maintaining native habitat at higher levels where it currently exceeds the 20% minimum, and performed a literature review that shows that even more than 50% native habitat restoration is needed in particular landscapes. The post-2020 Global Biodiversity Framework is an opportune moment to include a minimum habitat restoration target for working landscapes that contributes to, but does not compete with, initiatives for expanding protected areas, the UN Decade on Ecosystem Restoration (2021–2030) and the UN Sustainable Development Goals. Fil: Garibaldi, Lucas Alejandro. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Oddi, Facundo José. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Miguez, Fernando E.. University of Iowa; Estados Unidos Fil: Bartomeus, Ignasi. Consejo Superior de Investigaciones Cientificas. Instituto de Recursos Naturales y Agrobiología de Sevilla; España Fil: Orr, Michael C.. Chinese Academy of Sciences; República de China Fil: Jobbagy Gampel, Esteban Gabriel. Instituto Sudamericano de Estudios de Resiliencia y Sostenibilidad; Uruguay. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Kremen, Claire. University of British Columbia; Canadá Fil: Schulte, Lisa A.. University of Iowa; Estados Unidos Fil: Hughes, Alice C.. Chinese Academy of Sciences; República de China Fil: Bagnato, Camilo Ernesto. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Abramson, Guillermo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Bridgewater, Peter. Utrecht University; Países Bajos. University of Canberra; Australia Fil: Gómez Carella, Dulce Sol. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Díaz, Sandra Myrna. 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; Argentina Fil: Dicks, Lynn. University of Cambridge; Reino Unido. University of East Anglia; Reino Unido Fil: Ellis, Erle C.. University of Maryland; Estados Unidos Fil: Goldenberg, Matías Guillermo. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Huaylla, Claudia Alejandra. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Kuperman, Marcelo Nestor. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Locke, Harvey. Yellowstone to Yukon Conservation Initiative; Canadá Fil: Mehrabi, Zia. University of British Columbia; Canadá Fil: Santibañez Ossa, Fernanda Andrea. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Zhu, Chao Dong. Chinese Academy of Sciences; República de China

We synthesize research on the magnitude and dynamisms of salt stocks in the Chaco-Pampas. While current soil maps characterize one-fourth of the region’s soils as saline; integrated soil-hydrology-vegetation studies show salinity to be more widespread and dynamic due to the presence of shallow and stagnant groundwater systems. Two salt retention mechanisms that are turned “off” or “on” by land use changes are proposed: “arrested drainage” and “landscape stagnation.” In the Chaco and Espinal, deforestation and cultivation have relaxed arrested drainage, raising the groundwater and bringing a diluted salt pool to the surface that damages crops and soils. Over the shallower and fresher water tables of the Pampas, tree plantations trigger local arrested drainage and in the landscape stagnation context work as virtual lowlands, consuming groundwater and increasing salt pools. While land use changes highlight the dominant role of vegetation dictating the dynamics of salt pools, key fundamental questions about long-term salt dynamics remain open. Rapid and widespread land use changes offered a unique laboratory to understand saline environments showing that they are more dynamic and sensitive to our interventions, than previously thought.

Hosting the flattest sedimentary plains and highest Andean range of the continent, southern South America faces hydrological transformations driven by climate and land use changes. Although water stable isotopes can help understand these transformations, regional synthesis on their composition is lacking. We compiled for the first time a dataset of H and O isotopic composition for 1659 samples (precipitation, rivers, groundwater and lakes) along latitude (22.4°S to 41.6°S), longitude (55.3°W to 71.5°W), elevation (1–4700 m) and precipitation (∼50 to ∼1500 mm/a) gradients encompassing the Chaco-Espinal-Pampas plains, their adjacent Andean Cordillera and smaller mountain ranges in-between. Emerging patterns reveal (i) only slight seasonal isotope trends in precipitation with no effects of event size, (ii) Atlantic/Amazonian vs. Pacific moisture supply to rivers north and south of the ‘arid diagonal’ of the continent, respectively, (iii) uniform isotopic composition in Atlantic/Amazonian-fed rivers vs. poleward isotope enrichment in Pacific-fed rivers caused by the elevation decline of the Andes, (iv) strong direct evaporation effect in rivers and shallow (

Fil: Aguiar, Sebastián. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Laboratorio de Análisis Regional y Teledetección; Argentina. Fil: Texeira, Marcos. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Laboratorio de Análisis Regional y Teledetección; Argentina. Fil: Garibaldi, Lucas A. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Fil: Garibaldi, Lucas A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Fil: Jobbágy, Esteban G. Universidad Nacional de San Luis. Instituto de Matemática Aplicada San Luis. Grupo de Estudios Ambientales; Argentina. Fil: Jobbágy, Esteban G. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Matemática Aplicada San Luis; Argentina. Over the past decades, the choices of farmers and societies regarding what to grow and eat are being reshaped drastically, as suggested by the diversification of crop supply within countries and its simultaneous homogenization across them. Such a trend could be supported by parallel shifts in production (i.e. diversification within countries, homogenization across countries) or by the growing redistribution introduced by international trade which can even mask reductions in production diversity (i.e. specialization) within countries. Here we assessed the spatial and temporal trends in crop production, exports, imports, and supply diversity based on data from the Food and Agriculture Organization (FAO) for 152 countries and 49 crops from 1961 to 2013. Within countries, the diversity of crop supply increased at a faster rate than the diversity of production, which grew only slightly. Both were surpassed by the diversification of trade, which, within countries, involved a much faster diversity growth of imports compared to exports. Across countries, crop production homogenized at slower rates than crop supply, indicating that crop trade was important for explaining this decoupling. Mirroring country-based analyses, a crop-perspective indicates that crops are becoming more geographically ubiquitous for all the components of the food balance. However, this pattern had important exceptions, like oil palm which has increased its production concentrating in a few specialized countries. We evaluate our results in the context of the multiple social-ecological trade-offs related to international trade and the resilience of the global food system.

The semiarid Espinal in central Argentina, being recently transformed from natural semiarid grasslands into agriculture, represents an interesting scenario to understand the early stages of weed community assembly and its relationship with crop identity and management. Our aim was to characterize the weed communities in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.], the main crops of the Espinal region, under the dominant rainfed conditions. Weed surveys were carried out in 53 fields, and farmers were interviewed to collect information about crop management. Floristic composition was compared within and between crops by calculating the additive partition of the abundance-based Bray-Curtis dissimilarity. We compared the frequency and mean cover of functional groups between crops through generalized linear models. Finally, canonical correspondence analysis was carried out to analyze the associations between floristic composition and agronomic variables. Mean alpha and gamma diversity was greater in corn (10.0 and 80 species, respectively) than in soybean (7.6 and 46 species, respectively). Furthermore, species composition of weed communities was more similar among soybean fields than among either cornfields or fields of both crops. Hence, floristic differences between crops are potentially the result of different microenvironmental heterogeneity above- and belowground, with corn likely to be more permissive to weed establishment compared with soybean. The higher frequency of annual, dicotyledonous, and native species, and the high proportion of rare species, mostly native, suggest a strong legacy of the original vegetation that thrived in these recently cultivated systems. The functional composition was also affected by agronomic management, with sulfur, nitrogen, and grass herbicide application being the most important factors related to the floristic composition of weed communities. This early description can be used as a starting point for studies concerning trajectories, mechanisms, and processes of weed communities related to environment and management. Fil: Rauber, Ruth Bibiana. Instituto Nacional de Tecnología Agropecuaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Demaría, Manuel R.. Instituto Nacional de Tecnología Agropecuaria; Argentina Fil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Arroyo, Daniel N.. Instituto Nacional de Tecnología Agropecuaria; Argentina Fil: Poggio, Santiago Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina

Chemical changes produced by the establishment of tree plantations on grasslands occupying sedimentary plains could potentially impact their highly productive soils through multiple mechanisms. Some of the reported chemical changes following this vegetation shift include soil salinization, sodification, alkalization and acidification. While the associated hydrological, chemical and biological processes have been characterized in most cases, their quantitative integration remains as a complex challenge. The present work explored the simultaneous occurrence of the four mentioned soil chemical changes using reactive transport modeling and hydrological and chemical datasets (water, soil and plants) for a well described afforested grassland in the Pampas of Argentina. Processes included in the numerical model were unsaturated water flow, chemical reactions (soil cation exchange, mineral dissolution-precipitation), the intrusion of salty deep water induced by tree groundwater consumption, rhizosphere-plant processes (respiration, selective solute uptake/exclusion, root mediated electric charge compensation, and elemental recycling and uplift). Modeling results suggest that the dominant soil chemical changes depend on the interplay of all the aforementioned processes and help explain strong soil variation across very short distances (250 m) along edge-core gradients within the tree plantation. This complexity is hard to expect and explain from an isolated treatment of each of the aforementioned processes, calling for the application of numerical tools.

Land use changes affecting ecological and hydrological processes often shape the biogeochemistry of deserts. As highly productive hotspots, Prosopis flexuosa woodlands located in interdune lowlands of the Monte Desert are subject to intense transformations by humans and livestock, and offer a unique opportunity to understand how phreatophyte vegetation, groundwater, rainfall variability, and vertical solute fluxes connect with each other. In this ecosystem, we evaluated the consequences of heavy disturbance by livestock settlements (partial tree removal, intense grazing) on shallow (7–15 m deep) groundwater recharge/discharge dynamics and vertical solute (nutrients and salts) transport. We compared three relatively undisturbed woodlands with three paired livestock stations in the Telteca Reserve (Mendoza, Argentina). At these locations we monitored groundwater levels and chemical and isotopic compositions during six years (2011–2017). Seasonal groundwater level fluctuations reflected shifts in water demand (lower in the cold season) rather than rainfall (high in the warm season), as shown by fall-winter rises and spring-summer declines. These seasonal fluctuations were more intense in undisturbed woodlands than in livestock stations. At a shorter time scale, intense rainfall events were associated to groundwater level raises, suggesting a partial decoupling of phreatophyte vegetation from the free aquifer and, less likely, recharge episodes. Livestock stations also affected groundwater chemistry by locally increasing chloride and nitrate concentrations, and salinity, suggesting higher water percolation and nitrate leaching to the aquifer in livestock stations than in control woodlands. This study addressed ecohydrological processes, which are necessary to understand the coupling between phreatophyte vegetation and groundwater, and its relationships with human and livestock activities.