Juan Gaitan

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Verified

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• PhD
• Professor at National University of Luján

Drylands cover about 41% of E arth's land surface, and 65% of their area supports domestic livestock that depends on the above‐ground net primary productivity ( ANPP ) of natural vegetation. Thus, understanding how biotic and abiotic factors control ANPP and related ecosystem functions can largely help to create more sustainable land‐use practices...

Drought is an increasingly common phenomenon in drylands as a consequence of climate change. We used 311 sites across a broad range of environmental conditions in Patagonian rangelands to evaluate how drought severity and temperature (abiotic factors) and vegetation structure (biotic factors) modulate the impact of a drought event on the annual int...

The biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems1. It has been suggested that the C, N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elemen...

Assessing the spatial variability of ecosystem structure and functioning is an important step towards developing monitoring systems to detect changes in ecosystem attributes that could be linked to desertification processes in drylands. Methods based on ground-collected soil and plant indicators are being increasingly used for this aim, but they ha...

Experiments suggest that biodiversity enhances the ability of ecosystems to maintain multiple functions, such as carbon storage, productivity, and the buildup of nutrient pools (multifunctionality). However, the relationship between biodiversity and multifunctionality has never been assessed globally in natural ecosystems. We report here on a globa...

Este estudio se centró en evaluar la tendencia del Índice de Vegetación de Diferencia Normalizada (NDVI) para el período 2000-2023, a nivel de píxel de 250 m, en las Áreas Protegidas terrestres gestionadas por la Administración de Parques Nacionales y sus entornos, incorporando corrección por lluvias.

Este documento resume los resultados y la metodología aplicada para producir los mapas de uso y cobertura del suelo (LULC) correspondientes al sector Agricultura, Silvicultura y Cambio de Uso de la Tierra (AFOLU, por sus siglas en inglés: Agriculture, Forestry, and Others Land Uses) de Argentina para los años 2000, 2010 y 2020. El objetivo de estos...

Increases in the abundance of woody species have been reported to affect the provisioning of ecosystem services in drylands worldwide. However, it is virtually unknown how multiple biotic and abiotic drivers, such as climate, grazing, and fire, interact to determine woody dominance across global drylands. We conducted a standardized field survey in...

Estimating tephra fall volumes is critical for assessing the impacts of explosive eruptions and calculating eruption source parameters (ESPs). Estimates are subject to uncertainties that span from measuring deposit thicknesses to the different volume integration models implemented. In this sense, the number of field control points (FCPs) may produ...

Native forests host important pools of soil organic carbon (SOC). This is a key element not only for ecosystem functioning, but also for the global carbon cycle. Globally, and particularly in Argentina, native forests are being rapidly replaced by other land uses, raising questions about the impact of these transformations on SOC and its environmen...

Earth harbours an extraordinary plant phenotypic diversity¹ that is at risk from ongoing global changes2,3. However, it remains unknown how increasing aridity and livestock grazing pressure—two major drivers of global change4–6—shape the trait covariation that underlies plant phenotypic diversity1,7. Here we assessed how covariation among 20 chemic...

Mineral-associated organic carbon (MAOC) constitutes a major fraction of global soil carbon and is assumed less sensitive to climate than particulate organic carbon (POC) due to protection by minerals. Despite its importance for long-term carbon storage, the response of MAOC to changing climates in drylands, which cover more than 40% of the global...

https://redargentinadegeografiafisica.wordpress.com/wp-content/uploads/2024/06/actas-de-resumenes-extendidos-jngf-2024--1.pdf

Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in dryla...

Greenspaces are important for sustaining healthy urban environments and their human populations. Yet their capacity to support multiple ecosystem services simultaneously (multiservices) compared with nearby natural ecosystems remains virtually unknown. We conducted a global field survey in 56 urban areas to investigate the influence of urban greens...

The accurate representation of spatio-temporal precipitation patterns is an essential input for numerous environmental applications. However, the estimation of precipitation patterns derived solely from rain gauges is subject to large uncertainties, especially in data-scarce regions. We present a new database of Monthly Precipitation of the Argenti...

Vegetation Type (VT) mapping using Optical Earth observation data is essential for the management and conservation of natural resources, as well as for the evaluation of the supply of provisioning ecosystem services (ESs), the maintenance of ecosystem functions, and the conservation of biodiversity in anthropized environments. The main objective of...

The nationally determined contribution (NDC) presented by Argentina within the framework of the Paris Agreement is aligned with the decisions made in the context of the United Nations Framework Convention on Climate Change (UNFCCC) on the reduction of emissions derived from deforestation and forest degradation, as well as forest carbon conservation...

The largest stocks of soil organic carbon can be found in cold regions such as Arctic, subarctic and alpine biomes, which are warming faster than the global average. Discriminating between particulate and mineral-associated organic carbon can constrain the uncertainty of projected changes in global soil organic carbon stocks. Yet carbon fractions a...

The rewilding of modern agriculture is challenged by our current uncertainties on the microbiome of major crop wild progenitors (CWPs). Here, we conducted the first global standardised field survey to investigate the edaphoclimatic conditions and soil microbiome of 125 wild populations associated with 10 of the most important CWPs at their centres...

Soil mosses are among the most widely distributed organisms on land. Experiments and observations suggest that they contribute to terrestrial soil biodiversity and function, yet their ecological contribution to soil has never been assessed globally under natural conditions. Here we conducted the most comprehensive global standardized field study to...

Acceso al mapa: https://intamapacosargentina.users.earthengine.app/view/cos

Urban greenspaces support multiple nature-based services, many of which depend on the amount of soil carbon (C). Yet, the environmental drivers of soil C and its sensitivity to warming are still poorly understood globally. Here we use soil samples from 56 paired urban greenspaces and natural ecosystems worldwide and combine soil C concentration and...

Este trabajo tiene por objetivo ajustar una función predictora regional del volumen total de palo santo (Gonopterodendron sarmientoi) por unidad de superficie para tres tipos de bosques con presencia de palo santo, usando como variables regresoras el área basal, la densidad y la altura dominante de palo santo

Questions (1) Is the co‐dominance of grasses and shrubs a general feature of Patagonian steppes? (2) At a local scale, does it change with domestic grazing intensity or decadal changes in precipitation? Locations Question 1. Patagonia region in southern South America. Question 2. Shrub–grass steppes (45°24′S, 70°17′W) subjected to different grazin...

While the contribution of biodiversity to supporting multiple ecosystem functions is well established in natural ecosystems, the relationship of the above- and below-ground diversity with ecosystem multifunctionality remains virtually unknown in urban greenspaces. Here we conducted a standardized survey of urban greenspaces from 56 municipalities a...

The general objective of this study was to provide information regarding the productivity and site quality of Palo Santo forests in their Argentinean distribution area in order to establish guidelines for sustainable management and use. We used data taken from 482 plots as part of national, regional and local forest inventories in northern Argent...

In Argentina, current food and land-use systems are drivers of greenhouse gas emissions, biodiversity loss, nutrient outflows, chemical pollution and water stress, while they fail to produce sustainable livelihoods for farmers and herders. Argentina must transition toward more sustainable food and land-use systems to achieve the sustainable develop...

Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that in...

Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that in...

Grazing by domestic livestock is both the main land use across drylands worldwide and a major desertification and global change driver. The ecological consequences of this key human activity have been studied for decades, and there is a wealth of information on its impacts on biodiversity and ecosystem processes. However, most field assessments of...

The ability of a species to colonize new geographical areas is closely related to its morphological response to environmental gradients. Previous studies compared native and alien invasive species in their ability to modify their morphology in reaction to climatic and edaphic factors; however, taxonomically close species have been scarcely analyzed...

The constant provision of plant productivity is integral to supporting the liability of ecosystems and human wellbeing in global drylands. Drylands are paradigmatic examples of systems prone to experiencing abrupt changes in their functioning. Indeed, space-for-time substitution approaches suggest that abrupt changes in plant productivity are wides...

For management and conservation strategies in the long term is necessary to know the species distribution and main biophysical aspects that determine the structure and dynamics of the forest. The aim of this work was to determine the potential and current spatial distribution of Gonopterodendron sarmientoi, an emblematic and endangered tree species...

Peri, P et al (2022). Informe Técnico Final. Carbono almacenado en suelos en los bosques nativos de diferentes ecorregiones del país. http://hdl.handle.net/20.500.12123/14594

El clima modula los efectos del pastoreo sobre la productividad primaria en ecosistemas áridos de Argentina Introducción A nivel mundial se considera a la desertificación como una pro-blemática ambiental causada por actividades humanas (European Commission's Joint Research Centre 2016) que avanza sobre los ecosistemas áridos, semiáridos y seco subh...

Temporal variations on NDVI predict temporal changes in vegetation cover across Patagonian drylands (Argentina). In drylands, natural vegetation is an important source of livelihood as they provide food, fuel and forage for livestock. In addition to the provision of goods and services, dryland vegetation also plays an important role in many ecologi...

MARAS (Environmental monitoring of arid and semiarid lands) is a vegetation and soil monitoring system in Patagonia, a 700.000 km2 area in southern South America. Installed between 2008-2015 within INTA-Argentina and INIA-Chile national agricultural research institutes, it includes photographs, 500-point intercepts, 50-m canfield lines to detect pa...

Emerging evidence suggests that ecosystem responses to increases in atmospheric aridity, a hallmark of climate change, exhibit multiple thresholds across global drylands. However, it is not clear whether aridity thresholds exist in the relationships between ecosystem functions and remotely sensed indicators (RSIs). Assessing this is important becau...

Forests structure of palo santo (Gonopterodendron sarmientoi): Regional assessment for forest management and conservation in Argentine. Gonopterodendron sarmientoi is a threatened native tree of the Dry Chaco region in South America, adapted to semiarid conditions. However, the relationships among climatic and edaphic conditions and its forest stru...

Extensive sheep production is an important agricultural industry in the Patagonia region of Argentina, where the most important production metric is the effective lambing rate of the sheep (L%). Climate factors can affect sheep production in two ways: (i) directly on the survival of the lamb, and (ii) indirectly by determining the start of the grow...

We present the MaRaS (Environmental Monitoring of arid and Semiarid Regions) dataset, which stores vegetation and soil data of 426 rangeland monitoring plots installed throughout Patagonia, a 624.500 km 2 area of southern argentina and Chile. Data for each monitoring plot includes basic climatic and landscape features, photographs, 500 point interc...

En las últimas décadas, el Gran Chaco Americano, ecorregión forestal de diversidad ambiental y social excepcional –segunda en superficie en Sudamérica, después del Amazonas– se convirtió en una de las tres áreas con mayores tasas de deforestación a escala mundial. En la región del Gran Chaco –que abarca territorios en Argentina, Paraguay, Bolivia y...

En este informe técnico se presentan los resultados de la Segunda Fase del Acuerdo cuyo objetivo es cuantificar indicadores de impacto de avance de la frontera agropecuaria para los distintos escenarios, a partir de la informacion secundaria y de los escenarios al 2028 ( generados en la Primera Fase). Espeficicamente, se trabajo en estimar los impa...

En este informe tecnico se presentan los resultados de la Segunda Fase del Acuerdo cuyo objetivo es cuantificar indicadores de impacto de avance de la frontera agropecuaria para los distintos escenarios, a partir de la informacion secundaria y de los escenarios al 2028( generados en la Primera Fase). Especificamente, se trabajo en estimar los impac...

Thresholds of aridity Increasing aridity due to climate change is expected to affect multiple ecosystem structural and functional attributes in global drylands, which cover ∼45% of the terrestrial globe. Berdugo et al. show that increasing aridity promotes thresholds on the structure and functioning of drylands (see the Perspective by Hirota and Ol...

Multiple ecosystem functions need to be considered simultaneously to manage and protect the several ecosystem services that are essential to people and their environments. Despite this, cost effective, tangible, relatively simple and globally relevant methodologies to monitor in situ soil multifunctionality, that is, the provision of multiple ecosy...

Drylands contain 25% of the world’s soil organic carbon (SOC), which is controlled by many factors, both abiotic and biotic. Thus, understanding how these factors control SOC concentration can help to design more sustainable land-use practices in drylands aiming to foster and preserve SOC storage, something particularly important to fight ongoing g...

La capacidad de una especie de colonizar nuevas zonas geográficas se ha relacionado estrechamente con la plasticidad fenotípica. En estudios previos se ha comparado la plasticidad fenotípica de especies nativas con la de especies congéneras introducidas e invasoras. En este estudio evaluamos la plasticidad fenotípica asociada a factores climáticos...

Water erosion is the main problem of land degradation in Argentina which has substantial implications for nutrient and carbon cycling, land productivity and in turn socioeconomic conditions. In this study, we used an USLE-based modelling approach for: 1) mapping the rate of soil loss due to water erosion for Argentina, and 2) analyze the economic l...

En la primera etapa de la implementación del Sistema Nacional de Monitoreo y Evaluación de la Degradación de Tierras y Desertificación a nivel local se seleccionaron y consensuaron un conjunto mínimo de indicadores que proporcionan información para describir el estado o la calidad del ambiente en los Sitios Piloto y para determinar la línea de base...

The Argentinian Patagonia is a vast area (790,000-km2 ) of southern South America between 36� and 55�S. Almost 90% of the area is arid, semiarid or dry- subhumid (drylands) and covers important and heterogeneous ecological zones that are determined primarily by climatic gradients and a highly complex geomorphology. That gives rise to different soil...

RESUMEN El monitoreo de variables biofísicas de cambio lento de vegetación y suelos se hace a escalas regionales y en períodos que se cuentan en décadas. Requiere colaboración de equipos científicos, de instituciones en diversas biozonas que deben acordar métodos comunes y compartir información georreferenciada. Se presenta en este trabajo la base...

MARAS (Monitoring of Arid and Semiarid Regions) consists of 379 ground monitors in Patagonia, a 624.500 km² semiarid area of southern Argentina and Chile. The objective of this paper was to describe the system and analyze four variables of the initial data base. Floristic composition, diversity and cover were analyzed with intercept lines (500 poin...

El trébol blanco (Trifolium repens) es una Leguminosa perenne que constituye uno de los recursos forrajeros más importante de las zonas templadas y templado frías, brindando un pasto de alta calidad con gran aporte proteico. Se lo utiliza puro o en mezclas forrajeras con gramíneas, y a través de la propagación por estolones y resiembra natural tien...

Significance Securing the stable delivery of ecosystem services related to plant biomass (e.g., food, carbon sequestration, and soil fertility) is a pressing issue under ongoing climate change. Biodiversity increases ecosystem stability, but climate change may alter this positive relationship. We coupled a field survey of plant diversity conducted...

We standardized the Stocks soil organic carbon (SOC) at 0-30 cm depth for 5,073 soil samples. We spatially predicted SOC stock (kg/m2) using regression forest and associated prediction uncertainties using quantile regression forest at 1000 m resolution. Global accuracy based on cross-validation. We obtained a RMSE 2.624 and Rsquared 0.464. Cita: O...

Dryland vegetation is characterized by discrete plant patches that accumulate and capture soil resources under their canopies. These “fertile islands” are major drivers of dryland ecosystem structure and functioning, yet we lack an integrated understanding of the factors controlling their magnitude and variability at the global scale. We conducted...

1. Dryland vegetation is characterized by discrete plant patches that accumulate and capture soil resources under their canopies. These "fertile islands" are major drivers of dryland ecosystem structure and functioning, yet we lack an integrated understanding of the factors controlling their magnitude and variability at the global scale. 2. We cond...

En las últimas décadas Argentina ha transitado un proceso de agriculturización favorecido por la macroeconomía y la adopción de nuevas tecnologías. La expansión de la frontera agropecuaria y la incorporación de tierras al cultivo intensivo de granos y monocultivo de soja afectó a muchas provincias del centro y norte del país. Como resultado de esta...

En las últimas décadas Argentina ha transitado un proceso de agriculturización favorecido por la macroeconomía y la adopción de nuevas tecnologías. La expansión de la frontera agropecuaria y la incorporación de tierras al cultivo intensivo de granos y monocultivo de soja afectó a muchas provincias del centro y norte del país. Como resultado de esta...

En el presente Manual quedan plasmados los avances logrados a través de las últimas dos carteras de proyectos de INTA, enmarcados en el anterior Programa Nacional Ecorregiones y el actual Programa Nacional Suelo. El aporte de los grupos de investigación activos de INTA de diferentes puntos del territorio, en articulación con investigadores de recon...

Informe sobre el estado de suelo, vegetacion, recursos hídricos y fauna en la Patagonia Sur (Santa Cruz y Tierra del Fuego)

Over 65% of drylands are used for grazing of managed livestock. Understanding what drives grazing effects on the structure and functioning of rangelands is critical for achieving their sustainability. We studied a network of 239 sites across Patagonian rangelands (Argentina), which constitute one of the world's largest rangeland area. We aimed to (...

p>Una elevada proporción del territorio argentino corresponde a tierras secas y una tercera parte de éstas se hallan en la Patagonia. Esta región históricamente ha sufrido procesos de deterioro del pastizal. Generalmente, la degradación es atribuida al uso ganadero; sin embargo, el efecto del clima sobre estos sistemas ha sido poco analizado. El ob...

Wind erosion of freshly-deposited volcanic ash causes persistent storms, strongly affecting ecosystems and human activity. Wind erosion of the volcanic ash was measured up to 17 months after the ash deposition, at 7 sites located within the ash-deposition area. The mass flux was measured up to 1.5 m above ground level. Mass transport rates were ove...

The advance of desertification is one of the major environmental problems affecting the Argentinian Patagonia. Overgrazing and recurrent droughts are the main drivers of desertification in this region. According to climate models, the occurrence of drought will increase in the future in drylands worldwide, including those from Patagonia. However, l...

Most of Argentina territory is classified as dry lands, one third of them is located in Patagonia. The grasslands in this region have been historically affected by deterioration. This degradation has been associated to excessive grazing. However, little attention has been paid to the effect of climate on these systems. The aim of this work was to e...

Understanding how drylands respond to ongoing environmental change is extremely important for global sustainability. In this review, we discuss how biotic attributes, climate, grazing pressure, land cover change, and nitrogen deposition affect the functioning of drylands at multiple spatial scales. Our synthesis highlights the importance of biotic...

Introduction: Long-term land monitoring technology is needed to track slow changes in arid lands and evaluate biodiversity, biological invasions, local extinctions and physical or chemical soil variations including carbon storage. Consistent data sets are lacking because researchers and government agencies use multiple techniques to evaluate the sa...

Argentinian Patagonia is a 750,000 km2 semi-arid region. Sheep were introduced there in the late 19th century, peaked at about 20 million head in 1960 and fell sharply thereafter reaching 8 million at present. Decline in productive capacity was blamed on overgrazing or climate change alternatively, but maps in 1998 indicated that 34 % of the region...

Despite the importance of microbial communities for ecosystem services and human welfare, the relationship between microbial diversity and multiple ecosystem functions and services (that is, multifunctionality) at the global scale has yet to be evaluated. Here we use two independent, large-scale databases with contrasting geographic coverage (from...

Supplementary Figures 1-15, Supplementary Table 1 and Supplementary References.

La degradación de tierras es uno de los mayores problemas ambientales de la Argentina. Para gestionar esta problemática se requieren sistemas de monitoreo que permitan detectar su tendencia y proporcionen alertas tempranas. Recientemente se han desarrollado metodologías de monitoreo basadas en índices de imágenes satelitales, siendo NDVI (Normalize...

Significance Climate change is increasing the degree of aridity in drylands, which occupy 41% of Earth’s surface and support 38% of its population. Soil bacteria and fungi are largely responsible for key ecosystem services, including soil fertility and climate regulation, yet their responses to changes in aridity are poorly understood. Using a fiel...

Argentina is one of the countries with a vibrant agricultural sector, which provides both economic development opportunities and environmental challenges. Argentina was selected as a case study due to its rich land degradation data, its diverse agroecological systems, and rapid poverty reduction. The country also represents high human development i...

Aims Climate and human impacts are changing the nitrogen ( N ) inputs and losses in terrestrial ecosystems. However, it is largely unknown how these two major drivers of global change will simultaneously influence the N cycle in drylands, the largest terrestrial biome on the planet. We conducted a global observational study to evaluate how aridity...