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The relationships among social capital (SC) and collective actions (CA) for nature conservation and management were analyzed across five case studies characterised by specific land-use dynamics in the South American continent. Data on SC and CA were obtained through a semi-structured questionnaire to groups of selected social actors. Multivariate statistical analysis was used to identify SC components and to evaluate SC across actors and cases. The results reaffirm that: i) the multidimensional nature and complexity of SC; ii) Higher levels of SC are related to higher levels of CA; iii) social actors with developed internal and external SC can better counter adverse conditions through CA compared to actors who only have one type of SC; iv) vulnerable social actors do not necessarily have a higher SC or engage in more CA, despite their higher dependence on natural resources; v) those who hold more power or influence in the territory, have higher levels of SC and CA; vi) vulnerable actors often carry out civil/community, economic and judicial actions, while dominant and structuring actors carry out more educational/technical and political actions. Therefore, the formation and maintenance of SC of the most vulnerable actors and those who support them must be a priority for political action, in order to counteract the asymmetric power relations that lead to the exclusion and marginalization of many rural actors.

We thank R Romero-Calcerrada and J M Requena-Mullor for helpful discussions, and three anonymous reviewers for their constructive suggestions to improve this paper. We also thank the Spanish Ministry of Economy and Business (Project CGL2014-61610-EXP) for the financial support, as well as the Spanish Ministry of Education for the FPU Predoctoral Fellowship of MPR (FPU14/06782) and MTTG (16/02214). MPR gratefully acknowledges funding from Universidad de Almeria for a research stay at the Laboratory of Regional Analysis and Remote Sensing (LART) of University of Buenos Aires to develop this study. This research was done within the LTSER Platforms of the Arid Iberian South East-Spain (LTER_EU_ES_027) and Sierra Nevada/Granada (ES- SNE)-Spain (LTER_EU_ES_010), and contributes to the Global Land Programme., The spatial mapping of social-ecological system (SES) archetypes constitutes a fundamental tool to operationalize the SES concept in empirical research. Approaches to detect, map, and characterize SES archetypes have evolved over the last decade towards more integrative and comparable perspectives guided by SES conceptual frameworks and reference lists of variables. However, hardly any studies have investigated how to empirically identify the most relevant set of indicators to map the diversity of SESs. In this study, we propose a data-driven methodological routine based on multivariate statistical analysis to identify the most relevant indicators for mapping and characterizing SES archetypes in a particular region. Taking Andalusia (Spain) as a case study, we applied this methodological routine to 86 indicators representing multiple variables and dimensions of the SES. Additionally, we assessed how the empirical relevance of these indicators contributes to previous expert and empirical knowledge on key variables for characterizing SESs. We identified 29 key indicators that allowed us to map 15 SES archetypes encompassing natural, mosaic, agricultural, and urban systems, which uncovered contrasting land sharing and land sparing patterns throughout the territory. We found synergies but also disagreements between empirical and expert knowledge on the relevance of variables: agreement on their widespread relevance (32.7% of the variables, e.g. crop and livestock production, net primary productivity, population density); relevance conditioned by the context or the scale (16.3%, e.g. land protection, educational level); lack of agreement (20.4%, e.g. economic level, land tenure); need of further assessments due to the lack of expert or empirical knowledge (30.6%). Overall, our data-driven approach can contribute to more objective selection of relevant indicators for SES mapping, which may help to produce comparable and generalizable empirical knowledge on key variables for characterizing SESs, as well as to derive more representative descriptions and causal factor configurations in SES archetype analysis., Spanish Government CGL2014-61610-EXP FPU14/06782 16/02214, Universidad de Almeria, LTSER Platforms of the Arid Iberian South East-Spain LTER_EU_ES_027, Sierra Nevada/Granada (ES- SNE)-Spain LTER_EU_ES_010

We report state-and-transition models for Uruguayan grasslands built on a methodological approach that objectively defined states/phases associated, a priori, with rangeland management. Such approach was based on randomly sampled areas corresponding to mapped grassland communities. Each sampled area matched a MODIS pixel. Vegetation structural indicators were recorded in every pixel. After a multivariate analysis, field observations were grouped according to similarities in terms of structure, and different “states” and “phases” were identified. Ecosystem functioning and the supply of regulating ecosystem services were estimated for each grassland state/phase using the normalized difference vegetation index derived from the MODIS sensor. Finally, workshops were held in order to detect local stakeholders’ perceptions and discuss the management practices to promote the desired transitions among phases. Results were presented for two vegetation units of the Basaltic “Cuesta” region. The “inductive approach” applied led to not only the description of “states” but also the identification of more subtle changes in vegetation ("phases"). Our approach minimized biases due to personal experience, as well as differences derived from using different observation protocols. The two vegetation units presented an internal heterogeneity associated with changes in basal stratum height, total cover, stratification, frequency of decreasing species due to grazing, and proportion of plant life forms. The ecosystem functioning descriptors of each phase responded to extreme climatic events differently. On the basis of stakeholder’s opinions and experiences, stocking rate, sheep/cattle ratio, and grazing method were the main management practices promoting the transition among phases.

Livestock grazing has degraded many arid and semi‐arid rangelands around the world, and the drier climate predicted by climate change scenarios may amplify these effects and even lead to catastrophic vegetation shifts. We assess the long‐term effects (1900–2100) of grazing and rainfall on various aspects of vegetation structure including the grass‐shrub balance, the maintenance of spatial vegetation patterns, and the decline or recovery of palatable grasses (e.g. Poa ligularis) on a cover and/or density basis. We used the eco‐hydrological and individual‐based simulation model DINVEG for this purpose, which describes the spatiotemporal dynamics of Patagonian grass‐shrub steppes based on six decades of field research (1955–2018). Rainfall and grazing affected the simulated vegetation structure in different ways. Total plant cover was mostly influenced by rainfall, but the cover of palatable grasses was mostly influenced by stocking rate. Dry conditions and low stocking rates (122 mm/year and 0.2 sheep/ha). High stocking rates and/or drier conditions caused only gradual shifts in spatial vegetation patterns, but maintained the observed positive association for grasses around shrubs. In contrast, shrub encroachment was associated with repulsion between grasses and shrubs and the formation of shrub clusters into a matrix of scattered less palatable grasses. Plant compositional changes occurred through grass species replacement (e.g. P. ligularis is replaced by Pappostipa humilis) and the associated hysteresis effect of palatable grass species: model simulations suggest that 2–3 decades of heavy and year‐long continuous grazing can drive palatable grasses to close to extinction, whereas natural recovery of degraded steppes may take 100 years or longer. Synthesis and applications. Desertification and climate change challenge grazing management in semi‐arid rangelands, especially in already degraded ecosystems. Management that alternates between years of grazing and resting was effective to maintain the cover of palatable grasses, but this allowed for only very slow recovery of degraded steppes. While drier climate and grazing may not change the overall spatial patterns of vegetation, our results are rather pessimistic regarding the short‐term recovery of palatable grasses. This will require increasing complexity in ecosystem restoration efforts, combined with interventions such as sowing, watering, reseeding or major changes in land use.

The temporal trend of aboveground net primary production (ANPP) is frequently used to estimate the effect of humans on ecosystems. In water-limited ecosystems, like most grazing areas in the world, the effect of humans act upon ANPP in combination with environmental variations. Our main objective was to quantify long-term (1981-2012) changes of ANPP and discriminate the causes of these changes between environmental and human at a subcontinental scale, across vast areas of Patagonia. We estimated ANPP through a radiative model based on remote sensing data. Then, we evaluated the relation between ANPP and environmental interannual variations of two hierarchically related factors: El Nino Southern Oscillation (ENSO) through the Southern Oscillation Index (SOI), and precipitation. We described the effect of humans through the shape of the temporal trends of the residuals (RESTREND) of the environmental model and quantified human relative impact through the RESTREND: ANPP trend ratio. ANPP interannual variation was significantly explained by ENSO (through SOI) and precipitation in 65% of the study area. The SOI had a positive association with annual precipitation. The association between ANPP and annual precipitation was positive. RESTREND analysis was statistically significant in 92% of the area where the tested environmental model worked, representing 60% of the study area, and it was mostly negative. However, its magnitude, revealed through the RESTREND: ANPP trend ratio, was relatively mild. Our analysis revealed that most of ANPP trends were associated with climate and that even when human density is low, its incidence seems to be mainly negative.

Deforestation control is one of the major challenges worldwide. The aim of this study was to analyse deforestation under the Forest Law in the Argentine Dry Chaco ecoregion a decade after its enactment and to assess compliance with forest protection standards in this region. For this purpose, we overlapped the provincial land zoning maps with an annual plot level deforestation database and, for some provinces, with the rural cadastral cartography. Deforestation exceeding the values allowed by the Forest Law and the provincial zonings during this period totalized 722,782 ha (28% of the total deforested area in this period), of which 59,732 ha were deforested in high conservation value areas, 644,396 ha in medium conservation value areas and 18,654 ha in low conservation value areas. While Santiago del Estero was the province with the highest deforested area in medium conservation value areas, Córdoba was the province with the highest deforested area in high conservation value areas. Our results are an important step towards identifying discrepancies between the legal objectives and the observed results and represent an input to think about solutions to improve the environmental governance of the region. © 2021 Elsevier B.V.

South America is experiencing profound land use and land cover changes. Their consequences on the Ecosystem Services (ES) supply and human well-being need to be diagnosed and monitored in order to support informed decisions both in management and territorial planning. The ES concept provides a key framework to evaluate human impacts on nature. The use of spatially explicit indicators able to characterize ES supply can turn operative the ES framework, enabling for sustainability assessment. The Ecosystem Services Supply Index (ESSI) is a synoptic indicator that estimates and maps supporting and regulating ES related to water and carbon dynamics from data provided by remote sensors of free access and wide spatial coverage. The ESSI merges two attributes of the Normalized Difference Vegetation Index (NDVI) annual dynamics: the annual average (NDVIMEAN, a proxy of total C gains) and the intra-annual coefficient of variation (NDVICV, an indicator of seasonality). In this article we proposed two objectives: 1) to describe the conceptual foundation of the ESSI and to gather the empirical support that shows its ability to explain the spatial-temporal variation in different ES, and to present a new case of empirical ESSI assessment, and 2) to synthesize the contribution of the ESSI in socio ecosystem diagnosis, monitoring and territorial planning stages in 8 existing cases of application. We also explored the links to the decision-making process by diverse stakeholders including local research and development institutions, NGOs and government agents. Cases corresponded to a wide range of situations from humid and dry forests to grasslands, and from local to subcontinental scales in southern South America. We found that ESSI was successfully applied for diagnosis, planning and monitoring processes which helped to better define interventions in management decisions and also to empower the most vulnerable stakeholders under territorial and environmental conflicts.

Agricultural expansion is altering the provision of ecosystem services and seriously affecting the well-being of the indigenous communities still living in forests. In this paper, we evaluate the impact of forest loss and degradation on the indigenous forest dependent communities of Eastern Salta, Argentina, between 2001 and 2015. First, we identified the demand area of ten final ecosystem services for 202 indigenous communities using participatory mapping data. Second, we calculated the remaining usage area using a deforestation geodatabase based on Landsat images. Third, we analyzed the significance of trends in forest productivity processing vegetation spectral indices from MODIS products. By last, we detected changes in the growing season length by evaluating monthly trends in spectral indices. Our results show a reduction of 21% in the area used by indigenous communities for capturing final ecosystem services, and significant negative trends in forest productivity for the demand area of 64% of the communities, indicating that the area of use is not only being reduced, but also remnant forest area is being degraded and the growing season is being shortened. These aspects indicate an important loss in the provision of ecosystem services that deeply affects the wellbeing of indigenous communities.

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

Land use changes are occurring with unprecedented magnitude and intensity, imposing global impacts on ecosystem services (ES) and biodiversity. While the impacts of land use changes are increasingly recognized, understanding how landscape connectivity is related to ecosystem functioning is lacking. In the Argentinian Dry Chaco, deforestation increased forest fragmentation but strips of native forest (linear remnants) were usually left after clearings. Although the number of ecological studies on forest strips has increased, their contribution to forest connectivity and functioning has not been assessed. We evaluated the contribution of forest strips to forest connectivity and estimated its effect on forests' functioning considering low, moderate, and high species' dispersal abilities in our estimation. The effects of forest strip connectivity contribution to the forests' Ecosystem Services Supply Index (Forests' ESSI) was also analyzed. Forest strips contributed on average 6% and up to 40% to forest connectivity for moderate dispersal abilities, while low and high dispersals presented low values in almost all cases. The connectivity contribution was highest (between 15 and 40%) and variable for moderate dispersal abilities in landscapes with between 25 and 35% of forest cover. High connectivity contribution was generally achieved for low and moderate dispersals when forest strips conformed a network among forest patches. Forest strip connectivity significantly increased the forests' ESSI (between 1.3 and 2.4% per unit of connectivity contribution) and its effect was higher in comparison to forest amount and fragmentation. This study provides insights for planning the location of forest strips and forest remnants in agricultural landscapes, thus increasing forest connectivity for enhancing ecosystem functioning.

The lack of an organizing conceptual framework to address ecosystem changes reduces our capacity to distinguish biophysical from direct human impacts on grassland dynamics. This is particularly important for subhumid temperate grasslands, one of the world’s most threatened biomes. We identified and mapped 4 functional syndromes of grassland change at the wettest end of its worldwide distribution, the Campos in Uruguay. Syndromes were defined by differences in precipitation use efficiency (PUE, ANPP/precipitation), and in precipitation marginal response (PMR, slope of the linear regression between ANPP and precipitation) between two periods (1981–1995 and 2001–2011). Temporal trends in aboveground net primary production (ANPP, obtained by splicing two sources of NDVI, LTDR and MOD13Q1) were also characterized. To rule out the effect of precipitation we analyzed temporal trends of the residuals from the relationship between ANPP and annual precipitation (RESTRENDS). Functional syndromes associated with increases in seasonality or in the abundance of annual vegetation (ΔPMR > 0, ΔPUE 5000 km2) were the most abundant. ANPP trends were significantly negative in 3.7% of the area (2475 km2) and only positive in 0.3%. However, RESTRENDS were significant in 11% of the area (>7700 km2), and mostly negative (in ∼7200 km2). Most of these negative trends and residual trends were associated to seasonality increase and vegetation loss syndromes. These patterns were consistent with observed changes in the region. We highlight that this conceptual framework is suitable for describing patterns of change and potential causes. Moreover, it provides policymakers with a novel tool to guide management and conservation policies, pointing to sites where intervention (i.e. conservation, restoration) is needed.

Latin America, and particularly, the Rio de la Plata Grasslands (RPG), are one of the regions with the highest rates of land use change worldwide. These changes drastically alter ecosystems energy flows, affecting biodiversity, atmospheric composition, and the ecosystem capacity to provide services. In this work we evaluated the impact of these changes on Net Primary Production (NPP), one of the most important and integrative ecosystem attributes, through the calculation of Human Appropriation of NPP (HANPP), a very complete indicator of human impact on ecosystems. Our results provide a comprehensive and fine grained description of HANPP patterns over an entire biogeographycal region for two periods that encompass a strong agricultural intensification process. We used medium resolution land use maps and NPP estimates from sub-national level agricultural statistics and remotely sensed data modeling. Results show that the human impact on the energy flow in RPG ecosystems reached very high levels compared to other regions of the world. The average appropriation of was 42% of the potential vegetation NPP in 2001/2002 and it increased 4.5% during the last years due to an intense land use changes. Most of the HANPP was explained by harvest rather than by land use changes, mainly in the last period due to crops yield increase and the expansion of double crop system as a common agronomic practice. High HANPP values found were associated to a set of environmental impacts that affect ecosystems sustainability and their ability to provide ecosystem services.

La percepción de que las estrategias que llevan adelante los gobiernos para asegurar la conservación de la biodiversidad y la provisión de servicios ecosistémicos son ineficaces o insuficientes dieron lugar a nuevas alternativas basadas en instrumentos económicos, impulsadas tanto por actores privados (en particular, ONG) como por los mismos gobiernos. Algunos de estos instrumentos buscan internalizar una externalidad positiva al compensar al proveedor del servicio ecosistémico (SE) por los costos en los que incurre al asegurar su provisión. Actualmente, no existe consenso respecto a las ventajas y desventajas de los instrumentos económicos basados en mercados para la conservación (IEBMC), y la mayor parte de este debate ha ocurrido en el plano teórico. Esto hace imprescindible la necesidad de evaluaciones empíricas. El objetivo de este trabajo fue caracterizar 60 proyectos que incluyeran IEBMC en Latinoamérica en cuanto a su efectividad y equidad social, y la relación de éstas con diversas características económicas, políticas e institucionales de los proyectos. A través de ello buscamos explorar si existen sinergias o compromisos entre objetivos ambientales y sociales, y si hay características que determinan que los proyectos sean más exitosos respecto a estos objetivos. El 43% de los proyectos resultaron efectivos en cuanto a sus objetivos ambientales, mientras que ~17% resultaron equitativos. La relación entre efectividad y equidad no resultó estadísticamente significativa, lo que indica que no hay sinergias ni compromisos entre ellas. En general, tanto la efectividad como la equidad no se asociaron de manera significativa con ninguna de las características relevadas. Esto implica que no hay un único arreglo institucional que asegure el buen desempeño de este tipo de mecanismos. Nuestros resultados sugieren que no existen evidencias suficientes de que los IEBMC sean ventajosos para conservar la biodiversidad y los SE de forma efectiva y socialmente equitativa en Latinoamérica. The perception that the strategies carried out by governments for biodiversity conservation and ecosystem services provision are ineffective or insufficient, led to diverse new alternatives based on economic instruments driven by both private actors (fundamentally NGO’s) and governments. Some of these instruments seek to internalize a positive externality by compensating the ecosystem service (ES) provider for the costs incurred in ensuring its provision. Currently, there is no consensus on the strengths and weaknesses of the market based economic instruments for nature conservation (MBEINC), and most of this debate has taken place in a theoretical arena. Thus, the need for empirical assessment is essential. The objective of this work was to characterize 60 projects, which included MBEINC, in Latin America in terms of their effectiveness and social equity, and the relation of them with diverse economic, political and institutional characteristics. Through this we seek to explore whether there are synergies or tradeoffs between environmental and social objectives, and determine which characteristics determine that the projects are more successful with respect to these objectives. 43% of the projects were effective in terms of their environmental objectives, while approximately 17% were socially equitable. The relationship between effectiveness and social equity was not statistically significant, indicating that there are no synergies or tradeoffs between them. In general, both effectiveness and social equity were not significantly associated with any of the characteristics surveyed. This implies that there is no single institutional arrangement to ensure the positive outcomes of this type of mechanism. Our results suggest that there is insufficient evidence of the advantages of MBEINC to conserve biodiversity and ES in an effective and socially equitable manner in Latin America.

Temperate subhumid grasslands extend in the eastern part of South America. This region represents one of the most diverse, largest and less transformed grassland areas in the world. The grasslands occupy the vast and continuous plains of central-eastern Argentina, Uruguay and southern Brazil that surround the Rio de la Plata estuary. For this reason, they are referred to as the Rio de la Plata grasslands. These grasslands, despite its apparent physiognomic homogeneity, hold high diversity of species, having grasses as the dominant life form except for few scattered shrubs and trees, and show a year-round photosynthetic activity. In this article we describe structural and functional characteristics of the vegetation of the Rio de la Plata grasslands. We give an overview on biogeography, ecosystem functioning and services, human appropriation of primary production, disturbances, land use change, biological invasions and conservation status.

Fil: Baeza, Santiago. Universidad de la República. Facultad de Agronomía. Departamento de Sistemas Ambientales. Montevideo, Uruguay. Fil: Paruelo, José María. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Laboratorio de Análisis Regional y Teledetección (LART) Buenos Aires, Argentina. Latin America in general and the Rio de la Plata Grasslands (RPG) in particular, are one of the regions in the world with the highest rates of change in land use/land cover (LULC) in recent times. Despite the magnitude of this change process, LULC descriptions in the RPG are far from being complete, even more those that evaluate LULC change through time. In this work we described LULC and its changes over time for the first 14 years of the 21st century and for the entire grassland biome of the Rio de la Plata, one of the most extensive grassland regions in the world. We performed simple but exhaustive classifications at regional level based on vegetation phenology, using extensive LULC field database, time series of MODIS NDVI satellite images and decision trees classifiers, generating an annual map for all RPG. The used technique achieved very good levels of accuracy at the regional (94.3%–95.5%) and sub-regional (78.2%–97.6%) scales, with commission and omission errors generally low (Min = 0.6, Max = 10.3, Median = 5.7, and Min = 0, Max = 41.8, Median = 6.8 for regional and sub regional classification respectively) and evenly distributed, but fails when LULC classifications are generated in years when the climate is very dierent from those used to generate spectral signatures and train decision trees, or when the NDVI time series accumulates large volumes of lost data. Our results show that the RPG are immersed in a strong process of land use change, mainly due to the advance of the agricultural frontier and at the expense of loss of grassland areas. The agricultural area increased 23% in the analyzed period, adding over than 50,000 Km2 of new crops. Most agricultural expansion, and therefore the greatest losses of grassland, concentrates on both sides of Uruguay river (Mesopotamic Pampa and the western portion of Southern and Northern Campos) and the western portion of Inland Pampa. The generated maps open the door for more detailed and spatially explicit modeling of many important aspects of ecosystem functioning, for quantification in the provision of ecosystem services and for more efficient management of natural resources. grafs., tbls., mapas

The intensification of agricultural production has become a topic of intense debate in academic and socio-political media worldwide. In southern South America agricultural intensification operates in two ways. On one hand, through the rThe intensification of agricultural production has become a topic of intense debate in academic and socio-political media worldwide. In southern South America agricultural intensification operates in two ways. On one hand, through the replacement of natural covers (forests and native grasslands dedicated, in general, to livestock) by annual or perennial crops (in general soybeans or pine and eucalyptus plantations). On the other hand, intensification is associated with the increasing input use and/or the implementation of management practices that increase production per area unit.eplacement of natural covers (forests and native grasslands dedicated, in general, to livestock) by annual or perennial crops (in general soybeans or pine and eucalyptus plantations). On the other hand, intensification is associated with the increasing input use and/or the implementation of management practices that increase production per area unit. Fil: Paruelo, José. 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

El pastoreo es una perturbación importante en los ecosistemas de pastizales, ya que altera su estructura y su funcionamiento. Las micorrizas arbusculares son interacciones cosmopolitas de estos ecosistemas, y se destacan por su incidencia elevada en las gramíneas. Las micorrizas muestran respuestas diversas y contradictorias al pastoreo (ser beneficiadas, perjudicadas o no ser afectadas). Una posible hipótesis es que cada componente del pastoreo (defoliación selectiva, deyecciones y pisoteo) diferiría en su importancia relativa al afectar la micorrización. El objetivo del presente trabajo fue evaluar el efecto del pisoteo, la selectividad y la deposición de orina sobre las micorrizas de Paspalum dilatatum, una de las principales gramíneas nativas de los pastizales del Río de la Plata. En un experimento manipulativo en el que se simularon los distintos componentes del pastoreo se evaluó el efecto de cada componente de forma aislada y en interacción sobre la colonización micorrícica total, así como de las diferentes estructuras fúngicas (arbúsculos, ovillos y vesículas). La colonización micorrícica total y por arbúsculos no fueron afectadas por ninguno de los componentes del pastoreo, mientras que sí se observaron efectos sobre las demás estructuras fúngicas. La colonización por ovillos (una de las estructuras que participan en el intercambio con el hospedante) fue afectada de forma positiva por la selectividad y negativa por el agregado de nitrógeno (simulando la deposición de orina); estas estructuras también fueron afectadas por las interacciones selectividad x pisoteo y pisoteo x agregado de N. El pisoteo afectó negativamente la presencia de vesículas, lo que podría deberse, en parte, al daño mecánico que esta perturbación causa tanto sobre las raíces como sobre el micelio extra-radical. El estudio de los componentes del pastoreo de manera aislada mostró que cada uno ejerce efectos diferentes sobre las micorrizas, y su importancia relativa podría afectar el resultado global del pastoreo sobre esta interacción. Grazing by large herbivores represents an important disturbance in natural grasslands, affecting its structure and function. Arbuscular mycorrhizas (AM) are cosmopolitan interactions in these ecosystems, particularly in grasses, main constituent of this ecosystem. Mycorrhizas show contradictory responses to grazing (AM colonization has been positively, negatively and not affected by grazing). We hypothesized that each grazing component (selective defoliation, trampling and urine deposition) would differentially affect mycorrhizal colonization, and this could explain the high variability in AM responses. Our objective was to assess the effect of trampling, selective defoliation and nitrogen (N) addition on AM colonization of one of the most important grasses in Río de la Plata grasslands: Paspalum dilatatum. Grazing components were simulated in a manipulative experiment where we evaluated their individual and combined effects on total AM colonization and the occurrence of different fungal structures (arbuscules, coils and vesicles). No grazing component affected total AM colonization and arbuscules, while other fungi structures were affected by different treatments. Coil colonization (one of the nutrient interchange structures between the symbionts) was positively affected by selective defoliation and it was negatively affected by N addition; these structures were also affected by the combined effect between selectivity x trampling and by trampling x N addition. Vesicle colonization was negatively affected by trampling, maybe because of mechanical damage to roots and to extraradical mycelium caused by this disturb. The study of the individual grazing components showed that each one caused different effects on mycorrhizal interaction and their relative influence could affect the overall grazing effect on this interaction.

Sustainability science recognizes the importance of the integrated assessment of the ecological and social systems in land-use planning. However, most studies so far have been conceptual rather than empirical. We developed a framework to characterize the social-ecological systems heterogeneity according to its functioning through the identification of social–ecological functional types (SEFT). The SEFT framework builds on the plant, ecosystem and agent functional type approaches, taking a step forward to integrate the dimensions of social–ecological systems into an operational product to characterize administrative units in a hierarchical way. To illustrate this novel framework, we described the heterogeneity of SEFT in the Argentine Chaco by clustering administrative entities. This area is a global deforestation hotspot and has diverse social actors that harness ecosystem services in multiple, and sometimes contrasting and conflictive, ways which determines an urgent need for land-use planning. We combined data from national census and remote sensing to identify SEFT by clustering census tracts based on 17 input variables that integrate key human, ecological and interaction processes across landscapes. We identified three classes and eight subclasses of SEFT. Ecological variables defined the first level of heterogeneity (classes), while human variables and the variables of interactions between the human and ecological components defined a second level of heterogeneity (subclasses). The degree of anthropization and mean annual productivity were important variables to explain the first two axes in the ordination (32% of the total variance). This framework offers a conceptually novel and comprehensive approach to understand the spatial heterogeneity of social–ecological systems functioning, which could play a pivotal role to support conservation or land-use planning in rural areas. Fil: Vallejos, María. 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 Buenos Aires. Facultad de Agronomía; Argentina Fil: Aguiar, Sebastián. 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 Buenos Aires. Facultad de Agronomía; Argentina 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 Fil: Mastrangelo, Matias Enrique. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gallego, Federico. Universidad de la República; Uruguay Fil: Pacheco Romero, Manuel. Universidad de Almería; España Fil: Alcaraz Segura, Domingo. Universidad de Almería; España. Universidad de Granada; España Fil: Paruelo, José. 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 Buenos Aires. Facultad de Agronomía; Argentina. Universidad de la República; Uruguay

We present an approach to generate estimates and to map Ecosystem Services (ES) related to C and water dynamics (Soil Carbon sequestration, evapotranspiration and groundwater recharge) and biodiversity (Avian Richness) from remotely sensed data in two ecoregions of South America: the Semiarid Chaco woodlands and the Rio de la Plata grasslands. Two attributes of the seasonal dynamics of the Normalized Difference Vegetation Index (NDVI); the annual mean (NDVI mean), an indicator of light interception and hence of total C gains and the intra-annual Coefficient of Variation of the NDVI (NDVI CV), a descriptor of seasonality; were combined into an ES provision index (ESPI = NDVImean * (1-NDVICV)). The proportion of the variance in ES provision explained by the ESPI varied from 0.484 for avian richness up to 0.662 for C sequestration. A relatively large proportion of the studied area presented changes in ES provision. A 32,4% of the Semiarid Chaco and the Rio de la Plata grasslands presented significant (p < 0.01) trends. Most of the trends (30.2%) were negative, showing a decrease in ESPI. An index like the one proposed here can be used as an aggregated indicator of the status and/or trends of ES supply at large spatial scales (subcontinental in our case). Fil: Paruelo, José. 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. Facultad de Ciencias; Uruguay Fil: Texeira González, Marcos Alexis. 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 Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina Fil: Staiano, Luciana. 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 Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina Fil: Mastrangelo, Matias Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Amdan, María Laura. 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 Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina Fil: Gallego, Federico. Universidad de la República. Facultad de Ciencias; Uruguay