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The Río de la Plata Grasslands (RPG) are one of the largest areas of open ecosystems (grasslands, shrublands and savannas) in the world. Historically, these systems have experienced, and continue to experience, an enormous loss of natural habitats. Moreover, their importance has been largely invisible in comparison to forested systems. The remaining area of open ecosystems in the RPG region varies according to the source from 38 to 58% of the original area. Open Ecosystems (OE) are a special case of agroecosystems because they can combine the supply of both provisioning and regulating and supporting ecosystem services (ES). Preserving the provision of ES in these natural habitats depends, in part, on understanding the role of the two main disturbances operating in them: grazing and fire. Although these two disturbances are natural components of OE, both are manipulated by humans. In this paper we reviewed the role played by fire and grazing in the structure and functioning of the RPG starting from the late Pleistocene and Holocene, and summarizing current evidence on the effects of fire and grazing on vegetation, fauna and biogeochemical processes. The evidence indicates that among agricultural activities, direct grazing systems in OE have the lowest environmental footprint. At the same time are the key for habitat preservation and ES supply. Overall, the OE of the RPG still represent a high proportion of the area, are capable of covering 2.5% of the world's population needs of high quality protein and, at the same time, guarding the regulation of key processes. [ABSTRACT FROM AUTHOR]

El aumento de los gases de efecto invernadero (GEI) en la atmósfera es el más comentado —y uno de los más estudiados— de los impactos humanos sobre el planeta por ser motor del cambio climático y de su consecuencia más general y conocida: el calentamiento global. Hay consenso acerca de que estos cambios serán en su mayoría perjudiciales, y por lo tanto también hay muchos análisis sobre cómo evitarlos, o por lo menos atenuarlos. Está claro que las emisiones que resultan en los cambios de composición de GEI provienen de actividades humanas, en parte de la intensificación del uso de la tierra, pero, sobre todo, del uso de combustibles fósiles como carbón, gas y petróleo. Esta conexión entre clima y uso de energía lleva (al igual que la de biodiversidad vs. uso de la tierra) al más general y necesario de los debates ambientales: cómo resolver el aparente conflicto entre desarrollo económico y cuidado del ambiente...

Agriculture and animal production have a great environmental impact, which is steadily growing. In a previous article, we highlighted how biodiversity is vital for agricultural production, emphasizing the role of animal pollinators. Here, we discuss the different dimensions of food security and the key role of our food choices in the cities to drive land use in rural areas and minimize the environmental footprint. Although the environmental impact of agriculture and animal production are commonly justified for the need of greater production to achieve food security, the dimensions of food access and utilization are nowadays of critical importance. For example, worldwide, there are more people with nutritional problems associated with overweight than hunger. In addition, increasing agricultural production in some developed countries does not imply greater food availability in the poor regions where is needed. If the world population eat less meat of animals feed on grains (e.g. feedlots) the environmental impact will be lower, including lower greenhouse gas emission. It is key to identify the origin of the meat that we consume, given that there are other animal production systems with lower environmental impacts. Dietary change to reduce the excess of meat consumption in some sectors of the population can prevent many deaths because of lower obesity, and reduce the incidence of diseases such as coronary heart disease, stroke, and type 2 diabetes (the latter one is increasing all over the world at epidemic rates). The achievement of food security and sustainability relies on many pathways and includes changing the way in which we distribute and utilize the food, using the grains and beans to feed people instead of animals, reducing food waste, and changing our diets. [ABSTRACT FROM AUTHOR]