The Patagonian steppe—a massive rain-shadow on the lee side of the southern Andes—is assumed to have evolved ~15–12 Myr as a consequence of the southern Andean uplift. However, fossil evidence supporting this assumption is limited. Here we quantitatively estimate climatic conditions and plant richness for the interval ~10–6 Myr based on the study and bioclimatic analysis of terrestrially derived spore–pollen assemblages preserved in well-constrained Patagonian marine deposits.

We focus on Shannon Entropy (SE) for the characterization of polarimetric Synthetic Aperture Radar (PolSAR) images. This approach analyzes the information contribution made by individual pixels to the whole image for assessment of land degradation in the information content of ALOS PALSAR images. Additionally, the performance of other polarization parameters, and polarization decomposition is illustrated and discussed.

Se realizó un estudio comparativo entre un sistema de producción de cereales de secano de conservación y otro tradicional, con el fin de evaluar los efectos a largo plazo de diferentes prácticas culturales en el combate a la desertificación. El sistema de conservación ha recurrido a siembras directas a lo largo de 10 años consecutivos, mientras que el tradicional al laboreo del suelo. En un suelo tipo Chromic Vertisol en Portugal se evaluó a partir de imágenes en 2D, la continuidad del espacio poroso y, por tanto, la dinámica del agua del suelo.

El artículo tiene el objetivo de exponer la situación socioambiental actual y su vínculo con las prácticas sociales de producción propias del sistema productivo ovino extensivo en Santa Cruz, Patagonia austral, Argentina. El emergente más significativo que se puede apreciar actualmente es la desertificación y su impacto en los diferentes niveles del sistema socioproductivo.

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This paper reports on a workshop held in Ethiopia in 2004, targeting stakeholders involved in implementing Ethiopia’s National Action Plan (NAP) for the United Nations Convention to Combat Desertification (UNCCD). The workshop was based on international, national and regional experiences, principles and practices related to dryland management and combating desertification to the development of community driven processes.

This report presents a panorama of the environmental status of the world’s deserts: their location and extent, uniqueness and vulnerability, biodiversity and natural resources. The report provides a balanced picture of deserts as ecosystems which form a special part of the world’s natural and cultural heritage, and not simply as land that is the end result of the process of desertification.The Global Deserts Outlook is the first thematic assessment report in the Global Environment Outlook (GEO) series of the United Nations Environment Programme (UNEP).

It is clear from the failure of our efforts in many countries to halt the desertification process - deserts are now advancing at a rate of nearly 15,000,000 acres a year worldwide (Worrall 1984) (that something was missing in our knowledge of the problem). Four discoveries have been made that enabled us to design a simple holistic model to manage resources successfully in a sustained and economic manner.