Where did the forest go? Post-deforestation land use dynamics in the Dry Chaco region in Northwestern Argentina

Land transformation is a major component of global change, directly altering habitat composition and spatial configuration, biodiversity, and ecosystem functioning. Over the last decades, the Dry Chaco region in Northwestern Argentina has become one of the regions most heavily transformed worldwide due to the expansion of its agricultural frontier. Many questions remain unanswered about how this process of change occurred. In this study, a parcel-scale database was used to assess the conversion of natural landscapes to different agroecosystems. The magnitude and direction of land use transitions during the last 20 years (2001–2019) were analyzed. Ranching is the main proximate cause of deforestation, accounting for more than 63% of the area cleared annually, though the land use expansion pattern has varied in space and time. Trajectories of land use transitions revealed a spatial arrangement where croplands have displaced ranching to drier areas. The analysis of the intensity of these transitions has shown that the trajectory of post-deforestation land use dynamics has followed a permanent systematic spatio-temporal pattern of change: (1) Dry Forest to Pastures; (2) Pastures to Single Crops; and (3) Single Cropping and Double Cropping systems, where processes of expansion, replacement, and intensification have been identified. Information on transition patterns has allowed us to develop a deeper understanding of land transformation processes, essential in the design of effective land use management strategies.Fil: Mosciaro, María Jesús. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Seghezzo, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; ArgentinaFil: Texeira González, Marcos Alexis. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina. 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; ArgentinaFil: 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. Instituto Nacional de Investigacion Agropecuaria (inia); UruguayFil: Volante, José Norberto. Instituto Nacional de Tecnología Agropecuaria; Argentin

Transformation dynamics of the natural cover in the Dry Chaco ecoregion: A plot level geo-database from 1976 to 2012

The aim of this work was to characterize the spatial and temporal dynamics of the transformation of the natural cover in the Dry Chaco ecoregion from 1976 to 2012. Dry forests in this region have one of the highest deforestation rates in the world. We analyzed 44 Landsat scenes, including part of Argentina, Paraguay and Bolivia. The analysis was based on tracking individual transformed plots of the entire Dry Chaco region for over more than three decades using the same protocol. Until the end of 2012 15.8 million ha of the original habitats of the Chaco were transformed into croplands or pastures. Our study showed that the greater annual rates of transformation were observed in Paraguay, where deforestation increased dramatically in the last decade, reaching values higher than 4.0% in 2010, the highest historical value in the entire region. The size of the transformed plots increased significantly through the studied period both in Argentina and Paraguay, while in Bolivia decreased. At the landscape level, the use of several fragmentation indices showed the disruption of the continuity and connectivity of the original vegetation. The spatially explicit description of the dynamics of transformed areas is an indispensable tool for natural resources management, territorial planning and deforestation impacts assessment. The developed geo-database is available online at http://monitoreodesmonte.com.ar/ for further analyses and use.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; ArgentinaFil: Volante, José Norberto. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Mosciaro, Jesús. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Vale, Laura. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Bustamante, Laura Andrea. Universidad de Buenos Aires. Facultad de Agronomia; ArgentinaFil: 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; Argentin

Expansión agrícola 2000-2010 en Argentina, Bolivia, Paraguay, Uruguay y Chile: Caracterización espacial mediante series temporales de índices de vegetación

 In South America major landscape transformations occurred in the last decades as a consequence of technological improvements and new international market and prices conditions. Grasslands, shrublands and forests were cleared mainly for soybean production for export. Based on remote sensing and GIS techniques, we analyzed MODIS products time series, to detect the major cropping systems in 5 countries of South America. We mapped annual crop areas for the 2000/01 and 2010/growing seasons, we evaluated in a spatially explicit way the changes between these periods, and we developed hypotheses in order to understand the changes. There was a 43% increase in the cropped area between growing seasons, with a heterogeneous spatial distribution. The most notable changes at the regional level were a 66% decreased in the area cover by winter crops as unique practice, and increases of 62% for summer crops and 52% in the double cropped area. The methodology used was adequate to carry out analyzes that combine a large expanse of territory and time.En Sudamérica ocurrieron, en las últimas décadas grandes transformaciones del paisaje. Como consecuencias de mejoras tecnológicas, de nuevas condiciones en el mercado y precios internacionales, tanto pastizales como bosques o arbustales fueron transformados, principalmente para la producción de soja con fines de exportación. A partir de teledetección y Sistemas de Información Geográfica se analizaron series temporales de productos del sensor MODIS, y se detectaron los principales sistemas de cultivos de 5 países de Sudamérica. Se cartografíaron las áreas de cultivos anuales para los ciclos productivos 2000/01 y 2010/11; se evaluó de manera espacialmente explícita los cambios ocurridos entre los mencionados ciclos; y se elaboraron hipótesis a fin de entender dichos procesos de cambios. Se observó un incremento del 43% de la superficie cultivada entre ciclos, con una distribución espacial heterogénea. Los cambios más destacables a nivel regional fueron la disminución del 66% cultivos de invierno como práctica única, y los incrementos del 62% de los cultivos de verano y del 52% en la superficie de doble cultivos. La metodología planteada fue adecuada para llevar a cabo análisis que combinan una gran extensión de territorio y tiempo