Land use and land cover dynamics in South American temperate grasslands

BALDI, GERMÁN; PARUELO, JOSÉ M.

Ecology and Society

Año: 2008 vol. 13 p. 6 - 26

1708-3087

Agriculture activities in the South American temperate grasslands (the Rio de la Plata grasslands biogeographical region) experienced -during the last 15-18 years- important changes due to technological improvements and new national and international market conditions. In this study, we characterized changes in landscape structure between two periods (1985-1989 and 2002-2004) for eight pilot areas distributed across the main regional environmental gradients. These areas incorporated approximately a 35% of the 750,000 km2 of the system. Our approach included the generation of land use - land cover maps, the analysis of landscape metrics and the computation of annual transition probabilities between land cover types. All the information was summarized in 3,383 cells of 8x8 km. During the study period, the area covered by grasslands decreased from 67.4% to 61.4%. This retraction was associated to an increase in the annual crops area (mainly soybean, sunflower, wheat, maize). In some of the subunits of the Rio de la Plata grasslands, i.e the Flat Inland Pampa, the grassland/cropland transition showed a high probability (pbG→C = 3.7x10-2), while there were others, i.e. the Flooding Pampa, where this probability was low (pbG→C = 6.7 x10-3). Our study not only describes the magnitude, direction and spatial distribution of land use - land covers changes but also provides the basis to develop spatially-explicit scenarios land cover changes.