Land use change patterns in the Rio de la Plata grasslands: The influence of phytogeographic and political boundaries

VEGA, E; BALDI G.; JOBBAGY, E.G.; PARUELO, J. M.

AGRICULTURE, ECOSYSTEMS AND ENVIRONMENT

ELSEVIER SCIENCE BV

Año: 2009 vol. 134 p. 287 - 292

0167-8809

The Rı ´o de la Plata grasslands (RPG) in South America are one of the largest temperate grasslands regionsof the world. This region plays a key role in international crop production and land use change rates insome areas are among the highest detected nowadays. Our objective was to characterize the spatialheterogeneity of land use change dynamics in the RPG and to relate it with biophysical and politicalboundaries. Based on Landsat imagery we characterized land use changes at two time periods (1986–1990, 2002–2005) and we performed a comparison of markovian models and their properties (stableproportion vector and sensitivity analysis) for each phytogeographic district and country of the region.Temporal transitions between natural and implanted forests (Fo), crops (Cr), and grasslands (Gr) werecalculated in order to buildmatrix probabilisticmodels.We found that 1.2  106ha of grassland surfacehas been transformed into implanted forests and croplands (6% reduction of grasslands, 60% increase ofafforestations, 3% increase of croplands). Transition probability Cr!Cr displayed the largest spatialvariation, followed by the other three transitions linking croplands and grasslands (Cr!Gr, Gr!Gr,Gr!Cr). The less variable transition rate among districts was Cr!Fo.Projections for Argentina and parts of Uruguay suggest that grassland loss would continue in most ofanalyzed territory, whereas in Brazil and parts of Uruguay the projected trend was the opposite,grassland cover would increase. Forested area increment would continue in Uruguay and partially inArgentina,while in Brazil itwould decrease. Considering thewhole region, crop areawouldmaintain theincreasing trends. Transition probabilities for the same phytogeographical district (Northern Campos)differed significantly among the three countries that occupy it, showing the relative importance ofhuman context driving land use change