Deforestation and precipitation patterns in the Arid Chaco forests of central Argentina

Abstract

Worldwide land cover changes have caused a net loss of 7 to 11 million km2 of forests in the past 300 years. In subtropical forests of South America crops production has become the main cause of deforestation mainly in the areas with highest precipitation. We now present a map showing the distribution of land cover units in part of the dry Chaco (central Argentina), and we assess the changes in land cover occurred between 1979 and 2010 in three sectors with different precipitation patterns, but with similar access to technology. The classification of Landsat MSS and TM images resulted in reliable maps (overall accuracy of 80 %). Our results showed that the vegetation cover in the area is highly disturbed and that the present status of vegetation cover and the dynamic of land cover changes differ among the three sectors. In the more humid sector land cover changes have been dominated by a replacement of closed forests by crops, while in the driest portion of the study area, forest loss was less pronounced and not related to agriculture. Additionally, we found that significant increases in precipitation have occurred in the three sectors but in the humid one, the increase was highest. The differences observed among the three sectors suggest that precipitation may have effectively played a predominant role in the process of forest conversion to agriculture.