Oral Session - Human Influences on Landscape and Watershed Processes Chair(s): Lopez, Ricardo ¹, ¹ Landscape Ecology Branch, Las Vegas, NV
Wednesday, March 31, 2004 1:00 PM - 4:20 PM Zeus Room B

Amazon deforestation in the last 18 years in central Rondônia: landscape dynamics assessment and perspectives. Ferraz, Silvio^*,1, Theobald, David², Vettorazzi, Carlos Alberto¹, Ballester, Maria Victoria³, ¹ Escola Superior de Agricultura Luiz de Queiroz - ESALQ, Piracicaba, SP, Brazil² Natural Resource Ecology Laboratory - NREL, Fort Collins, CO, USA³ Centro de Energia Nuclear na Agricultura - CENA, Piracicaba, SP, Brazil

ABSTRACT- In the Brazilian Amazon, central Rondônia is actually one of the most deforested regions, including areas at different stages of degradation. Fine resolution data from satellite imagery are available since 1980′s but, besides many studies related to deforestation assessment, landscape structure dynamics in this region has not been well studied at a broad scale. In this presentation, we will show the assessment of landscape changes between 1984 and 2002 in a watershed located in central Rondônia, Brazil due to a systematic deforestation and pasture introduction since the 1970′s. Bi-annual Landsat TM/ETM+ images were classified, resulting in a time series of land use/cover maps. Landscape changes were evaluated using cross tabulation between years, transition rates, landscape metrics related to size, density, edge, shape, connectivity, configuration and deforested patches distribution related to patch size and spatial proximity of roads and old deforested areas. Transition probability functions were fitted to temporal series in order to predict land use changes for the next years, considering three different scenarios: land use changing at current rates; stopping clear cutting and selective logging; and stopping clear cutting, selective logging and secondary vegetation clearing. Current dynamics can be maintained in the region for 10 years, but present-day land use changes cannot be sustained for more than 15 years. Alternatives for a more sustainable scenario are for the region are discussed, and includes ceasing the deforestation process, implementing the ′Permanent Preservation Area′ along rivers and controlling the dynamics at balanced levels of transition.

KEY WORDS: Amazon, Land use, Landscape Structure, Rondonia, Deforestation