High Resolution Remote Sensing based Quantification of the Remnant Vegetation Cover in the Araguaia River Basin, Central Brazil

摘要

The Araguaia/Tocantins watershed, with 380,000 km2 drainage basin towards the north portion of Brazil, is one of the major fluvial and phyto-physiognomic system in South America. Its headwaters are situated in the southern portion of the Brazilian savannas (locally known as Cerrado biome), considered one of the world's biodiversity hotspot. Based on 2006 high spatial resolution CCD imagery (20m) of the CBERS II satellite, in this study we mapped the land cover of the high and middle Araguaia basin (120,000 km2). Our results indicate that only 38.5% of the basin are still preserved, while the others 61.5% present some kind of environmental disturbance. In relation to the riparian vegetation, approximately 44% of the area (directly under the influence of hydrograph network) are already unprotected. This information, currently supporting the Araguaia basin hydrological modelling, certainly will be instrumental for the long term conservation of this unique fluvial ecosystem.