Vincent Dubreuil

Combining socio-economic development with environmental governance in the Brazilian Amazon: The Mato Grosso agricultural frontier at a tipping point

Agricultural landscapes of the southern Brazilian Amazon are the result of 80 years of governmental policies to install a powerful agricultural sector. Yet, this rapid expansion raised important environmental considerations especially with regard to deforestation. The agricultural frontier is thus now facing a huge challenge: to combine socioeconomic development with environmental conservation in the context of frontier expansion. Based on a conceptual model of the agricultural frontier, we review historical changes in environmental and development policies in the Brazilian state of Mato Grosso and emphasize their ambivalent trend to both encourage and control the progress of the frontier. We then extend this model with an integration stage where environmental governance and economic development evolve from competing to complementary concepts. At this stage, the efforts to slow down deforestation are accompanied with programs to promote new agricultural practices and support industrialization. Finally, we put into perspective this recent evolution with regard to the underlying reasons for changing the agricultural model, thus considering the agricultural frontier to be at a tipping point where first positive results need to be confirmed in spite of an unstable economic and political situation.

MONITORAMENTO DE SECAS NA BRETANHA reconstituição histórica e abordagem por teledetecção

Brittany, as many French territories, experiences sometimes drought issues which can vary in intensity and duration. The aim of this study is to determine the impacts of droughts on soil water resources since the early XIXth century. Thus, a soil water balance suited to regional scales was used and applied to different cities of Brittany and surroundings such as Rennes, Plougonvelin and Nantes. The evaporation deÞ ciency obtained at a monthly scale revealed droughts intensity and inter-annual variability. At a yearly scale a positive tendency of the deÞ ciency was noticed. At a monthly scale the inter-annual variability was clearly shown and revealed a 4-year period rhythm with soils lacking of water for one summer month. Finally, we used the NDVI calculated from SPOT-Vegetation images for monitoring the spatial extent of drought in Brittany. For 2003 (the last great drought observed in western France), we found a good relationship between the NDVI and the evapotranspiration but bidirectional res ectance effects, angular values and compositing’s procedures may also have a great impact on observed values of NDVI.