Bushfire in Fiherenana and Onilahy Watersheds (SW Madagascar)

For a long time, fires were regarded as harmful by territory managers, especially by foresters, and today in a contextwhere the protection of the environment debated. European regulations criminalizing fires have been transmittedin the “South” countries during colonization: fires were perceived as a threat to vegetation, which could lead todesertification processes. In that respect, in Madagascar, since its colonization in 1895, “the foresters were alarmedby what they saw as wasteful fires”. Back «In the early 19th century, the island’s petty kingdoms were transformedinto a sophisticated modern state, leading to the first recorded state-level regulation of fires». “The state criminal-ized burning due to concern that fire destroys the island’s natural resources and blocks development».However, recent studies on bushfire in West Africa, have changed this depiction. «Thus, above the image of apowerful constraint on the vegetation, scientific progress in ecology and paleoecology allowed gaining a betterunderstanding that ecologically, fire is part of savannah systems. Fire is an element of the system that forms sa-vannah landscapes in intertropical countries. For West Africa, the authors use the term ‘pyroclimax’, climax offire. Generally, in a climax plant vegetation used as reference, unwavering set of operating principles of biophys-ical processes is required, and an exclusion of human influence. However, it has been admitted that ecosystemsneed perturbation in order to remove some elements, to make way for young, regenerating stands. Moreover, wenotice that plant formations are able to adapt to a new permanent factor ecologic. Systems have the capacity tolearn, adapt and self-organize around various factors affected. Human factors can be studied as ecological agents;geosystem determines as a structuring form of natural systems, the anthropisation factor. When the plant vegetationdynamics is ‘artificial nature’, it’s systematically pejorative connotations, whereas heterogenous landscapes gen-erate biodiversity. A number of studies demonstrate the antiquity of anthropogenic actions and the environementsresultant have sometimes acquired a patrimonial character. Fire is an example of an agent dictated by the Manactions. His regular and frequent passage change wood plant vegetation into savannah; filter, pyrophiles woodyspecies and grasses. Identify permanent fire spaces could reveal landscapes organised by anthropogenics actions.To study these phenomena, the south-west of Madagascar is a good case. The Public policies have made the choiceto strictly prohibit fire because it is identify as the principal agent of degradation of climax wood plant vegetation.Our study aim is to take another look at the role of fire in environmental and landscapes dynamics in south-westof Madagascar on many space and time scales. To account quantitative and qualitative evolutions of surface condi-tion, teledetection method using satellite data Modis and Landsat, are cross whith field observations: quantificationof biophysical components and land use, surveys and interviews about uses and their transformations, perceptionsand representations. Contribution will draw on a caracterisation of fire spaces and their evolution since 20 years onthe Fiherenana and Onilahy watershed, on the South-west of Madagascar.