Local environmental information system to assess the risk of desertification: circumSaharan compared situations (Roselt network). (Surveillance environnementale a long terme dans les zones arides et semi-arides (Long-term environmental monitoring in

摘要

Within the context of environmental surveillance and combating desertification in rural drylands, a local environmental information system (Siel, systeme d'information sur l'environnement a l'echelle locale) has been developed and implemented on agropastoral areas in Africa. Using a generic approach and appropriate environmental models, Siel makes it possible to assess the intensity of land degradation risk (past, current and future) relative to local human pressure and biophysical characteristics. This intensity differs in time and space depending on the level and spatial distribution of human and biophysical causes. The aim and characteristics of Siel are described in this article. Evaluation is carried out of its capacity to feed and organize a sustainable device for environmental monitoring and assessment using a network of local observatories, such as Reseau d'observatoires de surveillance ecologique a long terme (Roselt, Long Term Ecological Monitoring Observatories Network), to give useful information (diagnosis and forecasting) for a better dialogue with decision-makers through explorative modelling. To illustrate these points we focus on two selected results (degree of artificialization and index of human pressure on natural vegetation). These results come from four Roselt/OSS (Observatoire du Sahara et du Sahel, Sahara and Sahel Observatory) observatories on which the most relevant progress has been made.