Modelling regional land change scenarios to assess land abandonment and reforestation dynamics in the Pyrenees (France)

International audienceOver the last decades and centuries, European mountain landscapes have experienced substantial transformations. Natural and anthropogenic LULC changes (land use and land cover changes), especially agro-pastoral activities, have directed influenced the spatial organization and composition of European mountain landscapes. For the past 60 years, natural reforestation has been occurring due to a decline in both agricultural production activities and rural population. Stakeholders, to better anticipate future changes, need spatially and temporally explicit models to identiy areas at risk of land change and possible abandonment. This paper presents an integrated approach combining forecasting scenarios and a LULC changes simulation model to assess where LULC changes may occur in the Pyrenees Mountains, based on historical LULC trands and a range of future socio-economic drivers. The proposed methodology considers local specificities of Pyrenan valleys, sub-regional climate and topographical properties, and regional economic policies. Results indicate that some regions are projected to face strong abandonment, regardless of scenario conditions. Overall, high rates of change are associated with administrative regions where land productivity is highly dependent on socio-economic drivers and climatic and environmental conditions limit intensive (agricultural and/or pastoral) production and profitability. The combination of the results for the four scenarios allows assessements of where encroachment (e.g. colonization by shrublands) and reforestation are the most probable. This assessment intends to provide insight into the potential future development of the Pyrenees to help identify areas that are the most sensitive to change and to guide decision makers to help their management decisions

255 TESTS FOR CARCINOGENESIS USING NEWBORN MICE: 1,2- BENZANTHRACENE, 2-NAPHTHYLAMINE, 2-NAPHTHYLHY- DROXYLAMINE AND ETHYL METHANE SULPHONATE

THE possibility of testing compounds for carcinogenicity by injecting them subcutaneously into newborn mice has been discussed by Roe, Rowson and Salaman (1961). Pietra, Spencer and Shubik (1959) recorded the induction of malignant lymphoma and lung adenomas in Swiss mice by the injection of only 30,ug. 9,10-dimethyl-1,2-benzanthracene (DMBA) on the first day of life. Stich (1960) obtained a similar result using a 60,tg. dose of DMBA. Later, Pietra and his colleagues (Pietra, Rappaport and Shubik, 1961) confirmed their findings with DMBA and tested four other known carcinogens: 3,4-benzopyrene, 20-methylcholanthrene, 1,2,5,6-dibenzanthracene and urethane. In this paper the induction of tumours at sites other than the lung and lymphatic system is described. Comparable results were reported by Roe, Rowson, and Salaman (1961) using DMBA in CBA and " 101 "-strain mice, by Fiore-Donati et al. (1961) using urethane and by Kelly and O'Gara (1961) using 20-methylcholanthrene and 1,2,5,6-dibenzanthracene. According to the Pullmans ' theory of the relation between electronic structur