After an overview on the regions concerned and a review of the concepts of rangeland, fodder production and pastoral value, the vegetation, productivity and potential improvement of mediterranean and dry tropical rangelands are assessed. The main range vegetation types are described and characterised by their physiognomy, plant morphology and main ecological constraints. Rangeland fodder production is assessed by analysing the main limiting production factors and by comparing the intra and interannual variations of fodder productivity and quality. Vegetation dynamics of some common range types is discussed according to range management techniques (fire, cutting, cultivation) or livestock management criteria (stocking rate, type of animal, fodder system). Some examples of range improvements applied to contrasted ecological and socio-economical conditions are discussed by analysing their impact on soil, fodder species, vegetation dynamics and range management. To conclude, the need of splitting from fodder production models to range management models is evoked.