This study aims to characterise the proliferation of Sida cordifolia L. on natural rangelands in Niger. The data, collected by means of phytosociological surveys, made it possible to characterise the abundance and dominance of herbaceous species by bioclimatic zone, with particular emphasis on Sida cordifolia L. A typology of pastures according to their degree of colonisation by this species made it possible to distinguish three types of pasture. Pastoral pressure would be the main cause of the proliferation of Sida cordifolia L., a species that is usually not eaten on these pastures. Thus, pastures that are not or only slightly colonised would be heavily colonised if grazing pressure is not reduced. It is therefore necessary to adapt the animal load to the carrying capacity of these pastures in order to reverse the degradation of these pastoral ecosystems and improve their pastoral value.