The various consequences of the breakdown of reproductive barriers between distinct species, leading to interspecific hybridization, are of growing concern in ecology and evolution. In this thesis, I explore the large range of outputs that hybridization may produce from both conservation and evolutionary biology perspectives. My main aim is to investigate the impact of interspecific hybridization on the diversity of organisms through the development of novel modelling approaches that integrate natural and anthropogenic factors. I thus developed original models that allow to better evaluate the extinction risk or the evolutionary opportunities brought by hybridization. The development of several modelling approaches that I have applied to very different subjects (fishes, amphibians, birds, mammals and humans) allowed me to draw a large picture of the effects of hybridization on biodiversity. I finally state the conditions under which hybridization may represent priorities for conservation programmes or, alternatively, new evolutionary opportunities.