How is biodiversity affected by environmental challenges? Describing the evolutionary ecology of organisms from local to global scales, this course provides an overview of processes that shape the origin, expansion and extinction of species in space and time. Through series of lectures and personal work, it compares the biodiversity and biogeography of varied ecosystems such as drought-related deserts, long-populated Mediterranean regions and alpine ranges in order to organize main drivers of variation in a coherent framework. Such an integrated approach to species responses to environmental changes is key to interpret the current distribution of biodiversity and to appraise and manage future challenges.