nderstanding the mechanisms and dynamics of natural ecosystems is a major goal for ecologists and biogeographers. In this project we will focus on the description, characterisation, and analysis of macroecological patterns and the mechanisms that create t hese patterns. The macroecological patterns we will study are altitudinal patterns of species richness, endemic ri chness, species-to-family ratio, and distribution of species ranges. These patterns will be compared between mountain ranges worldwide and b etween taxonomical or functional groups. These comparisons will in turn be used to discuss how broad-scale factors influence ecological processes such as speciation, extinction, and immigration. The factors we will pay most attention to are (1) the enviro nmental setting, especially climate, (2) distance between areas of similar environments, (3) distance between areas of different environments, (4) size of the area of similar environments, and (5 ) history of the area. The project will also provide a sign ificant contribution in handling several problems associated with the use of broad-scale data by simulation and analytical methods. In sum, this project aims at increasing our understanding of bro ad-scale patterns and processes in ecology and in species diversity.