The rate of trait evolution within a clade varies depending on the organism and the trait. Some traits are evolutionary conserved, some are more labile. If traits related to habitat adaptation are conserved it leads to phylogenetic clustering, i.e. that local coexisting species are more closely related than species drawn randomly from the regional species pool. I have used eco-evolutionary models of an adaptively radiating clade to theoretically study the origin and maintenance of such phylogeographic patterns. Of particular interest is what type of traits are conserved during and after an adaptive radiation, i.e. what part of an organism's niche that are expected to be conserved. One conclusion is that patterns of niche conservatism become successively more pronounced through cycles of extinction and speciation events, such that old clades are predicted to show stronger patterns than young clades. The underlying mechanism can be described as habitat monopolization, or more generally niche monopolization. These results are discussed in relation to extant well-studied adaptive radiations.