When analyzing dissemination protocols in mobile adhoc networks the underlying mobility model is an important factor because it strongly influences the performance of these protocols. So far most of the research only deals with homogeneous mobility models like the very common Random Waypoint Mobility Model and the Random Walk Mobility Model. In this paper we introduce a new model, the Area Graph-based Mobility Model, which considers the major characteristics of realistic scenarios such as their heterogeneity. By analyzing the results of experiments using different broadcast protocols we examine the characteristics of the Area Graph-based Mobility Model. Furthermore, we show that in heterogeneous scenarios it is necessary to use adaptive broadcast protocols, otherwise an efficient dissemination in areas with differing topologies and densities is not possible.