In addition, migration processes have resulted in the development of religious pluralism in numerous countries, and the landscape changes that accompany the movement and settlement of communities defined by religion is a key focus in the study of geography and religion. More work needs to be done to examine the intersections and collisions that occur due to the movement of communities (for example, the migration of Muslim communities to western countries) and highlight how these communities negotiate their religious experiences in new spaces. Recent research in this area has been published by Barry A. Vann who analyzes Muslim population shifts in the Western world and the theological factors that play into these demographic trends.