Is it feasible for natural ecosystems to survive in close contact with modern urban ecosystems? It can happen if the people in the area are concerned and active enough to ensure that the natural ecosystems are not polluted, destroyed or excessively disrupted. The coexistence of cities and chaparral in southern California provides an example. Chaparral ecosystems are characterized by a dense growth of tall shrubs and small trees about 2 - 3 metres in height. They have a rich assortment of birds and other small animals as well as larger animals such as deer, mountain lions (puma), bobcats (lynx), coyotes and foxes. The residential areas of some cities in southern California have convoluted edges that place a large number of homes in close proximity to natural chaparral ecosystems (see Figure 11.2a). These are sometimes shaped by foothills that form part of the terrain around the cities. The dense chaparral vegetation restricts human activity to paths and roads, protecting the natural ecosystem from excessive human impacts while providing opportunities for hiking, mountain biking and other relatively unobtrusive activities.