wide, and this trend is most likely to continue (Liu et al., 2003b). Even in areas with declining population size, household numbers are nevertheless increasing substantially. While population explosion (Ehrlich and Ehrlich, 1990) appears to be ebbing, household explosion is intensifying, elevating demands for household products and releasing more wastes, which in turn exert tremendous impacts on the environment, such as the loss and fragmentation of wildlife habitat.

Human impact on the environment is so widespread that it exists not only in nonprotected common property areas (e.g., Foster, Chapter 12; Matson et al., Chapter 10), but also in many of the world’s approximately 100,000 protected areas (accounting for approximately 12 percent of the Earth’s land surface) (World Conservation Union and World Commission on Protected Areas, 2003), which have been established to protect natural resources and biodiversity (Dompka, 1996; Liu, 2001). Although protected areas are believed to be the cornerstone of biological conservation (McNeely and Miller, 1983) and are often perceived as the safest preserves for nature (Armesto et al., 1998), human encroachments and threats are still very common (Dompka, 1996; Kramer et al., 1997; Liu et al., 2001). Although in some protected areas there are no local residents or land use has been restricted to designated zones, numbers of local residents have been increasing and human activities have been becoming more extensive in many protected areas. Understanding population-environment interactions in protected areas is critically important because such areas usually contain rich biodiversity that is vulnerable to human disturbances. Many ecological studies have been conducted in reserves (e.g., Schaller et al., 1985), but relatively few of those studies have explicitly investigated human dimensions, and even fewer studies have coupled ecological and human components (Hansen et al., 2002).

In this chapter, we use the Wolong Nature Reserve in China for the endangered giant panda to illustrate complex linkages among human population structure, land use, and panda habitat. We focus on two basic types of land use—agriculture and fuelwood collection. The former is the main source of human subsistence (food), whereas the latter provides energy for cooking and heating. Questions that we are particularly interested in are:

• What are the reciprocal interactions among human population structure, land use, and panda habitat (e.g., how do changes in human population structure influence land use and panda habitat)?

• How do human population structure, land use, and panda habitat as well as their interrelationships respond to changes in government policies?