We have seen that utilitarian and preservationist resource managers tend to envision nature as moving toward equilibrium. In this view, ecological systems are seen as closed and self-regulating. Like a pendulum, they return to their original state if they are altered. This balance-of-nature view generated many important insights in at least three areas of inquiry. First, when biologists looked at populations from this perspective, they focused on those that were in equilibrium with their resources, that is, populations near carrying capacity (Chapter 2). Intraspecific competition and density-dependent population growth were elucidated in this context. Second, community ecologists viewed communities as proceeding toward a stable climax and focused their attention on disturbances that set back succession. This allowed ecologists to distinguish between the existing plant community on a site and the potential vegetation at that location.