An Experiment in Managing the Human Animal: The PHVA Process and Its Role in Conservation Decision-Making

An alarming proportion of the world’s catalog of biological diversity appears to be in decline (Wilson, 1992; Purvis and Hector, 2000), and the steady losses of species may have serious or even catastrophic impacts on the stability and functioning of ecosystems (Tilman and Downing, 1994; McGrady-Steed et al., 1997; Naeem and Li, 1997; McCann, 2000). Consequently, many of the services and benefits that humans derive from the natural world may be dangerously diminished (Chapin et al., 2000; Tilman, 2000). The primary causes of the decline of nearly all endangered species can be directly related to the activities of human populations, both urban and rural (Caughley, 1994): wildlife populations are over-harvested; landscapes are polluted with the infusion of toxins into the air, water, and soil through industrial activity; exotic competitors, predators, parasites, and diseases are introduced into naive communities that lack the proper defenses to combat these new invaders; wild habitat is converted to agricultural land; and recent evidence suggests that local and now even global climates are substantially modified by the actions of humans (e.g., Walthier et al., 2002). Sadly, we have likely reached a point in time for much our world’s biodiversity where these agents of decline will be difficult to reverse. Even if the original forces are relaxed, a remnant isolated wildlife population becomes vulnerable to other forces, intrinsic to the dynamics of small populations, which may drive the population to extinction despite our best attempts at scientifically based species and habitat management (Shaffer, 1981; Soule, 1987). Chapter 8 An Experiment in Managing the Human Animal: The PHVA Process and Its Role in Conservation Decision-Making