U.S. Department of Commerce


Date of this Version



Published in The Endangered Species Act at Thirty, Volume 2: Conserving Biodiversity in Human-Dominated Landscapes, edited by J. Michael Scott, Dale D. Goble, & Frank W. Davis (Washington: Island Press, 2006), pp. 150-163.


To consider the broader environmental significance of protecting species at risk of extinction, we must first consider the roles or functions that species fulfill in nature. Although "nature" has many definitions, here we define it to mean the end product of ecological and evolutionary processes. That is, within ahabitat, region, or biosphere, the condition of the soil, water, air, and biota reßects the outcome of physical, chemical, ecological, and evolutionary processes. We refer to this combination of abiotic and biotic conditions as "nature" and to the ecological and evolutionary processes that create it as "natural processes."

Using these definitions, we propose three approaches in which environmental actions can protect or conserve nature. The first approach is to preserve natural processes by directly managing them or providing suitable substitutions. For example, we can directly manage apolluted watershed to restore its water quality, or we can build expensive water treatment facilities to treat the water (Chichilnisky and Heal1998). The second approach is to protect nature itself, assuming that with adequate protection nature and its natural processes will persist. For example, we can designate marine protected areas that exclude human activities. The third approach is to protect the biotic components of nature that govern the environment. This approach encompasses the intent of the Endangered Species Act (ESA): to protect nature by protecting species.

In this chapter, we examine the broader environmental significance of the Endangered Species Act by reviewing the roles species play in natural processes and by examining how natural processes govern our environment, how human activities modify nature, and how the Endangered Species Act can ameliorate the impacts of human activities.