U.S. Department of Commerce


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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. 104-126.


The U.S. Endangered Species Act (ESA) relies heavily on science, and not surprisingly science has become a major battleground in the controversy surrounding its implementation (Doremus, this volume). Apparently, Congress hoped that ESA decisions could be made based on science alone and thereby insulated from politics (U.S. Congress 1982, 19). This hope was unrealistic for at least two reasons. First, science cannot answer with certainty many of the questions that must be answered in ESA decision making, especially in the time frames demanded by the statute. Second, while science has a central role in informing natural resource decisions, scientific information alone cannot "make decisions." Criticizing the science seems to be one outcome of hard policy choices (Mapes 2001; Boyle 2002; Dalton 2002; Seattle Times 2002; Stokstad 2002; Strassel 2002; Pianin 2003; Sacramento Bee 2003a and 2003b; Cart and Weiss 2004).

The ESA requires agency reliance on science in several areas: The secretaries of commerce and the interior must designate critical habitat based on the best available scientific data (ESA sec. 4(b)(2)); federal agencies must rely on the best available scientific and commercial data but ensure that their actions will not jeopardize the continued existence of listed species or adversely modifY their critical habitat (ESA sec. 7(a)(2)); and recovery plans must adopt objective criteria for delisting (ESA sec. 4(f)(1)(B)(ii)). In requiring that decisions affecting endangered species be made primarily on the basis of science, Congress sought to insulate agencies from political pressure. Instead, perversely, intense political pressure has forced underground the agency policy choices inherent in sciencebased decisions (Doremus 1997).

Some scholars have argued that "better science" will not reduce the controversy surrounding the act. Instead, they call for more openness about the policy choices embedded in ESA decisions (Doremus 1997; Myer 2001; Yaffee 2006). The authors wholeheartedly agree, but we also believe that better scientific information and processes of eliciting and translating science can improve decision making under the act.

The ESA has been the subject of intense debate in the scientific literature in terms of its effectiveness in protecting species (Schwartz 1999; Boersma et al. 200 1; Crouse et al. 2002; Scott et al. 2006, chap. 2). Federal agency use of scientific information in implementing the act was evaluated by the National Research Council (1995). In this chapter, we focus on the role of science in the act and how the agencies use science in practice. We address the following questions for each stage of the ESA process from listing through recovery planning: (1) What is the role of science, and what has agency practice revealed to be the difficulties of incorporating science? (2) How have the public and courts responded? (3) How could either the science or the process of providing science be improved? We also consider whether decision makers are prepared to make and explain decisions based on incomplete science. We close with suggestions for how scientists can better serve decision making under the act.