Public Opinion on Species and Endangered Species Conservation

By: Brian Czech and Paul R. Krausman


Species endangerment has been a major concern in the United States for over a century. A rich history of legislation prior to 1973 (Table 1) provided the foundation upon which the Endangered Species Act of 1973 (ESA) was built, but the ESA arguably provides more protection from extinction than all prior laws combined. Certainly, no prior law was as comprehensive, nor as controversial.

The purposes of the ESA (Section 2(b)) are to "provide a means whereby the ecosystems upon which endangered species and threatened species depend may be conserved, to provide a program for the conservation of such endangered species and threatened species, and to take such steps as may be appropriate to achieve the purposes of the [international conservation] treaties and conventions..." The ESA provides those means through an array of domestic and international tactics (Table 2). Every federal agency is affected, as are state and local agencies that use federal money. Many private landowners are affected, too.

The regulatory power created by the ESA is wielded by the Secretary of Interior through the Fish and Wildlife Service (FWS) and, to a lesser extent, by the Secretary of Commerce through the National Marine Fisheries Service (NMFS). The ESA has a history of strict interpretation by the courts (Coggins 1991), and two ESA issues have become increasingly controversial: 1) the types of species that are listed (Williams 1996, Bergman 1995, Dingell 1989), and, 2) the limitations that the ESA imposes on development projects, especially in the private sector (Dwyer et al. 1995, Heinen 1995). The accrual of political peril to the ESA is reflected in its reauthorization and appropriations history (Campbell 1991). The ESA was originally authorized for five years, and reauthorization and/or authorization amendment has occurred in 1976, 1978, 1979, 1982, and 1988, when the ESA was again authorized appropriations for a five-year period. A conventional reauthorization formulated during fiscal year 1992 would have authorized appropriations for the five-year fiscal period of October 1, 1992 to September 31, 1997. However, Congress has only authorized funds in one-year increments since 1993, and bills to weaken the ESA were introduced in both houses of the 104th Congress (Cheever 1996). In fact, the ESA was "at the top of the list of environmental statutes targeted by the 104th Congress to be weakened or outright eliminated" (Ehrlich and Ehrlich 1996:116).

With controversial issues, public opinion is an important factor for policy makers. Unfortunately, there is little current data on national public opinion. To determine what data did exist, we conducted literature database searches with Quicksearch©, using "Endangered Species Act" as a key phrase. As of June 1996, the Congressional Record Index contained 273 records, corresponding approximately to the number of hearings in which the ESA was a primary topic.

We found reference to 1,341 ESA articles published in natural science journals, most of which are concerned with the biology and evolutionary ecology of species, and with conservation strategies. We found 48 ESA articles in social science journals, most of which are accounts of the social and political effects of the ESA and species endangerment on landowners. Most of the research conducted on public opinion (summarized by Kellert 1996) has focused on attitudes toward various taxa, and was conducted prior to 1990. Much of it was conducted on regional populations.

In light of this, we decided to conduct a survey to ascertain public opinion on different types of species, species conservation, the ESA, and related institutions, and to investigate relationships among demographic factors and conservation attitudes. The purpose of this preliminary article, however, is limited to providing the mean responses to our survey questions and some preliminary interpretations thereof.


We mailed questionnaires to a random sample of 2,000 American households, following the protocol of Salant and Dillman (1994). We defined eight types of species (birds, mammals, reptiles, amphibians, fish, plants, invertebrates, and microorganisms) and seven factors which might influence the perceived importance of an animal's conservation: apparent ecological importance, body size, cultural and historical traits, intelligence or behavioral complexity, monetary value, physical attractiveness, and rarity ( hereby referred to as prioritization factors). To determine respondents' valuation of species types and prioritization factors, we used visual analog scaling, whereby the respondent indicates relative value by marking a point along a spectrum ranging from 0 to 100 (i.e., no importance to most importance). The data obtained are therefore ratio, allowing for finer distinctions in difference and more precise statistical analyses than do ordinal data such as those obtained with Likert scales (Rubin 1983).

We also used visual analog scaling to analyze public attitudes toward species conservation and related institutions. First, to address issues of landowner rights, respondents rated three statements on a visual analog scale in which 0 represented total disagreement, 100 represented total agreement, and 50 represented neutrality. Second, using a scale from "not important" to "extremely important," we explored the importance of maintaining economic growth, ecosystem health, democracy, property rights, conservation of species, and resources for future generations in American society. Finally, we used multiple choice questions to assess public opinion on the causes of species endangerment, the propriety of the ESA, and the acceptability of other types of policies important to species conservation. The results are proportions of people responding to various choices, so are immediately interpretable in terms of majorities and minorities.

Results and Discussion

We obtained 643 questionnaire responses. Accounting for delivery problems, the response rate was 40%. The geographic distribution of respondents closely resembled that of the population at large, and the proportions of respondents belonging to the two major political parties were nearly the same as with the voting public. Respondents were also similar to the voting public in terms of education and employment levels. Respondents averaged about five years older (mean age = 51.6) than United States voters (U. S. Bureau of the Census 1996). Despite instructions intended to obviate a skewed sex ratio of respondents, 70% of respondents were male. This could be related to KellertÕs (1987) finding that males were more concerned about conserving wildlife species and habitats than were females, who tended to be more concerned about domestic animals and individual animal welfare.

We found significant (a= 0.05) differences in respondents' valuation of types of species. On a relative valuation scale of 0-100, respondents value plants (72), birds (71), and mammals (71) significantly higher than all other types. Fish (68) constitute a second level of importance. Reptiles (59), amphibians (59), and invertebrates (57) occupy a third level, and microorganisms (52) are valued significantly less than all other types.

Despite these taxonomic preferences, respondents considered ecological importance (77) and rarity (73) to be the most important factors in judging the importance of species for conservation. Other important factors were cultural significance (57) and intelligence (53). Monetary value (32), physical attractiveness (29), and body size (28) were deemed much less important.

On an agree-ment scale of 0-100 (where a score of 50 indicates neutrality), respondents support (62) the statement, "Landowners should not have the right to use their property in ways that endanger a species." Similarly, respondents disagree (41) with the notion that, "Endangered species protection should not interfere with a landownerÕs right to develop property." Respondents also believe (58) that, "Landowners prevented from developing their property because of endangered species laws should be paid for any lost income by respondents." Agreement with the latter is positively correlated with ageÑolder respondents feel more strongly that landowners should be compensated for lost income.

On a scale from 0-100, respondents rated the importance of conserving species at 76.5, similar to the importance of property rights (76.3) and economic growth (75.4). Each of these concepts are valued significantly (a = 0.05) less than ecosystem health (80.5) and democracy (82.5). However, the availability of resources for future generations (85.8) is the concept considered most important.

Fifty-five percent of respondents realize that habitat loss due to natural resource extraction and economic development is the biggest cause of species endangerment in the United States today. Thirty-six percent feel endangerment is due to toxic chemicals, while 7% blame harvesting (e.g., hunting). Only 2% believe that introduced species are the biggest cause.

Five-percent of respondents would like the ESA revoked, 11% would like it weakened, 35% want it retained as written, and 49% want the ESA strengthened. There was no significant difference in overall species valuation between people from the East (eastward of the Great Plains) and people from the West, and similarly low proportions from the East (14%) and West (19%) favor weakening or revoking the ESA. However, among those preferring to maintain the ESA as written or strengthen the ESA to protect more species, a higher proportion (53%) from the East want it strengthened. In the West, 41% want the ESA strengthened.

RespondentsÕ awareness of habitat loss is reflected in attitudes toward remedial strategies. Sixty-eight percent of respondents favor eliminating subsidies for practices that degrade endangered species habitat (12% oppose that strategy, and 20% are undecided). Sixty-one percent favor policies that would promote a stable human population rather than population growth (22% opposed, 17% undecided). Forty-eight percent favor policies that would lower the consumption of resources, especially by wealthy individuals (30% opposed, 21% undecided). Judging by the comments of respondents, the clause "especially by wealthy individuals" dissuaded many respondents that would otherwise have favored consumption policies. It is difficult to estimate, however, how many respondents would have favored such policies without an emphasis on wealthy individuals. Only 6% favor a ban on hunting, fishing, trapping, and wildlife harvesting of all sorts (87% opposed, 7% undecided).

Finally, respondents were asked to rate the statement, "I consider myself to be an environmentalist," on a scale from 0-100 (0=disagree, 100=agree). On average, respondents view themselves as environmentalists (59).


Our results suggest that species conservation is of greater concern than other issues and attitudes that have become associated with the concept of environmentalism. Specifically, the Endangered Species Act seems to be highly valued for 2 reasons. First, the public is generally concerned about the extinction of species, and the ESA is the only law that directly addresses that concern. Second, the public is most concerned about posterity, and has a basic understanding that the ESA dissuades activities that liquidate depleted resources and make them unavailable to future generations. In addition to the ESA, the public, on average, favors policies that would eliminate subsidies to resource extractors, promote population stabilization, and temper the consumption of natural resources.


Numerous professors of statistics, political science, psychology, and biology at The University of Arizona, students, and citizens outside of academia reviewed the questionnaire for unconventional phraseology, vagueness, predisposition, and other questionnaire design problems. We are especially indebted to Terry Daniels, Bill Shaw, and Tom Brown for their reviews of the questionnaire, and to Pat Jones for statistical advice. We thank the United States Forest Service, The University of ArizonaÕs School of Renewable Natural Resources, and The University of ArizonaÕs Agricultural Experiment Station for fiscal support.

Literature cited

Bergman, B. J. 1995. Leader of the pack. Sierra 8(6):50-55.

Campbell, F. 1991. The appropriations history. Pages 134-146 in K. A. Kohm, editor. Balancing on the brink of extinction: the Endangered Species Act and lessons for the future. Island Press. Washington, D.C.

Coggins, G. C. 1991. Snail darters and pork barrels revisited: reflections on endangered species and land use in America. Pages 62-74 in K. A. Kohm, editor. Balancing on the brink of extinction: the Endangered Species Act and lessons for the future. Island Press. Washington, D.C.

Dingell, J. D. 1989. Foreword. Pages 1-6 in D. J. Rohlf, author. The endangered species act. Stanford Environmental Law Society. Stanford, Calif.

Dwyer, L. E., D. D. Murphy, and P. R. Ehrlich. 1995. Property rights case law and the challenge to the Endangered Species Act. Conservation Biology 9(4):725-741.

Echeverria, J. D., and R. B. Eby, eds. 1995. Let the people judge: wise use and the private property rights movement. Island Press. Washington, D.C.

Ehrlich, P. R., and A. H. Ehrlich. 1996. Betrayal of science and reason: how anti-environmental rhetoric threatens our future. Island Press. Washington, D.C.

Heinen, J. T. 1995. Thoughts and theory on incentive-based endangered species conservation in the Untied States. Wildlife Society Bulletin 23(3):338-345.

Kellert, S. R. 1996. The value of life. Island Press. Washington, D.C.

Kellert, S. R. 1987. Attitudes, knowledge, and behaviors toward wildlife as affected by gender. Wildlife Society Bulletin 15:363-371.

Rubin, H. J. 1983. Applied social research. Charles E. Merrill Publishing Company. Columbus, Ohio.

Salant, P., and D. A. Dillman. 1994. How to conduct your own survey. John Wiley and Sons, Inc. New York.

U. S. Bureau of the Census. 1996. Statistical abstract of the United States: 1996. National Technical Information Service. Springfield, Virginia.

Williams, T. 1996. Defense of the realm. Sierra 81(1):34-39.

Brian Czech, Ph.D. is a wildlife biologist certified by The Wildlife Society. Brian has spent 13 years working for federal, state, and tribal government. He conducted a policy design analysis of the Endangered Species Act for his Ph.D. at The University of Arizona. Paul R. Krausman, Ph.D. is a certified wildlife biologist, professor of Wildlife and Fisheries Science at The University of Arizona, and past editor of the Journal of Wildlife Management and of the Desert Bighorn Council Transactions. He has also edited several books and symposium proceedings.

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