The North American Model of Wildlife Conservation. Mahoney, S. P., and V. Geist, editors. 2019 Johns Hopkins University Press, Baltimore, MD, U.S.A. ix+166 pp. US$74.95 (hardcover). ISBN 978-1-421-43281-6.

International Wildlife Management: Conservation Challenges in a Changing World. Koprowski, J. L., and P. R. Krausman, editors. 2019. Johns Hopkins University Press, Baltimore, MD, U.S.A. xv+226 pp. US$74.95 (hardcover). ISBN 978-1-421-43285-4.

The model for wildlife conservation in the United States and Canada is “a system of laws, principles, institutions, and policies” that promoted the recovery of many species from low numbers at the end of the 19th century. The North American Model of Wildlife Conservation describes the history of the model's emergence. In 1901 just a few hundred bison (Bison bison) were left in the United States and Canada and the last wild passenger pigeon (Ectopistes migratorius) was killed. Populations of many other species were decimated—herons and cranes for their ornamental feathers, sea otters (Enhydra lutris) for their pelts, and Eskimo curlews (Numenius borealis) for food. Although never explicitly stated in the book, recreational hunters with wealth and influence appear to have been shocked by a lack of game, resulting in lobbying, public mobilization, and legislation. The prime impetus for conservation was to enable recreational and subsistence hunting. Subsequently, many––but not all––of the decimated species have recovered.

The model's essential elements are that wildlife is publicly owned and maintained, available to all, and hunting is allocated democratically, that commercial harvesting is prohibited (enshrined in the Lacey Act of 1900, which is considered by one contributor the most significant wildlife enforcement act in the U.S. history) and that science is the basis for policy. The model is considered by the editors of this multiauthored volume to have been “enormously successful” (p. 14). According to 2 authors, “American conservation is one of the greatest ideas in all humanity,” and another argues that the early conservationists would be amazed by the present-day status of game populations and acreage of wildlife lands (p. 126). Whether one considers these statements to be hyperbole, this series of essays is valuable and informative. First, understanding the underlying drivers of success has obvious relevance to conservation efforts today. Second, present-day management approaches still follow key features of the model and are facing new challenges.

One essay describes the main personalities involved in the model's development. Aldo Leopold looms large. His name is mentioned in 9 of the 13 chapters, and one author ranks Leopold's book, The Sand County Almanac, to be one of the 2 most significant environmental books of the 20th century (alongside Rachel Carson's Silent Spring). A chapter on science laments that two-thirds of the U.S. public fail to accept a role for natural selection in evolution. Just as dispiriting is that the same survey shows that almost 1 in 8 of all scientists have a similar view. A recommended chapter describes the emergence of protection in Yosemite, the Adirondacks, and Yellowstone, which is valuable because it gives additional perspectives on the value of conservation, beyond that of the enjoyment of hunting. For example, deforestation of the Adirondacks was reversed partly in consequence of siltation of the Erie Canal; John Muir championed the wonder of nature for its own “glorious sake”; and President Theodore Roosevelt emphasized the importance of conservation not just for his electorate, but future generations, in ways difficult to predict.

The authors make the case for the contribution of recreational hunting to conservation. For example, in Texas alone, every year 600,000 people hunt white-tailed deer (Odocoileus virginianus) for enjoyment. In addition, herbivore control may be required to replace the predators that formerly limited these populations and prevented overgrazing. Finally, revenue comes from hunters, including a federal tax on guns, bows, arrows, and ammunition that was introduced by an innovative 1937 act, and hunting licenses, which together annually contribute >$1 billion to conservation. Given these contributions from hunting, the editors of the volume are concerned about the decline in public interest. Less than 5% of the U.S. population now hunt, down from 10% in 1990. Most hunters are old. Concerns include loss of tax revenue, fewer hunters personally supporting conservation, and an increasing disconnect of the public from nature. Remedies suggested include taxing other items beyond guns and ammunition (such as camouflage clothing) and encouraging children to attend hunting camps. Alternatively, other ways to enjoy nature may be substituted. Indeed, the editors raise the possibility of taxing additional outdoor recreational equipment and supplies. I add that conservation of wildlife has widespread support among the general public in the United States. One study estimates that the “no-use benefits of parks,” or the amount people prepared to pay even if they were never to visit a park, totals to $33 billion annually (Haefele et al., 2016).

Accepting that the U.S. and Canadian model works, why is it not implemented elsewhere, and how well do alternatives work? This question is addressed in both The North American Model and International Wildlife Management. Three features of the model are public ownership, emphasis on hunting as a conservation tool, and a ban on commercial trading. The hallmarks of the model's success are strong enforcement, scientific underpinnings to restrictions on hunting, and recognition by hunters of the value of restraint. These are all more difficult to establish in developing countries. First, public ownership of a resource might be expected to result in a tragedy of the commons, whereby individuals have little to lose and much to gain from overexploitation. Indeed, in many places, government ownership has led to overharvesting, resulting from failures of legislation or enforcement (Benítez-López et al., 2017). Second, the importance of hunting is a key feature of the model. In most parts of the world, however, hunting is a threat, not a conservation tool (Benítez-López et al., 2017; Koerner et al., 2017). Third, unlike under the model, legal trade of hunted animals is allowed in many places. This contributes to species declines from overharvesting of the resource and because illegal harvest (e.g., harvesting beyond a quota) is more easily passed off as legal. However, there are some examples where alternative approaches to the model have worked in favor of conservation. Development of private hunting ranches in southern Africa has led to management to improve stocks. In developed countries, commercial annual harvesting of more than 10 million kangaroos in Australia, 600,000 wild boar in Germany, and the American alligator in the United States have had no effect on populations.

International Wildlife Management is broader in scope than The North American Model. It is designed for students interested in the practicalities of wildlife conservation and starts by emphasizing the value and importance of international collaboration and experience. Like The North American Model, it is focused on land and does not consider problems in the oceans. One chapter lists the main global conservation organizations; a second gives suggestions on how to get involved in management and research. Another illustrates the importance of international collaborations and differences in the problems and solutions faced by developed and developing countries. It does so by highlighting investments in Europe in conservation of breeding migrant birds, which may be in vain given the challenges faced by these same species when they overwinter in Africa in locations threatened by hunting and desertification. A fourth chapter details successes in generating local support for conservation in developing countries, including the designation of fair-trade labels, funneling of tourist dollars to locals living near a park, and employment of motivated individuals as park rangers. The book comes with a surprising lack of figures that show data, only 3 in total.

Several chapters are devoted to describing specific environmental threats (climate change, habitat loss, etc.). Each starts with an overview of the threat, referencing studies that illustrate general points. The chapters conclude with a discussion of how management actions might ameliorate impacts. The enduring impression one gets is how varied management approaches need to be. The chapter on habitat fragmentation describes the types of corridors one can install (e.g., bridges over roads), but the chapter on climate change gives no specific prescriptions, although some have advocated and already implemented translocation to keep up with climate change (St. George, 2020). The chapter on invasive species lists successful control programs, with an interesting explanation on what makes a control effort successful, but a chapter on carnivore control concludes that beyond small islands “we will probably never be able to eradicate invasive predators” (p. 136) and one on invasive pathogen control calls it “a costly or impossible enterprise for most systems” (p. 101).

An exceptional chapter by Wisely offers examples of the many problems conservation scientists face. The chapter is on wildlife disease. It not only gives a broad overview of the effect of disease on wildlife, but also addresses the underlying causes of disease spread. Vampire bats (Diaemus spp.) that carry rabies have increased as forest has been converted to pasture. International trade in amphibians (>8000 t of frog legs are annually exported) has spread disease. Artificial breeding, as well as the provision of feeding sites, has led to high densities of some game species, resulting in transmission of diseases, such as chromic wasting disease in the white tailed deer in Texas. This chapter also explicitly justifies management approaches by noting not only threats to wildlife from disease, but also threats to domestic animals and humans. (The book came too late for COVID-19, but earlier coronavirus outbreaks have been linked to animal reservoirs.) Finally, the chapter describes the feasibility of alternative control mechanisms, including vaccination, animal culling, and sterilization. For example, vaccination of cattle against rabies has a benefit:cost ratio of 6:1.

Wisely's chapter is important for its description of threats from disease and the role of management and because it gives an overview of some more general principles of conservation and management that are not made explicitly anywhere else in either book. First, she lays out the 4 options for management: prevention, control, eradication, or doing nothing, thereby providing a framework for cost–benefit analysis. Second, the problem is not only that of multiple threats, but their interaction. Wisely notes how climate change is altering host population distributions and densities as well as pathogen generation times. Her essay explains how habitat degradation increases human contact rates with wildlife, which not only has led to transmission from wildlife to humans, but also from humans to wildlife. She describes how nutrient pollution has led to an increase in pathogen densities and their hosts. Finally, Wisely raises the important issue of uncertainty. In the United Kingdom, a cull of badgers (Meles meles) to limit bovine tuberculosis failed because it led to increased badger movements, spreading the disease. Although this may have been difficult to anticipate, Wisely provides a lead into an increasingly sophisticated modeling literature that aims to improve predictions. Uncertainty is clearly appreciated in management decisions, and indeed much of the content in both books is associated with how to improve outcomes. However, when anticipating challenges in the future, a range of possible outcomes should be incorporated more widely into plans than they are at present.

These are important books, linking science with management in a way I have not seen before. A judicious reading of various chapters would benefit everyone.