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Large Carnivores and the Conservation of Biodiversity
By Justina C. Ray, Kent H. Redford, Robert S. Steneck, Joel Berger
ISLAND PRESSCopyright © 2005 Island Press
All rights reserved.
Introduction: How to Value Large Carnivorous Animals
Kent H. Redford
According to a quote attributed to Marjory Stoneham Douglas, "The Everglades is a test, if we pass, we get to keep the planet." This evocative challenge can be applied equally to the conservation of large carnivorous animals. Over the entire surface of the globe, these animals, wolves (Canis spp.), bears (Ursus spp.), large cats, sharks, and orcas (Orcinus orca) are fighting a rearguard action for survival. As the world increasingly becomes a handmaiden to the human race, saving these species has become one of the most difficult tests we face in biological conservation. The urgent need to develop and implement strategies to conserve such creatures has led to two approaches, one based on the ecological roles or services played by these species in maintaining biodiversity, and the other on their intrinsic value as a component of biodiversity.
In this volume we probe the relationship between these two approaches and the science underlying them, seeking to understand the relationship between the presence of large carnivorous animals and the conservation of all attributes and components of biodiversity. We specifically address the conservation challenges of these species, whose diets consist mainly or exclusively of large animal prey. As such, they are often in direct and indirect conflict with humans (c.f. Treves and Karanth 2003). We describe the species of interest as large and carnivorous because we are interested in the conservation problems and opportunities posed by species with these characteristics, and not in their taxonomic position per se. We have worked to include studies from the marine as well as the terrestrial realm. We have been only partially successful in this effort; although the loss of large carnivores in the marine realm has been well documented (e.g., Myers and Worm 2003), the effects of such loss have only recently begun to be examined. We were unable to find cases that include reptiles and avian species and welcome further analysis that extends the scope of this volume and its conclusions. The book is intended as a representative review of what is currently known about the relationship between carnivores and biodiversity and how it relates to the conservation of both. It is aimed at practitioners and academics, with a hope that the work of the former can more effectively inform the work of the latter.
This volume is based on a conference convened by the Wildlife Conservation Society (WCS) at the White Oak Conservation Center of the Gilman Foundation in 2003. We invited professionals who had worked on the relationship between large carnivorous animals and biodiversity or had long-term data sets that might be used to examine this issue. WCS is a conservation organization with a mission of conserving wildlife and wildlands using science-based, field-grounded work. As well as operating the world's largest set of urban zoos in New York City, WCS is engaged in field conservation at over 300 sites in over 50 countries. In many places WCS works with large carnivorous animals and everywhere finds this work complicated.
Conservation organizations and individual conservation biologists have been very effective in drawing attention to the plight of these animals by arguing that they play critical roles in the conservation of their ecosystems. As such, conservation of these species is said to be a prerequisite for achieving larger-scale conservation.
This is a very important claim. As practitioners of science-based conservation, and strong supporters of the value of large carnivorous animals, we thought it a critical time to bring together experts from the scientific community to assess this link. Therefore, we convened the White Oak meeting to address the question: Is the conservation of large carnivorous animals equivalent to the conservation of biological diversity? Aware of the complicated history of ecological thought that addresses versions of this question, we have worked to place our volume in the perspective of larger ecological theory. Also aware of the efforts of others addressing similar questions, we have placed our work in the context of the work of others. We have also found that as we worked on this book the question we had posed to the workshop has proven more complicated than expected to answer, and our efforts to answer it have led us into unexpected quarters (see the concluding chapter). We have found that our search for a simple answer has been frustrated by, but also informed by, the paucity of scientific investigation addressing the role of large carnivores; the conclusion that even when there is sufficient science, the answer will depend on context; and the rich, complicated mix of ethics, values, and science that envelops and obscures virtually everything having to do with the interactions between humans and large carnivores. But despite this ambiguity, we have worked throughout this book to bring to the surface the management implications of and actions connected with conserving both large carnivorous animals and the biodiversity that enrobes them. This constant eye on conservation action makes this book different from many others. We hope this book will be of use to those charged with the conservation and management of both wildlife and wildlands.
The book is organized into four parts. The first part, Setting the Stage, lays out the theoretical and practical issues underlying the question of whether conservation of carnivores is equivalent to the conservation of biodiversity. The two chapters review both the ecological foundations that are at the core of this question and the assumptions and uncertainties underlying the ways in which large carnivorous animals have been used as tools for conserving biodiversity. Part Two, The Scientific Context for Understanding the Role of Predation, consists of six chapters. The first set presents several of the best-known research projects that have examined the ecosystem-structuring role of large carnivorous animals including sea otter (Enhydra lutris)–kelp systems, Lago Guri, Venezuela, and wolves (Canis lupus) of the Greater Yellowstone Ecosystem. The remaining chapters contribute through examining research results from a set of systems less frequently appreciated as central to the topic of this book. These include examining the general phenomenon of trophic cascades and top-down controls in large marine carnivores, the forests of the northeastern United States where large carnivores are gone and ungulates "rule the world," and what is known about redundant roles in groups of large carnivores, focusing particularly on the African guilds.
In Part Three, From Largely Intact to Human-Dominated Systems: Insight on the Role of Predation Derived from Long-Term Studies, five case studies are presented by ecologists who have worked on a long-term basis in various systems and provide information essential for determining whether the functional importance of carnivores necessarily means that focusing conservation efforts on them will achieve conservation of biodiversity. Their contributions are arranged from those that examine relatively intact ecosystems to those heavily influenced by humans, in the Russian Far East, African savannas, European temperate forests, tropical coral reefs, and Patagonian Steppe. In Part Four, Achieving Conservation and Management Goals through Focus on Large Carnivorous Animals, five chapters address the practical applications that may be derived from the science of understanding carnivory. These include discussions of how long-term studies on carnivores designed to address management issues can play a role in conserving landscapes and biodiversity, an analysis of whether hunting by humans and hunting by other large carnivorous animals are functionally redundant, and a conceptual framework for assessing whether populations of large herbivores are regulated by top-down or bottom-up processes. The final two chapters in Part Four offer contrasting perspectives on how top carnivores are related to biodiversity conservation in boreal forest ecosystems and the "half-full" forests of Europe.
This book is not meant to be another book about carnivores. It is intended to be a book about the relationship between carnivores and conservation. All authors were asked specifically to address the conservation implications of their work. The book concludes with Chapter 20, an overall synthesis that draws the conservation implications from the rich mix of chapters, making the point that despite the lack of a simple answer to a complicated question, there are ways to improve our thinking and action to conserve both large carnivorous animals and biodiversity.
There has been a good deal of ecological work done on the impact of biodiversity loss on ecosystem structure and function (Scheffer and Carpenter 2003), with trophic interactions appearing to play important roles in these processes (Worm and Duffy 2003). But there continues to be debate about the relative role of consumer-driven (top-down) versus resource-driven (bottom-up) control, with both appearing to operate at some times, in some systems (Meserve et al. 2003; Sinclair et al. 2003). Yet little of this work has provided tools that would help conservation practitioners in their efforts to conserve biodiversity.
To us, the question, Is the conservation of large carnivorous animals equivalent to the conservation of biological diversity? is a vital one for the conservation community to address head-on. It is fashionable to argue in some quarters that large carnivorous animals are a "tool" whose presence is required in order to achieve conservation of all components and attributes of biodiversity. And further, this argument states that restoration of this full spectrum of biodiversity is not possible without reintroduction of large carnivorous animals. If this utilitarian approach to large carnivore conservation is correct, then we must be able to prove the vital role played by these species. If it is not correct, then we must proceed with caution (c.f. Warren et al. 1990), for these species may not be necessary (in this utilitarian sense) and, given the negative costs of their presence and the conservative nature of scientific proof, a limited version of conservation success might be easier to achieve in their absence. Difficult though this question is, it exists as a reality in the world of the "Designer Ark" (Weber in press).
A different, though perhaps complementary, argument for the conservation of large carnivorous animals is value based and draws on the long-intertwined history of humans and these species and the roles they played and play in the human psyche. As Quammen (2003: 13) has written: "For as long as Homo sapiens has been sapient ... alpha predators have kept us acutely aware of our membership within the natural world. They've done it by reminding us that to them we're just another flavor of meat." The power that large carnivorous animals had over humans is bred in the bone and has resulted in complex accounting of the relationship between the two (Redford and Robinson 2002). Origin myths place humans descended from jaguars (Panthera onca) (Benson 1997) or sharing the same mother as tigers (Panthera tigris) (Wessing 1986). And a common theme is the blurred boundary between the two with lycanthropy, or humans turning into wolves, found in Europe (Otten 1986), echoing beliefs from throughout the world that humans transform into jaguars, pumas (Puma concolor), leopards (Panthera pardus), lions (Panthera leo), tigers, and bears (Boomgaard 2001).
The power of the relationship between humans and large carnivorous animals lies in its ambiguity and blurring of boundaries (Wessing 1986; Benson 1997; Boomgaard 2001). For example, in some of the early European illustrations of the New World—such as a Dutch woodcut published in 1695—there is a conflating of human and jaguar, with the jaguar pictured standing in a human position (Saunders 1990). Large carnivorous animals are symbols of the nonhuman world both within and outside of the human body, as illustrated by the human–lion hybrid, the sphinx. The nature of this relationship between such animals and the nonhuman world is well illustrated in a Javanese tale related by Crawford (1967) (in Wessing 1986):
Make choice of an equal friend, and do not like the tiger and the forest. A tiger and a forest had united in close friendship, and they afforded each other mutual protection. When men wanted to take wood or leaves from the forest, they were dissuaded by their fear of the tiger, and when they would take the tiger, he was concealed by the forest. After a long time, the forest was rendered foul by the residence of the tiger and it began to be estranged from him. The tiger thereupon quitted the forest, and men having found out that it was no longer guarded came in numbers and cut down the wood, and robbed the leaves, so that, in a short time, the forest was destroyed, and became a bare place. The tiger, leaving the forest, was seen and although he attempted to hide himself in clefts and valleys, men attacked him and killed him, and thus, by their disagreement the forest was terminated, and the tiger lost his life.
Undoubtedly, there is no single unifying theory to tell us when the tiger and the forest are locked into this symbiotic relationship. We do not know enough to predict the role of large carnivorous animals in the ecology of every place, time, and circumstance. We must therefore be careful not to assume that we know when and where such species must be conserved in order to conserve other components and attributes of biodiversity. Their existence is worth more than just the role they play in ecosystems.
In an evolutionarily abrupt turning of the tables, humans are now responsible for the survival of large carnivorous animals. Will Quammen (2003) be correct in his prediction of the year 2150 as a probable end point to the special relationship between humans and alpha predators? We certainly hope not. Boomgaard (2001) recounts early Dutch reports from Indonesia documenting the existence of a kind of tiger called the volgtiger, literally a following or attendant tiger or a "familiar." The concept of a familiar (meaning a spirit, usually taking the form of an animal but also a close friend or companion) that helps someone (often a witch) is apt in this context. Large carnivorous animals are a part of humans and of our past. But they are also a test of our humanity and of our ability to save the earth. Perhaps it is true, as told in a Colombian indigenous myth, that "the jaguar was sent to the world as a test of the will and integrity of the first humans" (Davis 1996). If we are to save ourselves, we must save all the parts of our humanity. As go these wild animals, so goes the human soul.CHAPTER 2
An Ecological Context for the Role of Large Carnivores in Conserving Biodiversity
Robert S. Steneck
How important are large carnivorous animals for conserving biodiversity? Today they are rare or absent from most terrestrial, aquatic, and marine ecosystems. Should we invest heavily in political and real capital to restore them? These questions require that we understand their ecological roles in ecosystems. However, most studies are too limited in scope to provide answers to such broad questions. One way around this lack of data that would allow a more holistic perspective is to apply ecological theory to help sort out which concepts are most appropriate, most compelling, and most robust.
Most general ecological concepts begin with observations made in nature. Fortunately, people have always been keen observers of predators. Cave paintings in France made 35,000 years ago depict large carnivores stalking prey; some of which were humans. Obviously, our preoccupation with carnivores is primal, and it has resulted in a wealth of knowledge about them and their effects. However, over time perceptions of their roles in ecosystems have changed and, accordingly, observations could have been colored by prevailing dogma and existing social and scientific paradigms. Therefore, we can better understand contemporary concepts by knowing their conceptual history.
Considerable empirical and theoretical ecological research supports the thesis that large predators can affect community structure and biodiversity. It is less well known under which conditions predators do exert, or could exert, major influences on the structure and functioning of ecosystems. Today, relatively few ecosystems have large predators that play important roles, often due to extirpations induced by hunting and habitat change. But it is also possible that some habitats and ecosystems never had ecologically significant large predators. Under what conditions should we expect predators to be important regulators of biodiversity? Obviously there is no point in trying to restore large carnivores if they were never major players in the system.
Excerpted from Large Carnivores and the Conservation of Biodiversity by Justina C. Ray, Kent H. Redford, Robert S. Steneck, Joel Berger. Copyright © 2005 Island Press. Excerpted by permission of ISLAND PRESS.
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