Using a Magnetic Mammal to Conserve an Ecosystem


The Return of the Unicorns: a Natural History and Conservation of the Greater One-Horned Rhinoceros. Dinerstein, E. 2003. Columbia University Press, New York. 334 pp. (316 + xviii). $59.50 (hardcover). ISBN 0–231–08450–1.

Although the scene could be anywhere in the world, and repeated with any appealing mammal, this case derives from southern Asia. A government worker confronts angry villagers:

“Who is more important, people or rhinoceros?”

“There are only four hundred rhinoceros in Chitwan, and … over 80,000 human residents. I am sorry, but it is my duty to protect the rights of the minority.”

This all-too-familiar refrain—limited space, too many people, a rare but very large species, and the human face of conservation—sets the stage for Eric Dinerstein's description of a fascinating real-world success story. This detailed account, spanning parts of nearly 20 years in Nepal's Royal Chitwan National Park, offers significantly more depth than reflected in the modest subtitle, Natural History and Conservation of the Greater One-Horned Rhinoceros. Dinerstein's thesis stems from concepts steeped deeply in the basics of conservation biology—genetics, metapopulation structure, reserve design, restoration biology, and keystone ecological roles—but moves far beyond these ideas because he masterfully integrates the science of conservation biology with the human dimension. Sections on local economics, tourism, farming, and human perspectives are mixed with others rich in natural history, behavioral ecology, and landscape ecology.

The central question that frames the book is simple: Is optimism about the conservation of large mammals in human-dominated landscapes misplaced? Getting to an answer has not been an easy road, however, and has involved far more than applied science. Dinerstein depicts dedicated local people, Nepalese government officials, and conservation practitioners within the context of the challenges of work in remote locations and with people whose aspirations for sustenance depend on the same lands as the rhinoceros.

This rhinoceros field project was conceived and supported jointly by the Smithsonian Institution's once fertile Conservation and Research Center, a hub that brought in situ conservation to the global forefront, and the Nepalese government. Dinerstein subsequently joined the senior ranks of the World Wildlife Fund, where, as is clear in this book, he continues to facilitate the protection of global biological treasures such as the Terai Arc.

The Return of the Unicorns is divided into three primary areas, each using the greater one-horned rhinos to develop increasingly sophisticated themes while imparting crisp and novel information about rhinoceroses themselves. The first topics under “Vanishing Landscapes” offer details on the evolutionary rise and fall of rhinoceroses, their current endangerment, and the progressively jeopardized existence of southern Asia's flood plain ecosystems. The second section, “The Biology of an Endangered Megaherbivore,” examines questions about the dynamics of sexual dimorphism, the role of canine teeth versus that of horns in mating success, predation by tigers on young rhinoceroses, population trends, demographic and genetic threats, and the growing importance of understanding ranging patterns and spatial limitations on population viability. A true bonus in the last chapter of this section is the consideration of the ecological role of rhinoceroses as landscape architects. Here, experimental manipulations are combined with measures of fecal deposition, seedling mass and germination rates in and away from latrines, and feeding habits and gut dynamics to test hypotheses about potentially coevolved relationships involving the tough endocarps of Trewia fruits and rhinos and about their more ecologically relevant influences on current plant community and ecosystem structure.

The book's final theme focuses on recovery of large-mammal populations and their habitats in southern Asia. It is here that Dinerstein excels, detailing the economics of human sustenance and poverty, understanding opportunities and limitations of employment within the context of ecotourism, promoting local guardianship, and outlining the ambitious but very reasoned Terai Arc landscape program to link protected zones from Corbett National Park in India to the Parsa Wildlife Reserve east of Chitwan.

This book offers much to anyone interested in practical, how-to conservation, far-away landscapes, large and exotic-sounding mammals, biodiversity, planning, and tropical ecology. I particularly liked Dinerstein's bluntness in dealing with the failure of some ex situ breeding programs and in his call for the controversial green labeling of scrupulous tourist operators and establishments. Some readers will cherish his attention to factual details that range from variation and changes over time in rhinoceros density to figures on human density. Shortcomings include some maps with fonts so small that they are difficult to read, some univariate analyses (especially those in which sample-size limitations are not considered), and too few literature citations on African rhinoceroses that extend much beyond Norman Owen-Smith's 1988 book on megaherbivores. If readers are interested solely in the evolutionary explanation of a family of mammals that celebrated its heyday several millions years ago, then this is not the book for them.

By contrast, what The Return of the Unicorn achieves is potency. It is a beautifully candid account of how to deal with the sobering reality of data collection on a very large species when sample sizes are limited. It illustrates, by example, how ecological investigation is made cogent for conservation. Critically, it demonstrates how people and their economies can be subsumed within a rich and diverse ecosystem so that a healthy future may be possible.

This is a book that all zoo administrators should read to help frame a perspective on how and why field science dovetails with planning and action to maintain systems in situ. And, this is the book that conservation pragmatists and cynics should read to discover why optimism about the conservation of (at least some) large mammals in human-dominated landscapes is not misplaced.