Serengeti III Human Impacts on Ecosystem Dynamics
edited by A. R. E. Sinclair, Craig Packer, Simon A. R. Mduma and John M. Fryxell
University of Chicago Press, 2008
Cloth: 978-0-226-76033-9 | Paper: 978-0-226-76034-6 | Electronic: 978-0-226-76035-3


Serengeti National Park is one of the world’s most diverse ecosystems, a natural laboratory for ecology, evolution, and conservation, with a history that dates back at least four million years to the beginnings of human evolution. The third book of a ground- breaking series, Serengeti III is the result of a long-term integrated research project that documents changes to this unique ecosystem every ten years.       
Bringing together researchers from a wide range of disciplines—ecologists, paleontologists, economists, social scientists, mathematicians, and disease specialists— this volume focuses on the interactions between the natural system and the human-dominated agricultural system. By examining how changes in rainfall, wildebeest numbers, commodity prices, and human populations have impacted the Serengeti ecosystem, the authors conclude that changes in the natural system have affected human welfare just as changes in the human system have impacted the natural world. To promote both the conservation of biota and the sustainability of human welfare, the authors recommend community-based conservation and protected-area conservation. Serengeti III presents a timely and provocative look at the conservation status of one of earth’s most renowned ecosystems.  


A. R. E. Sinclair is professor in the Biodiversity Research Centre at the University of British Columbia. Craig Packer is professor of Ecology, Evolution, and Behavior at the University of Minnesota. Simon A. R. Mduma is director of the Tanzania Wildlife Research Institute. John M. Fryxell is professor of integrative biology at the University of Guelph.


“This book builds on the previous two volumes on the Serengeti ecosystem. The first volume, Serengeti: The Dynamics of an Ecosystem synthesizes the previous twenty years of research on herbivore-carnivore population dynamics and vegetation-herbivore systems. The second, Serengeti II updates information on ecosystem dynamics, conservation, and changes brought about by a growing population of pastoralists and agriculturalists surrounding the Serengeti. Serengeti III focuses on major changes taking place in this ecosystem and their impact on the future, intensified by the growing human population near the protected area. In sixteen multiauthored chapters, ecologists, paleontologists, epidemiologists, economists, social scientists, and mathematicians report on a program that integrates socioeconomic research and decision making with ecological research. The goal is to develop a better understanding of the feedback loop between natural and human components of the Serengeti ecosystem. This work is best studied in the context of the other two volumes. The three together provide an unparalleled long-term study of natural and anthropogenic changes to a large, intact ecosystem and offer approaches to conservation. A critical addition to the conservation biology library. . . . Essential.”
— Choice

"This book illustrates the complexity of the challenges ahead for the Serengeti ecosystem, as well as the need for integrative, multidisciplinary approaches."
— Nathalie Pettorelli, Ecoscience

"An important extension of previous volumes and a valuable case study in community-based conservation."
— Ian Powell, Biologist

"Serengeti III's value lies in its extensive coverage of the ecosystem processes, providing the background for conservation planning and management. . . . A valuable and important reference for students, scientists and managers in landscape ecology, park management, rangeland management, wildlife conservation, and social ecology."
— W.G. Doerrgeloh, Integrative and Comparative Biology

Serengeti III belongs on the shelves of any ecological research or teaching library in the world, and in the private collections of all those who have a more than passing interest in African ecology.”
— African Zoology

“The book brings much new material and novel analyses, particularly modeling expertise, to build on existing work. It also heralds a change of emphasis. . . . This is in recognition that in order to understand the changes Serengeti has seen and its different possible futures, it is necessary to move on from the biophysical ‘hard’ science to the difficult science of social, economic and political drivers. This is an exciting and groundbreaking move. . . . I am already looking forward to Serengeti IV.”
— Pastoralism: Research, Policy and Practice


Preface and Acknowledgments

- Craig Packer, Stephen Polasky
DOI: 10.7208/chicago/9780226760353.003.0001
[Serengeti, ecosystem, ecological systems, conservation, socioeconomic research]
This third volume of the Serengeti series develops a fully integrated research program that includes socioeconomic research on human activities and human decision making, in concert with ecological research. The major goal is to begin to understand the complex feedback loops between natural and human components of the greater Serengeti ecosystem and how their disturbance propagates throughout the system. Serengeti III is principally the outcome of a series of workshops held at the National Center for Ecological Analysis and Synthesis (NCEAS) in Santa Barbara, California, in 2001, 2002, and 2003. A secondary outcome of the workshops was the eventual award of an NSF grant on the Biocomplexity of the Serengeti, which in turn sponsored a workshop in the Serengeti National Park in 2004. The NCEAS workshops and the Biocomplexity grant produced a shared database and a related series of mathematical approaches to model the Greater Serengeti ecosystem, leading to this book. The book addresses two main questions. First, how can new insights from complex ecological systems help improve the management of the greater Serengeti ecosystem? Second, can our knowledge of the Serengeti enhance the understanding and conservation of other ecosystems? (pages 1 - 6)
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- A. R. E. Sinclair, J. Grant C. Hopcraft, Han Olff, Simon A. R. Mduma, Kathleen A. Galvin, Gregory J. Sharam
DOI: 10.7208/chicago/9780226760353.003.0002
[Serengeti ecosystem, human-nature interactions, geography]
This chapter discusses recent historical changes in the Serengeti ecosystem and possible future changes. It sets the scene for the later analysis and modeling of the human-nature interactions. First, it describes the Serengeti in terms of geography, climate, soils, habitats, and animals, and places it in the human context of surrounding tribes and the larger region. Second, it gives an overview of available information on the ecosystem. Third, it outlines the various changes to the system that are either currently occurring or are expected in the future. These are treated as experimental perturbations, with which to alter the models in later chapters. These changes are described, and why and how they may occur. (pages 7 - 46)
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- Charles R. Peters, Robert J. Blumenschine, Richard L. Hay, Daniel A. Livingstone, Curtis W. Marean, Terry Harrison, Miranda Armour-Chelu, Peter Andrews, Raymond L. Bernor, Raymonde Bonnefille, Lars Werdelin
DOI: 10.7208/chicago/9780226760353.003.0003
[migratory system, geoecology, eastern plain, wildebeest, zebra, Mara River, Lake Victoria, large mammals, hominin]
This chapter considers three aspects of the evolution of the Serengeti–Mara ecosystem, focusing on the possible origins of a broadscale migratory system. Firstly, it examines the geoecology of the system, including the evolution of the eastern plain, the wet-season pasture of the wildebeest and zebra today, and the Mara River and Lake Victoria as potential drought refugia. Secondly, it sketches the evolution of large mammals, especially the larger herbivores and carnivores. Thirdly, it assesses the hominin factor, the use of the system by prehistoric hunter-gatherers and pastoralists, and the more dramatic historical human impacts. (pages 47 - 94)
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- Han Olff, J. Grant C. Hopcraft
DOI: 10.7208/chicago/9780226760353.003.0004
[human population density, land use, rainfall, soil fertility, herbivores, East Africa, hunter-gatherer, ecotourism, wildlife, savannas]
This chapter analyzes how current human population density and land use respond to environmental gradients, with an emphasis on rainfall and soil fertility, and compares this to the responses of large resident herbivores. It identifies historic shifts that led to intensified human land use in East Africa, identifying three distinct phases: hunter-gatherer, agripastoralist, and modern commercialized societies. These three historic phases of human land use are analogous to current main land use systems in the Serengeti–Mara ecosystem: (1) parks for wildlife and ecotourism; (2) protected multiple-use areas where people and wildlife coexist; and (3) the rural/village areas, with agricultural and livestock systems managed by a variety of more or less formal land tenure systems. This sets the scene for a discussion of the resource basis of human-wildlife interactions in savannas, from which we can learn to manage these interactions better in the future. (pages 95 - 134)
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- T. Michael Anderson, Jan Dempewolf, Kristine L. Metzger, Denné N. Reed, Suzanne Serneels
DOI: 10.7208/chicago/9780226760353.003.0005
[abiotic sources, biotic sources, heterogeneity, Serengeti]
This chapter describes the abiotic (e.g., soils, climate, landscape) and biotic (e.g., plant, animal) patterns of heterogeneity in the Serengeti, and identifies processes that contribute to their generation and maintenance. It describes patterns of heterogeneity in terms of the nature of their measurement—whether qualitative or quantitative—and the extent to which they included a spatial component. Furthermore, it identifies how humans have impacted natural patterns of heterogeneity across the Serengeti ecosystem within the last century. Because abiotic and biotic sources of heterogeneity can interact in complex ways and can produce unpredictable results, the chapter concludes by discussing three examples of heterogeneity generated and maintained by complex interactions between abiotic and biotic sources. (pages 135 - 182)
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- Mark E. Ritchie
DOI: 10.7208/chicago/9780226760353.003.0006
[environmental change, Serengeti ecosystem, atmospheric CO2, climate change, nitrogen, food web]
This chapter examines the likely global-level environmental changes that will affect the Serengeti, and the impact of these changes on the functioning of the Serengeti ecosystem and its member humans, habitats, flora, and fauna. In particular, it focuses on the impact of elevated atmospheric CO2, climate changes in rainfall and temperature, and increased deposition of nitrogen. The chapter considers both the projections of several different general circulation models and, where data are available, regional observed trends in climate over the past 50 years. Average and variability in rainfall in the Serengeti ecosystem should continue to decline over the next three decades. Temperature is expected to increase by perhaps 1°C over this same time period. CO2 concentrations are expected to increase by another 75–100 ppm. These global changes should result in somewhat lower aboveground productivity but increased nutrient concentrations, creating cascading changes through the diverse food web of the Serengeti. Changes in rainfall may also alter the distribution of grassland versus woodland and free surface water, which will further alter the distributions of wildlife and livestock. (pages 183 - 208)
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- Sarah Cleaveland, Craig Packer, Katie Hampson, Magai Kaare, Richard Kock, Meggan Craft, Tiziana Limbo, Titus Mlengeya, Andy Dobson
DOI: 10.7208/chicago/9780226760353.003.0007
[pathogens, canine distemper virus, rabies, rinderpest, anthrax, malignant catarrhal fever, trypanosomiasis, HIV, AIDS]
This chapter describes research on specific pathogens that illustrates the multiple roles of infectious diseases in the Serengeti, including (a) impacts on individual hosts (canine distemper virus); (b) threats to endangered populations (rabies) and to the ecosystem (rinderpest); (c) impacts of disease on community structure and vegetation dynamics (rinderpest and anthrax); (d) wildlife as reservoirs of diseases that threaten livestock economies (malignant catarrhal fever) and human health (trypanosomiasis); (e) the consequences of animal diseases on rural poverty and land use decisions around the Serengeti; (f) the dynamics of multiple-host pathogens; and (g) the impact of major human diseases (Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome). (pages 209 - 240)
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- Robert D. Holt, Peter A. Abrams, John M. Fryxell, T. Kimbrell
DOI: 10.7208/chicago/9780226760353.003.0008
[ecosystem response, lions, wildebeests, mortality, grass species, Serengeti ecosystem]
This chapter uses some simple models to determine what kinds of predictions can be made about ecosystem responses to some plausible perturbations, and what additional information is needed to either enable or improve these predictions. It begins by proposing three potential perturbations: (1) increased mortality of lions, which could arise due to upsurges in disease such as canine distemper, or direct attacks from humans; (2) increased mortality of wildebeest, which, for instance, could reflect an outbreak of rinderpest; and (3) an increase in the growth rate of the major grass species (a potential, although far from certain, outcome of global climate change). It then evaluates current knowledge of the Serengeti food web and applies it to the task of determining the consequences of these perturbations. In addition to assessing how well the fate of major players within the ecosystem can be predicted, this exercise can shed light on the potential ability to make similar types of predictions in other ecosystems. (pages 241 - 276)
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- John M. Fryxell, Peter A. Abrams, Robert D. Holt, John F. Wilmshurst, A. R. E. Sinclair, Ray Hilborn
DOI: 10.7208/chicago/9780226760353.003.0009
[species diversity, large ungulates, Serengeti ecosystem, competitive exclusion]
Two characteristics define the Serengeti grazer community in the minds of many observers: exceptional species diversity and exceptional mobility. Twenty-eight species of large ungulates are found in the greater Serengeti ecosystem. Many of these species have similar resource needs and occupy similar habitats. Under these circumstances, one would normally expect to witness competitive exclusion by the dominant competitor and hence reduced diversity; yet there is unparalleled diversity in the Serengeti. This chapter uses simulation models to explore three possible explanations for this seeming paradox, all of which point to size variation among herbivores, spatial variation in resources, and behavioral responses to this variation. The first hypothesis is that no grazer is consistently at a competitive advantage. A second plausible hypothesis is that Serengeti grazers facilitate each other, rather than compete for food resources. A third hypothesis is that seasonal migration by the predominant species—the wildebeest—prevents competitive exclusion of other grazers. (pages 277 - 300)
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- Christopher Costello, Nicholas Burger, Kathleen A. Galvin, Ray Hilborn, Stephen Polasky
DOI: 10.7208/chicago/9780226760353.003.0010
[local communities, wildlife, Serengeti, conservation]
This chapter develops a model of the interactions between local communities, wildlife, and management options in the Serengeti. The purpose is to provide a framework for analyzing management decision making and to evaluate different strategies for improving the lives of local people while preserving the park's wildlife. The chapter begins by describing the joint human-ecosystem model, including the model of household decision making, production and consumption, and how human population, livestock numbers, and wildlife populations evolve through time. It then explains the parameter values used in the model. Some results of several hypothetical scenarios are provided to illustrate the model's application. (pages 301 - 324)
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- Kathleen A. Galvin, Steven Polasky, Christopher Costello, Martin Loibooki
DOI: 10.7208/chicago/9780226760353.003.0011
[livelihood strategies, Serengeti National Park, household livelihoods, human vulnerability, resilience, climate variability, market prices, maize, bushmeat]
This chapter has the following objectives: (1) it places the decision making and livelihood strategies of people who live on the west side of Serengeti National Park within a conceptual framework of adaptation and vulnerability; (2) it looks at livelihood strategies of those people who live on the west side of Serengeti National Park; (3) it uses a household, individual-based model to address scenarios of change that may affect household livelihoods; and (4) it addresses the model implications for human vulnerability and resilience. The scenarios chosen include one of increasing climate variability, through changes in average annual precipitation and changes in variability of precipitation; and one that addresses the change in market prices for maize and for bushmeat. (pages 325 - 346)
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- Stephen Polasky, Jennifer Schmitt, Christopher Costello, Liaila Tajibaeva
DOI: 10.7208/chicago/9780226760353.003.0012
[Tanzania, national policy international policy, human demography, land use, antipoaching policy, wildlife management areas, human population dynamics]
This chapter begins by reviewing important national and international policies that set the institutional context for the Serengeti ecosystem. Though the greater Serengeti ecosystem contains portions of Tanzania and Kenya, the discussion focuses on Tanzanian national policy. Policies determined at the national level in Tanzania define allowable human uses in various land designation categories. On the international level, the most important policy that affects the Serengeti ecosystem is the Convention of International Trade in Endangered Species. The chapter also examines the influence of changes in human population on the Serengeti ecosystem. The household model developed in Chapter 10 is used to simulate the impact on the Serengeti ecosystem of three potential changes in policy, economic, and demographic conditions. In particular, it explores the effects of: (1) changes in antipoaching policy; (2) the establishment of wildlife management areas; and (3) changes in human population dynamics. (pages 347 - 378)
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- Mike Norton-Griffiths, Mohammed Y. Said, Suzanne Serneels, Dixon S. Kaelo, Mike Coughenour, Richard H. Lamprey, D. Michael Thompson, Robin S. Reid
DOI: 10.7208/chicago/9780226760353.003.0013
[land use, Maasai households, wildlife tourism, Mara, land development, group ranches]
The northern part of the Serengeti/Mara ecosystem falls within the two Kenyan districts of Narok and Trans Mara. Within these two districts, major land use changes have been clear for quite some years. Previous work indicates that losing what are called the group ranches that surround the Maasai Mara National Reserve and the Mara Triangle could cause a permanent loss of perhaps 20% of the migratory wildebeest, which in turn could trigger major changes in the Serengeti ecosystem itself. These changes in land use are perplexing in view of the large revenues generated from wildlife tourism which should encourage investment in conservation on the part of landowners rather than land development. This chapter examines the apparent contradiction between the revenues generated by wildlife, on the one hand, and the land use changes initiated by the Maasai on the other. The objective is to describe the economic conditions of the Mara portion of the Serengeti ecosystem within which individual economic agents—Maasai households—are making decisions about land use investment and development. (pages 379 - 416)
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- Ray Hilborn, A. R. E. Sinclair, John M. Fryxell
DOI: 10.7208/chicago/9780226760353.003.0014
[Serengeti ecosystem, habitat, anthropogenic perturbations, species diversity, migration]
The Serengeti ecosystem is of special importance both because of the unusual diversity of wildlife, birds, and other taxa, and because it is one of the few large ecosystems that has been well studied, is largely unaltered by human agriculture and forestry, and has been subject to a wide range of perturbations. The perturbations are both natural and anthropogenic, and provide an opportunity to examine how naturally functioning ecosystems respond to both natural and direct human-induced perturbation. This chapter begins with a discussion of the major perturbations seen in the Serengeti. It then reviews the theories available to understand Serengeti dynamics, and specific models of components of the system. The uniqueness of the Serengeti is seen in the size and scale of the migration, the diversity of species, and the scale and diversity of the habitat, which remains in a wild state. None of the enormous natural and anthropogenic perturbations have significantly altered any of these three characteristics. (pages 417 - 442)
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- Simon Thirgood, Charles Mlingwa, Emmanuel Gereta, Victor Runyoro, Rob Malpas, Karen Laurenson, Markus Borner
DOI: 10.7208/chicago/9780226760353.003.0015
[Tanzania, conservation, protected areas, national park, local communities]
This chapter focuses on the financial structure supporting conservation activities in the Tanzania sector of the Serengeti ecosystem. It starts with an introduction to the management authorities responsible for the different components of the protected-area network that together comprise the Tanzanian Serengeti. It then gives a detailed budget breakdown of revenues and expenditures for the national park and surrounding protected areas for the period 1998–2002, to assess whether financial returns from tourism and other forms of wildlife utilization are sufficient to finance conservation in the Tanzanian sector of the ecosystem, or whether external financial support is required. It also assesses the financial returns to local communities resident in the multiple-use buffer areas adjacent to the core protected areas from both consumptive and nonconsumptive use of wildlife. Finally, the chapter attempts to predict how conservation activities in the different components of the Tanzanian Serengeti might be financed in the coming decade and how this may impact local communities. (pages 443 - 470)
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- A. R. E. Sinclair
DOI: 10.7208/chicago/9780226760353.003.0016
[biota, human welfare, conservation, community-based conservation, protected-area conservation, sustainability]
This chapter argues that both the conservation of biota and the sustainability of human welfare require the combination of community-based conservation and protected-area conservation. Each is essential, but neither is sufficient alone for the conservation and sustainability of resources. Unless human population increase in areas surrounding protected areas is stopped—even reversed—the future of conservation in both the community areas and the protected areas will be seriously compromised. At the same time, the most effective way to increase human wealth is to slow population growth. (pages 471 - 496)
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Appendix: The Main Herbivorous Mammals and Crocodilesin the Greater Serengeti Ecosystem - Simon A. R. Mduma and J. Grant C. Hopcraft