Serengeti IV

Sustaining Biodiversity in a Coupled Human-Natural System

Anthony R. E. Sinclair, Kristine L. Metzger, Simon A. R. Mduma, John M. Fryxell, Anthony R. E. Sinclair, Kristine L. Metzger, Simon A. R. Mduma, John M. Fryxell

• Publisher: University of Chicago Press
• Year: 2015
• ISBN:
  9780226196336
• Topic: Scienze biologiche
• Subtopic: Scienza generale

The vast savannas and great migrations of the Serengeti conjure impressions of a harmonious and balanced ecosystem. But in reality, the history of the Serengeti is rife with battles between human and non-human nature. In the 1890s and several times since, the cattle virus rinderpest—at last vanquished in 2008—devastated both domesticated and wild ungulate populations, as well as the lives of humans and other animals who depended on them. In the 1920s, tourists armed with the world's most expensive hunting gear filled the grasslands. And in recent years, violence in Tanzania has threatened one of the most successful long-term ecological research centers in history. Serengeti IV, the latest installment in a long-standing series on the region's ecology and biodiversity, explores the role of our species as a source of both discord and balance in Serengeti ecosystem dynamics. Through chapters charting the complexities of infectious disease transmission across populations, agricultural expansion, and the many challenges of managing this ecosystem today, this book shows how the people and landscapes surrounding crucial protected areas like Serengeti National Park can and must contribute to Serengeti conservation. In order to succeed, conservation efforts must also focus on the welfare of indigenous peoples, allowing them both to sustain their agricultural practices and to benefit from the natural resources provided by protected areas—an undertaking that will require the strengthening of government and education systems and, as such, will present one of the greatest conservation challenges of the next century.

One

Conservation in a Human-Dominated World

Anthony R. E. Sinclair and Andy Dobson

The world’s few remaining protected ecosystems are becoming progressively threatened from human exploitation. Serengeti is one outstanding example of a protected area that retains an almost complete biota that has existed for millennia (Peters et al. 2008). It also generates substantial revenue from tourism that goes toward supporting the remaining protected areas in Tanzania. The system is therefore important as a globally significant biodiversity site and as a mainstay of the Tanzanian economy. Yet the Serengeti National Park is under threat both from within and outside of Tanzania. Development from proposed roads through the protected area and airports adjacent to it will have negative impacts possibly causing the decline of the wildebeest migration and alter the whole ecosystem (Dobson et al. 2010; Sinclair 2010; Holdo et al. 2010). Rhetoric against protected area conservation in general has lead to proposals for a focus on conservation in human-dominated ecosystems at the expense of protected areas (Shellenberger and Nordhaus 2011; Kareiva and Marvier 2012). These statements beg three important questions: Do protected areas play a role in conservation that is not achieved in human ecosystems? Can human dominated systems contribute to conservation objectives? Do these two—protected areas and human-dominated areas—support each other? We examine these questions in this volume. The natural ecosystem is changing from environmental disturbances within and human impacts outside the system. We ask how the greater Serengeti ecosystem, including both the human and natural components, can be made sustainable in the face of these changes.

Many of the chapters in this volume are central to a larger argument in conservation biology that urges society to move away from the protected area paradigm and to focus on altered landscapes outside parks, a world that is being taken over and modified by humans. We recognize that new approaches to conservation are needed in a world of burgeoning human numbers, but this does not mean that protected areas have no useful function. The chapters, therefore, address both the function of the protected ecosystem and the contribution of the human system that surrounds it.

To place this volume in a broader context we review briefly the background to the debate on what was originally called community-based conservation in contrast to protected area conservation. The original, historical policy of conservation has been to secure areas such as national parks and reserves to maintain a suite of biota that was disappearing in the face of human exploitation. Yellowstone National Park in the United States was an early example, a response to the combination of illegal settlement, vandalism, and wildlife slaughter which put the US Army in charge of the park in 1886 (D. Houston pers. comm.; see also Olliff et al. 2013). Kruger National Park in South Africa was the first such protected area in Africa (proclaimed by the Transvaal Republic in 1898 as the Sabi Game Reserve), a reaction to encroaching agriculture and extermination of wildlife from grazing lands (Carruthers 1995; N. Owen-Smith, pers. com.). Since then a large number of protected areas have been set up around the world specifically to provide protection for biota (Wright 1996; Nelson and Serafin 1997; Terborgh et al. 2002; Stolton and Dudley 2010) and clearly larger ones do provide protection (Cantú-Salazar and Gaston 2010). A selected set of such areas has been designated as World Heritage Sites since 1972.

However, the past two decades have seen a movement toward community-based conservation (CBC), the attempt to maintain sustainable biological communities in the presence of human exploitation, largely in agriculture and forestry-dominated systems (Bhagwat et al. 2008; Harvey et al. 2008; Chazdon et al. 2009). The motive for CBC was threefold. First, a considerable proportion of the world’s biota, some 50%, fall outside of protected areas (Sinclair 2008) and it is necessary to find some way of preserving this. Second, protected areas are failing to meet their objectives; many are experiencing attrition of territory (Sinclair et al. 1995) and losing biota (Craigie et al. 2010). For example, in an analysis covering 20–30 years of 60 tropical forest reserves around the globe, Laurance et al. (2012) found that half experienced loss of biodiversity over a wide array of animal groups. Habitat modification, exploitation, and hunting were the main disturbances. Third, no protected area is a self-sustaining system in isolation, not even the largest area (Lindenmayer, Franklin, and Fischer 2006). The analysis of forest reserves showed that environmental changes outside were as important as those inside in determining the course of ecological change. All protected areas rely on processes that emanate from outside, whether these be water flows from rivers, recolonization of plant communities, or dispersal of animals; in short, no park is an island (Janzen 1983). Thus, to maintain a protected area indefinitely we must maintain the greater ecosystem within which it is embedded. The combination of reserves and agriculture can maintain a majority of the biota in some cases; Daily et al. (2003) demonstrate this for forests and coffee estates in Costa Rica. So in this volume we examine whether the Serengeti is maintaining its biota, and how it relies on outside influences.

The problems with protected area conservation provide the rationale for renewed conservation efforts in human ecosystems. Much of community-based conservation still focuses on preserving the biota rather than the needs of the people (Harvey et al. 2008), but unless the aspirations of humans are placed as a top priority there will be no conservation (Wells and McShane 2004; Garcia et al. 2009). Several of the chapters in this volume document the livelihoods, health, and welfare of the peoples and explore how the Serengeti benefits and impedes them.

The new debate argues that a world already at 7 billion and heading toward 10 billion people will simply overrun protected areas by 2100 in the scramble for new resources, and we may as well recognize that eventuality. To some extent this is already happening (Scholte 2003; Scholte and de Groot 2009). These peoples, largely in the developing world, emulating present- day western societies, will demand and achieve energy-expensive lifestyles. Thus, if we are to save the world’s natural heritage we must embrace technology and “garden” our environments—we create novel ecosystems (Rosenzwieg 2003; Shellenberger and Nordhaus 2011; Kareiva and Marvier 2012; Doak et al. 2013, 2014; Marvier and Kareiva 2014). Humans live not in natural ecosystems but in human ecosystems modified by agriculture, forestry, urbanization, and industry. Ellis (2011), Sagoff (2011), and Kareiva, Lalasz, and Marvier (2011) argue that these areas have been extremely resilient to human population and climate change over the past centuries. This view contrasts with what they claim was a prevailing concept of nature as fragile, ready to collapse with any disturbance. Thus, conservation in the twenty-first century must embrace human-made systems. If it is to be relevant it must move away from protected areas as the old model, and use technology to conserve the new biota (Kareiva, Lalasz, and Marvier 2011). This, then, is the argument of the new “gardeners” of the world.

Despite the certainty with which these statements are made, evidence is not entirely consistent with them. The authors point to the meta-analysis of Jones and Schmitz (2009), which showed that many ecosystems can recover from single human perturbations, a pulse; these could be “accidents” from inadvertent human impacts. But this is not the issue. The question is whether human ecosystems under persistent, chronic abuse can maintain both viable processes and a majority of the biota—a press perturbation—and the data would suggest that the systems would not recover under such persistent exploitation (Rosenzweig 2003). Thus, one major set of problems with community-based conservation relates to its lack of sustainability. Problems arise with sustainable harvesting of wildlife populations, increasing expectation of livelihoods, shrinking land areas, and increasing human numbers (Sinclair 2008). The claim that agricultural systems have been sustainable and resilient over historical time is questionable. The progressive loss of both biodiversity and ecosystem processes in British and European agricultural systems, due to intensification of the agribusiness, is now well documented (Donald, Green, and Heath 2001; Gregory, Noble, and Custance 2004; Gaston and Fuller 2008; Gaston 2010; Cardinale et al. 2012). There is a similar decline in the avifauna of the eastern forests of North America probably due to changes in both the Neotropical forests and temperate woodlands (Terborgh 1992). Soil loss destroyed 40,000 km² of cropland in the United States by 1979 due to the continued application of fertilizers; productivity has declined (Jackson 1980 in Rosenzweig 2003; Myers and Kent 1998) and caused distortions of the ecosystem (Jefferies, Rockwell, and Abraham 2004). The development of agriculture across Australia, through the removal of eucalypt woodlands, has resulted in progressive salinization of soils and continuing loss of agricultural production (Grieve 1987; McFarlane, George, and Farrington 1993). Rangelands that have been shared by humans and abundant wildlife for thousands of years now show signs of collapse (Harris et al. 2009)—the great herds of migrating Tibetan antelope (Panthalops hodgsoni), gazelle (Procapra picticaudata), and wild ass (Equus kiang) on the Tibetan Chang Tang Reserve have almost gone (Schaller 1998); the migrations of Saiga antelope (Saiga tatarica) in Kazakhstan have collapsed (Milner-Gulland et al. 2001), and the wildebeest migrations of Botswana have disappeared (Williamson, Williamson, and Ngwamotsoko 1988). The staggering loss of biota in New Zealand with the arrival of humans in 1300 resulted in a change in species composition and loss of ecosystem function (Atkinson and Cameron 1993; Cooper et al. 1993; Campbell and Atkinson 1999; Worthy and Holdaway 2002); there is no sense of sustainability and species continue to decline toward extinction today (Sinclair and Byrom 2006).

In 1700 most of the world’s terrestrial biomes were without humans (over 50%) or seminatural (45%), with only minor use for agriculture and settlement. By 2000 only 25% was wild and 20% seminatural, the rest now under human modification. For the future most terrestrial ecosystems will be under human modification (Ellis et al. 2010). These authors conclude that conservation must focus on the remaining remnants, or recovering ecosystems embedded within human-modified systems. It has also been suggested that the progressive deforestation of Europe from the Middle Ages (1250) to the 1800s resulted in the concomitant increase in albedo and hence environmental cooling, seen as the “little ice-age.” This temperature trend was only reversed by a similarly unsustainable increase in temperature starting with the Industrial Revolution in the early 1800s (Britannica 2008). In short, although one can point to some examples where biota have returned to human-modified landscapes, there is a far greater array of cases showing that the historical impacts of humans were unsustainable and continue to be so into the future.

But the debate is not really about that dichotomy. Rather, it concerns whether we can create sustainable human landscapes and whether protected areas are a necessary component of this, as Daily et al. (2003) have illustrated. The present volume addresses this issue.

The assertions made by the new “gardeners” of human ecosystems that they are sustainable and resilient need to be tested by comparison with areas that have less human impact. These are de facto the protected areas; they are the controls for human impacts. This is one fundamental reason why protected areas must not be lost; their presence is the best way of judging whether community-based conservation is sustainable, and that human ecosystems are robust. What protected areas are not—and in the modern context not intended to be—are “pristine, prehuman landscapes” as suggested by Kareiva, Lalasz, and Marvier (2011). Historically some may have thought that way (Adams 2003), but it is not the prevailing concept of protected areas today (Jope and Dunstan 1996; Wright and Mattson 1996).

In this book we examine the greater Serengeti ecosystem with two sets of questions in mind. First, what is the biodiversity inside the protected area, and the nature of the heterogeneity that affects it, and is the system sustainable? To address these questions we describe the spatial and temporal variation in the environment, the responses of the biota to this variation, and the changes in the system as a whole.

Second, what are the dynamics of the human ecosystem, and what would be required to make the human-wildlife interaction sustainable? We analyze aspects of human livelihoods to identify what is required to further the development of local communities. We further document changes in the biota and suggest ways to mitigate human impacts while advancing the aspirations of the people.

We divide the chapters into five sections. The first section addresses the issue of what determines biodiversity in the Serengeti. We address the effects of abiotic environmental heterogeneity (Metzger et al.), disturbance from fire (Eby et al.), and climate (Fryxell et al.) on biodiversity, then go on to describe plant diversity (Anderson et al.) and the role of the huge migrating herds in seasonal and spatial diversity (Hopcraft et al.).

In the second section, disturbance effects on biodiversity are documented for microbes (Verchot et al.), plant dynamics in forests (Turkington et al.), insects in general (de Visser et al.) and butterflies in particular (Sinclair et al.), rodents (Byrom et al.), birds (Jankowski et al., Nkwabi et al.), and carnivores (Craft et al.). These provide the data to examine how disturbance within the protected area and human influences outside alter biodiversity.

The third section documents the human social and ecological systems in the agricultural west (Eli Knapp et al.) and pastoral east (Galvin et al.), the changes in agriculture (Estes et al...