When nature won’t stay still: Conservation, equilibrium and control by William M Adams
Posted: Fri May 19, 2017 3:52 am
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In summary:
Bill Adams explores some of the implications of the growing discourse about non-equilibrium ecology for conservation. He argues that a deeper understanding of the complex processes involved in ecosystem change can give humans a new sense of control over nature, particularly visible in the rise of restoration ecology.
Adams, William H (Bill)
Bill Adams is Reader in the Geography of Conservation and Development at the Department of Geography, University of Cambridge, UK. He has written several books,including Future Nature: A Vision for Conservation(Earthscan,1996) and Green Development: Environment and Sustainability in the Third World (Routledge, 2001). He is interested in conservation and rural change, especially in Africa and the UK, and has served on the councils of the Cambridgeshire Wildlife Trust, the British Association for Nature Conservationists and Fauna and Flora International.
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When nature won’t stay still: Conservation, equilibrium and control
William M Adams
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FIELD WORK
Two memories suggest themselves to me. In the first, I am standing on the slope of a rounded limestone hill in southern England, looking south across a huge vista of woods and fields, the rolling lowlands of the Kentish Weald. Near at hand there is thin grass with the little bumps of ant hills, and on the hilltop the remains of a Bronze Age earthwork approximately 3500 years’ old. One or two of my fellow students are on their hands and knees, peering excitedly through hand lenses at grasses and flowers, and uttering the shrill squeaks of the conservationist at play. To our right lies what looks like a battlefield, a sea of hawthorn stumps and the ash mounds that marked the sites of small, hot fires. We are on a National Nature Reserve (NNR), a Site of Special Scientific Interest (SSSI), and this was the result of careful scientific conservation management. [1]
The reserve was famous for its chalk grassland plants and insects; but this ‘natural’ diversity was, in fact, artificial. Chalk grassland, I was being told, was human-made, an ‘anthropogenic ecosystem’, ‘semi-natural’ vegetation. In the intense agricultural and urbanized landscape of south-east England, nothing remained of the mix of vegetation communities that must once have existed on the unoccupied chalk and clays left at the end of the last glacial maximum 10,000 years ago. As the climate shifted, and plants and animals and eventually people arrived, the landscape changed, and ‘natural’ vegetation was forced to change with it. Under tens of centuries of human management, plants and insects that could thrive on the nutrient-poor limestone of the chalk hills, and cope with the inexorable nibbling of countless generations of sheep, accumulated in wonderfully diverse assemblages in what ecologists during the 20th century came to call chalk grassland.
I was told that human action had destroyed the ‘natural’ post-glacial vegetation. However, in its place anthropogenic activity had created a diverse, new vegetation assemblage in which a multitude of plants and insects found a foothold. In time, this, too, began to disappear. People had long ago cleared and ploughed almost all the rest of the chalk downland in southern England (especially during the period since World War II), and the chalk grassland species, presumably once common, were now rare. As a result, the whole of a much wider heritage of natural diversity was invested in this fragment of human-created sward. That is why it was a nature reserve.
However, even in a nature reserve it seemed that nature could not be left to itself.In this environment,chalk grassland was not a stable equilibrium vegetation community. Left alone, this grassy paradise would slowly turn into a dull, species-poor scrubland and, eventually, woodland. The only way to keep the diversity of grassland species was to stop vegetation succession. Conservation management was needed in order to hold back the tendency of nature to restore the natural balance. Since World War II, chalkland sheep-grazing had become uneconomic, the grassland had become rougher, and the scrub moved in – hence, the need to cut and remove the scrub in order to reset the clock of ecological succession at the stage with maximum species richness.
A second memory occurs a couple of years later and far away. I am peering through the windscreen of a Land Rover in northern Nigeria at a patch of bare soil, surrounded by scrubby trees. The screech of acacia thorns against the body work has mercifully stopped, and we are in an area of totally bare land in a clearing in the grazing reserve through which we have been driving. It is long after the rains and blindingly hot. We get out to inspect vegetation and soil. At some time in the past, people have cleared and cultivated this land. The lines of the cultivation ridges are still visible, but the soil has sealed over and the surface is mirror hard. Nothing grows now, not even weeds. The acacia trees have failed to recolonize. The land seems irrevocably spoiled. My companion is kicking the toe of his shoe against the hard surface, muttering and shaking his head.
A few kilometres on, we stop again in a new clearing in the thin forest. This time we find a small stockade of cut thorn branches with a large white bull inside. It is part of a Fulani pastoralist camp; but there is nobody about. The bull is tall and rangy, but surprisingly sleek. A pile of green branches has been cut for fodder, for on the dry, grey earth there is only a faint suggestion of wispy grass stems. On the edge of the clearing, small, scrubby acacia trees have been half-cut through quite recently and their green leaves eaten; others have been cut to make the small stockade. This seems like the scene that must logically precede the one before, where the healthy forest is being cut by unwary people, eventually to be farmed and spoiled, and abandoned. We talk about the processes that seem to be going on, the probability that the grazing reserve is slowly being destroyed by overgrazing. We eventually drive away, the Land Rover still protesting at the thorns.
At the time, these experiences seemed to offer classic morality tales. On the chalk hills of England, careful conservation management was needed to maintain the diversity of nature against its own powers of deterioration. In Nigeria, on the edge of the Sahel, management was required to stop people from destroying the environment. There were too many people in the wrong place, trying to grow crops on degraded soil and exhausting the soil, or cutting trees to feed livestock because the grassland was overgrazed. At that time, in the aftermath of the ‘Sahel drought’ of the early 1970s, the problem of desertification was a hot topic of debate in seminar rooms and learned journals. To me, conditioned by the literature on drought and human-induced desertification in the Sahel, it was easy to build in my mind a scenario for the future of these places. It was one of environmental degradation, with the natural vegetation progressively transformed by people and their livestock, the natural productivity of the land destroyed by unsustainable land use, the balance of nature upset by human action. It did not occur to me that this interpretation might be wrong. It did not (at least, not then) occur to me to wait until the bull’s owner returned to see what he thought was happening in that hot place. [2]
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THE BALANCE OF NATURE
The balance of nature is a powerful symbol. It was the single ‘Big Idea’ that underpinned the environmental revolution that began during the 1960s in Europe and North America, and which progressed in various ways and at various speeds until the 1990s, when it was mainstreamed by the 1992 Earth Summit in Rio. There was a ‘balance of nature’ that humans had disrupted. This certainly seemed self-evident to me through my childhood (trekking to Alexandra Palace in London to see the National Nature Week exhibition in 1963, or watching television pictures of the oil tanker Torrey Canyon, aground and burning on Seven Stones Reef between Land’s End and the Scilly Isles in March 1967, and being bombed by the navy and the air force, while leaking Kuwaiti oil onto the Cornish coast). [3] To a child, the evidence was plain: nature was precious and under threat, it had found its own balance and this was being upset. People, in their greed and technological arrogance, were disrupting the balance of nature. As a basic environmentalist route-map to the ills of the late 20th century, the idea of nature in balance served me well enough for a long while, providing the oxygen for more late evening conversations and arguments with friends than I care to remember.
These ideas are as deep as the history of environmentalism (Grove, 1992; 1995). One need look no further than George Perkins Marsh’s Man and Nature (1864):
Nature, left undisturbed, so fashions her territory as to give it almost unchanging permanence of form, outline, and proportion.
…whenever the Indian, in consequence of war or the exhaustion of the beasts of the chase, abandoned the narrow fields he had planted and the woods he had burned over, they speedily returned, by a succession of herbaceous, arborescent and arboreal growths, to their original state. Even a single generation sufficed to restore them almost to their primitive luxuriance of forest vegetation (Marsh 1864, pp 29, 30).
Marsh’s theme was clear: nature established an equilibrium and humans disrupted it. This simple idea was still providing the take-home message of Rachel Carson’s Silent Spring, the proof text of Western environmentalism and the sound bite of countless television documentaries and Walt Disney animal movies 100 years after Marsh’s writing. [4] It reflects, too, ideas that ran through the science of ecology. When this was in its infancy, during the late 19th century, shortly after Marsh was writing, it took on board a powerful, organic metaphor of nature, a view of nature balanced and integrated and threatened by change from ‘outside’, from human action (Botkin, 1990; Livingstone, 1995).
The idea of a balance of nature continues to be seductive and to have a powerful appeal for environmentalists, in general, and conservationists, in particular. However, during the last decade of the 1990s, it began to be challenged by other ideas that suggest a more complex approach to understanding ecosystem change. These ideas allow nature much more dynamism and variability. No longer can the gendered image of rapacious human and passive equilibrial nature be accepted comfortably. [5] Using two case studies, this chapter describes the implications of this change for conservation in understanding nature. The first is the semi-arid lands of Africa, both the classic terrain of ‘big nature’ (the ‘big five’ and savanna national parks) and the home ground of African pastoral people. The second is the more domestic scale of small nature reserves in the densely packed and intensively managed rural landscape of the UK. Although, at one level, very different, common ideological currents run through conservationist thinking. In both cases, a challenge to the dominant mode of understanding nature as balanced and threatened offers radical and challenging opportunities for conservation action. First, however, let me explain what I mean by the ‘ecology of equilibrium’.
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THE ECOLOGY OF EQUILIBRIUM
During the first decades of this century, nature was portrayed by the emerging science of ecology as, essentially, rather static, an array of habitat fragments as natural objects. In this thinking, ecology drew (like conservation) on the strength of amateur natural history and the Victorian mania for collecting (Allen, 1976, Griffiths, 1996). The links between ecology and conservation in industrialized countries were very close. In Research Methods in Ecology, the American ecologist F E Clements provided a scientific basis for identifying vegetation ‘types’ (Clements, 1905; McIntosh, 1985). In the UK, Arthur Tansley drew on the work of amateur botanists to write the classic Types of British Vegetation (Tansley, 1911), and provided both a classification of vegetation and a framework for the first lists of proposed nature reserves in the UK (Sheail, 1976; Adams, 1996). When Clements developed ideas about plant succession, he suggested a process of continuous change towards a ‘climatic climax’. He likened the ‘vegetation formation’ to a complex organism ‘developing’ through time. This way of understanding ecological change drew deliberate analogies with the growth of individual organisms (Clements, 1916).
These ideas of vegetation as organism were subsequently challenged by Harold Gleason and by Tansley; but ecology’s dependence upon the organic metaphor survived. In 1920, Tansley argued against the idea that all aggregations of plants had the properties of organisms, and in 1935 he published a sharp critique of Clementsian thinking about the climatic climax (McIntosh, 1985). He suggested that succession involved complex patterns, with soils, physiography and human action all driving change in different (but specific) directions under different conditions. To capture this complexity he framed the new concept of the ecosystem (Tansley, 1935; 1939; Sheail, 1987). In time this, too, came to be understood as a balanced system whose components meshed and integrated to create equilibrium through negative feedback.
The development of increasingly sophisticated theoretical and experimental approaches to ecology eventually led to a more mechanistic framework of analysis. This was based upon Tansley’s concept of the ecosystem, to which the analysis of ecological energetics and, subsequently, systems analysis were applied (Tansley, 1935; Lindemann, 1942; McIntosh, 1985; Botkin, 1990). However, although the science of ecology developed in scope and sophistication, historians of ecology argue that the fundamental notion that ecosystems tended towards equilibrium endured (McIntosh, 1985; Worster, 1994). The classic ‘equilibrium paradigm’ in ecology dominated ecology until the 1970s (Steward et al, 1992). Ecological systems were closed, and ecosystems were self-regulating so that, if disturbed, they would tend to return towards an equilibrium state. This paradigm, in turn, fed ideas in the wider environmental movement, underpinning the notion that there was a balance of nature easily upset by inappropriate human action.
During the second half of the 20th century, when both ecosystem management, development planning and conservation were all becoming established in government planning, ecologists mostly portrayed nature as a kind of homeostatic machine (Pahl-Wostl, 1995). Nature was seen as a system whose state was maintained by processes of internal feedback; but it was also susceptible to external control. In fact, ecosystems were analysed as if they were ‘19th-century machines, full of gears and wheels, for which our managerial goal, like that of any traditional engineer, is steady-state operation’ (Botkin, 1990, p12). Human action could upset the delicate working of the machine; but, fortunately, the ecologist could diagnose the problem and (potentially, at least) work out how to put the balance right. Ecological science could therefore be used to generate technocratic recipes for managing nature. Ecologists coined words and concepts drawn from thermodynamics and engineering (such as system, energetics, equilibrium, feedback, balance and control) to describe nature. Conservationists, schooled in ecology, saw themselves in some senses as ‘engineers of nature’ (Livingstone, 1995, p368).
Ecological science also offered a series of ‘natural’ subdivisions of nature. This is the fruit of a desperate desire to classify, dating back to the origins of taxonomy (see Chapter 2 in this book). The arbitrary distinction between species and subspecies are universally accepted, although modern genetic techniques may prove to have some surprises for those conservationists whose programmes are dependent upon these categories. Attempts to provide a taxonomy at larger scales (habitat, ecosystem or vegetation community) are graced by convention, but are less satisfactory. These ‘natural’ units are quite clearly social constructs, whether or not they carry the imprimatur of Two-Way Indicator Species Analysis (TWINSPAN) (Hill, 1979) and the reliable algebra of the National Vegetation Classification (Rodwell, 1991). [6] The attempt to classify the turbulent diversity of nature is based upon assumptions of equilibrium. Only if nature stays still can science get a long enough look at it to provide a usable classification. In that nature is not still, science has to work as if it is. Nature is therefore treated as dynamic, but tending to equilibrium – diverse, but open to simple classification that is robust enough to be useful.
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CONSERVATION AND EQUILIBRIUM
Ideas of ecosystem equilibrium have been highly influential for conservation in the temperate environment of the UK. For British conservationists, it was for almost all of the 20th-century axiomatic that nature not only had to be reserved, but also managed within those reserves. Ecological ideas about ecosystem succession demonstrated nature’s own capacity to change in undesirable ways. Awareness grew of the capacity of nature itself to cause change that could bring about the loss of valued features of a reserve (for example, a rare species), particularly through ecosystem succession. As nature conservation became an accepted form of land use in the UK, after the end of World War II, conservationists had to establish rules for reserve management, and for this it drew upon ecological science.
Conservation needed science, and science needed conservation. It was believed that effective reserve management demanded ‘deep scientific knowledge’ of ecosystems: ‘paradoxically, we can ensure the survival of wild places of Britain only by finding out what happens when we interfere with them’ (Nicholson, 1957, pp26, 19). In 1964, Pearsall argued that ecological research required large nature reserves for experiments ‘large enough to allow [for] repeatable assessments of the systems or processes under investigation’ (Pearsall, 1964, p8). Some ecologists were reluctant to accept that wildlife communities might need to be managed (Duffey and Watt, 1970); but conservation demanded an interventionist approach in order to control nature.
Conservation adopted ecology’s language (system, equilibrium, balance, succession, competition, climax), and drew upon it to explain vegetation succession and to prescribe management treatments. In due course, ‘management by interference’ (Nicholson, 1957, p19) became the standard model and also, arguably, the distinguishing feature of British conservation (Henderson, 1992).
Woodwalton Fen in Cambridgeshire provides one example of the emerging need for intervention management. Until the mid 19th century, Woodwalton Fen was undrained, lying adjacent to the open water of Whittlesey Mere. In 1851, this last fenland mere was drained and reclaimed, Woodwalton Fen peat was dug and parts were cultivated. In 1910, it was purchased by a wealthy visionary, the banker Charles Rothschild, as a nature reserve. This purchase, of course, did nothing to stop the rapid plant succession taking place (Nicholson, 1970). By 1959, when the reserve was leased to the Nature Conservancy, about 90 per cent of it was covered with birch or sallow scrub. Many of the species for which it was originally famous had died out, or were close to doing so. The wetland had become a wood, standing like turf on a beach – a tuft of wet woodland, stranded by the drainage of the surrounding farmland that stretched as flat as a pancake away to the level line of the horizon, far away to the north-east.
Conservation of the fen’s fauna and flora seemed to demand decisive intervention. Ecological knowledge directed conservation action to control ecosystem succession, and a programme of clearance, followed by cattle grazing, was begun. It was argued that ‘detailed ecological knowledge’ would be required to maintain the vegetation in the forms that gave the fen its conservation interest (Duffey, 1970, p595).
Although the basic principles of managing wildlife habitat are, today, widely known and taught (see, for example, Green, 1981; Sutherland and Hill, 1995), when conservation was established institutionally during the 1940s, little research had been done. Knowledge of either the need for ecosystem management, or of how and when to intervene in order to maintain the desired characteristics of ‘seral, plagio or sub-climax ecosystems’ (Green, 1981, p178), was rudimentary, at best (Sheail, 1995). New knowledge and skills were required to manage National Nature Reserves. Neither contemporary agriculture (already obsessed with technical and economic ‘efficiency’ through intensification) nor forestry (focused since the end of World War I upon developing skills in tree-farming with exotic conifers, often in exposed upland sites) provided adequate models for very many of the new tasks of conservation.
New methods were required to manage less modified ecosystems for conservation, rather than production. These methods were progressively developed. Some involved the recovery of former rural management practices, such as cutting reed on wetlands, coppicing woodland or laying hedgerows. Some adapted farming systems, such as livestock grazing, but substituted a concern for altering grass swards (by resowing and fertilizing) to maximize production with a concern for maximizing plant or insect species diversity (through minimizing fertility and adjusting stock type and stocking density). After 200 years of animal breeding for production, conservationists rediscovered less improved breeds and ‘rare breeds’ of livestock; and even lowland fields and fens began to be grazed by Highland cattle, Hebridean sheep and Konik horses. Other techniques were more novel, including the use of mechanized cutters, manipulation of water levels or the selective use of herbicides (Green, 1981; Sutherland and Hill, 1995; Wallis DeVries et al, 2001). These skills were adapted and institutionalized into new and standardized regimes of management. They were shared within groups of often urban-based volunteers (for example, the British Trust for Conservation Volunteers) and became elements in formal college-taught courses.
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ECOLOGY CONSERVATION AND DISEQUILIBRIUM
New ideas of ‘non-equilibrium’ ecology call into question the tradition of intensive conservation management in places such as the UK that assumes that nature is (and should be) in equilibrium, and seeks to control ‘natural’ processes. The abundance and distribution of organisms, as well as the appearance of the landscape, are controlled by natural physical processes. One of the most important sources of disturbance in ecosystems is the working of physical processes in the landscape, particularly processes of erosion and deposition (Werrity et al, 1994). Some landscapes, such as sand dunes, beaches or river floodplains, are highly dynamic. Physical processes also drive environmental change elsewhere – for example, in woodlands affected by storms that cause trees to fall, or on mountain tops affected by freeze-thaw processes.
Standard approaches to sand dune management are based upon the control of ecological change and dune stabilization. This kind of intensive management is ineffective since it also leads to loss of early successional stages in dune ecosystems. You cannot ‘preserve’ such ecosystems by ‘managing’ them any more than you can by putting a fence around them and declaring them ‘protected’. Their biodiversity depends directly upon natural patterns of disturbance, driven by climate change. Indeed, their very existence depends upon such natural change, and in such environments disturbance must be seen as part of the ‘nature’ with which conservation is concerned. What you can do, of course, is to protect them, both from direct human exploitation (for example, quarrying of sand or shingle in the case of sand dunes) and from indirect human-induced change (for example, offshore dredging, or starvation of sediment by inappropriate coastal defence works). However, conservation then becomes not a matter of trying to dictate through management the exact form that nature takes, but of protecting processes of natural change from incompatible changes in economy and technology (Worster, 1994).
Ecologists have increasingly acknowledged the scientific challenge to old equilibrial ideas and have begun to consider the instabilities in landscapes, particularly the problem of disturbance, and different scales in space and time.
As the historian Donald Worster put it, ‘nature, we are told now, should be regarded as a landscape of patches of all sizes, textures, and colours, changing continually through time and space, responding to an unceasing barrage of perturbations’ (Worster, 1994). A ‘non-equilibrium paradigm’ in ecology emphasizes the openness of natural systems, and the need to understand them in the context of their surroundings, as well as the past events and disturbances that have affected them. Non-equilibrium ecology recognizes that the factors that are important in explaining how things change will depend upon the length of time and the area over which change is analysed (Steward et al, 1992). Ecology has undergone a profound shift from the notion that nature is a well-behaved, deterministic system towards a view in which equilibrium states are relatively unusual (Zoest, 1992).
Ideas about the fractal geometry of nature, and the idea that we should think of ecosystems as exhibiting the maths of chaos rather than the more comfortable dynamics of equilibrium, allow ecologists to begin to explore the ways in which different processes determine landscape pattern at different scales. Disturbances come in many shapes and sizes, from annual river floods or seasonal droughts to disease outbreaks. Ecologists suggest that in any given landscape, disturbances tend to occur at a characteristic scale, frequency and intensity that is determined by climate, weather, topography, geology and the species present. In river channels and floodplains, characteristic species and communities are maintained within different parts of the channel and the floodplain by processes of erosion and deposition, and by patterns of overbank flooding and groundwater recharge. If those processes are altered, ecological changes are likely to follow (Hughes, 1999; 2001).
Increasingly, during the last two centuries, there has been a human dimension to many ‘natural’ disturbances, and humans themselves have been major originators of disturbance (from local engineering activity to the release of carbon dioxide or ozone-depleting chemicals into the atmosphere). Ecologists can no longer work on the assumption that terrestrial ecosystems simply respond to climate changes and internal processes of competition. The scale and intensity of human activity is such that ecosystem change, driven by human action, can itself potentially drive climatic change. Ecology has to be able to shift scales in pursuit of explanation, reaching down to the molecular level and up to the global scale (May, 1989).
Conservationists should no longer conceive of nature in equilibrium, and therefore portray human-induced changes in those ecosystems as somehow ‘unnatural’. Nature is dynamic and highly variable. Its patterns at one particular place and time are contingent upon preceding events; its trajectory through time is open ended and does not tend towards an equilibrial point. Human actions are part of the web of influences on ecological change, not external equilibrium-disturbing impacts. The implication of this is that science cannot tell conservationists what nature ‘ought’ to be like, and it may not always even be able to describe what it used to be like, and how and why it has changed. Conservationists will very often need ecology, but their science gives them no privileged insight into the way nature should be. They will have to work that out the same way everyone else does, by thinking and talking about it.
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EQUILIBRIUM IN THE DRYLANDS
The idea that ecosystems have a ‘natural’ equilibrium state has also had significant impacts upon people, ecosystems and conservation in Africa. As in the case of conservation, pastoral policy has both needed and, in its turn, aided the growth of ecological science during the second half of the 20th century. In Africa, and in the US, from where the science mostly came, rangeland science drew upon wider advances in ecology, and provided clear evidence of ecology’s usefulness (see Chapter 2 in this book). Throughout the 20th century, most analyses of ecological change in the drylands of Africa were based upon this view of the ways in which ecosystems respond to human action – and upon rather sweeping assumptions about the ways in which people use land. From most perspectives (certainly those of pastoralists, although, by and large, nobody asked them), the impacts of equilibrium thinking have been negative.
The conventional scientific view of rangeland management and mis-management has been built around ideas of range condition class and carrying capacity. Scientific research has established that there is a general relationship between rainfall and biomass of herbivores, whether these are wild or domesticated (Coe et al, 1976). The conventional logic is that the environment is capable of supporting a certain fixed number of livestock (or biomass of herbivores) that for any given ecosystem can be calculated primarily as a function of rainfall. It can then be argued that at stocking levels lower than this carrying capacity, pasture resources are being underused, and that at higher stocking levels resources are being overused. In an unmanaged grazing system, such overgrazing would be likely to lead to ecological change that would reduce its productivity (for example, by causing the extinction of palatable species and the eventually loss of vegetation cover), leading to loss of condition in grazing animals and, eventually, to a reduction in their numbers.
Pastoralist overgrazing was widely seen by scientists and policy-makers in the 1970s as a principal cause of desertification. The Sahel drought of 1972–1974, and the longer period of reduced rainfall that began in 1968, led some observers to believe that climate was undergoing permanent change. A range of hypotheses suggested that rainfall reduction could result from overgrazing – for example, through the loss of green vegetation cover from the savanna and increased surface albedo, or increased levels of dust at high altitude, both of them leading to stable air masses and dry conditions (Adams, 2001). Rising human and livestock population densities were blamed for reductions in vegetation cover and enhanced soil erosion, and these, in turn, were blamed for producing ‘a new state of self-perpetuating drought’ (Sinclair and Fryxell, 1985, p992).
Rangeland scientists have applied exactly the same logic to human-managed grazing systems. Studies of pastoral people in Africa (and elsewhere) suggested that they lacked an understanding of the ecological impacts of high stock densities, and lacked institutions for controlling livestock numbers, or controlling who had access to grazing land. Ecological studies of pasture change seemed to confirm this. Superficial accounts of decision-making by stock-keepers (often made by Northern researchers arguing from ‘first principles’, rather than by anthropologists who might actually have discussed the question with local people, or by or indigenous people themselves) suggested that a ‘tragedy of the commons’ (the phrase coined by Hardin, 1968) was inevitable.
The concepts of overgrazing and carrying capacity condemned nomadic pastoralists because of their apparently feckless management of seemingly fragile rangelands (Swift, 1982; Horowitz and Little, 1987). In addition to the apparent scientific rationale for such strategies, governments also tended to distrust people who are mobile and difficult to locate, tax, educate and provide with services. Typical government pastoral policies had several components. They were aimed, for example, at adjusting grazing intensity to available grazing resources and, thus, at improving stock health and weight. This was done by reducing stock numbers through compulsory de-stocking, controlling stock distribution though fencing, and providing evenly distributed watering points and improvement of range condition through bush clearance, pasture reseeding and controlled burning. Projects also typically sought to persuade stock-keepers to sell their cattle commercially, and to promote breed improvement (by importing European or North American stock and breeding them) and disease control, all with the hope of instilling a proper regard for the weight and health of each animal. None of these strategies fitted with nomadic or semi-nomadic subsistence livestock production; therefore, government pastoral policy also emphasized fixed settlements, formal land tenure (freehold or leasehold) and capitalist production.
In conservation terms, this approach to pastoralism essentially achieved two things, neither of them helpful. Firstly, it failed to recognize, or allow for, the historical tolerance of pastoralists for wildlife (Homewood and Rodgers, 1991; Homewood and Brockington, 1999). In doing so, it forced a conceptual and practical separation of areas managed for wildlife – protected areas (PAs) – and those managed for people and ‘development’. It defined conservation as something done in spite of, against the interests of, and in the face of the opposition of pastoral people. Wherever pastoral management became more intensive (for example, where ranching systems were adopted), wildlife became increasingly unwelcome, a reservoir of disease (rinderpest, foot and mouth, bovine pleuropneumonia and sleeping sickness). Until the rise of game farming for safari hunting in southern Africa from the 1980s, and the growth of game-watching safari tourism, livestock grazing and wildlife were seen as mutually inimical activities.
The second result of this view of pastoralists as degrading the environment was the rigorous exclusion of pastoral people from protected areas: if nature ought to be in equilibrium, and humans and their livestock disrupted that equilibrium, then ‘natural’ areas had to be rid of people and their animals. And they were: most of the famous savanna national parks and reserves in eastern Africa were established on former pastoralist land (admittedly, sometimes on land whose users had been decimated by warfare and famine following the introduction of rinderpest and various other disasters; see Waller, 1988; Anderson and Johnson, 1988). In many parks (for example, at Amboseli National Park and Maasai Mara Game Reserve in Kenya; in the Serengeti National Park and Ngorogoro Conservation Area, Arusha National Park and the Mkomazi Game Reserve in Tanzania), people were evicted, or restricted in their use of land and resources. Access has been, in some instances, the subject of long-running and bitter dispute (Lindsay, 1987; Homewood and Rodgers, 1991; Brockington and Homewood, 1996; Neumann, 1998; Brockington 2002). This notion that people can and should be excluded from protected areas because they are places for ‘wild’ nature reflects the broader Western enthusiasm for wilderness (see Chapter 2). The portrayal of African savannas as ‘wilderness’, untouched, until recently, by human hand, is, of course, fundamentally flawed, as it is elsewhere – for example, Australia (see Chapters 3 and 4)
Researchers have increasingly expressed reservations about the universal applicability of the concept of overgrazing and with the unreflective links drawn between it and desertification (Sandford, 1983; Horowitz and Little, 1987; Mace, 1991). It has been argued that overstocking or overgrazing are rarely defined, and that judgements about carrying capacity are subjective, although that subjectivity is rarely admitted (Hogg, 1983; Homewood and Rodgers, 1984; 1987). They have become both entrenched and self-reinforcing.
It is now recognized that there are wide gaps between pastoral policy prescriptions and the ways in which pastoral people actually manage their herds and rangelands. Pastoral development planning tends to focus upon commercial cattle production for slaughter for the production of meat and hides, whereas indigenous production systems tend to emphasize the production of products from live animals (milk or blood). Commercial production systems also typically focus upon a single species (usually cattle of an improved variety), whereas indigenous production systems tend to mix different kinds of livestock in their herds (cattle and camels and goats, for example, among the Turkana in northern Kenya; Coughenour et al, 1985). Moreover, poorer pastoral households will hold different a range of stock from wealthy ones. Mixed flocks and herds allow flexible use of land, water and vegetation resources in space and time. Unlike commercial ranching systems, indigenous pastoral ecosystems seem well adapted to exploit the spatial and temporal variability in biological production. Such systems offer a relatively low output compared to modern capitalist systems, such as ranching. However, they are remarkably robust in terms of providing a predictable, if limited, livelihood. Standardized assumptions about herd management, and formulaic prescriptions of carrying capacity are a poor guide to what happens on the ground.
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DISEQUILIBRIUM AND DRYLAND ENVIRONMENTS
Despite massive research and a multitude of publications on the subject of desertification, which began with the Sahel drought of the 1970s and has been maintained in the face of persistent low rainfall in Africa ever since, it has slowly come to be recognized that the data necessary to assess ‘long-term degradation’ of vegetation or desertification, in most cases, simply does not exist (Warren, 1996; Swift, 1996; Adams, 2001). While it is clear that dryland rainfall in Africa varies from year to year (and in the timing and consistency of rainfall within years), this is not now blamed on farmers and pastoralists. Today, explanations emphasize the larger-scale links to global ocean–atmosphere circulation, particularly sea surface temperatures in the southern Atlantic and Indian oceans (Hulme, 1996; 2001).
Conventional thinking about carrying capacity and overgrazing began to be challenged during the 1980s and 1990s by so-called ‘new range ecology’ (Behnke and Scoones, 1991). New ideas hold that pastoral strategies are designed to track environmental variation (taking advantage of wet years,and coping with dry ones), rather than being conservative (seeking a steady-state equilibrial output). This awareness of the non-equilibrial nature of savanna ecosystem dynamics reflects a wider understanding of the importance of non-linear processes in ecology, as a whole (see, for example, Botkin, 1990; Pahl-Wostl, 1995). Much of what appeared to be perversity or conservatism on the part of pastoralists is revealed to be highly adaptive (Behnke and Scoones, 1991; Behnke et al, 1993).
The productivity of semi-arid rangelands varies a great deal both seasonally and between years. The primary cause of this variation is rainfall, which is now acknowledged to be highly variable in space and time in sub-Saharan Africa, particularly in drier rangelands. Here, ecosystems exhibit non-equilibrial behaviour, and ecosystem state and productivity are largely driven externally. The varied influences of fire, soil fertility and groundwater add to the complexity of rangeland productivity and its capacity to support grazing at particular places and times. There is no automatic ecological succession under grazing pressure towards an overgrazed state; instead, there are complex patterns of ecological change in response to exogenous conditions (especially rainfall) and stock numbers and management. Such ecological changes can take many forms, not all of them serious, and they can proceed by diverse routes, some of which can be reversed more easily than others, and some of which are more sensitive to particular management than others. Arguably, there are no ‘naturally’ stable points in semi-arid ecosystems that can usefully be taken to define an ‘equilibrial’ state.
Studies of the responses of vegetation to different stocking levels, or of livestock numbers, tend to take no account of seasonal or annual variations in fodder availability, and tend to be built upon estimates of regional stocking rates. Such estimates are notoriously unreliable because livestock are difficult and expensive to count, particularly if their owners do not want you to do so. Studies identifying overgrazing also tend to concentrate on absolute numbers of livestock and not on densities, rarely consider spatial mobility, and fail to take account of spatial and temporal variations. Conventional ideas about the overstocking of rangelands also typically fail to take account of the ways in which indigenous pastoralists understand the environment and adapt to it – particularly the skill with which they move stock around in response to seasonal environmental change in drier and wetter years, and the importance of institutions for the exchange and recovery of stock through kinship networks. Indigenous pastoralists can manage herds, and grazing land, in detailed, complex and often effective ways.
The attempt to define a single carrying capacity for an ecosystem with great annual variation in primary productivity is problematic (Homewood and Rodgers, 1987). The attempt to do so implies that the ecosystem has an optimal equilibrium state. If that equilibrium is illusory (because of the variability and resilience of the ecosystem), the concept of carrying capacity can only be relevant as a social or economic, rather than an ecological, concept – a judgement about the density of animals and plants that allows managers to get what they want out of the ecosystem (Homewood and Rodgers, 1987). The goals of a subsistence pastoralist, a rancher and a conservationist are likely to be very different. The pastoralist might wish to maintain herd size as capital and exchange value, as well as yields of milk and blood. The rancher needs to ensure profitable returns of capital through disease-free meat off-take. The conservationist seeks to maintain the ‘naturalness’ of the ecosystem and, like the rancher, probably wishes to fix the changing ecosystem in what is assumed to be its ‘natural’ state.
It may therefore be perfectly rational for the pastoralist to run a larger biomass of livestock than the rancher would, or than the conservationist would wish to do. Many African systems do, indeed, have a subsistence stocking rate that is higher than commercial ranchers would adopt, giving low rates of production per animal but high output per unit area (Homewood and Rodgers, 1987). This is not a mistake; it reflects people managing their assets in response to a different set of needs and different kinds of social arrangements and market signals.
It is now widely accepted that pastoral ecosystems should not be thought of as having a specific carrying capacity, equating to the density of livestock that can be supported at equilibrium, particularly if that density has been calculated for a commercial meat extraction system. Actual stocking levels can exceed such a standardized carrying capacity in a number of years successively (Behnke and Scoones, 1991). The critical point is that there is a constantly changing balance of grazing pressure and range resources. In wetter years, stock numbers rise (and animal condition and disease status improves). In dry years, stock lose condition and health. Severe drought years first reduce the condition of stock and then (through disease, death and destitution-forced sales) reduce stock numbers. When good rains follow, they allow pastures to recover, resulting in a lagged recovery of herd numbers as pastoralists track environmental conditions. Livestock numbers, like the ecosystem more generally, boom and bust with the rainfall.
To survive without degrading the environment, herd managers not only need their extensive knowledge of environmental conditions and opportunities in different areas open to them, but require access to those areas. Prevention of access because of government schemes for irrigation of large-scale agriculture (Hogg, 1983; Lane, 1992), or because of the establishment of protected areas (Brockington and Homewood, 1996; Homewood and Brockington, 1999; Brockington, 2002), can be a disaster.
Nature in the dry grasslands of Africa is not in equilibrium at all. Strategies to support environmental and social sustainability need to foster indigenous capacity in order to track rainfall and maintain social and economic networks, rather than demand a shift to a static, equilibrial capitalist form of production. Conservation need not automatically sign up to a policy of excluding people and their livestock. There is evidence that livestock and wildlife can run together without disaster at a wide range of densities; where they are incompatible, it is often livestock that suffer because of their susceptibility to disease (Homewood and Rodgers, 1991). Even in protected areas where pastoralist evictions are recent (for example, the Mkomazi Game Reserve in northern Tanzania, cleared in 1988), evidence of environmental degradation due to human occupation can be inconclusive or inadequate (Homewood and Brockington, 1999; Brockington, 2002)
Conservation planning in pastoral areas needs to ask more careful questions about people’s role in the ways in which the environment is changing. Firstly, the long historical role of people in savanna ecosystems needs to be acknowledged, and any discussion of naturalness must be based upon clear historical and palaeo-environmental research. Secondly, arguments about the incompatibility of human occupation and biodiversity need to be based upon clear and specific research, and not upon general assumptions founded on unproved hypotheses about the equilibrial state of ecosystems and the risk of ‘overgrazing’. Thirdly, conservation visions need to take specific account of the ideas that local residents have about nature – what is the area like, how is it changing, and which aspects of that change are acceptable and which not? Fourthly, in drylands, as everywhere else, conservation needs to learn to move forward in collaboration with local land users, instead of trying to bulldoze them aside.
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NATURALNESS AND THE CONTROL OF NATURE
The idea that nature can be thought of as a set of ecosystems that tend to exist in equilibrium has led to an intrusive, and sometimes destructive, approach to conservation and to thinking about human use and degradation of natural resources. This seems to be so in contexts as widely divergent as the petite nature reserves of the UK and the expanses of African savannas. Of course, in many ways, these environments are not far apart at all; they are linked by the developing discipline of ecology and the colonial networks of science and ideology (see Chapters 2 and 7 in this book). Both of these reflect the scientific
rationalization of nature that is characteristic of 20th-century colonial ideas (see Chapter 3). Nature conservation can be seen as a social practice that regulates (or seeks to regulate) relations between humans and non-human nature. It operates both within certain terrains or spaces (such as protected areas) and through a generalized moral discourse. That discourse often revolves around, and is developed through, specific conserved (or ‘threatened’) spaces.
The history of conservation practice reveals two contrasting dimensions (see Table 10.1). The first is what I would call ‘the conservation of wildness’. This arises from a concern for wild nature, naturalness and unaltered ‘non-human’ nature. Robert Elliot (1997) points out in Faking Nature the importance of the view that ‘wild nature’ has intrinsic value. This wildness of nature comprises the basis for the cultural values of nature that have come to dominate conservation in the industrialized world. It explains one fundamental reason why people in countries such as the UK value nature (Adams, 1996). [7] The historical dimensions of this enthusiasm for notions of ‘the wild’ are discussed in Chapter 2 of this book
The second dimension of conservation is very different, and I have called it ‘conservation as control’ (see Table 10.1). This is conservation as the technical practice of the control of nature. It has become the characteristic approach to conservation in the UK and in places that have adopted British conservation ideas. The science of ecology, the techniques of habitat management and the bureaucratic/planning procedures of nature reserve management all represented an attempt to define and control the forms that non-human nature took (Adams, 1997). Reserves and other defined terrain were designated because of the ‘wildness’or ‘naturalness’of nature;but once established,they were mostly closely managed in order to keep nature within fixed bounds. Indeed, ecological research told conservation planners what nature ought to look like. Nature reserves were places where non-human nature could be maintained as it ought to be – its naturalness preserved and sometimes recreated (for example, this occurred when myxamatosis wiped out rabbits and chalk grasslands became hawthorn scrub, or when shallow water bodies became wet woodland habitats).
The tight management regimes of British nature reserves are one obvious context for this tradition of conservation as control, but the principle is more widely applicable. In the language of Birch (1990), any attempt to bound and protect ‘nature’ effectively put wildness in prison. He suggests that wilderness preservation (the US’s defining contribution to global conservation; Henderson, 1992), is ‘another stanza in the same old imperialist song of Western civilization’ (Henderson, 1992, p4). His argument is an interesting one. He suggests that by the very act of designating ‘wilderness’ reserves for wild nature, the ‘otherness’ of wild land is itself locked up. Such reservation limits what humans can do to specified pieces of nature, and keeps people who might destroy wildness out; but it also allows humanity to contain and control the wild completely. Such ‘wilderness’ exists at the whim of legislators and government policy. Furthermore, such wilderness reservations can be (and are) managed in various ways, even if that management is disguised to hide it from human visitors’ eyes. Thus, the wildness of nature is subjugated to a specified regime of human planning, bringing the outcomes of natural processes within a range acceptable to society. Birch comments: ‘the imperium [the supreme or imperial power of Western civilization] has the power to manage, invade, declassify, abolish, de-sanctify the legal wildland entities it has created, and the creation of such entities on its terms does little to diminish this power’ (Birch, 1990, p22).
The tension between the values attached to ‘wild’ nature and the need to control that wildness is much more broadly relevant than simply wildlife conservation. Perhaps the clearest example lies in the way river floods are understood and managed. For centuries, river management has tended to follow the ‘rational use’ element within conservation, informed by the need to control floods and bring the benefits of water (irrigation, water meadows, water supply and, latterly, hydroelectric power) to society.
This has demanded control of rivers and their waters: the dominant metaphors of river engineering are damming, harnessing, taming the mighty river, or bringing the desert to bloom. These ideologies were central to the American West as Donald Worster’s Rivers of Empire (1985) and Mark Reisner’s Cadillac Desert (1986) make clear, just as they were to imperial dreams in the Sahara (see Chapter 2) and colonial and post-colonial engineers who dammed Africa’s major rivers (the Nile, Zambezi, Volta and Niger; Adams, 1992). Dams personified the ‘can-do’ of engineering, the capacity to out-think and control nature, to tame the wild. They create a macho world of concrete, steel and human endeavour.
Of course, in the UK things have been less butch; but the family resemblance to colonial ideologies of controlling nature is clear. One might consider the urge for developing the Scottish hydropower schemes of the 1930s (Sheail, 1981), the creation of Lake Efyrnwy and the flooding of the Elan Valley during the late 19th century to supply Birmingham with water, or the development of hydropower in north Wales (Gruffudd, 1990). The spirit of control is beautifully captured by the character of ‘Mr Galvanic’, fictional employee of the British Electricity Authority in the Clough Williams-Ellises’ book Headlong Down the Years: ‘If I had my way, this disgusting water would soon know its place! The place for water is behind dams and in pipes – all under control’ (Gruffudd, 1990, p165, quoting Amabel and Clough Williams-Ellis, 1951)
Conservationists have frequently been opposed to dam construction, along with the wider environmental movement. One could think of the classic dispute over a dam in the Hetch Hetchy Valley in the US Yosemite National Park between the romantic preservationist John Muir and the gritty utilitarian conservationist Gifford Pinchot; Edward Abbey’s book The Monkey Wrench Gang (1975), whose heroes are obsessed with the destruction of the Glen Canyon Dam on the Colorado River; or the work of Dan Brouwer and the Sierra Club (Brouwer was quoted as saying: ‘I hate all dams, large and small’; Finkhouse and Crawford, 1991). Outside the US, the protests of local people and Indian environmentalists against the Sardar Sarovar Dam on the Narmada River comprise one example of the strength and diversity of environmentalist opposition to large dams (Adams, 2001).
In summary:
Bill Adams explores some of the implications of the growing discourse about non-equilibrium ecology for conservation. He argues that a deeper understanding of the complex processes involved in ecosystem change can give humans a new sense of control over nature, particularly visible in the rise of restoration ecology.
Adams, William H (Bill)
Bill Adams is Reader in the Geography of Conservation and Development at the Department of Geography, University of Cambridge, UK. He has written several books,including Future Nature: A Vision for Conservation(Earthscan,1996) and Green Development: Environment and Sustainability in the Third World (Routledge, 2001). He is interested in conservation and rural change, especially in Africa and the UK, and has served on the councils of the Cambridgeshire Wildlife Trust, the British Association for Nature Conservationists and Fauna and Flora International.
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When nature won’t stay still: Conservation, equilibrium and control
William M Adams
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FIELD WORK
Two memories suggest themselves to me. In the first, I am standing on the slope of a rounded limestone hill in southern England, looking south across a huge vista of woods and fields, the rolling lowlands of the Kentish Weald. Near at hand there is thin grass with the little bumps of ant hills, and on the hilltop the remains of a Bronze Age earthwork approximately 3500 years’ old. One or two of my fellow students are on their hands and knees, peering excitedly through hand lenses at grasses and flowers, and uttering the shrill squeaks of the conservationist at play. To our right lies what looks like a battlefield, a sea of hawthorn stumps and the ash mounds that marked the sites of small, hot fires. We are on a National Nature Reserve (NNR), a Site of Special Scientific Interest (SSSI), and this was the result of careful scientific conservation management. [1]
The reserve was famous for its chalk grassland plants and insects; but this ‘natural’ diversity was, in fact, artificial. Chalk grassland, I was being told, was human-made, an ‘anthropogenic ecosystem’, ‘semi-natural’ vegetation. In the intense agricultural and urbanized landscape of south-east England, nothing remained of the mix of vegetation communities that must once have existed on the unoccupied chalk and clays left at the end of the last glacial maximum 10,000 years ago. As the climate shifted, and plants and animals and eventually people arrived, the landscape changed, and ‘natural’ vegetation was forced to change with it. Under tens of centuries of human management, plants and insects that could thrive on the nutrient-poor limestone of the chalk hills, and cope with the inexorable nibbling of countless generations of sheep, accumulated in wonderfully diverse assemblages in what ecologists during the 20th century came to call chalk grassland.
I was told that human action had destroyed the ‘natural’ post-glacial vegetation. However, in its place anthropogenic activity had created a diverse, new vegetation assemblage in which a multitude of plants and insects found a foothold. In time, this, too, began to disappear. People had long ago cleared and ploughed almost all the rest of the chalk downland in southern England (especially during the period since World War II), and the chalk grassland species, presumably once common, were now rare. As a result, the whole of a much wider heritage of natural diversity was invested in this fragment of human-created sward. That is why it was a nature reserve.
However, even in a nature reserve it seemed that nature could not be left to itself.In this environment,chalk grassland was not a stable equilibrium vegetation community. Left alone, this grassy paradise would slowly turn into a dull, species-poor scrubland and, eventually, woodland. The only way to keep the diversity of grassland species was to stop vegetation succession. Conservation management was needed in order to hold back the tendency of nature to restore the natural balance. Since World War II, chalkland sheep-grazing had become uneconomic, the grassland had become rougher, and the scrub moved in – hence, the need to cut and remove the scrub in order to reset the clock of ecological succession at the stage with maximum species richness.
A second memory occurs a couple of years later and far away. I am peering through the windscreen of a Land Rover in northern Nigeria at a patch of bare soil, surrounded by scrubby trees. The screech of acacia thorns against the body work has mercifully stopped, and we are in an area of totally bare land in a clearing in the grazing reserve through which we have been driving. It is long after the rains and blindingly hot. We get out to inspect vegetation and soil. At some time in the past, people have cleared and cultivated this land. The lines of the cultivation ridges are still visible, but the soil has sealed over and the surface is mirror hard. Nothing grows now, not even weeds. The acacia trees have failed to recolonize. The land seems irrevocably spoiled. My companion is kicking the toe of his shoe against the hard surface, muttering and shaking his head.
A few kilometres on, we stop again in a new clearing in the thin forest. This time we find a small stockade of cut thorn branches with a large white bull inside. It is part of a Fulani pastoralist camp; but there is nobody about. The bull is tall and rangy, but surprisingly sleek. A pile of green branches has been cut for fodder, for on the dry, grey earth there is only a faint suggestion of wispy grass stems. On the edge of the clearing, small, scrubby acacia trees have been half-cut through quite recently and their green leaves eaten; others have been cut to make the small stockade. This seems like the scene that must logically precede the one before, where the healthy forest is being cut by unwary people, eventually to be farmed and spoiled, and abandoned. We talk about the processes that seem to be going on, the probability that the grazing reserve is slowly being destroyed by overgrazing. We eventually drive away, the Land Rover still protesting at the thorns.
At the time, these experiences seemed to offer classic morality tales. On the chalk hills of England, careful conservation management was needed to maintain the diversity of nature against its own powers of deterioration. In Nigeria, on the edge of the Sahel, management was required to stop people from destroying the environment. There were too many people in the wrong place, trying to grow crops on degraded soil and exhausting the soil, or cutting trees to feed livestock because the grassland was overgrazed. At that time, in the aftermath of the ‘Sahel drought’ of the early 1970s, the problem of desertification was a hot topic of debate in seminar rooms and learned journals. To me, conditioned by the literature on drought and human-induced desertification in the Sahel, it was easy to build in my mind a scenario for the future of these places. It was one of environmental degradation, with the natural vegetation progressively transformed by people and their livestock, the natural productivity of the land destroyed by unsustainable land use, the balance of nature upset by human action. It did not occur to me that this interpretation might be wrong. It did not (at least, not then) occur to me to wait until the bull’s owner returned to see what he thought was happening in that hot place. [2]
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THE BALANCE OF NATURE
The balance of nature is a powerful symbol. It was the single ‘Big Idea’ that underpinned the environmental revolution that began during the 1960s in Europe and North America, and which progressed in various ways and at various speeds until the 1990s, when it was mainstreamed by the 1992 Earth Summit in Rio. There was a ‘balance of nature’ that humans had disrupted. This certainly seemed self-evident to me through my childhood (trekking to Alexandra Palace in London to see the National Nature Week exhibition in 1963, or watching television pictures of the oil tanker Torrey Canyon, aground and burning on Seven Stones Reef between Land’s End and the Scilly Isles in March 1967, and being bombed by the navy and the air force, while leaking Kuwaiti oil onto the Cornish coast). [3] To a child, the evidence was plain: nature was precious and under threat, it had found its own balance and this was being upset. People, in their greed and technological arrogance, were disrupting the balance of nature. As a basic environmentalist route-map to the ills of the late 20th century, the idea of nature in balance served me well enough for a long while, providing the oxygen for more late evening conversations and arguments with friends than I care to remember.
These ideas are as deep as the history of environmentalism (Grove, 1992; 1995). One need look no further than George Perkins Marsh’s Man and Nature (1864):
Nature, left undisturbed, so fashions her territory as to give it almost unchanging permanence of form, outline, and proportion.
…whenever the Indian, in consequence of war or the exhaustion of the beasts of the chase, abandoned the narrow fields he had planted and the woods he had burned over, they speedily returned, by a succession of herbaceous, arborescent and arboreal growths, to their original state. Even a single generation sufficed to restore them almost to their primitive luxuriance of forest vegetation (Marsh 1864, pp 29, 30).
Marsh’s theme was clear: nature established an equilibrium and humans disrupted it. This simple idea was still providing the take-home message of Rachel Carson’s Silent Spring, the proof text of Western environmentalism and the sound bite of countless television documentaries and Walt Disney animal movies 100 years after Marsh’s writing. [4] It reflects, too, ideas that ran through the science of ecology. When this was in its infancy, during the late 19th century, shortly after Marsh was writing, it took on board a powerful, organic metaphor of nature, a view of nature balanced and integrated and threatened by change from ‘outside’, from human action (Botkin, 1990; Livingstone, 1995).
The idea of a balance of nature continues to be seductive and to have a powerful appeal for environmentalists, in general, and conservationists, in particular. However, during the last decade of the 1990s, it began to be challenged by other ideas that suggest a more complex approach to understanding ecosystem change. These ideas allow nature much more dynamism and variability. No longer can the gendered image of rapacious human and passive equilibrial nature be accepted comfortably. [5] Using two case studies, this chapter describes the implications of this change for conservation in understanding nature. The first is the semi-arid lands of Africa, both the classic terrain of ‘big nature’ (the ‘big five’ and savanna national parks) and the home ground of African pastoral people. The second is the more domestic scale of small nature reserves in the densely packed and intensively managed rural landscape of the UK. Although, at one level, very different, common ideological currents run through conservationist thinking. In both cases, a challenge to the dominant mode of understanding nature as balanced and threatened offers radical and challenging opportunities for conservation action. First, however, let me explain what I mean by the ‘ecology of equilibrium’.
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THE ECOLOGY OF EQUILIBRIUM
During the first decades of this century, nature was portrayed by the emerging science of ecology as, essentially, rather static, an array of habitat fragments as natural objects. In this thinking, ecology drew (like conservation) on the strength of amateur natural history and the Victorian mania for collecting (Allen, 1976, Griffiths, 1996). The links between ecology and conservation in industrialized countries were very close. In Research Methods in Ecology, the American ecologist F E Clements provided a scientific basis for identifying vegetation ‘types’ (Clements, 1905; McIntosh, 1985). In the UK, Arthur Tansley drew on the work of amateur botanists to write the classic Types of British Vegetation (Tansley, 1911), and provided both a classification of vegetation and a framework for the first lists of proposed nature reserves in the UK (Sheail, 1976; Adams, 1996). When Clements developed ideas about plant succession, he suggested a process of continuous change towards a ‘climatic climax’. He likened the ‘vegetation formation’ to a complex organism ‘developing’ through time. This way of understanding ecological change drew deliberate analogies with the growth of individual organisms (Clements, 1916).
These ideas of vegetation as organism were subsequently challenged by Harold Gleason and by Tansley; but ecology’s dependence upon the organic metaphor survived. In 1920, Tansley argued against the idea that all aggregations of plants had the properties of organisms, and in 1935 he published a sharp critique of Clementsian thinking about the climatic climax (McIntosh, 1985). He suggested that succession involved complex patterns, with soils, physiography and human action all driving change in different (but specific) directions under different conditions. To capture this complexity he framed the new concept of the ecosystem (Tansley, 1935; 1939; Sheail, 1987). In time this, too, came to be understood as a balanced system whose components meshed and integrated to create equilibrium through negative feedback.
The development of increasingly sophisticated theoretical and experimental approaches to ecology eventually led to a more mechanistic framework of analysis. This was based upon Tansley’s concept of the ecosystem, to which the analysis of ecological energetics and, subsequently, systems analysis were applied (Tansley, 1935; Lindemann, 1942; McIntosh, 1985; Botkin, 1990). However, although the science of ecology developed in scope and sophistication, historians of ecology argue that the fundamental notion that ecosystems tended towards equilibrium endured (McIntosh, 1985; Worster, 1994). The classic ‘equilibrium paradigm’ in ecology dominated ecology until the 1970s (Steward et al, 1992). Ecological systems were closed, and ecosystems were self-regulating so that, if disturbed, they would tend to return towards an equilibrium state. This paradigm, in turn, fed ideas in the wider environmental movement, underpinning the notion that there was a balance of nature easily upset by inappropriate human action.
During the second half of the 20th century, when both ecosystem management, development planning and conservation were all becoming established in government planning, ecologists mostly portrayed nature as a kind of homeostatic machine (Pahl-Wostl, 1995). Nature was seen as a system whose state was maintained by processes of internal feedback; but it was also susceptible to external control. In fact, ecosystems were analysed as if they were ‘19th-century machines, full of gears and wheels, for which our managerial goal, like that of any traditional engineer, is steady-state operation’ (Botkin, 1990, p12). Human action could upset the delicate working of the machine; but, fortunately, the ecologist could diagnose the problem and (potentially, at least) work out how to put the balance right. Ecological science could therefore be used to generate technocratic recipes for managing nature. Ecologists coined words and concepts drawn from thermodynamics and engineering (such as system, energetics, equilibrium, feedback, balance and control) to describe nature. Conservationists, schooled in ecology, saw themselves in some senses as ‘engineers of nature’ (Livingstone, 1995, p368).
Ecological science also offered a series of ‘natural’ subdivisions of nature. This is the fruit of a desperate desire to classify, dating back to the origins of taxonomy (see Chapter 2 in this book). The arbitrary distinction between species and subspecies are universally accepted, although modern genetic techniques may prove to have some surprises for those conservationists whose programmes are dependent upon these categories. Attempts to provide a taxonomy at larger scales (habitat, ecosystem or vegetation community) are graced by convention, but are less satisfactory. These ‘natural’ units are quite clearly social constructs, whether or not they carry the imprimatur of Two-Way Indicator Species Analysis (TWINSPAN) (Hill, 1979) and the reliable algebra of the National Vegetation Classification (Rodwell, 1991). [6] The attempt to classify the turbulent diversity of nature is based upon assumptions of equilibrium. Only if nature stays still can science get a long enough look at it to provide a usable classification. In that nature is not still, science has to work as if it is. Nature is therefore treated as dynamic, but tending to equilibrium – diverse, but open to simple classification that is robust enough to be useful.
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CONSERVATION AND EQUILIBRIUM
Ideas of ecosystem equilibrium have been highly influential for conservation in the temperate environment of the UK. For British conservationists, it was for almost all of the 20th-century axiomatic that nature not only had to be reserved, but also managed within those reserves. Ecological ideas about ecosystem succession demonstrated nature’s own capacity to change in undesirable ways. Awareness grew of the capacity of nature itself to cause change that could bring about the loss of valued features of a reserve (for example, a rare species), particularly through ecosystem succession. As nature conservation became an accepted form of land use in the UK, after the end of World War II, conservationists had to establish rules for reserve management, and for this it drew upon ecological science.
Conservation needed science, and science needed conservation. It was believed that effective reserve management demanded ‘deep scientific knowledge’ of ecosystems: ‘paradoxically, we can ensure the survival of wild places of Britain only by finding out what happens when we interfere with them’ (Nicholson, 1957, pp26, 19). In 1964, Pearsall argued that ecological research required large nature reserves for experiments ‘large enough to allow [for] repeatable assessments of the systems or processes under investigation’ (Pearsall, 1964, p8). Some ecologists were reluctant to accept that wildlife communities might need to be managed (Duffey and Watt, 1970); but conservation demanded an interventionist approach in order to control nature.
Conservation adopted ecology’s language (system, equilibrium, balance, succession, competition, climax), and drew upon it to explain vegetation succession and to prescribe management treatments. In due course, ‘management by interference’ (Nicholson, 1957, p19) became the standard model and also, arguably, the distinguishing feature of British conservation (Henderson, 1992).
Woodwalton Fen in Cambridgeshire provides one example of the emerging need for intervention management. Until the mid 19th century, Woodwalton Fen was undrained, lying adjacent to the open water of Whittlesey Mere. In 1851, this last fenland mere was drained and reclaimed, Woodwalton Fen peat was dug and parts were cultivated. In 1910, it was purchased by a wealthy visionary, the banker Charles Rothschild, as a nature reserve. This purchase, of course, did nothing to stop the rapid plant succession taking place (Nicholson, 1970). By 1959, when the reserve was leased to the Nature Conservancy, about 90 per cent of it was covered with birch or sallow scrub. Many of the species for which it was originally famous had died out, or were close to doing so. The wetland had become a wood, standing like turf on a beach – a tuft of wet woodland, stranded by the drainage of the surrounding farmland that stretched as flat as a pancake away to the level line of the horizon, far away to the north-east.
Conservation of the fen’s fauna and flora seemed to demand decisive intervention. Ecological knowledge directed conservation action to control ecosystem succession, and a programme of clearance, followed by cattle grazing, was begun. It was argued that ‘detailed ecological knowledge’ would be required to maintain the vegetation in the forms that gave the fen its conservation interest (Duffey, 1970, p595).
Although the basic principles of managing wildlife habitat are, today, widely known and taught (see, for example, Green, 1981; Sutherland and Hill, 1995), when conservation was established institutionally during the 1940s, little research had been done. Knowledge of either the need for ecosystem management, or of how and when to intervene in order to maintain the desired characteristics of ‘seral, plagio or sub-climax ecosystems’ (Green, 1981, p178), was rudimentary, at best (Sheail, 1995). New knowledge and skills were required to manage National Nature Reserves. Neither contemporary agriculture (already obsessed with technical and economic ‘efficiency’ through intensification) nor forestry (focused since the end of World War I upon developing skills in tree-farming with exotic conifers, often in exposed upland sites) provided adequate models for very many of the new tasks of conservation.
New methods were required to manage less modified ecosystems for conservation, rather than production. These methods were progressively developed. Some involved the recovery of former rural management practices, such as cutting reed on wetlands, coppicing woodland or laying hedgerows. Some adapted farming systems, such as livestock grazing, but substituted a concern for altering grass swards (by resowing and fertilizing) to maximize production with a concern for maximizing plant or insect species diversity (through minimizing fertility and adjusting stock type and stocking density). After 200 years of animal breeding for production, conservationists rediscovered less improved breeds and ‘rare breeds’ of livestock; and even lowland fields and fens began to be grazed by Highland cattle, Hebridean sheep and Konik horses. Other techniques were more novel, including the use of mechanized cutters, manipulation of water levels or the selective use of herbicides (Green, 1981; Sutherland and Hill, 1995; Wallis DeVries et al, 2001). These skills were adapted and institutionalized into new and standardized regimes of management. They were shared within groups of often urban-based volunteers (for example, the British Trust for Conservation Volunteers) and became elements in formal college-taught courses.
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ECOLOGY CONSERVATION AND DISEQUILIBRIUM
New ideas of ‘non-equilibrium’ ecology call into question the tradition of intensive conservation management in places such as the UK that assumes that nature is (and should be) in equilibrium, and seeks to control ‘natural’ processes. The abundance and distribution of organisms, as well as the appearance of the landscape, are controlled by natural physical processes. One of the most important sources of disturbance in ecosystems is the working of physical processes in the landscape, particularly processes of erosion and deposition (Werrity et al, 1994). Some landscapes, such as sand dunes, beaches or river floodplains, are highly dynamic. Physical processes also drive environmental change elsewhere – for example, in woodlands affected by storms that cause trees to fall, or on mountain tops affected by freeze-thaw processes.
Standard approaches to sand dune management are based upon the control of ecological change and dune stabilization. This kind of intensive management is ineffective since it also leads to loss of early successional stages in dune ecosystems. You cannot ‘preserve’ such ecosystems by ‘managing’ them any more than you can by putting a fence around them and declaring them ‘protected’. Their biodiversity depends directly upon natural patterns of disturbance, driven by climate change. Indeed, their very existence depends upon such natural change, and in such environments disturbance must be seen as part of the ‘nature’ with which conservation is concerned. What you can do, of course, is to protect them, both from direct human exploitation (for example, quarrying of sand or shingle in the case of sand dunes) and from indirect human-induced change (for example, offshore dredging, or starvation of sediment by inappropriate coastal defence works). However, conservation then becomes not a matter of trying to dictate through management the exact form that nature takes, but of protecting processes of natural change from incompatible changes in economy and technology (Worster, 1994).
Ecologists have increasingly acknowledged the scientific challenge to old equilibrial ideas and have begun to consider the instabilities in landscapes, particularly the problem of disturbance, and different scales in space and time.
As the historian Donald Worster put it, ‘nature, we are told now, should be regarded as a landscape of patches of all sizes, textures, and colours, changing continually through time and space, responding to an unceasing barrage of perturbations’ (Worster, 1994). A ‘non-equilibrium paradigm’ in ecology emphasizes the openness of natural systems, and the need to understand them in the context of their surroundings, as well as the past events and disturbances that have affected them. Non-equilibrium ecology recognizes that the factors that are important in explaining how things change will depend upon the length of time and the area over which change is analysed (Steward et al, 1992). Ecology has undergone a profound shift from the notion that nature is a well-behaved, deterministic system towards a view in which equilibrium states are relatively unusual (Zoest, 1992).
Ideas about the fractal geometry of nature, and the idea that we should think of ecosystems as exhibiting the maths of chaos rather than the more comfortable dynamics of equilibrium, allow ecologists to begin to explore the ways in which different processes determine landscape pattern at different scales. Disturbances come in many shapes and sizes, from annual river floods or seasonal droughts to disease outbreaks. Ecologists suggest that in any given landscape, disturbances tend to occur at a characteristic scale, frequency and intensity that is determined by climate, weather, topography, geology and the species present. In river channels and floodplains, characteristic species and communities are maintained within different parts of the channel and the floodplain by processes of erosion and deposition, and by patterns of overbank flooding and groundwater recharge. If those processes are altered, ecological changes are likely to follow (Hughes, 1999; 2001).
Increasingly, during the last two centuries, there has been a human dimension to many ‘natural’ disturbances, and humans themselves have been major originators of disturbance (from local engineering activity to the release of carbon dioxide or ozone-depleting chemicals into the atmosphere). Ecologists can no longer work on the assumption that terrestrial ecosystems simply respond to climate changes and internal processes of competition. The scale and intensity of human activity is such that ecosystem change, driven by human action, can itself potentially drive climatic change. Ecology has to be able to shift scales in pursuit of explanation, reaching down to the molecular level and up to the global scale (May, 1989).
Conservationists should no longer conceive of nature in equilibrium, and therefore portray human-induced changes in those ecosystems as somehow ‘unnatural’. Nature is dynamic and highly variable. Its patterns at one particular place and time are contingent upon preceding events; its trajectory through time is open ended and does not tend towards an equilibrial point. Human actions are part of the web of influences on ecological change, not external equilibrium-disturbing impacts. The implication of this is that science cannot tell conservationists what nature ‘ought’ to be like, and it may not always even be able to describe what it used to be like, and how and why it has changed. Conservationists will very often need ecology, but their science gives them no privileged insight into the way nature should be. They will have to work that out the same way everyone else does, by thinking and talking about it.
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EQUILIBRIUM IN THE DRYLANDS
The idea that ecosystems have a ‘natural’ equilibrium state has also had significant impacts upon people, ecosystems and conservation in Africa. As in the case of conservation, pastoral policy has both needed and, in its turn, aided the growth of ecological science during the second half of the 20th century. In Africa, and in the US, from where the science mostly came, rangeland science drew upon wider advances in ecology, and provided clear evidence of ecology’s usefulness (see Chapter 2 in this book). Throughout the 20th century, most analyses of ecological change in the drylands of Africa were based upon this view of the ways in which ecosystems respond to human action – and upon rather sweeping assumptions about the ways in which people use land. From most perspectives (certainly those of pastoralists, although, by and large, nobody asked them), the impacts of equilibrium thinking have been negative.
The conventional scientific view of rangeland management and mis-management has been built around ideas of range condition class and carrying capacity. Scientific research has established that there is a general relationship between rainfall and biomass of herbivores, whether these are wild or domesticated (Coe et al, 1976). The conventional logic is that the environment is capable of supporting a certain fixed number of livestock (or biomass of herbivores) that for any given ecosystem can be calculated primarily as a function of rainfall. It can then be argued that at stocking levels lower than this carrying capacity, pasture resources are being underused, and that at higher stocking levels resources are being overused. In an unmanaged grazing system, such overgrazing would be likely to lead to ecological change that would reduce its productivity (for example, by causing the extinction of palatable species and the eventually loss of vegetation cover), leading to loss of condition in grazing animals and, eventually, to a reduction in their numbers.
Pastoralist overgrazing was widely seen by scientists and policy-makers in the 1970s as a principal cause of desertification. The Sahel drought of 1972–1974, and the longer period of reduced rainfall that began in 1968, led some observers to believe that climate was undergoing permanent change. A range of hypotheses suggested that rainfall reduction could result from overgrazing – for example, through the loss of green vegetation cover from the savanna and increased surface albedo, or increased levels of dust at high altitude, both of them leading to stable air masses and dry conditions (Adams, 2001). Rising human and livestock population densities were blamed for reductions in vegetation cover and enhanced soil erosion, and these, in turn, were blamed for producing ‘a new state of self-perpetuating drought’ (Sinclair and Fryxell, 1985, p992).
Rangeland scientists have applied exactly the same logic to human-managed grazing systems. Studies of pastoral people in Africa (and elsewhere) suggested that they lacked an understanding of the ecological impacts of high stock densities, and lacked institutions for controlling livestock numbers, or controlling who had access to grazing land. Ecological studies of pasture change seemed to confirm this. Superficial accounts of decision-making by stock-keepers (often made by Northern researchers arguing from ‘first principles’, rather than by anthropologists who might actually have discussed the question with local people, or by or indigenous people themselves) suggested that a ‘tragedy of the commons’ (the phrase coined by Hardin, 1968) was inevitable.
The concepts of overgrazing and carrying capacity condemned nomadic pastoralists because of their apparently feckless management of seemingly fragile rangelands (Swift, 1982; Horowitz and Little, 1987). In addition to the apparent scientific rationale for such strategies, governments also tended to distrust people who are mobile and difficult to locate, tax, educate and provide with services. Typical government pastoral policies had several components. They were aimed, for example, at adjusting grazing intensity to available grazing resources and, thus, at improving stock health and weight. This was done by reducing stock numbers through compulsory de-stocking, controlling stock distribution though fencing, and providing evenly distributed watering points and improvement of range condition through bush clearance, pasture reseeding and controlled burning. Projects also typically sought to persuade stock-keepers to sell their cattle commercially, and to promote breed improvement (by importing European or North American stock and breeding them) and disease control, all with the hope of instilling a proper regard for the weight and health of each animal. None of these strategies fitted with nomadic or semi-nomadic subsistence livestock production; therefore, government pastoral policy also emphasized fixed settlements, formal land tenure (freehold or leasehold) and capitalist production.
In conservation terms, this approach to pastoralism essentially achieved two things, neither of them helpful. Firstly, it failed to recognize, or allow for, the historical tolerance of pastoralists for wildlife (Homewood and Rodgers, 1991; Homewood and Brockington, 1999). In doing so, it forced a conceptual and practical separation of areas managed for wildlife – protected areas (PAs) – and those managed for people and ‘development’. It defined conservation as something done in spite of, against the interests of, and in the face of the opposition of pastoral people. Wherever pastoral management became more intensive (for example, where ranching systems were adopted), wildlife became increasingly unwelcome, a reservoir of disease (rinderpest, foot and mouth, bovine pleuropneumonia and sleeping sickness). Until the rise of game farming for safari hunting in southern Africa from the 1980s, and the growth of game-watching safari tourism, livestock grazing and wildlife were seen as mutually inimical activities.
The second result of this view of pastoralists as degrading the environment was the rigorous exclusion of pastoral people from protected areas: if nature ought to be in equilibrium, and humans and their livestock disrupted that equilibrium, then ‘natural’ areas had to be rid of people and their animals. And they were: most of the famous savanna national parks and reserves in eastern Africa were established on former pastoralist land (admittedly, sometimes on land whose users had been decimated by warfare and famine following the introduction of rinderpest and various other disasters; see Waller, 1988; Anderson and Johnson, 1988). In many parks (for example, at Amboseli National Park and Maasai Mara Game Reserve in Kenya; in the Serengeti National Park and Ngorogoro Conservation Area, Arusha National Park and the Mkomazi Game Reserve in Tanzania), people were evicted, or restricted in their use of land and resources. Access has been, in some instances, the subject of long-running and bitter dispute (Lindsay, 1987; Homewood and Rodgers, 1991; Brockington and Homewood, 1996; Neumann, 1998; Brockington 2002). This notion that people can and should be excluded from protected areas because they are places for ‘wild’ nature reflects the broader Western enthusiasm for wilderness (see Chapter 2). The portrayal of African savannas as ‘wilderness’, untouched, until recently, by human hand, is, of course, fundamentally flawed, as it is elsewhere – for example, Australia (see Chapters 3 and 4)
Researchers have increasingly expressed reservations about the universal applicability of the concept of overgrazing and with the unreflective links drawn between it and desertification (Sandford, 1983; Horowitz and Little, 1987; Mace, 1991). It has been argued that overstocking or overgrazing are rarely defined, and that judgements about carrying capacity are subjective, although that subjectivity is rarely admitted (Hogg, 1983; Homewood and Rodgers, 1984; 1987). They have become both entrenched and self-reinforcing.
It is now recognized that there are wide gaps between pastoral policy prescriptions and the ways in which pastoral people actually manage their herds and rangelands. Pastoral development planning tends to focus upon commercial cattle production for slaughter for the production of meat and hides, whereas indigenous production systems tend to emphasize the production of products from live animals (milk or blood). Commercial production systems also typically focus upon a single species (usually cattle of an improved variety), whereas indigenous production systems tend to mix different kinds of livestock in their herds (cattle and camels and goats, for example, among the Turkana in northern Kenya; Coughenour et al, 1985). Moreover, poorer pastoral households will hold different a range of stock from wealthy ones. Mixed flocks and herds allow flexible use of land, water and vegetation resources in space and time. Unlike commercial ranching systems, indigenous pastoral ecosystems seem well adapted to exploit the spatial and temporal variability in biological production. Such systems offer a relatively low output compared to modern capitalist systems, such as ranching. However, they are remarkably robust in terms of providing a predictable, if limited, livelihood. Standardized assumptions about herd management, and formulaic prescriptions of carrying capacity are a poor guide to what happens on the ground.
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DISEQUILIBRIUM AND DRYLAND ENVIRONMENTS
Despite massive research and a multitude of publications on the subject of desertification, which began with the Sahel drought of the 1970s and has been maintained in the face of persistent low rainfall in Africa ever since, it has slowly come to be recognized that the data necessary to assess ‘long-term degradation’ of vegetation or desertification, in most cases, simply does not exist (Warren, 1996; Swift, 1996; Adams, 2001). While it is clear that dryland rainfall in Africa varies from year to year (and in the timing and consistency of rainfall within years), this is not now blamed on farmers and pastoralists. Today, explanations emphasize the larger-scale links to global ocean–atmosphere circulation, particularly sea surface temperatures in the southern Atlantic and Indian oceans (Hulme, 1996; 2001).
Conventional thinking about carrying capacity and overgrazing began to be challenged during the 1980s and 1990s by so-called ‘new range ecology’ (Behnke and Scoones, 1991). New ideas hold that pastoral strategies are designed to track environmental variation (taking advantage of wet years,and coping with dry ones), rather than being conservative (seeking a steady-state equilibrial output). This awareness of the non-equilibrial nature of savanna ecosystem dynamics reflects a wider understanding of the importance of non-linear processes in ecology, as a whole (see, for example, Botkin, 1990; Pahl-Wostl, 1995). Much of what appeared to be perversity or conservatism on the part of pastoralists is revealed to be highly adaptive (Behnke and Scoones, 1991; Behnke et al, 1993).
The productivity of semi-arid rangelands varies a great deal both seasonally and between years. The primary cause of this variation is rainfall, which is now acknowledged to be highly variable in space and time in sub-Saharan Africa, particularly in drier rangelands. Here, ecosystems exhibit non-equilibrial behaviour, and ecosystem state and productivity are largely driven externally. The varied influences of fire, soil fertility and groundwater add to the complexity of rangeland productivity and its capacity to support grazing at particular places and times. There is no automatic ecological succession under grazing pressure towards an overgrazed state; instead, there are complex patterns of ecological change in response to exogenous conditions (especially rainfall) and stock numbers and management. Such ecological changes can take many forms, not all of them serious, and they can proceed by diverse routes, some of which can be reversed more easily than others, and some of which are more sensitive to particular management than others. Arguably, there are no ‘naturally’ stable points in semi-arid ecosystems that can usefully be taken to define an ‘equilibrial’ state.
Studies of the responses of vegetation to different stocking levels, or of livestock numbers, tend to take no account of seasonal or annual variations in fodder availability, and tend to be built upon estimates of regional stocking rates. Such estimates are notoriously unreliable because livestock are difficult and expensive to count, particularly if their owners do not want you to do so. Studies identifying overgrazing also tend to concentrate on absolute numbers of livestock and not on densities, rarely consider spatial mobility, and fail to take account of spatial and temporal variations. Conventional ideas about the overstocking of rangelands also typically fail to take account of the ways in which indigenous pastoralists understand the environment and adapt to it – particularly the skill with which they move stock around in response to seasonal environmental change in drier and wetter years, and the importance of institutions for the exchange and recovery of stock through kinship networks. Indigenous pastoralists can manage herds, and grazing land, in detailed, complex and often effective ways.
The attempt to define a single carrying capacity for an ecosystem with great annual variation in primary productivity is problematic (Homewood and Rodgers, 1987). The attempt to do so implies that the ecosystem has an optimal equilibrium state. If that equilibrium is illusory (because of the variability and resilience of the ecosystem), the concept of carrying capacity can only be relevant as a social or economic, rather than an ecological, concept – a judgement about the density of animals and plants that allows managers to get what they want out of the ecosystem (Homewood and Rodgers, 1987). The goals of a subsistence pastoralist, a rancher and a conservationist are likely to be very different. The pastoralist might wish to maintain herd size as capital and exchange value, as well as yields of milk and blood. The rancher needs to ensure profitable returns of capital through disease-free meat off-take. The conservationist seeks to maintain the ‘naturalness’ of the ecosystem and, like the rancher, probably wishes to fix the changing ecosystem in what is assumed to be its ‘natural’ state.
It may therefore be perfectly rational for the pastoralist to run a larger biomass of livestock than the rancher would, or than the conservationist would wish to do. Many African systems do, indeed, have a subsistence stocking rate that is higher than commercial ranchers would adopt, giving low rates of production per animal but high output per unit area (Homewood and Rodgers, 1987). This is not a mistake; it reflects people managing their assets in response to a different set of needs and different kinds of social arrangements and market signals.
It is now widely accepted that pastoral ecosystems should not be thought of as having a specific carrying capacity, equating to the density of livestock that can be supported at equilibrium, particularly if that density has been calculated for a commercial meat extraction system. Actual stocking levels can exceed such a standardized carrying capacity in a number of years successively (Behnke and Scoones, 1991). The critical point is that there is a constantly changing balance of grazing pressure and range resources. In wetter years, stock numbers rise (and animal condition and disease status improves). In dry years, stock lose condition and health. Severe drought years first reduce the condition of stock and then (through disease, death and destitution-forced sales) reduce stock numbers. When good rains follow, they allow pastures to recover, resulting in a lagged recovery of herd numbers as pastoralists track environmental conditions. Livestock numbers, like the ecosystem more generally, boom and bust with the rainfall.
To survive without degrading the environment, herd managers not only need their extensive knowledge of environmental conditions and opportunities in different areas open to them, but require access to those areas. Prevention of access because of government schemes for irrigation of large-scale agriculture (Hogg, 1983; Lane, 1992), or because of the establishment of protected areas (Brockington and Homewood, 1996; Homewood and Brockington, 1999; Brockington, 2002), can be a disaster.
Nature in the dry grasslands of Africa is not in equilibrium at all. Strategies to support environmental and social sustainability need to foster indigenous capacity in order to track rainfall and maintain social and economic networks, rather than demand a shift to a static, equilibrial capitalist form of production. Conservation need not automatically sign up to a policy of excluding people and their livestock. There is evidence that livestock and wildlife can run together without disaster at a wide range of densities; where they are incompatible, it is often livestock that suffer because of their susceptibility to disease (Homewood and Rodgers, 1991). Even in protected areas where pastoralist evictions are recent (for example, the Mkomazi Game Reserve in northern Tanzania, cleared in 1988), evidence of environmental degradation due to human occupation can be inconclusive or inadequate (Homewood and Brockington, 1999; Brockington, 2002)
Conservation planning in pastoral areas needs to ask more careful questions about people’s role in the ways in which the environment is changing. Firstly, the long historical role of people in savanna ecosystems needs to be acknowledged, and any discussion of naturalness must be based upon clear historical and palaeo-environmental research. Secondly, arguments about the incompatibility of human occupation and biodiversity need to be based upon clear and specific research, and not upon general assumptions founded on unproved hypotheses about the equilibrial state of ecosystems and the risk of ‘overgrazing’. Thirdly, conservation visions need to take specific account of the ideas that local residents have about nature – what is the area like, how is it changing, and which aspects of that change are acceptable and which not? Fourthly, in drylands, as everywhere else, conservation needs to learn to move forward in collaboration with local land users, instead of trying to bulldoze them aside.
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NATURALNESS AND THE CONTROL OF NATURE
The idea that nature can be thought of as a set of ecosystems that tend to exist in equilibrium has led to an intrusive, and sometimes destructive, approach to conservation and to thinking about human use and degradation of natural resources. This seems to be so in contexts as widely divergent as the petite nature reserves of the UK and the expanses of African savannas. Of course, in many ways, these environments are not far apart at all; they are linked by the developing discipline of ecology and the colonial networks of science and ideology (see Chapters 2 and 7 in this book). Both of these reflect the scientific
rationalization of nature that is characteristic of 20th-century colonial ideas (see Chapter 3). Nature conservation can be seen as a social practice that regulates (or seeks to regulate) relations between humans and non-human nature. It operates both within certain terrains or spaces (such as protected areas) and through a generalized moral discourse. That discourse often revolves around, and is developed through, specific conserved (or ‘threatened’) spaces.
The history of conservation practice reveals two contrasting dimensions (see Table 10.1). The first is what I would call ‘the conservation of wildness’. This arises from a concern for wild nature, naturalness and unaltered ‘non-human’ nature. Robert Elliot (1997) points out in Faking Nature the importance of the view that ‘wild nature’ has intrinsic value. This wildness of nature comprises the basis for the cultural values of nature that have come to dominate conservation in the industrialized world. It explains one fundamental reason why people in countries such as the UK value nature (Adams, 1996). [7] The historical dimensions of this enthusiasm for notions of ‘the wild’ are discussed in Chapter 2 of this book
The second dimension of conservation is very different, and I have called it ‘conservation as control’ (see Table 10.1). This is conservation as the technical practice of the control of nature. It has become the characteristic approach to conservation in the UK and in places that have adopted British conservation ideas. The science of ecology, the techniques of habitat management and the bureaucratic/planning procedures of nature reserve management all represented an attempt to define and control the forms that non-human nature took (Adams, 1997). Reserves and other defined terrain were designated because of the ‘wildness’or ‘naturalness’of nature;but once established,they were mostly closely managed in order to keep nature within fixed bounds. Indeed, ecological research told conservation planners what nature ought to look like. Nature reserves were places where non-human nature could be maintained as it ought to be – its naturalness preserved and sometimes recreated (for example, this occurred when myxamatosis wiped out rabbits and chalk grasslands became hawthorn scrub, or when shallow water bodies became wet woodland habitats).
The tight management regimes of British nature reserves are one obvious context for this tradition of conservation as control, but the principle is more widely applicable. In the language of Birch (1990), any attempt to bound and protect ‘nature’ effectively put wildness in prison. He suggests that wilderness preservation (the US’s defining contribution to global conservation; Henderson, 1992), is ‘another stanza in the same old imperialist song of Western civilization’ (Henderson, 1992, p4). His argument is an interesting one. He suggests that by the very act of designating ‘wilderness’ reserves for wild nature, the ‘otherness’ of wild land is itself locked up. Such reservation limits what humans can do to specified pieces of nature, and keeps people who might destroy wildness out; but it also allows humanity to contain and control the wild completely. Such ‘wilderness’ exists at the whim of legislators and government policy. Furthermore, such wilderness reservations can be (and are) managed in various ways, even if that management is disguised to hide it from human visitors’ eyes. Thus, the wildness of nature is subjugated to a specified regime of human planning, bringing the outcomes of natural processes within a range acceptable to society. Birch comments: ‘the imperium [the supreme or imperial power of Western civilization] has the power to manage, invade, declassify, abolish, de-sanctify the legal wildland entities it has created, and the creation of such entities on its terms does little to diminish this power’ (Birch, 1990, p22).
The tension between the values attached to ‘wild’ nature and the need to control that wildness is much more broadly relevant than simply wildlife conservation. Perhaps the clearest example lies in the way river floods are understood and managed. For centuries, river management has tended to follow the ‘rational use’ element within conservation, informed by the need to control floods and bring the benefits of water (irrigation, water meadows, water supply and, latterly, hydroelectric power) to society.
This has demanded control of rivers and their waters: the dominant metaphors of river engineering are damming, harnessing, taming the mighty river, or bringing the desert to bloom. These ideologies were central to the American West as Donald Worster’s Rivers of Empire (1985) and Mark Reisner’s Cadillac Desert (1986) make clear, just as they were to imperial dreams in the Sahara (see Chapter 2) and colonial and post-colonial engineers who dammed Africa’s major rivers (the Nile, Zambezi, Volta and Niger; Adams, 1992). Dams personified the ‘can-do’ of engineering, the capacity to out-think and control nature, to tame the wild. They create a macho world of concrete, steel and human endeavour.
Of course, in the UK things have been less butch; but the family resemblance to colonial ideologies of controlling nature is clear. One might consider the urge for developing the Scottish hydropower schemes of the 1930s (Sheail, 1981), the creation of Lake Efyrnwy and the flooding of the Elan Valley during the late 19th century to supply Birmingham with water, or the development of hydropower in north Wales (Gruffudd, 1990). The spirit of control is beautifully captured by the character of ‘Mr Galvanic’, fictional employee of the British Electricity Authority in the Clough Williams-Ellises’ book Headlong Down the Years: ‘If I had my way, this disgusting water would soon know its place! The place for water is behind dams and in pipes – all under control’ (Gruffudd, 1990, p165, quoting Amabel and Clough Williams-Ellis, 1951)
Conservationists have frequently been opposed to dam construction, along with the wider environmental movement. One could think of the classic dispute over a dam in the Hetch Hetchy Valley in the US Yosemite National Park between the romantic preservationist John Muir and the gritty utilitarian conservationist Gifford Pinchot; Edward Abbey’s book The Monkey Wrench Gang (1975), whose heroes are obsessed with the destruction of the Glen Canyon Dam on the Colorado River; or the work of Dan Brouwer and the Sierra Club (Brouwer was quoted as saying: ‘I hate all dams, large and small’; Finkhouse and Crawford, 1991). Outside the US, the protests of local people and Indian environmentalists against the Sardar Sarovar Dam on the Narmada River comprise one example of the strength and diversity of environmentalist opposition to large dams (Adams, 2001).