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Some avenues of compromise

After arguing at such length for the essential differences between the natural and the social sciences as factors inhibiting satisfactory treatment of the human factor, it would be encouraging to be able also to wind up this chapter by pointing to some theoretical convergence. There have, in fact, been several developments that deserve some discussion here, some promising, some not so promising.

First, a recent movement that has led to some cooperation between social and natural scientists is socio-biology (See, for example, Chagnon and Irons 1979). Although sociobiology is in fact unlikely to produce work immediately relevant to the concerns of this essay, it is useful to note it here, because it provides an example of the problems that any cooperation bridging the social and natural sciences is bound to face. The root of these problems lies in the fact that claims to objectivity are less likely to be questioned and are more easily upheld in the natural sciences than the social sciences, because in the natural sciences the investigator is further removed from his subject matter and there is less likely to be any suspicion of conflict of interest.

Socio-biology is based on the natural-science premise that human behaviour is to at least some degree determined by the interaction of genetic and environmental factors, and that these factors continue to interact in complex determining ways throughout the life of each individual. It does not, therefore, deny the basic social science premise that it should be possible to change behaviour by changing the social or cultural environment. However, since it minimally involves the idea that biological variation can cause cultural variation, it threatens the autonomy of social theory. For, it suggests not only that sociological analysis might be dependent on biological analysis, but that biological analysis might illuminate moral issues. Hence the common accusation that biological analyses of social and cultural data encourage reactionary politics (Chagnon and Irons 1979, p. XV). When people study non-human subject matter, they can avoid moral positions (or ignore moral implications). When they study people, the moral implications surface, and recent social and political history has made them more obvious.

Implicit confusion between investigation of the nature of the world and pursuit of the best way of living has been a perennial problem in philosophy. Both the natural and the social sciences have suffered from it. Their cooperation in a single theoretical framework is made so difficult because they suffer from it in different degrees; and while the natural sciences can ignore the confusion, the social sciences cannot, because of the kinship between investigator and investigated. At the theoretical level socio-biology also fails to provide an integrative mechanism because it depends exclusively on the correct application of an essentially natural-science concept: natural selection. Any integrating mechanism must be equally appropriate to each dimension of reality. In this case, natural selection cannot be allowed to upstage the moral issues.

Secondly, transactionalism, an important theoretical development in social science which has been pursued in anthropology in the 1960s and 1970s primarily by Barth (1966, 1967 and 1972), offers some hope. As yet it has undergone little empirical testing (See Kapferer 1976). Its promise lies in the fact that it is generally accepted even by the more isolationist social scientists, and it is based on a model of society that should seem familiar and acceptable to natural scientists because it focuses on individual transactions and chains of transactions (in a manner reminiscent of, but not borrowed from, the biologists' focus on natural selection) between actors with a repertoire of statuses in an environment that is both cultural (or historical) and ecological. Despite some rather strong criticism, mainly on the familiar grounds that it ignores power and values (Paine 1974), and the effects of group membership {Cohen 1974, p. 40), Barth's and others' development of transactionalism could provide a basis for cooperation between the natural and the social sciences at the theoretical level (parallel to public policy at the practical level) because it de-fuses the difficult (for the nonanthropologist) problem of cultural relativism and moral values by focusing on the minimal units of social process in a way similar to game theory, and by equating culture with environment.

Thirdly, reference has already been made to the argument that different types of process - biological,

social, cultural - interact over time in ways that can be usefully summarised and interpreted as co-adaptation. The particular argument cited was based on a historical view of the ecology of pastoralism (developed in Nyerges 1982). it depends on the extension of concepts from one discipline to another, not directly (in the ways we castigated above) but by analogy. A more detailed example of the potential of this analogical method can be developed from a consideration of a recent characterization of arid ecosystems by Noy-Meir (1973, 1974).

Particular attention has been given during the 1970s to the modelling of varieties of ecosystems for the purpose of developing more reliable principles for land-use management within them. Modelling alone does not provide a mechanism for the integration of social with natural theory, but it could produce results that would be helpful in this enterprise. For example, the exercise leads Noy-Meir to formulate the following three basic attributes of arid ecosystems:

- precipitation is so low that water is the dominant controlling factor for biological purposes;
- precipitation is highly variable through the year and occurs in infrequent and discrete events; and
- variation in precipitation has a large random (unpredictable) component.

There fore, he concludes, it is useful to define desert ecosystems as "water-controiled ecosystems with infrequent, discrete and largely unpredictable water inputs" (1973, p. 26).

Working from these basic attributes he lists seven features of arid ecosystems for the purpose of modelling:

- the dominant influence of the space-time distribution and dynamics of water (sometimes in conjunction with heat and salt) on energy flows and species adaptations,
- the occurrence in discrete pulses of the major input and many biological activities,
- the importance of reserve forms and stages and of the transfers between them and active pulses,
- the large random component in environmental variation and the special adaptations to uncertainty,
- the marked effects of spatial heterogeneity in the environment on total energy, water, and nutrient flows and on survival of many species,
- the opportunistic food habits of many animals, leading to complex food webs,
- the very different "stabilities" of the arid ecosystem at different time scales and in relation to different types of "disturbance." (1974, pp. 209-210, emphasis added).

As a result of these conditions, the plant ecology of arid environments (and by extension also the animal ecology and the human ecology) is characterized by the struggle with aridity- up to the point where success brings a degree of population density such that the main problem becomes competition for water.

These principles are sufficient to explain the following general characteristics of arid ecosystems:

"In mature arid shrub communities, root systems may occupy most of the area where canopy is only 3 to 5 per cent. Evidence for within-species competition is the regular spatial pattern sometimes observed in desert shrub populations; in other cases, evidence may be obscured by habitat micro-heterogeneity. Mortality due to competition for water has been indicated in desert annuals populations.

Competitive inhibition of shrub seedlings by mature shrubs, to a distance 5 times the canopy radius, has been demonstrated. . . Many phenomena in the distribution of species and communities in arid and semiarid zones can be explained only by assuming strong between-species competition for water. The yield of forage grasses and fortes in semiarid rangelands is inversely related to density of woody perennials.

Some desert shrubs produce allelopathic substances that inhibit germination and growth of other species. . . Salinisation of the soil surface by salt accumulating and excreting halophytes, with consequent inhibition of nonhalophytes, is apparently common.

Positive effects of shrubs and trees on other plants, as expressed in spatial association, are also often observed in deserts. The microenvironmental modifications involved are partly atmospheric (reduction of radiation, temperature, wind, and evaporativity) and partly edaphic (increased organic and nutrient contents, accumulation of windblown sand and silt). Other mechanisms are concentrations of windblown seeds and protection from grazing. (Noy-Meir 1973, p. 47)

The critical factors affecting production and survival in deserts are those which determine water supply and the efficiency of conversion from water to energy. For example, the rate of herbivore consumption is controlled by the availability of water, and the water balance (which is further conditioned by the heat and salt balance) of the animal. The input of water into the system is stochastic. The system is driven by irregular pulses of short duration. Typically, there are ten to fifty rainy days per year in three to fifteen rain events or clusters of rainy days, of which probably no more than five or six (sometimes only one) are large enough to affect the biotic components of the system. The periods between these events receive a zero input. The system as a whole operates in an irregular pulse-reserve pattern. No cycles have been demonstrated. The main adaptational problem, therefore, lies in the adjustment of response to exogenous environmental signals so as to optimise growth and survival. All animals have the added problem of heat and salt balance coupled with water balance in the typically extreme desert temperatures, but they also have the advantage of mobility which allows them to exploit spatial variation. In some special cases, the use of available water is inhibited by special conditions, such as very cold winters in Central Asia.

There are two basic adaptations to these conditions:

— slow quiet exploitation of secure niches with defenses against aridity and competition, and behavioural restriction of transpiration to periods of low evaporation, as in the case of shrubs with a secure underground water source and no competition; and

— bursts of energy in response to precipitation, putting all effort into getting as large a share as possible followed by return to dormancy; unrestricted, rapid inefficient transpiration is an optimum strategy for annuals in competition with each other. Some plants known as C4 plants because carbon dioxide is first assimilated into a four-carbon carbohydrate - have developed a more water efficient way of taking in carbon dioxide in photosynthesis.

In either case, the major problem for each species lies in how to survive the dry period between (exogenous) rain events. Survival is generally by means of reserves. The nature of these reserves constitutes the most significant field for research.

In this characterization of arid ecosystems based on the current state of knowledge there is an abundance of ideas for the formulation of hypotheses about the organization of human activity in arid areas, and such hypotheses can be used without imposing an ecosystemic framework on human activity. For example, in human populations in arid lands a similar pulse-reserve pattern may be seen. Most traditional systems of food production are adapted in this way. Nomadic pastoralism is a good example. It is opportunistic. Strategies of herding and husbandry are designed to make the most of the pulses and accumulate enough stock to make it through the reserve periods (See Sandford 1982). Most pastoral development schemes, on the other hand, are based on estimation of continuous sustainable production levels. That is, they focus on the reserve period.

The only way to evade the constraints of the pulsereserve pattern involves some form of manipulation of the water input on a massive scale such as modern irrigation engineering. Such engineering requires investment beyond the means of the small local populations. Exogenous investment in the economy of arid lands is analogous to stochastic rain inputs in the ecology.

This reasoning by analogy leads to insights into the relationships between populations and their environment that do not prejudice social theory. Analogy serves as an integration mechanism at the level of the formulation of hypotheses.

A final example derives from the characteristic assessment of arid ecosystems as fragile. Analogy leads to the hypothesis that social systems in arid lands are similarly fragile. Examples can easily be found to corroborate this hypothesis, though not to prove it. But it is worth considering that deficiencies in human wellbeing generally are as much or more due to the fragility of cultural and social systems than of ecosystems. A solution to a desertification problem is not a solution unless it comprehends the problem of human welfare in a socionatural universe. A technical solution - in the sense of a method to de-salinise land or to develop a new soil base is not a solution. It is simply an engineering technique.

For similar reasons desertification is sometimes wrongly diagnosed. If a community living on the edge of moving sand migrates, it does not necessarily mean that the sand is evidence of their abuse of their resources. It can mean that the socio-economic system of which they form a part has changed in such a way that they choose to move. When they move, they cease to maintain their investment in the productivity of the area and the sand does then encroach, so lending credence to the wrong explanation. (An example from northeastern Iran is given in Spooner et a/. 1980.)

This review of the various trends of reorientation in human ecology over the last decade has led us to a consideration of the value of analogy as a means of interaction and communication between orientations. Analogy is an element in all inductive investigation (Stebbing 1933, p. 256), and is therefore well suited to serve as a bridge between what are different, largely deductive disciplinary investigations. By drawing attention to similarity in certain respects, it suggests new hypotheses which can be valuable and lead to genuine dialogue, so long as the attendant dissimilarities are also noted and the hypotheses are tested according to independent criteria. In the following chapter we attempt to construct a threedimensional picture of two ecological problem situations in historical perspective, using public policy as a value base and this type of analogical reasoning as a heuristic tool.

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