the concept of cc for system of shifting cultivation

Seediscussions,stats,andauthorprofilesforthispublicationat:https://www.researchgate.net/publication/229787323

TheConceptofCarryingCapacityforSystemsofShiftingCultivation1ARTICLEinAMERICANANTHROPOLOGISTOCTOBER2009ImpactFactor:1.49DOI:10.1525/aa.1975.77.4.02a00040

CITATIONS29

READS44

1AUTHOR:

StephenBrushUniversityofCalifornia,Davis81PUBLICATIONS2,292CITATIONS

SEEPROFILE

Availablefrom:StephenBrushRetrievedon:09February2016

Wiley and American Anthropological Association are collaborating with JSTOR to digitize, preserve and extend access toAmerican Anthropologist.

http://www.jstor.org

The Concept of Carrying Capacity for Systems of Shifting Cultivation Author(s): Stephen B. Brush Source: American Anthropologist, New Series, Vol. 77, No. 4 (Dec., 1975), pp. 799-811Published by: on behalf of the Wiley American Anthropological AssociationStable URL: http://www.jstor.org/stable/674789Accessed: 18-08-2014 13:29 UTC

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of contentin a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship.For more information about JSTOR, please contact [email protected].

This content downloaded from 128.120.194.194 on Mon, 18 Aug 2014 13:29:58 UTCAll use subject to JSTOR Terms and Conditions

The Concept of Carrying Capacity for Systems of Shifting Cultivation'

STEPHEN B. BRUSH College of William and Mary

The concept of carrying capacity is related to homeostatic regulation as part of the "new ecology" paradigm. Formulas designed to measure the man-land balance of tropical horticulturalists reveal two problem areas. Theoretically, the relationship between homeostasis, change, and evolution remains indefinite. Methodologically, there are substantial difficulties in defining cultural and environmental components of the formula and in obtaining diachronic data to test the concept.

CARRYING CAPACITY FOR HUMAN GROUPS is generally defined by anthropologists as the man-land balance which is maintained by native populations practicing simple food producing methods such as shifting cultivation. Although it has usually been associated with the study of shifting cultivation, this concept of balance between resources and human demands theoretically may be applied to any technological system.2 Moreover, it relates to the whole question of optimum population which economists and others have debated at length (Gottlieb 1945). The balance is maintained for the ecologically and economically sound reason that if the carrying capacity is exceeded, there will be environmental degradation which in turn will adversely affect the group. The concept of carrying capacity involves one of the most interesting paradoxes in the theoretical spheres of ecological anthropology and systems analysis. The paradox is that although the concept is apparently valid for the life-system of the earth as a whole, the application of the concept to specific human subsystems (cultures) is difficult if not impossible. The solution of this paradox brings into play many of the themes which mark the current debate between biocultural anthropologists and cultural ecologists. Like other models borrowed from biology by anthropologists, this concept has been theoretically provocative but pragmatically difficult. This paper will suggest several theoretical problem areas and empirical weaknesses inherent to the concept of carrying capacity which may limit its utility in anthropology.

The conceptual basis for an idea of carrying capacity has been present ever since Malthus wrote An Essay on the Principle of Population almost two hundred years ago. The principles of the concept have been debated as they concern other animal and plant populations. The attractiveness of adopting the concept for anthropological purposes is manifest for several reasons. First, it represents an attempt to use the deductive nomothetic method in anthropology. This is one of the few such attempts in the discipline. Second, it provides anthropology with an empirical problem which can be dealt with in a quantitative fashion and theoretically can thereby be tested. Third, it provides anthropology a rubric under which comparisons may be made between human groups and other biological systems and communities which have been described by other sciences. This rubric may harbor other insights which are applicable to understanding human groups. Fourth, many human groups do practice population control in an apparent effort to hold down both population size and

Submitted for publication March 27, 1975 Accepted for publication July 7, 1975

799


800 AMERICAN ANTHROPOLOGIST [77,1975 density (Meggers 1971). It is certainly valid to hypothesize that this is related to carrying capacity.

The computation of carrying capacity has become common for field biologists and, increasingly, for anthropologists, geographers, and other social scientists (Allan 1965; Brookfield and Brown 1959; Carneiro 1960; Conklin 1959; Gourou 1966; Rappaport 1968; Bayliss-Smith 1974). Most research on carrying capacity in human communities has focused on systems of shifting cultivation. Besides being among the simplest production systems, these systems are relatively self-sufficient and isolated from other cultural or economic systems. Moreover, the operation of systems of shifting cultivation may be measured according to a limited number of easily defined and quantified variables: (a) land available, (b) land requirements per capita, (c) number of fallow years, (d) number of productive years per plot, and (e) population.

The aim in computing carrying capacity for systems of shifting cultivation is to indicate the point beyond which population cannot grow, ceteris paribus, without causing some damage to the basic resource of the system, land. This damage has been described as a process of land degradation which ensues when population passes a critical point without altering its diet, food production technology, or the extent of its land base. Allan (1949:1) describes this critical population point:

If this practical limit of population is exceeded, without a compensating change in the system of land usage, then a cycle of degenerative changes is set in motion which must result in deterioration or destruction of the land and ultimately in hunger and reduction of the population. The term "erosion" in its widest sense is sometimes used for this cycle of destruction, but the word as it is generally understood has too limited a connotation to describe a process which results in radical changes in the whole character of the land; loss of mineral plant foods, oxidation and disappearance of organic matter, breakdown of soil structure, degeneration of vegetation; and the setting up of a new train of land and water relationships. The whole process is best referred to as land degradation. Once the point of carrying capacity has been determined, some cultural response may be

hypothesized for groups which approach it. Such responses might include: (a) means of limiting population size by either lowering the birth rate or raising the mortality rate; (b) means of maintaining population densities through migration; (c) cultural control mechan- isms which limit the use of resources; and (d) technological change to an alternate food procurement system utilizing the resource base differently. Whereas these hypotheses are important and correlated to the concept of carrying capacity, this paper will focus mainly on the problems of calculating that point. To do this, however, one must be cognizant of the theoretical milieu of the concept.

FORMULAS FOR COMPUTING CARRYING CAPACITY

For systems of shifting cultivation at least four different formulas have been suggested for the computation of carrying capacity, that is the critical population size before land degradation begins. Allan (1949:14-15)

Area of land required per head = 100CL/P where:

cultivation period + fallow period C = "cultivation factor" = cultivation period

This is "an expression of the number of 'garden areas' required for each type to allow for the complete cycle of cultivation and regeneration."

L = "the mean acreage in cultivation at any one time per head of population." P = "the cultivable percentage of the type" (of soil and land). The "type" is based

on a survey and classification of soils and vegetation for a specific region.


Brush ] SHIFTING CULTIVATION: CARRYING CAPACITY 801

Critical population size = X where: 100 CL/P

X = total land area available to the community.

Carneiro (1960:230) T X Y Critical population size = (R + Y) where: A

A = "the area of cultivated land required to provide the average individual with the amount of food that he ordinarily derives from cultivated plants per year."

Y = "the number of years that a plot of land continues to produce before it has to be abandoned."

R = "the number of years an abandoned plot must lie fallow before it can be recultivated."

T = "the total area of arable land that is within practicable walking distance of the village."

Conklin (1959:63) Critical population size (Cs) = where: AT

L = "maximum cultivable land available." A = "minimum average acreage required for clearing, per individual, per year." T = "minimum average duration of a full agricultural cycle."

L Cs AT

Critical population density (Cd) = T X 100 = T X 100 Gourou (1966:45)

AX C Potential population density = B where:

A = "number of cultivable hectares per square kilometer." B = "the length of the rotation (cultivation plus fallow)"3 C = "the number of inhabitants per hectare cleared each year."

It is obvious that these formulas have much in common, although they utilize different units and a somewhat different organization of concepts. The formulas of Allan and Carneiro may be reworked so that they are completely equivalent to each other without altering the mathematical relationship among the variables. By reworking the formulas of these two authors, one may come to the following formula:

DA P = where: s C(A + B)

Ps = Critical Population Size A = Cultivation Period B = Fallow Period C = Acreage Needed Per Capita to Provide Average Subsistence D = Total Amount of Arable Land Available

APPLICATIONS OF THE FORMULAS

None of the carrying capacity formulas presented above were developed for purely theoretical purposes. Rather, they were developed to describe and measure the functioning


802 AMERICAN ANTHROPOLOGIST [77,1975 of specific systems of shifting cultivation. In looking at the various applications of the carrying capacity formulas, several patterns of use stand out. One application of the formula is to assess the potential of a certain subsistence system for growth. Perhaps the most ambitious use of the concept in this fashion was made by Allan (1949, 1965) in his attempt to measure, for development purposes, the population potential of large regions of Africa. In his later work Allan notes the utility of the concept in integrating social, economic, and agrarian aspects of development.

Another application of the formula is to measure the functioning of a system in an effort to predict how the system will function at a particular point. Both Carneiro (1960) and Rappaport (1968) have applied the concept of carrying capacity in this fashion. Carneiro uses the formula to dispel the notion that overpopulation, in an ecologically detrimental sense, is the major cause behind the pattern of shifting villages among Amazonian groups. Rappaport (1968) uses the concept in his treatment of ritual as a homeostatic device. Early in his book (1968:97) he argues that "a carrying capacity figure indicates ranges of values within which variables must remain if the system is to endure, but it does not indicate how values are kept within these ranges." He then goes on to show how these values are maintained by the ritual activities of the Tsembaga. In his conclusion he says,

Maring ritual, in short, operates not only as a homeostat-maintaining a number of variables that comprise the total system within ranges of viability-but also as a transducer-" translating" changes in the state of one subsystem into information and energy that can produce changes in the second subsystem [Rappaport 1968:229]. Another application of the concept is to place it in a causal relationship to other

socio-cultural events. Leeds, for instance, suggests that: If the population rose beyond this maximum capacity of the land-technology relationships, groups would either have to fission off, go on the warpath, regulate population by any of a number of internal institutions such as infanticide, or die either from extreme famines or from steady nutritional deficiency [Leeds 1961:21]. Finally, the formulas of carrying capacity have been increasingly used by archaeologists

and prehistorians to estimate aboriginal populations for specific areas and cultures. One such attempt is that of Bayliss-Smith (1974) who seeks to estimate the aboriginal populations of various islands of Polynesia.

From these applications of the carrying capacity formulas, one may appreciate the dual problems which must be dealt with in a critique of the concept. First, the measurement of carrying capacity was never designed to be an end in itself. Anthropologists like Rappaport who have used the concept include it as part of the larger field of biocultural systems analysis. On this level, it must be considered in relation to other ecological concepts such as energetics, trophic level, and niche, as well as sociological concepts such as intensification, equilibrium, and domestic and political organization. Second, it is a specific formula applied to certain data, and it must be evaluated as such. In assessing the concept on this level, one must consider the operational questions of the definition of variables and how to measure them.

EVALUATING THE CONCEPT OF CARRYING CAPACITY

In spite of the popularity of the concept of carrying capacity and some of the apparent success which various applications have achieved, I would like to suggest several problem areas of the concept which warrant caution in its use in the analysis of systems of shifting cultivation or other subsistence systems. These relate to the nature of science as described by Kuhn (1962).

In his lucid treatise on the structure of science, Kuhn (1962) suggests two basic concepts which are useful in the evaluation of any system of explanation. These two interrelated


Brush] SHIFTING CULTIVATION: CARRYING CAPACITY 803

concepts are those of "normal science" and of paradigm. Kuhn defines normal science as "research firmly based upon one or more past scientific achievements, achievements that some particular scientific community acknowledges for a time as supplying the foundation for its further practice" (1962:10). Certain of these scientific achievements have a special place in the history of a discipline in that they provided "models from which spring particular coherent traditions of scientific research" (1962:10). These achievements are defined as paradigms, and according to Kuhn, they share two essential characteristics: "Their achievement was sufficiently unprecedented to attract an enduring group of adherents away from competing modes of scientific activity. Simultaneously, it was sufficiently open-ended to leave all sorts of problems for the redefined group of practitioners to resolve" (1962:10).

The related concepts of normal science and paradigm provide a framework in which to view the conduct of scientific research as well as change within any given discipline. The history of any particular science may be viewed as the progression from one paradigm to another by the practitioners of that discipline. At any given time, certain paradigms serve to define both the problems and the methods of the research field. Included in a paradigm are the major elements of research: law, theory, application, and instrumentation. Most scientists, of course, work within the traditions of particular paradigms and do not concern themselves directly with the creation of new paradigms. The open-endedness of paradigms means that researchers spend most of their time and effort solving problems and extending limits of the original paradigm. Kuhn describes normal science as puzzle-solving:

To scientists, at least, the results gained in normal research are significant because they add to the scope and precision with which the paradigm can be applied .... Bringing a normal research problem to a conclusion is achieving the anticipated in a new way, and it requires the solution of all sorts of complex instrumental, conceptual, and mathematical puzzles. The man who succeeds proves himself an expert puzzle solver, and the challenge of the puzzle is an important part of what usually drives him on [1962:36]. One aspect of the paradigm-normal science framework is that paradigms play a

fundamental role in establishing the rules and assumptions under which normal science is conducted. They have a priority in shaping the problems, rules, and methods of a field at any given time. This priority is supported by the process of instruction which emphasizes problem-solving rather than paradigmatic inquiry. The priority of paradigms compels us, therefore, to scrutinize potential paradigms and their components very closely.

THE "NEW ECOLOGY" PARADIGM

During the last decade, a new paradigm has been proposed to analyze the relationship between human groups and their environment. This paradigm has been presented as an alternative to others, the best known being Steward's concept of cultural ecology. Among its leading proponents are Vayda (1969) and Rappaport (1967, 1968, 1974). The outlines of the new paradigm were described in an article by Vayda and Rappaport (1968) entitled, "Ecology, Cultural and Noncultural." Its major feature is a reintegration of the analysis of cultural adaptations with general ecological analysis: "human populations as units are commensurable with the other units with which they interact to form food webs, biotic communities, and ecosystems" (Vayda and Rappaport 1968:494). Human cultures are to be understood here not as unique but in terms which are applied to other living organisms: populations, communities, ecosystems. The advantages of such a paradigm are clear: as part of a unified science of ecology, generalizations concerning human behavior have a broader scope and applicability; and this type of analysis will allow us to ask the questions concerning the origin and presence of certain traits as opposed to merely functional questions.


804 AMERICAN ANTHROPOLOGIST [77,1975 Within the paradigm proposed by the new ecologists, the idea of carrying capacity

occupies an important place. In outlining the contributions to this new method, Vayda and Rappaport (1968:494-495) cite studies of the definition of territorial rights and social groups, the establishment of intertribal buffer zones, institutionalized camel raiding, ceremonial feasting, the sacralization of such animals as cows, and the practice of human sacrifice. The common thread of the new ecology paradigm which runs through all of these studies is that they may be understood in terms of ecological regulation, or more specifically homeostatic function:

the functioning of all these traits may be made more intelligible through investigation of their role in maintaining within an adaptive range certain variables (such as size or dispersion) pertaining to either particular human populations or the faunal and floral populations upon which these depend [ Vayda and Rappaport 1968:495 ].

The concept of ecological regulation and homeostatic function thus establishes the basis for the importance of carrying capacity within the paradigm of the new ecology.

As Kuhn demonstrates, any paradigm leaves a number of important problems unsolved, and these problems become the grist for normal science. Within the new ecology, one of the crucial, and unsolved, problems is the relationship between homeostasis, cultural change, and evolution. The concept of homeostasis implies fixed ranges for key variables (size, density, energy inputs and outputs), although the work done under the new ecology has had a difficult time in determining which values of these actually define homeostasis. Recently, Rappaport (1974:386) dealt with some of the difficulties encountered in specifying homeostasis:

It is difficult or impossible, however, to assess the long-run effects of any aspect of culture on particular biological variables, nor does it seem possible to identify any particular feature of biological structure or function that will always contribute to survival. Adaptiveness, therefore, is not to be identified with particular biological variables, but with the maintenance of general homeostasis in living systems.

Unfortunately, it remains unclear how we are to assess "general homeostasis" without measuring particular biological variables. The concept of carrying capacity stands at the crux of this problem of specifying what is and is not homeostasis, and this problem has both theoretical and empirical dimensions.

Much has been written by anthropologists concerning the dynamics of the relationship between population, systems of food production, political organization, and other aspects of socio-economic organization. The origins of modern anthropology, as well as many of the contemporary advances in the discipline, lie in the nineteenth-century recognition of the overall shape of the dynamics of evolutionary change which relate such factors as demography, technology, and social organization. Some anthropologists see this interest in homeostatic regulation as a refocus away from these dynamics toward the problem of demographic and technological stability. Murphy (1970:165) argues that the adoption of biological models such as homeostasis and carrying capacity in anthropology is fraught with contradictions:

If the logic of ecosystem analysis is pursued to its conclusions, however, a very different set of principles emerges: Ecosystem analysis in biology operates with far stricter equilibrium models than does social system analysis in anthropology, even when carried out by the most orthodox of structural functionalists, for nature at its most chaotic is more orderly than the activities of sapient creatures.

In evaluating the utility of a homeostatic paradigm, anthropologists might be well advised to be mindful of successes and failures of similar paradigms in the history of the discipline. The structural-functional paradigm elaborated by Radcliffe-Brown and other British social anthropologists in the 1940s and 1950s is similar to the new ecology in at least two general


Brush] SHIFTING CULTIVATION: CARRYING CAPACITY 805

aspects: (a) the emphasis on homeostasis rather than on change, and (b) the adoption of a model from another discipline (biology) for explanation in anthropology. The failure of the structural-functional paradigm may be traced, in part, to difficulties arising over the question of using a dynamic versus a homeostatic model (Leach 1954) for explaining social structure. Although it should be clear that not all theories and paradigms which present a homeostatic model lead necessarily to the typology of fixed systems which Leach (1961) aptly described as butterfly collecting, the history of theory in anthropology suggests that we be prudent in our assessment of their utility.

The structural-functional paradigm has also been criticized for misusing models derived from biology. Nagel (1961:534-535) concludes that "the cognitive worth of functional explanations modeled on teleological explanations in physiology is. . . in the main very dubious." While not criticizing the conceptual use of the "organismic analogy" in British social anthropology, Harris' (1968:526-527) critique of the structural-functional paradigm points out how easy it is to misuse and misapply a model derived from another discipline.

It may be objected that the concept of carrying capacity was never designed to oppose cultural evolution. Such an objection might argue that the concept of carrying capacity could be subsumed in a larger model of cultural evolution. Harris (1968:424) presents the case for this view:

Homeostatic functional paradigms should be kept distinct from statements of the conditions under which the system develops new functional or dysfunctional concatena- tions: in other words, the conditions under which cultural evolution takes place. When the system evolves, changes in the value of the elements in one sector accumulate and in so doing cause changes in other sectors .... An understanding of cultural evolution requires the study of both system-maintaining and system changing phenomena, and in both cases, we are concerned with probabilistic versions of causality.

The essence of carrying capacity is to discern how resource pressures are perceived and corresponding adjustments made to relieve that pressure. These adjustments may appear in either a homeostatic or a dynamic form. There is enough evidence for both types of response. The important question may be whether homeostasis or change is adaptive. Unfortunately, there appears to be an almost a priori assumption shared by many anthropologists that the former is adaptive while the latter is not.

The idea of homeostasis might be applicable to Pleistocene hunting and gathering groups where there is evidence of long-run demographic stability. The measurement of homeostasis using carrying capacity has, however, been generally applied to post-Pleistocene (Neolithic) food producing groups, that is to the very genre of human group which we know to be dynamic. This, of course, does not condemn the concept out of hand. Rather, the ideas of homeostasis and carrying capacity can play an important role in framing the dynamic relationship between population, resources, and technology (Spooner 1972). This is especially true in archaeology where the issues of intensification and technological change are receiving considerable attention. In designing models for prehistoric populations and technological systems, the concept of carrying capacity should play a heuristic role and may have explanatory value (Zubrow 1971, 1975).

If the concept of carrying capacity (a "homeostatic functional paradigm" in Harris' terminology) is to be included in a larger model of cultural evolution, the overall paradigm must include a set of laws and theories which demonstrate how homeostasis is transformed into evolution and culture change. As Harris (1968:424-425) notes, "when a functional statement cannot be made to yield a prediction of the changes of dependent and independent variables, it is not properly speaking a functional statement, but rather a functional equivocation." This "prediction of changes of dependent and independent variables" rests upon the empirical implementation of the homeostatic functional paradigm of carrying capacity to which we now turn.


806 AMERICAN ANTHROPOLOGIST [77,1975 EMPIRICAL WEAKNESS OF THE CONCEPT

One of the proposed merits of the new ecology paradigm is that it lends itself to quantitative analysis and some degree of testability. To this author, however, it seems as though the principal empirical weakness of the concept of carrying capacity lies in the fact that the theory of homeostasis inherent to the concept is neither testable nor refutable. This seems to be true in two senses. First, the definition of the system is only partial, and the variables within that system are poorly defined. Second, the specific relationship between these components is indefinite and ambiguous to the point that a meaningful predictive test may be impossible to conduct.

Measuring the carrying capacity of any subsistence system involves at least three steps. First, the scientist must select key components of the cultural system as well as those of the natural environment. In the process of selection, an unavoidable principle of operation is that not all component parts of culture are essential to an understanding of the balanced relationship between culture and nature, and, conversely, neither are all parts of nature essential to this understanding. The problem for the scientist is to choose which parts of both are important. The choice of culture components involves a description of the subsistence system (i.e., hunting and gathering, pastoralism, horticulture). The choice of environmental components involves the "effective environment." Second, having made the choice, variables which comprise the various components of both the subsistence system and the effective environment must be defined. Third, the interrelationship between these components and variables must be specified. This final step is the statement of the carrying capacity of a given subsistence system operating in a certain effective environment. The untestability of the concept of carrying capacity rests with problems encountered at each of these steps.

One of the first decisions in selecting components for the analysis of subsistence systems is to judge what food sources are crucial. The selection means that while some food resources are judged to be critical, others are ignored. An example of this is the omission of animal protein from the carrying capacity formulas dealing with swidden agriculture (e.g., Carneiro 1960). The component selection in these cases followed the decision that vegetable foods rather than animal foods were the crucial components in the demographic system. In some cases, such as Polynesian islands (Bayliss-Smith 1974), a decision to omit animal protein from the formula may be warranted, but it is a highly questionable decision for other systems. In Amazonia, however, animal and fish resources may be an essential part of the demographic formula of swidden agriculturalists (Denevan 1971).

Leibig's Law of the Minimum, one principle from biological analysis of ecosystems, relates directly to this problem of selecting components to be included in the carrying capacity formula. This concept states that the conditions which control a given species at one time may differ from those which control it at others. Dice (1952:217-218) phrases this concept as the "Law of the Limiting Factor," and explains, "as any environmental factor approaches either the upper or lower limit of toleration for a given species, that factor becomes of increasing importance in controlling the functioning, the growth, and even the existence of the individual member of the species."

The enormous variability of survival under different diet conditions must be appreciated, and the formulas as written are incapable of allowing for this. Moreover, one wonders about the possibility and desirability of including each and every factor which may become the limiting factor, either of the environment or of the culture. What is apparently marginal at one time may be decisive at another. As Aschmann (1959:78) points out in discussing the carrying capacity of the Indians of the central desert of Baja California, "a food available only in small quantity and ordinarily ignored may be the one that at critical moments prevented starvation. A consideration of only ten or twenty most important foods may miss



this critical aspect of the food economy." The wide potential for food substitution poses serious problems for testing a specific formula with predictions about the response of the other variables when population exceeds the defined carrying capacity. The use of such foods may mean that a given population is able to grow beyond the size indicated by the carrying capacity formulas without inducing environmental degradation.

There have been substantial difficulties in determining which components within the environment are significant. None of the carrying capacity formulas include specific variables which indicate land degradation or preservation of a given type of ecosystem. Rather, these are implied in the amount of land needed per capita, and the length of the fallow and cultivation periods. At what level do we say that a system is stable or in a process of degradation? What are the crucial elements within the soil which may limit the carrying capacity of the local ecosystem? Is a forest which takes thirty years to recover less "stable" than one which takes fifteen years? Very few of the studies of homeostatic regulation cited as examples of the new ecology have developed specific measures of the quality of the local ecosystem which actually demonstrate that ecological stability is a product of a particular cultural practice. Rather the environmental factors which indicate stability or degradation are unspecified, and analysis focuses on the cultural or individual perception of the environment.

One solution to the problem of selecting which components to include in a carrying capacity formula is to leave the formulas sufficiently open-ended that additional components may be added or others dropped. This is a logical strategy to adopt in the face of cultural and environmental dynamics which may introduce or eliminate certain factors as being critical to carrying capacity. The adoption of this strategy, however, erodes the empirical value of the formulas by rendering them essentially untestable. The convenient loophole which makes a formula open-ended enough to be adaptable to changing conditions means that rigid test procedures may not be applicable to the predictions of the formula. Thus the formulas become heuristic.

The selection of components, however, is not the only step which is problematic for the computation of carrying capacity. Once the general selection of components has been made, the researcher is faced with the problem of specifying which variables are crucial to those components. The components which have been selected for systems of shifting cultivation are: (1) cultivation period, (2) fallow period, (3) acreage needed per capita to provide average subsistence, and (4) total amount of arable land available. Although swidden agriculture is often treated as a relatively "simple" form of food production, anyone who has conducted fieldwork which was aimed at measuring the performance of this system knows that it is a complex system. This complexity is evident in a number of studies of swidden agriculture: Conklin (1963), Spencer (1966), de Schlippe (1956), Allan (1965), Freeman (1955), Brookfield and Brown (1963), Rappaport (1968), and Barrau (1958, 1961). It is evident that the people who practice shifting cultivation deal with ranges of variables rather than with fixed variables.

This is readily apparent when one looks at the determinates of the acreage needed per capita. These are both natural and cultural. On the cultural side, dietary, ritual, technological, and exchange factors must be included as variables. In technology alone, there are five major steps which must be accounted for: (a) site selection, (b) cutting, (c) burning, (d) cropping, and (e) fallowing. Each of these steps, in turn, must be approached as a set of variables with differential value ranges. In cropping, for instance, one must account for different skills and methods used in seed selection, seed preparation, ground preparation, planting, weeding, protection from pests, harvesting, storage, and food preparation. The ability to alter any one of these has wide implications for the process in general. This ability exists and is exercised.

The practice of fallowing is one step in which wide variation has been recognized. The


808 AMERICAN ANTHROPOLOGIST [77,1975 fallow period may be shortened by protecting the plot from fire or through enrichment by planting "nonswidden semidomesticates" (Conklin 1963:22). Pearson, who used Conklin's formula, notes that the value for the maximum number of years required for the agricultural cycle (cultivation plus fallow) is the most difficult term in the equation. He observes that this term "must take into account such dimensions as the differences in intercropping techniques, or differences in the productive period of each unit" (Pearson 1966:20). De Schlippe (1955:205-212) describes a system of "pseudo-rotation" which makes the use of a single figure of fallow years inappropriate.

The complexity of these variables means that each component of the formula assumes a wide range of values. Predictions and tests of the carrying capacity formulas are ultimately concerned with the upper ranges of some of the components (population, cultivation period for fields) and the lower ranges of other components (acreage need per capita, fallow period, and total arable land available). As certain components reach their upper range, certain changes should occur in other variables, and possible changes in the system may be indicated. Thus, a growing population should cause: (1) an increase in the total land available (D) and/or in the cultivation period (A), or (2) a decrease in the average acreage needed per capita (C) and/or in the fallow period (B). The elasticity of these components is different. Both the cultivation period and the fallow period would seem to be relatively inelastic, while the acreage needed per capita should be relatively elastic and responsive to changes in population density.

The final empirical problem with the formula lies in the difficulties in obtaining adequate information to test its operational role in swidden cultivation practice. The concept implies the possibility of human recognition of limits set by the formula. This recognition may be culturally coded as Rappaport's (1968) work suggests. Moveover, the concept indicates inevitable consequences for a human population which exceeds these limits. The question arises as to how to test this functional role of carrying capacity: how are limits recognized and maintained and what happens if they are not?

The primary difficulty in testing this role concerns the need to use diachronic data. All ecological systems are, of course, diachronic, and it is untenable to argue that anything as complex as homeostasis can be demonstrated with data from one or two years. In this regard, Zubrow (1971) notes that archaeological data may be the most useful type in evaluating the model of carrying capacity. It is probable that data from a number of generations would be necessary to test the concept, and the availability of this type of information for swidden agriculturalists is unlikely. Historical sources for the culture in question rarely, if ever, provide the necessary information. Once cultures have been contacted enough by Europeans or other outsiders to the point that an anthropologist or a team of researchers can spend a year or so collecting field data, it is likely that the culture will be well on the road toward a dynamic relationship with external economic systems. This type of relationship often leads to the abandonment of cultural patterns such as those which maintained the ecological balance between the human population and other factors in the environment. Nietschmann (1973, 1974) has described this sequence for the Miskito Indians of Nicaragua.

Street argues that many of the scientists who deal with primitive peoples tend to take the primitive's harmonious relationship with nature too much for granted and that this leads to "assumptions of technological and gastronomic stagnation... (which) depart so markedly from reality as to seriously diminish the utility of the computed density values" (1969:104). Of his own fieldwork in New Guinea relating to carrying capacity, Street says: "I tramped the trails of the Chimbu in October 1964, and saw numerous unmistakable signs of environmental deterioration, to wit: many land slips, hard soils with poor structures, sediment laden streams, rill wash, exposed subsoil" (1969:105).

Clarke (1971), who also worked in the New Guinea highlands, likewise notes a naive



propensity to assume that primitives have a stable relationship with nature. He points to several difficulties in the use of carrying capacity formulas to test this assumption, and he notes that damage to the land is a long term, diachronic process, while most ecological studies on human groups are synchronic. He concludes:

In sum, I think that carrying capacity should be thought of as a gradient rather than as a critical limit. Any change in population density along the gradient will prompt environmental change; at most points along the gradient some environmental change will be going on, even if the population remains constant. It follows that measurement of carrying capacity requires knowledge not only of length of actual fallow and cropping period, the amount of land needed to feed each person, and the total land available, but also of the rate of the processes of erosion, leaching, retrogression of vegetation and changing yields [1971:190]. The complexities involved in the collection of adequate diachronic data on all of the

components and variables which must comprise the computation of carrying capacity has led to a retreat from the original goals of the concept by several scientists who have attempted to apply it. Brookfield and Brown (1963) recognize the difficulties in obtaining adequate data and in establishing rigid test procedures for the concept. Faced with such difficulties, they are willing to lower the sights of carrying capacity as a concept, limiting their use of it to "empirical description of the present situation in the area" (Brookfield and Brown 1963:113). This, of course, is a serious limitation, and one which fundamentally alters the original intent of the concept as developed by Allan and Conklin. Both were expressly interested in determining what population could exist "in perpetuity" on the land and in calculating the critical density beyond which the productive capacity of the land would deteriorate.

Like Brookfield and Brown's retreat from a dynamic, predictive goal to a static, descriptive one is the conclusion, albeit warranted, by Bayliss-Smith (1974:262) that "the measure of carrying capacity must always be regarded as relative, not absolute." These reformulations of a descriptive and relative concept are logical responses to the difficulty of defining the components, the variables and their interrelationships, as well as the difficulty in gathering adequate information, which were overlooked by the authors of the original concept of carrying capacity.

In conclusion, I would say that the most productive uses of the concept of carrying capacity in anthropology have been essentially descriptive and heuristic. Perhaps the best example of this is Rappaport's work with the Tsembaga. Although there are suggestions relating the concept to such cultural phenomena as ritual and warfare, Rappaport stops short of specific empirical hypotheses and tests relating carrying capacity to these. The heuristic value of this concept is, however, a significant attribute. The concept of carrying capacity has contributed to the discussion and construction of models concerning prehistoric and modern populations, technology, and environment. The limitations imposed by pragmatic difficulties of definition and measurement of variables must be recognized. On the other hand, problems such as these are inherent to any new paradigm and become the essence of normal scientific activity.

NOTES

1I am grateful to Dr. Bernard Q. Nietschmann, Dr. William Denevan, and Dr. Rolland Bergman for their comments on an earlier draft of this paper.

2 For an excellent review of the general theoretical and practical issues related to carrying capacity as a "dynamic equilibrium system," the reader is advised to consult Zubrow (1975), Prehistoric Carrying Capacity: A Model.

3This variable is erroneous. The value of B, the length of the rotation, should be equal to:

cultivation + fallow years of cultivation


810 AMERICAN ANTHROPOLOGIST [77,1975 REFERENCES CITED

Allan, William 1949 Studies in African Land Usage in Northern Rhodesia. Rhodes-Livingston Papers,

No. 15. Cape Town: Oxford University Press. 1965 The African Husbandman. New York: Barnes and Noble.

Aschmann, Homer 1959 The Central Desert of Baja California: Demography and Ecology. Ibero

Americana, 42. Berkeley, CA. Barrau, Jacques

1958 Subsistence Agriculture in Micronesia. Bernice P. Bishop Museum Bulletin 219. Honolulu.

1961 Subsistence Agriculture in Polynesia and Micronesia. Bernice P. Bishop Museum Bulletin 223. Honolulu.

Bayliss-Smith, Tim 1974 Constraints on Population Growth: The Case of the Polynesian Outlier Atolls in

the Precontact Period. Human Ecology 2:259-295. Brookfield, Harold and Paula Brown

1959 Chimbu Land and Society. Oceania 30:1-75. 1963 Struggle for Land. Melbourne: Oxford University Press.

Carneiro, Robert 1960 Slash-and-Burn Agriculture: A Closer Look at Its Implications for Settlement

Patterns. In Men and Cultures. Anthony F. C. Wallace, Ed. Philadelphia: University of Pennsylvania Press. pp. 229-234.

Clarke, William 1971 Place and People: An Ecology of a New Guinean Community. Berkeley:

University of California Press. Conklin, Harold

1959 Population-Land Balance Under Systems of Tropical Forest Agriculture. Proceed- ings of the Ninth Pacific Science Congress of the Pacific Science Association, 1957, 7:63. Bangkok, Thailand.

1963 The Study of Shifting Cultivation. Pan American Union Monograph VI. Washington, DC.

Denevan, William M. 1971 Campa Subsistence in the Gran Pajonal, Eastern Peru. The Geographical Review

LXI:496-518. de Schlippe, Pierre

1955 Shifting Cultivation in Africa: The Zande System of Agriculture. London: Routledge and Kegan Paul.

Dice, Lee R. 1952 Natural Communities. Ann Arbor: University of Michigan Press.

Freeman, J. D. 1955 Iban Agriculture, a Report on the Shifting Cultivation of Hill Rice by the Iban of

Sarawak. Colonial Research Studies, Vol. 18. London: Her Majesty's Stationery Office.

Gottlieb, Manuel 1945 The Theory of Optimum Population for a Closed Economy. The Journal of

Political Economy 53:289-316. Gourou, Pierre

1966 The Tropical World (4th edition). New York: Ronald Press. Harris, Marvin

1968 The Rise of Anthropological Theory. New York: Thomas Y. Crowell. Kuhn, Thomas S.

1962 The Structure of Scientific Revolutions. Chicago: University of Chicago Press. Leach, Edmund

1954 Political Systems of Highland Burma (2nd edition). London: London School of Economics and Political Science.

1961 Rethinking Anthropology. London: Athlone. Leeds, Anthony

1961 Yaruro Incipient Tropical Forest Horticulture-Possibilities and Limits. In The Evolution of Horticultural Systems in Native South America: Causes and Con- sequences. Johannes Wilbert, Ed. Caracas: Sociedad de Ciencias Naturales La Salle.



Meggers, Betty 1971 Amazonia: Man and Culture in a Counterfeit Paradise. Chicago: Aldine.

Murphy, Robert 1970 Basin Ethnography and Ecological Theory. In Languages and Cultures of Western

North America. E. H. Swanson, Ed. Pocatello: Idaho State University Press. pp. 152-171.

Nagel, Ernest 1961 The Structure of Science. New York: Harcourt, Brace and World.

Nietschmann, Bernard Q. 1973 Between Land and Water. New York: Seminar Press. 1974 When the Turtle Collapses, The World Ends. Natural History 83:34-43.

Pearson, Richard 1966 Critical Population and Swidden Agriculture in Southeast Asia: Problems of

Quantification (abstract). Abstracts of the Proceedings of the Eleventh Pacific Science Congress 9:20. Tokyo.

Rappaport, Roy A. 1967 Ritual Regulation of Environmental Relations Among a New Guinea People.

Ethnology 6:17-30. 1968 Pigs for the Ancestors. New Haven, CT: Yale University Press. 1974 Commentary by Rappaport. In Biological Anthropology. Solomon H. Katz. Ed.

San Francisco: W. H. Freeman. pp. 384-387. Spencer, Joseph

1966 Shifting Cultivation in South East Asia. Berkeley: University of California Publications in Geography, Vol. 19.

Spooner, Brian, Ed. 1972 Population Growth: Anthropological Implications. Cambridge, MA: MIT Press.

Street, John 1969 An Evaluation of the Concept of Carrying Capacity. The Professional Geographer

21:104-107. Vayda, Andrew P.

1969 An Ecological Approach in Cultural Anthropology. Bucknell Review 17:112-119. Vayda, Andrew P., and Roy A. Rappaport

1968 Ecology, Cultural and Noncultural. In Introduction to Cultural Anthropology: Essays in the Scope and Methods of the Science of Man. James A. Clifton, Ed. Boston: Houghton Mifflin. pp. 477-497.

Zubrow, Ezra B. W. 1971 Carrying Capacity and Dynamic Equilibrium in the Prehistoric Southwest.

American Antiquity 36:127-138. 1975 Prehistoric Carrying Capacity: A Model. Menlo Park, CA: Cummings.


Article Contentsp. 799p. 800p. 801p. 802p. 803p. 804p. 805p. 806p. 807p. 808p. 809p. 810p. 811

Issue Table of ContentsAmerican Anthropologist, Vol. 77, No. 4 (Dec., 1975), pp. i-iv+753-1036Volume Information [pp. 990-1014]Front Matter [pp. i-iv]Academic Opportunity in Anthropology, 1974-90 [pp. 753-773]The Influence of Visual Perception on Culture [pp. 774-798]The Concept of Carrying Capacity for Systems of Shifting Cultivation [pp. 799-811]Primary Adult Lactase Deficiency: A Problem in Anthropological Genetics [pp. 812-835]Archaeology as Behavioral Science [pp. 836-848]The Interpretation of Ancient Symbols [pp. 849-855]The Role of the Drunk in a Oaxacan Village [pp. 856-863]Discussion and DebateBehavioral Archaeology: Four Strategies [pp. 864-869]Reinventing Anthropology: Response to Kaplan and Donald [pp. 869-870]Anti-Kaplan: Defining the Marxist Tradition [pp. 870-876]The Idea of Social Science and Its Enemies: A Rejoinder [pp. 876-881]Mennonites in the Paraguayan Chaco: Response to Redekop and Basso [pp. 881-883]Some Suggestions on File Structure [pp. 883-887]Addendum: General Principles of Classification and Nomenclature in Folk Biology [p. 887]The Perils of Pioneering Race Relations [pp. 887-888]Comment on Safa's Review of Cities under Siege [p. 888]

Archaeological Films: The Past as Present [pp. 889-897]Audiovisuals ReviewsArchaeological FilmsGeneral Introductory FilmsReview: untitled [pp. 898-899]Review: untitled [p. 899]Review: untitled [pp. 899-900]Review: untitled [p. 900]

Field Methods and Laboratory TechniquesReview: untitled [pp. 900-901]Review: untitled [pp. 901-902]Review: untitled [pp. 902-903]Review: untitled [pp. 903-904]Review: untitled [p. 904]Review: untitled [p. 904]Review: untitled [pp. 904-905]Review: untitled [pp. 905-906]Review: untitled [p. 906]Review: untitled [p. 907]Review: untitled [pp. 907-908]Review: untitled [pp. 908-909]Review: untitled [p. 909]Review: untitled [pp. 909-910]Dating TechniquesReview: untitled [pp. 910-911]Review: untitled [p. 911]

Underwater ArchaeologyReview: untitled [p. 911]Review: untitled [p. 912]

General Technology FilmsReview: untitled [p. 912]Review: untitled [pp. 912-913]Review: untitled [pp. 913-914]

Lithic Technology FilmsReview: untitled [pp. 914-915]Review: untitled [pp. 915-916]Review: untitled [pp. 916-917]

PaleolithicReview: untitled [p. 917]Review: untitled [pp. 917-918]Review: untitled [pp. 918-919]Review: untitled [pp. 919-921]Review: untitled [pp. 921-922]

Book ReviewsGeneral, Applied, and TheoreticalReview: untitled [pp. 923-929]Review: untitled [pp. 929-930]Review: untitled [pp. 930-931]Review: untitled [p. 931]Review: untitled [pp. 931-933]Review: untitled [pp. 933-934]Review: untitled [p. 934]Review: untitled [pp. 934-935]Review: untitled [p. 935]Review: untitled [pp. 935-936]Review: untitled [p. 936]Review: untitled [pp. 936-937]Review: untitled [pp. 937-938]Review: untitled [p. 938]Review: untitled [pp. 938-940]Review: untitled [p. 940]

EthnologyReview: untitled [p. 941]Review: untitled [pp. 941-942]Review: untitled [p. 942]Review: untitled [pp. 942-943]Review: untitled [p. 943]Review: untitled [pp. 943-944]Review: untitled [pp. 944-945]Review: untitled [pp. 945-946]Review: untitled [pp. 946-949]Review: untitled [p. 949]Review: untitled [pp. 949-950]Review: untitled [p. 950]Review: untitled [pp. 950-951]Review: untitled [p. 951]Review: untitled [pp. 951-952]Review: untitled [p. 952]Review: untitled [pp. 952-953]Review: untitled [p. 953]Review: untitled [pp. 953-954]Review: untitled [p. 954]Review: untitled [pp. 954-955]Review: untitled [pp. 955-956]Review: untitled [p. 956]

LinguisticsReview: untitled [pp. 957-958]Review: untitled [p. 958]Review: untitled [pp. 958-959]Review: untitled [pp. 959-960]Review: untitled [pp. 960-961]Review: untitled [pp. 961-962]Review: untitled [pp. 962-964]Review: untitled [p. 964]Review: untitled [pp. 964-965]

Physical AnthropologyReview: untitled [p. 966]Review: untitled [pp. 966-967]Review: untitled [pp. 967-968]

Book Notes [pp. 969-972]Back Matter [pp. 973-1036]

the concept of cc for system of shifting cultivation

Documents

concept of balance

conditionsthe concept

study of shifting cultivation

jstor terms

jstor archive

utcyour use

terms conditions of

utcall use subject