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Towards a classification of ecosystem manipulation
SHORT COMMUNICATION
TOWARDS A CLASSIFICATIONOF ECOSYSTEM MANIPULATION Most African societies have not yet gone through all the stages of environmental exploitation which societies in temperate latitudes have reached. Africans have certainly spent a long time at the earlier stages of gathering, hunting, agriculture, and pastoralism. That they have been able to stay at a single stage for the last several thousand years should be a credit to their skill in maintaining a balanced harmony with their environment, and in keeping to an optimal human population that could survive so long as the environment did not change drastically as a result of climatic or Man-induced disturbances. Those societies that are already in the midst of the industrialization-urbanization stage are suffering from a number of serious environmental diseases which are liable to threaten their very existence. This is why societies that have remained for thousands of years without showing signs of change should be considered successful in surviving without environmental problems and without exhausting their natural resources--a success which industrialized societies are, by nature, incapable of achieving. Some sections of African societies, however, are endeavouring to develop into new stages of industrialization and urbanization and possibly also weather control--either through planning or by the natural movement of social change activated by contacts with non-African societies. Such contacts have already caused a tip in the balance with the environment, and are creating new ambitions that have made economic development something of a vital necessity. It is therefore imperative to study the various patterns of human impact on ecosystems in order to control the course of economic development with a view to keeping environmental productivity at desirable levels. As the industrial stage is the one that seems destined to become the next prevalent stage in Africa, it is the duty of ecologists to predict the environmental problems that will have to be faced in the future
industrial development of Africa in the light of what has happened and is still happening in already industrialized societies. The message of ecological sciences ought to be helping industrialized societies to solve the problems at hand and also the hosts of problems originating with every innovation, while helping developing societies to avoid these problems before they appear in such societies' inevitable drive for industrialization (as far as avoidance is within their means). P. Dansereau (1970) and R. F. Dasmann (1972), among others, have offered separate, but similar, reviews of the human impact on ecosystems throughout history. They have analysed the escalation of human impact at every turn from one stage of existence into the next. With each turn, Man removes some environmental restraints on his population, which increases at the expense of other organisms and brings about more depletion and exhaustion of natural resources and less cycling in Nature. These aspects of human population growth become really manifest at the industrial stage. Dansereau and Dasmann have both shown clearly that human history can be interpreted as a sequence of ecological events. This may be termed the ecological interpretation of human history--one that may prove, in the future, as important as the earlier holistic interpretations of the 19th century. Such an interpretation can be considered a longitudinal tracing of history and can be usefully supplemented by a transverse tracing of present-day human impact on ecosystems, or, more conveniently, manipulation patterns. The biosphere is now regarded as an interconnected network of ecosystems that transcends national boundaries. A multitude of examples is known which shows that no society can make changes in an ecosystem within its jurisdiction without affecting neighbouring societies, which depend on, or enjoy, the benefits of fringing ecosystems and sometimes of ecosystems that are continents and oceans apart. It is also a fact that every economic or social change is now known to engender a further impact on the natural 153
Biological Conservation, Vol. 6, No. 2, April 1974---~ Applied Science Publishers Ltd, England, 1974---Printed in Great Britain
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Biological Conservation
ecosystems on which Man's livelihood depends. Therefore, a scheme for the classification of presentday manipulation patterns can help policy-makers in obtaining the insight necessary for formulating decisions on the management of ecosystems. The following is an attempt to draw up such a scheme, embracing natural ecosystems with which Man is interfering as well as artificial ecosystems for which Man is largely responsible as regards their establishment and maintenance. The latter may be called, collectively, the technosphere, of which they are divisional units. Abandoned (unmanaged or slightly managed) artificial ecosystems become semi-natural ones. Modern human action on ecosystems may be outlined as follows: A NATURAL ECOSYSTEMS
I Unmanaged: a Non-exploited, e.g. montane; b Exploited:
i Marginally, e.g. freshwater, brackish, and marine natural water bodies. ii Fundamentally (or drastically), e.g. by drainage of wetlands and mangroves, by deforestation, by fire. c Carelessly destroyed: i Pollution, e.g. by oil on water bodies, by
pesticides, by eutrophication, by radiation (heat, radioactivity).
1I Managed: a Rational utilization for conservation, e.g. national parks, afforestation programmes. b Preservation, e.g. nature reserves. B SEMI-NATURALECOSYSTEMS I Aquatic, e.g. man-made lakes, canals. II Terrestrial: a Annualproductivity, e.g. secondary pastures. b Perennial productivity, e.g. secondary forests of coconut or oil palms. C ARTIFICIALECOSYSTEMS
I Aquatic, e.g. fish-ponds. II Terrestrial: a Annual productivity, e.g. fields of cotton, of millet, of groundnuts. b Perennial productivity, e.g. artificial forests of cocoa, of rubber trees, of date palms, of conifers, of eucalyptus. III Urban Centres. In the semi-natural ecosystems, management is at a minimum during inception, maintenance, and harvesting, of produce. In artificial ecosystems, continued management is necessary for their continued existence. Urban centres are the most artificial of ecosystems, and are the sites where the manifestations of technology are most apparent. Still, they provide livelihood for a number of anthropophilic organisms which find excellent living conditions in households and refuse-tips.
ii Dereliction, e.g. by industrial plundering, by slag-heaps, by strip-mining.
References
iii Deliberate slaughter, e.g. poaching, hunting, sport.
DANSEREAU, P. (1970). Ecology and the escalation of
iv Overgrazing, e.g. by goats in deserts, by cattle in savanna. v Mismanagement, e.g. by unplanned land reclamation schemes, by bad drainage. vi Erection of projects, e.g. for industry, for urbanization, for recreation.
human impact. Int. Soc. Sci. J., 22(4), pp. 628-47. DASMANN,R. F. (1972). Planet in Peril. Penguin-Unesco: 135 pp. SAMIRI. GHABBOUR, Department of Natural Resources, Institute of African Research and Studies, University of Cairo, Giza, Egypt
TOWARDS A CLASSIFICATIONOF ECOSYSTEM MANIPULATION Most African societies have not yet gone through all the stages of environmental exploitation which societies in temperate latitudes have reached. Africans have certainly spent a long time at the earlier stages of gathering, hunting, agriculture, and pastoralism. That they have been able to stay at a single stage for the last several thousand years should be a credit to their skill in maintaining a balanced harmony with their environment, and in keeping to an optimal human population that could survive so long as the environment did not change drastically as a result of climatic or Man-induced disturbances. Those societies that are already in the midst of the industrialization-urbanization stage are suffering from a number of serious environmental diseases which are liable to threaten their very existence. This is why societies that have remained for thousands of years without showing signs of change should be considered successful in surviving without environmental problems and without exhausting their natural resources--a success which industrialized societies are, by nature, incapable of achieving. Some sections of African societies, however, are endeavouring to develop into new stages of industrialization and urbanization and possibly also weather control--either through planning or by the natural movement of social change activated by contacts with non-African societies. Such contacts have already caused a tip in the balance with the environment, and are creating new ambitions that have made economic development something of a vital necessity. It is therefore imperative to study the various patterns of human impact on ecosystems in order to control the course of economic development with a view to keeping environmental productivity at desirable levels. As the industrial stage is the one that seems destined to become the next prevalent stage in Africa, it is the duty of ecologists to predict the environmental problems that will have to be faced in the future
industrial development of Africa in the light of what has happened and is still happening in already industrialized societies. The message of ecological sciences ought to be helping industrialized societies to solve the problems at hand and also the hosts of problems originating with every innovation, while helping developing societies to avoid these problems before they appear in such societies' inevitable drive for industrialization (as far as avoidance is within their means). P. Dansereau (1970) and R. F. Dasmann (1972), among others, have offered separate, but similar, reviews of the human impact on ecosystems throughout history. They have analysed the escalation of human impact at every turn from one stage of existence into the next. With each turn, Man removes some environmental restraints on his population, which increases at the expense of other organisms and brings about more depletion and exhaustion of natural resources and less cycling in Nature. These aspects of human population growth become really manifest at the industrial stage. Dansereau and Dasmann have both shown clearly that human history can be interpreted as a sequence of ecological events. This may be termed the ecological interpretation of human history--one that may prove, in the future, as important as the earlier holistic interpretations of the 19th century. Such an interpretation can be considered a longitudinal tracing of history and can be usefully supplemented by a transverse tracing of present-day human impact on ecosystems, or, more conveniently, manipulation patterns. The biosphere is now regarded as an interconnected network of ecosystems that transcends national boundaries. A multitude of examples is known which shows that no society can make changes in an ecosystem within its jurisdiction without affecting neighbouring societies, which depend on, or enjoy, the benefits of fringing ecosystems and sometimes of ecosystems that are continents and oceans apart. It is also a fact that every economic or social change is now known to engender a further impact on the natural 153
Biological Conservation, Vol. 6, No. 2, April 1974---~ Applied Science Publishers Ltd, England, 1974---Printed in Great Britain
154
Biological Conservation
ecosystems on which Man's livelihood depends. Therefore, a scheme for the classification of presentday manipulation patterns can help policy-makers in obtaining the insight necessary for formulating decisions on the management of ecosystems. The following is an attempt to draw up such a scheme, embracing natural ecosystems with which Man is interfering as well as artificial ecosystems for which Man is largely responsible as regards their establishment and maintenance. The latter may be called, collectively, the technosphere, of which they are divisional units. Abandoned (unmanaged or slightly managed) artificial ecosystems become semi-natural ones. Modern human action on ecosystems may be outlined as follows: A NATURAL ECOSYSTEMS
I Unmanaged: a Non-exploited, e.g. montane; b Exploited:
i Marginally, e.g. freshwater, brackish, and marine natural water bodies. ii Fundamentally (or drastically), e.g. by drainage of wetlands and mangroves, by deforestation, by fire. c Carelessly destroyed: i Pollution, e.g. by oil on water bodies, by
pesticides, by eutrophication, by radiation (heat, radioactivity).
1I Managed: a Rational utilization for conservation, e.g. national parks, afforestation programmes. b Preservation, e.g. nature reserves. B SEMI-NATURALECOSYSTEMS I Aquatic, e.g. man-made lakes, canals. II Terrestrial: a Annualproductivity, e.g. secondary pastures. b Perennial productivity, e.g. secondary forests of coconut or oil palms. C ARTIFICIALECOSYSTEMS
I Aquatic, e.g. fish-ponds. II Terrestrial: a Annual productivity, e.g. fields of cotton, of millet, of groundnuts. b Perennial productivity, e.g. artificial forests of cocoa, of rubber trees, of date palms, of conifers, of eucalyptus. III Urban Centres. In the semi-natural ecosystems, management is at a minimum during inception, maintenance, and harvesting, of produce. In artificial ecosystems, continued management is necessary for their continued existence. Urban centres are the most artificial of ecosystems, and are the sites where the manifestations of technology are most apparent. Still, they provide livelihood for a number of anthropophilic organisms which find excellent living conditions in households and refuse-tips.
ii Dereliction, e.g. by industrial plundering, by slag-heaps, by strip-mining.
References
iii Deliberate slaughter, e.g. poaching, hunting, sport.
DANSEREAU, P. (1970). Ecology and the escalation of
iv Overgrazing, e.g. by goats in deserts, by cattle in savanna. v Mismanagement, e.g. by unplanned land reclamation schemes, by bad drainage. vi Erection of projects, e.g. for industry, for urbanization, for recreation.
human impact. Int. Soc. Sci. J., 22(4), pp. 628-47. DASMANN,R. F. (1972). Planet in Peril. Penguin-Unesco: 135 pp. SAMIRI. GHABBOUR, Department of Natural Resources, Institute of African Research and Studies, University of Cairo, Giza, Egypt