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2. Regional reports on desertification
Sahelian Zone
This was an area of critical interest for the United Nations Desertification Conference held in Nairobi in 1977. H. Mensching described studies of desertification in several parts of the region by geographers of Hamburg University. In Darfur Province, Sudan, Ibrahim has shown that 15 per cent of the north and central parts have been severely decertified, notably in the cultivated Goz belt and in the closely settled Dar Zaghawa area, whilst 30 per cent is moderately affected. The areas most vulnerable to desertification are the grazing lands with scattered millet cultivation in the north, and overgrazing is particularly marked in areas of Nubian sandstone, where permanent waters allow year-round stocking. In Upper Volta, Krings has demonstrated that desertification is associated with an increased agricultural use of the fixed dunes since 1955, at the expense of nomadic pasturing, in the zone of contact between sedentary and nomadic groups. A marked extension of cultivation followed the emancipation of the Iklan farmers from their former Tuareg masters and the rapid growth of population in the area, which has resulted in a shortening of fallow-cropping rotations. The seasonal use of pastures by pastoral nomads has also given place to permanent pasturing. In northern Niger, Taubert has studied the relationship between desertification and the growth of settlements and mobility of the population in Tahoua and Agadez provinces, particularly near the northern limit of millet cultivation, where cropping has also extended in defiance of regulation. Desertification here is linked with a growing seasonal emigration of the labour force, which acts as a safety factor in maintaining the economic balance of the region. These field studies have recently been completed and will shortly be published.
Monique Mainguet reported briefly on a wide range of Sahelian studies relevant to desertification by French physical geographers, including evidence of the chronology of pluvial and arid periods, the history of closed basins and their lakes, and the record of desert palaeosols.
A.T. Grove summarized English-language literature on desertification in the Sahel since 1976, much of it stimulated by the UN Conference on Desertification. Problems of long- and short-term climatic change have been covered in a number of publications, but one question which remains unresolved is whether the recent Sahelian drought was part of a continuing regime or whether it marks the onset of a significant climatic variation. Katz and Glantz have drawn attention to the tendency of decision-makers to underestimate the likelihood of recurrent drought in the Sahel and similar regions.
Grove cited a number of studies on population growth, increase in the numbers of cattle and its ecological effects, and resultant stresses between pastoralists and agriculturists. Overstocking, which has been linked with improved water supplies and veterinary services, now threatens the environmental balance and calls for solutions through social and economic changes: for example, the provision of alternative investment opportunities outside the pastoral sector and the reinforcement of the rights of individual groups to grazing in particular areas. A recent study of the Guidimaha region of Mauritania recommends that collective organizations should be encouraged amongst the villagers to make better use of water, to introduce new tools and varieties of crops and to produce fodder and improve livestock.
Southern Africa
P.D. Tyson reported on an extensive unpublished report on desertification in southern Africa by J.R.N. Wilcox in 1977. This dissertation shows that no factor has acted singly to cause desert encroachment. Periodic dry spells are the main natural cause, but anthropological factors are more important, notably overstocking into dry periods and the failure to allow impoverished veld vegetation to recover when rainfall increases before again restocking. The consequences have been an elimination of the climax vegetation, increased bare ground and run-off, and accelerated soil erosion, constituting progressive environmental deterioration.
Middle East
P.Beaumont gave an account of desertification in the Isfahan Basin of Iran, based on studies carried out in conjunction with staff of the Department of Geography at the University of Isfahan. The main water source is the snow-fed Zayandeh River, on which the Shah Abbas Dam was constructed in the mid-1960s. This has diminished flood damage and has provided hydroelectric power for regional industrial development, but has unfortunately resulted in an extension of secondary salinization in the lower part of the Basin, which depended on spring floods to leach the soils of accumulated salts.
The survey revealed several areas of rural depopulation, abandoned villages and loss of cultivated land. A major cause has been the attraction of relatively high urban wages, leading to the departure of younger men and a shortage of agricultural labour. An associated factor has been falling watertables and the drying out of several of the qanat systems serving the irrigation schemes. This is attributed to increasing cultivation and the sinking of wells in feeder upland basins over the past two decades, and also to increased pumping of shallow aquifers in the upper sector of the main alluvial fan.
I. Kobori presented a case study on Taibe village in the Palmyra Basin of Syria. This is part of a comparative study of oases dependent on foggara (qanat) supplies in the Old World, which will include investigations of Algerian oases. Extensive desertification around Taibe Oasis was not found, but some problems of falling watertables, accumulation of sands in neukhas, sedentarization of nomads, and abandonment of ancient canals were reported.
North America
Andrew W. Wilson commented briefly on desertification in the arid southwestern United States, emphasizing that only a minority of the population is concerned with desertification because economic and social adjustment to the local environment is for the most part not dependent on the quality of the land. The cattle ranchers, and to a lesser degree the irrigation farmers, are dependent on rainfall, but the bulk of the population prefers drought as providing more pleasant living conditions. This attitude will persist at least until domestic water supplies are affected, some time in the next century or beyond.
Latin America
H.J. Schneider reported growing public concern over environmental deterioration in Latin America, including desertification, following the Nairobi Conference. Expressions of this include the preparation of a coordinated national plan to combat desertification in Mexico, supported by regional development projects in soil conservation and ecosystem management, an integrated research programme in semi-arid Chile, and the establishment of research priorities and regional developmental methodologies in several Latin American countries.
Australia
J.A. Mabbutt reported some stabilization of conditions in the extensive rangelands following initial degradation in many areas. This has notably followed governmental measures limiting stocking levels and assisting the creation of leases of adequate size for economic operation in the face of rising costs. His review stressed the lack of quantitative evidence of long-term trends in range condition but noted concern at the lack of regeneration of many perennial pasture communities in the south of the arid zone under the impact of the introduced rabbit.
In the dry-farming lands, physical and economic conditions have improved with the introduction of longer rotations in mixed farming systems and the retreat of cropping from some marginal areas. However, a recent survey indicates that 20,000 ha require urgent treatment to combat wind erosion and that about 450,000 ha need constant surveillance, since a combination of drought and deteriorating economic conditions could lead to a resurgence of erosion. A widespread, although localized, problem in many dry-farming areas is secondary salinization resulting from the clearing of deep-rooted perennial vegetation for cropping.
About 250,000 ha of irrigated lands, mainly in the Murray Valley, are adversely affected by waterlogging and secondary salinization. A major regional problem here is the disposal of saline drainage and pumping effluent and the associated control of salinity levels in the lower Murray River, which is also subject to influent seepage of saline groundwater. The interests of three states are involved, and the federal government has recently reconstituted and strengthened the Murray River Commission in the interests of coordinated river management.
Desertification arising from non agricultural activities, such as mining and tourism and the associated settlements and constructions, differs in being localized. The fact that it is linked with capital-intensive enterprises makes mechanical remedial measures more feasible, whilst a growing concern for environmental conservation among the population outside the arid zone is enforcing action by mining companies and others in the interests of public relations. So far there has been little consideration of the social and economic impacts of these activities on existing communities such as aboriginal settlements or those of European pastoralists.
India
Mr. S.P. Malhotra of the Central Arid Zone Research Institute (CAZRI), Jodhpur, described studies on desertification and on measures to combat it in Rajasthan. Problems of increasing human and animal pressure on the land and concurrent declining productivity have increasingly engaged research at the Institute over the past years. The Institute was centrally involved in India's representation at the Nairobi Conference on Desertification, having authored the Indian Case Study on Desertification of the Luni Block, Rajasthan. Mr. Malhotra noted that Dr. M.S. Swaminathan, Director-General of the Indian Council of Agriculture, was elected Chairman of the Committee of the Whole at Nairobi.
Emphasis is on a multidisciplinary approach, involving physical, biological and social scientists, with increasing stress on extension and training, particularly through Operational Research Projects. Significant progress has been achieved in projects on Arid Land Management and on Drip and Sprinkler Irrigation as Related to Desertification.
Reference was made to a research project on Social Aspects of Desertification in collaboration with the United Nations Research Institute for Social Development (UNRISD). Fieldwork on this project is almost complete and a report is expected late in 1979. Rajasthan was one of the field areas chosen by the Science Associations' Nairobi Seminar to test the application of indicators for monitoring desertification, again in the area of the Luni Block.
CAZRI was to have been involved in the Southwest Asian Transnational Project on Monitoring Desertification under the UNEP Plan of Action, in which India was to collaborate with Iran, Pakistan and Afghanistan, but this has not yet got under way and may be initiated only on a national basis.
Other activities noted by Mr. Malhotra were the holding at Jodhpur of the International Symposium on Arid Zone Research and Development in January 1978, and the Post Plenary Session of the International Association of Archaeological and Ethnological Sciences, on Anthropology and Desertification, in December 1978.