ABSTRACT This paper develops a dynamic model of grazing land degradation. The model illustrates the relationship between live-stock levels and grazing land degradation over time. It identifies the mechanisms by which the factors internal to the livestock local production system and those drawn from the larger economic context of livestock marketing influence livestock-grazing land relationship. The paper shows that overstocking leads to degradation which leads to declining relative prices of livestock as quality declines and mortality increases. As relative price of livestock falls, consumption increases. The increased consumption and mortality ultimately leads to lower livestock population, which leads to de-creased degradation. The model results show that medium term dynamics of grazing land degradation are quite differ-ent from long term dynamics. It is shown that although grazing land sustainability situation is adverse in the medium term, yet it is favourable in the long term. The livestock system is dynamic and can adjust when longer term system dy-namics are allowed to play out. Part of the adjustment mechanism is built in the livestock system and the other part comes from the economic system. The built-in adjustment mechanism works through the two-way relationship between the stock and degradation. The external adjustment mechanism, originating from the economic system, works through economic growth, relative prices and foreign trade. In the medium term, opportunistic management strategy and poli-cies that facilitate access to grazing land and water are crucial for mitigating degradation. The results suggest that the views of the mainstream range management paradigm and the new thinking of range ecology can be reconciled.
Cite this paper
nullE. Abdelgalil and S. Cohen, "Modelling Livestock Activities and Environmental Sustainability: The African Case," Journal of Environmental Protection, Vol. 1 No. 1, 2010, pp. 1-9. doi: 10.4236/jep.2010.11001.
 L. R. Oldeman, R. T. A. Hakkeling, and W. G. Sombroek, “World map of the status of human induced soil degradation: An explanatory note,” ISRIC/UNEP, Wageningen, The Netherlands, 1991.
H. Dregne, M. Kassas, and B. Rozanov, “Status of deserti- fication and implementation of United Nations plan to combat desertification,” Desertification Control Bulletin, No. 20, pp. 6, 1991.
C. de Haan, H. Steinfeld, and H. Blackburn, “Livestock and the Environment: Finding a balance,” Study sponsored by the European Commission, FAO and World Bank, 1997.
I. Scoones, (Ed.) “Living under uncertainty: New directions in pastoral development in Africa,” Intermediate Techno- logy Publications, London, 1994.
T. Amede, et al., “Maximizing benefits from livestock- water venture in Sub-Saharan Africa: From concepts to practices,” The International Water Management Institute/ International Livestock Research Institute, Addis Ababa, Ethiopia, 2009.
A. K. Acharya and N. Kafle, “Land degradation issues in Nepal and its management: Through agroforestry,” The Journal of Agriculture and Environment, Vol. 10, June 2009.
A. de Sherbinin, “CIESIN thematic guide to land-use and land-cover change,” Center for International Earth Science Information Network (CIESIN), Columbia University, Palisades, NY, USA, 2002.
G. B. Thapa and G. S. Paudel, “Evaluation of the livestock carrying capacity of land: Resources in the Hills of Nepal based on total digestive nutrient analysis,” Agriculture, Ecosystems & Environment, Vol. 78, No. 3, pp. 223–235, May 2000.
D. G. Wilcox and J. F. Thomas, “The Fitzroy valley regeneration project in Western Australia,” in J. A. Dixon, D. E. James and P. B. Sherman, Eds., “Dry management: Economic case studies,” Earthscan Publications Ltd., London, 1990.
L. C. Braat and J. B. Opschoor, “Risk in the Botswana range-cattle system,” in J. A. Dixon, D. E. James and P. B. Sherman, Eds., “Dry management: Economic case studies,” Earthscan Publications Ltd., London 1990.
C. Berrings and D. I. Stern, “Modelling loss of resilience in agroecosystems: Rangelands in Botswana,” Environ- mental and Resource Economics, Vol. 16, No. 12, pp. 185–210, 2000.
D. Pearce, E. Barbier, and A. Markandya, “Sustainable development: Economics and environment in the Third World,” Edward Elgar, England, 1990.
A. R. Gigengack, C. J. Jepma, D. MacRae, and F. Poldy, “Global modelling of dryland degradation,” in J. A. Dixon, D. E. James and P. B. Sherman, Eds., “Dry management: Economic case studies,” Earthscan Publications Ltd., Lon-don, 1990.
H. A. Simon, “Causal ordering and identifiability,” in W. C. Hood and T. C. Koopmans, Eds., “Studies in econometric method,” Cowles Foundation Monograph, No. 14, Yale University Press, New Haven, 1953.
E. Abdelgalil, “Economic policies for sustainable resource development: Models applied to Sudan,” PhD thesis, Eras-mus University Rotterdam, The Netherlands, 2000.
M. Fafchamps, “The tragedy of the commons, livestock cycles, and sustainability,” Journal of African Economies, Vol. 7, No. 3, pp. 384–423, 1998.
J. Ellis, “Climate variability and complex ecosystem dy-namics: Implications for pastoral development,” in I. Scoones, Ed., “Living under uncertainty: New directions in pastoral development in Africa,” Intermediate Technology Publications, London, 1994.
R. Ramcharan, “Money, meat, and inflation: Using price data to understand an export shock in Sudan,” IMF Working Paper WP/02/84, 2002.
R. H. Behnke, I. Scoones, and C. Kerwin, “Range Eco- logy at Disequilibrium,” ODI, London, UK, 1993.