Abstract
Pastoralists who depend on their herds for their livelihoods need a minimum number of animals to support their household. Due to the dynamics of herd growth, pastoralists may find themselves at times below that minimum number. Previous studies have shown that there is a herd-size threshold below which households are unlikely to escape poverty. We explore the concept of a herd-size threshold using an agent-based model to examine the role of scale and stochasticity in family herd dynamics. The model was parametrized with data from the literature. The results from the computer simulations show (1) that offtake rates significantly limit herd growth; and (2) that herd-size threshold is better understood as a range of probabilities. We discuss the methodological and conceptual advantages of using agent-based modeling to examine demographic dynamics, including the possibility of conducting multiple experiments in silico to examine the dynamics of herd growth.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barth F. (1961). Nomads of South Persia: The Basseri tribe of the Khamseh confederacy, Little, Brown and Company, Boston (MA).
Borgerhoff Mulder M., and Sellen D. W. (1994). Pastoralist decisionmaking: A behavioral ecological perspective. In Fratkin E., Galvin K. A., and Roth E. A. (eds.), African Pastoralists Systems: An Integrated Approach, Lynne Rienner publishers, Boulder (CO).
Bradburd D. A. (1980). Never Give a Shepherd an Even Break: Class and Labor among the Komachi. American Ethnologist 7(4): 603–620.
Bradburd D. A. (1982). Volatility of Animal Wealth among Southwest Asian Pastoralists. Human Ecology 10(1): 85–106.
Bradburd D. A. (1989). Producing their Fates: Why Poor Basseri Settled but Poor Komachi and Yomut Did Not. American Ethnologist 16(3): 502–518.
Buffington, A., Yoak, A. J., Hamilton, I.M., Garabed, R., and Moritz, M.. (2016). Family herd model (version 1). CoMSES Computational Model Library.
Coulomb, J.( 1974). Methodes d'analyse statistique du troupeau. Paper read at Journees techniques: Production animale, at Paris.
Dahl G., and Hjort A. (1976). Having Herds: Pastoral Herd Growth and Household Economy, Stockholm Studies in Social Anthropology, Department of Social Anthropology, University of Stockholm, Stockholm (Sweden).
Fratkin E., and Roth E. A. (1990). Drought and Economic Differentiation among Ariaal Pastoralists of Kenya. Human Ecology 18(4): 385–402.
Grandin B. E. (1989). Labor Sufficiency, Livestock Management, and Time Allocation on Maasai Group Ranches. Research in Economic Anthropology 11: 143–178.
Grimm V., Revilla E., Berger U., Jeltsch F., Mooij W. M., Railback S. F., Thulke H.-H., Weiner J., Wiegand T., and DeAngelis D. L. (2005). Pattern-Oriented Modeling of Agent-Based Complex Systems: Lessons from Ecology. Science 310(11 November 2005): 987–991.
Grimm V., Berger U., Bastiansen F., Eliassen S., Ginot V., Giske J., Goss-Custard J., Grand T., Heinz S. K., and Huse G. (2006). A standard protocol for describing individual-based and agent-based models. Ecological Modelling 198(1–2):115–126.
Grimm V., Berger U., DeAngelis D. L., Polhill J. G., Giske J., and Railsback S. F. (2010). The ODD protocol: A review and first update. Ecological Modelling 221(23):2760–2768.
Heffernan C., and Rushton J. (2000). Restocking: A Critical Evaluation. Nomadic Peoples 4(1): 110–124.
Loftsdóttir K. (2008). The Bush is Sweet: Identity, Power, and Development among WoDaaBe Fulani in Niger, Nordiska Afrikainstituted, Uppsala (Sweden).
Lybbert T., Barrett C., Desta S., and Coppock L. (2005). Stochastic Wealth Dynamics and Risk Management among a Poor Population. Economic Journal 114: 750–777.
Mace R., and Houston A. (1989). Pastoralist Strategies for Survival in Unpredictable Environments: A Model of Herd Composition that Maximises Household Viability. Agricultural Systems 31(2): 185–204.
McCabe J. T. (1987). Drought and Recovery: Livestock Dynamics among the Ngisonyoka Turkana of Kenya. Human Ecology 15(4): 371–389.
McPeak J. G., and Barrett C. B. (2001). Differential Risk Exposure and Stochastic Poverty Traps among East African Pastoralists. American Journal of Agricultural Economics 83(3): 674–679.
Mitchell M. (2009). Complexity: A Guided Tour, Oxford University Press, Oxford (UK).
Moris J. R. (1988). Oxfam's Kenya Restocking Projects. ODI Pastoral Development Network paper 26c: 1–21.
Moritz, M. (2003). Commoditization and the pursuit of piety: The transformation of an African pastoral system. Dissertation, Department of Anthropology, University of California at Los Angeles, Los Angeles.
Njoya A., Bouchel D., Ngo Tama A.-C., Moussa C., Martrenchar A., and Letenneur L. (1997). Systèmes d'élevage et productivité des bovins en milieu paysan. World Animal Review 89(2): 12–23.
Raikes P. L. (1981). Livestock Development and Policy in East Africa, Scandinavian Institute of African Studies, Uppsala (Sweden).
Railsback S. F., and Grimm V. (2012). Agent-Based and Individual-Based Modeling: A Practical Introduction, Princeton University Press, Princeton (NJ).
Reynolds C. W. (1987). Flocks, Herds, and Schools: A Distributed Behavioral Model. Computer Graphics 21(4): 25–34.
Roth E. A. (1996). Traditional Pastoral Strategies in a Modern World: An Example from Northern Kenya. Human Organization 55(2): 219–224.
Sieff D. F. (1999). The Effects of Wealth on Livestock Dynamics among the Datoga Pastoralists of Tanzania. Agricultural Systems 59: 1–25.
Silverman E., Bijak J., Hilton J., Cao V. D., and Noble J. (2013). When Demography Met Social Simulation: A Tale of Two Modelling Approaches. Journal of Artificial Societies and Social Simulation 16(4): 9.
Stenning D. J. (1958). Household viability among the pastoral Fulani. In Goody J. (ed.), The Development Cycle in Domestic Group, Cambridge University Press, Cambridge.
Sutter J. W. (1987). Cattle and Inequality: Herd Size Differences and Pastoral Production among the Fulani of Northeastern Senegal. Africa 57(2): 196–218.
Wagenaar K. T., Diallo A., and Sayers A. R. (1986). Productivity of Transhumant Fulani Cattle in the Inner Niger delta of Mali, ILCA Research Report; No. 13, International livestock Centre for Africa, Addis Ababa, Ethiopia.
Wilensky U., and Rand W. (2015). An Introduction to Agent-Based Modeling: Modeling Natural, Social, and Engineered Complex Systems with NetLogo, MIT Press, Cambridge (MA).
Wilensky U. (1999). NetLogo. Center for Connected Learning and Computer-Based Modeling, Northwestern University. Evanston, IL. http://ccl.northwestern.edu/netlogo/.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
This research project was supported by a grant from the National Science Foundation (BCS-1546061).
Conflict of Interest
The authors declare that they have no conflict of interest.
Rights and permissions
About this article
Cite this article
Moritz, M., Buffington, A., Yoak, A.J. et al. No Magic Number: an Examination of the Herd-Size Threshold in Pastoral Systems Using Agent-Based Modeling. Hum Ecol 45, 525–532 (2017). https://doi.org/10.1007/s10745-017-9927-0
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10745-017-9927-0