Agent-Based Simulation of Holocene Monsoon Precipitation Patterns and Hunter-Gatherer Population Dynamics in Semi-arid Environments
- 546 Downloads
Based on archaeological evidence from Kutch-Saurashtra (N Gujarat, NW India), we use agent-based modelling (ABM) to explore the persistence of hunter-gatherer (HG) groups in semi-arid environments in the mid and late Holocene. Agents interact within a realistic semi-arid environment dominated by the monsoon. Precipitation trends are modelled from instrumental records (1871–2008) calibrated with existing models for the Asian monsoon in the Holocene (c. 12 ka–present). Experiments aim at exploring dependencies between population dynamics and climate-driven environmental change (in terms of resource availability) for precipitation patterns at the local, regional and continental scales. Resources are distributed across a simplified ground model. Average yearly precipitation (AYP, i.e. mean) and variance in yearly precipitation (VYP, i.e. standard deviation) are the main parameters affecting resource availability in the simulations. We assess the effects of environmental change on HG populations at different timescales: (1) patterns of seasonal (inter-annual) resource availability, (2) effects of changes in mean precipitation trends over the long (Pleistocene–Holocene) and the mid (Holocene, millennial) periods, and (3) effects of intra-annual precipitation variability, i.e. changes in standard deviation from mean precipitation trends over the short period (annual to decadal). Simulations show that (1) strong seasonality is coherent with the persistence of HG populations in India, independently of the geographical scale of the precipitation models, (2) changes in AYP over the mid period (Holocene) are not sufficient to explain the disappearance of HG populations in Kutch-Saurashtra (K-S) 4 ka and (3) precipitation variability (VYP) over the short period (annual to decadal) is the main parameter affecting population performance and overall ecosystem dynamics. To date, sufficiently refined palaeoclimatic records do not exist for the study area, but higher VYP values 4 ka do not exclude the possibility that other factors may have driven the disappearance of HG populations in Kutch-Saurashtra.
KeywordsArchaeology Simulation Monsoon Holocene Kutch-Saurashtra Gujarat India
This research has been supported by the SimulPast Project – Consolider Ingenio 2010 (CSD2010-00034, PI M. Madella), funded by the former Spanish Ministry for Science and Innovation (MICINN). AT, BR, CL, NL, MS and XRC have worked on this paper with contracts from the SimulPast project. AB with a contract from the Juan de la Cierva Program, funded by the Spanish Ministry of Economy and Competitiveness (MINECO). We wish to thank two anonymous reviewers for helping us improve the original text, H. Geffner for his generous support and insight and F. Cecília Conesa for his help with climate data mining.
- Allchin, B., Goudie, A., & Hedge, K. (1978). The prehistory and palaeogeography of the Great Indian Desert. London: Academic.Google Scholar
- Attri, S. D., & Tyagi, A. (2010). Climate profile of India. Contribution to the Indian network of climate change assessment. New Delhi: Environment Monitoring and Research Centre Indian Meteorological Department.Google Scholar
- Balbo, A. L., Rondelli, B., Cecília Conesa, F., Lancelotti, C., Madella, M., Ajithprasad, P. (2012). Contributions of geoarchaeology and remote sensing to the study of Holocene hunter–gatherer and agro-pastoral groups in arid margins: the case of North Gujarat (Northwest India). Quaternary International:1–13. doi: 10.1016/j.quaint.2012.12.016.
- Box, P. (2002). Spatial units as agents: making the landscape an equal player in agent-based simulations. In H. R. Gimblett (Ed.), Integrating geographic information systems and agent-based modeling techniques for simulating social and ecological processes (pp. 59–82). Oxford: Oxford University Press.Google Scholar
- Byrne, D. (1998). Complexity theory and the social sciences. An introduction. London: Routledge.Google Scholar
- Epstein, J. M. (2007). Generative social science: studies in agent-based computational modeling (Princeton studies in complexity). Princeton: Princeton University Press.Google Scholar
- Epstein, J. (2008). Why model? Journal of Artificial Societies and Social 11. http://jasss.soc.surrey.ac.uk/11/4/12.html.
- FAO/WHO/ONU (2005). Human energy requirements. Scientific background papers from the Joint FAO/WHO/UNU Expert Consultation. October 17–24, 2001. Rome, Italy. Food and Nutrition Technical Repost Series 1. FAO. http://www.ncbi.nlm.nih.gov/pubmed/19856424.
- Folke, C., Carpenter, S., Elmqvist, T., Gunderson, L., Holling, C. S., Walker, B. (2002). Resilience and sustainable development: building adaptive capacity in a world of transformations. Ambio 31,437–40. http://www.ncbi.nlm.nih.gov/pubmed/12374053.
- Hewlett, B. S. (1991). Demography and childcare in preindustrial societies. Journal of Anthropological Research, 47(1), 1–37.Google Scholar
- IPCC. (2012). Summary for policymakers. In C. B. Field, V. Barros, T. F. Stocker, D. Qin, D. J. Dokken, K. L. Ebi, M. D. Mastrandrea, K. J. Mach, G.-K. Plattner, S. K. Allen, M. Tignor, & P. M. Midgley (Eds.), Managing the risks of extreme events and disasters to advance climate change adaptation. A special report of working groups I and II of the intergovernmental panel on climate change (pp. 1–19). Cambridge: Cambridge University Press.Google Scholar
- Kelly, R. L. (1983). Hunter-gatherer mobility strategies. Journal of Anthropological Research, 39, 277–306.Google Scholar
- Lézine, A.-M., Tiercelin, J., Robert, C., Saliège, J., Cleuziou, S., Inizan, M., et al. (2007). Centennial to millennial-scale variability of the Indian monsoon during the early Holocene from a sediment, pollen and isotope record from the desert of Yemen. Holocene, 243, 235–249. doi: 10.1016/j.palaeo.2006.05.019.Google Scholar
- Meadow, R. H., & Patel, A. K. (2003). Prehistoric pastoralism in Northwestern South Asia from the Neolithic through the Harappan Period. In S. Weber & W. Belcher (Eds.), Indus ethnobiology: New perspectives from the field (pp. 65–93). Lanham: Lexington Books.Google Scholar
- Nagar, M. (2008). Hunter-gatherers of North and Central India: an ethnoarchaeological study. Oxford: Archaeopress. BAR International Series 1749.Google Scholar
- Singh, N., Ranade, A. (2010). Global temperature and Indian Monsoon. Geography and You. 41–43.Google Scholar
- Singh, V., Prasad, V., Chakraborty, S. (2007). Phytoliths as indicators of monsoonal variability during mid-late Holocene in mainland Gujarat, western India. Current Science 92, 8–13. http://www.pages-igbp.org/products/osmabstracts/Singh_Vartika.pdf.
- Tanaka, J., & Sugawara, K. (1996). The /Gui and //Gana of Botswana. In R. B. Lee & R. Daly (Eds.), The Cambridge encyclopedia of hunters and gatherers (pp. 195–199). Cambridge: Cambridge University Press.Google Scholar
- Wittek, P., Rubio-Campillo, X. (2012). Scalable agent-based modelling with Cloud HPC Resources for social simulations. In: 2012 I.E. 4th International Conference on Cloud Computing Technology and, Science. pp 355–362.Google Scholar