Mobility – a panacea for pastoralism? An ecological-economic modelling approach. Gunnar Dressler, Birgit Mueller, Karin Frank Department of Ecological Modeling

Page 2 Introduction Background and Motivation Mobility = Basic principle of nomadic life Fast & long-distance mobility due to new technologies Decline of nomadism & increased sedentarisation Fernandez-Gimenez et al. [2006]  Regions often drylands, resource-scarce  Wide range of transition processes political, climatic, economic, technological  Sustainable resource use is a central topic

Introduction Research questions  What are pitfalls and chances of new technologies, i.e. increased mobility?  How does mobility affect long-term conditions of pasture and livestock? Can mobility improve conditions of biomass and livestock? Page 3

Methods Model characteristics  Multi-Agent simulation model  Structural simplistic, structure based on empirical data  Dynamic feedback between ecological and economic component  Spatial structure: patch network Page 4 Figure 1: Snapshot of patch network and pathway of agents. Each color represents one agent.

Patches (Pastures) Methods Model overview: Entities, their relationships and main processes Page 5 Green Biomass Reserve Biomass Precipitation Lognormal Distribution Livestock (Sheep) FeedingReproduction Agents (Pastoralist households) Patch selection submodel (Optimization criteria) grazing income rainfall growth movement decision fodder ownership

Methods Patch selection Page 6 Enough biomass on patch? Found new best patch? Destocking necessary? Agent stays on current patch No destocking Agent moves Needs to destock Agent stays on current patch Needs to destock Agent moves No destocking Patch selection submodel Optimization criterion based on  Sheep value  Patch distance  Movement costs yes no yes no

Methods Movement costs vs. mobility  Intent of movement costs in the model:  low costs ≙ high mobility  high costs ≙ low mobility  Movement costs are a proxy to regulate mobility, both distance and frequency.  Movement costs are relative values, not specific prices. Page 7 Figure 2: Use of patches by one agent at low and high costs in one exemplary simulation run.

Methods Simulations and Hypotheses Parameter variation:  Number of agents in the system n a and  Movement costs cM.  Other parameters fixed (Mueller et al. [2007], Schulze [2011]). Hypotheses:  Higher density of agents will have a negative impact on biomass and livestock.  Mobility of agents can counteract and enhance livestock and biomass conditions. Page 8

Results Reserve biomass and livestock averages, time step t=100 Page 9 [kg/ha] [# sheep] Figure 3: Averages of reserve biomass and livestock at time step t = 100, calculated from 500 simulation runs.

Results Regulation of movement – resting of pastures Page 10 Low densityMedium densityHigh density Low costs Medium costs High costs Evaluation of combined effects of agent density and movement costs: System only sparsely populated No negative effects of mobility. Mobility too high. Negative effects on pasture conditions. Improvement of pasture and livestock conditions with increasing movement costs. Costs too low. All biomass reserves are used. No resting of pastures. Costs too high. No movement at all. No resting of pastures. Effective regulation of movement. Resting of pastures possible.

Conclusion  Mobility is not an answer to all problems that pastoralism faces: Resting of pastures is the crucial mechanism behind.  Pasture resting can be achieved through an appropriate level of mobility.  Exploratory model has proved useful to test the impact of new technologies (increased mobility). Page 11

Discussion and Outlook Next development steps  Dynamic decision criterion that also incorporates future livestock value.  Polarization: Is coexistence of agent groups with different resource sets or strategies possible? Can poor agents save their livelihood?  Access regimes: Traditional access regimes vs. new institutions – How should new institutions be designed to regulate pasture access? Page 12

Acknowledgements & References We would like to thank Dr. Sten Zeibig who inspired us to do this study. We acknowledge support of the German Research Foundation (DFG) within the Collaborative Research Centre „Difference and Integration: Interaction between nomadic and settled forms of life in the civilizations of the old world“. References: Fernandez-Gimenez, M.E. and S. Le Febre, Mobility in pastoral systems: Dynamic flux or downward trend?, International Journal of Sustainable Development & World Ecology, 13, 342–362, Mueller, B., K. Frank and C. Wissel, Relevance of rest periods in non-equilibirum rangeland systems - a modelling analysis, Agricultural Systems, 92, 295–317, Schulze, J., Risk Measures and Decision Criteria for the Management of Natural Resources Under Uncertainty - Application to an Ecological-Economic Grazing Model, Master Thesis, Helmholtz Centre for Environmental Research & Ernst-Moritz-Arndt-University of Greifswald, Page 13