Mobility – a panacea for pastoralism? An ecological-economic modelling approach.

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

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

3. IntroductionResearch questions •  What are pitfalls and chances of new technologies, i.e. increased mobility? •  Howdoesmobilityaffectlong-term conditionsofpastureandlivestock? Can mobility improve conditions of biomass and livestock?

4. MethodsModel characteristics •  Multi-Agent simulationmodel •  Structuralsimplistic, structurebased on empiricaldata •  Dynamic feedbackbetweenecologicalandeconomiccomponent •  Spatialstructure: patchnetwork Figure 1: Snapshot of patch network and pathway of agents. Each color represents one agent.

5. MethodsModel overview: Entities, theirrelationshipsandmainprocesses Precipitation Agents(Pastoralisthouseholds) Lognormal Distribution Patchselectionsubmodel (Optimizationcriteria) rainfall movement decision Patches(Pastures) ownership income growth Livestock (Sheep) Green Biomass Reserve Biomass fodder Reproduction Feeding grazing

6. MethodsPatch selection Patch selectionsubmodel Optimizationcriterionbased on  Sheepvalue Patch distance Movement costs no Enoughbiomass on patch? Foundnewbestpatch? yes Destockingnecessary? yes yes no no Agent moves Nodestocking Agent stays on currentpatchNodestocking Agent moves Needs todestock Agent stays on currentpatchNeeds todestock

7. MethodsMovement 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. Figure 2: Use of patches by one agent at low and high costs in one exemplary simulation run.

8. MethodsSimulationsandHypotheses • Parameter variation: •  Number of agents in the system naand •  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.

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

10. ResultsRegulation ofmovement – restingofpastures Evaluation ofcombinedeffectsofagentdensityandmovementcosts: • Costs too low. • All biomass reserves are used. • No resting of pastures. • Costs too high. • No movement at all. • No resting of pastures. 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. • Effective regulation of movement. • Resting of pastures possible.

11. 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 modelhas proved useful to test the impact of new technologies (increased mobility).

12. Discussionand OutlookNext developmentsteps •  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?

13. Acknowledgements & References • We would like to thank Dr. StenZeibig 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, 2006. • Mueller, B., K. Frank and C. Wissel, Relevance of rest periods in non-equilibirum rangeland systems - a modelling analysis, Agricultural Systems, 92, 295–317, 2007. • 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 Centrefor Environmental Research & Ernst-Moritz-Arndt-University of Greifswald, 2011.