Optimal strategies for the use of reindeer rangelands

The problem of optimal adaptation of reindeer herds to rangelands under uncertain environmental conditions and measurement errors is studied by stochastic dynamic programming (SDP) and by stochastic optimisation in policy space (SOPS). The study expands on earlier studies by including measurement error, body weights, alternatives to lichen in winter pastures, wastage of lichen by cratering reindeer, and by including both summer and winter pastures in the same model. The analysis shows that it is important to get precise estimates of lichen growth, alternatives to lichen are only important if their digestibility is above a minimum level, variable costs only matter for the optimal herd size when summer grazing is limiting, modest discounting has little effect, the policy is not sensitive to the degree of natural variation, while the value of reindeer husbandry is significantly reduced by increasing climatic variation, the policy is sensitive to measurement error, and there is a considerable value of higher precision in measurements.