We apply an age- and sex-structured reindeer-lichen model to examine the role of winter pastures, pasture rotation, and supplementary feeding on economically optimal reindeer management. The model includes 17 age classes of females, 13 classes of males and a detailed description of winter energy resource utilization by the reindeer population. Reproduction is specified by a modified harmonic mean mating system and the diet choice between different winter energy resources follows the principles of the optimal foraging theory. Wintertime energy intake defines an individual's weight decrease and its consequences on mortality and reproduction. Lichen growth depends on habitat type and lichen biomass. The decision variables are the animals chosen for slaughter from each age and sex class and the amount of supplementary food given. Results show that the availability of arboreal lichens, the growth rate of ground lichens, and pasture rotation all determine the optimal solutions. Reindeer management aiming to maximize long-term net economic revenues leads to very low lichen densities if intensive feeding becomes optimal in the long-term steady state. Government subsidies promote reindeer herders to base management on supplementary feeding leading to lower pasture conditions and to the depletion of lichens.
Fields of Science
- 1181 Ecology, evolutionary biology
- 412 Animal science, dairy science
- 519 Social and economic geography