THE DYNAMICS OF AN ANIMAL—VEGETATION SYSTEM: SHEEP FARMING

The paper studies the economy and ecology of sheep farming at the farm level in a Nordic context, with a crucial distinction between the outdoors grazing season and the winter indoors feeding season, and where climate conditions fix the length of the grazing season. Two different categories of animals, ewes (adult females) and lambs, and one plant species are included in our ecological model. The farmer is assumed to maximize present‐value profit where the revenue is made up income from meat and wool production. We find that livestock cycles may represent an optimal management policy. We also show that in a possible steady state with a constant number of animals and constant vegetation quantity, slaughtering either only lambs or only ewes is optimal.     

EXPLOITATION OF AN UNMANAGED LOCAL COMMON. ON THE PROBLEMS OF OVERGRAZING,REGULATION AND DISTRIBUTION

ABSTRACT. A system comprising grazing land and livestock is considered. The livestock is privately owned while the grazing land is communally owned. A model is formulated to analyze the utilization of this system, assuming that the pastoralists maximize the size of their livestock herd, subject to a minimum amount of income. This exploitation scheme is compared with the outcome of the standard neoclassical model where the resource rent is maximized. It is demonstrated that it is an open question as to which of these two models leads to the highest grazing pressure. However, as different economic and social mechanisms are working in the direction of economic overgrazing, the policy implications are quite different when it comes to managing and regulating grazing pressure.