LAND: Ecological effects of sheep grazing and the economy of sustainable husbandry in alpine habitats

Sheep husbandry is an important part of the rural economy in Norway, with a tradition going some 5000 years back into the Bronze age. However, increases in numbers (2-2.5 million sheep on summer pasture) and a more extensive use of alpine habitats (made a ccessible by roads) during the last century have caused considerable controversy during the last decade. On the one hand, it is urgent from a conservation perspective to assess the role of sheep grazing as a potential factor for some observed recent and d ramatic changes in mountain ecosystems (e.g., more irregular rodent cycles). On the other, it is urgent for sheepherders to get documentation of sheep grazing effects, as the uncertainty in itself has lead to several grazing contracts not being renewed. Here we propose a multi-disciplinary project analysing ecological and economic factors determining the optimal degree of sheep grazing for the two most controversial alpine ranges in Norway – Hardangervidda and Setesdal Vesthei og Ryfylkeheiene. The novel ty of our project is the explicit landscape-scale experimental design addressing scaling issues, the three levels of grazing enabling assessments of sustainable grazing levels, the contrast between fairly rich (such as Hardangervidda) and poor (Setesdal V esthei og Ryfylkeheiene) alpine habitat, and the inclusion of economic calculations of what reaching (suggested) sustainable levels (as defined by explicit ecological effects) will cost to the sheep herders and landowners as well as to the society. In the research proposal, we describe both specific botanical and zoological studies and analyses empirically addressing how sheep grazing effects (on plants, rodents and birds) depend on sheep population density, temporal and spatial scales and ecosystem properties (such as nutrient levels). The economic part of the project aims first to assess the various cost and income components of sheep farming, and the various indirect income effects in the study areas. Next, based on this cost and benefit structur e, a bioeconomic (dynamic) model analysing the vegetation-sheep interaction will be formulated. Through model simulations, the costs of reaching specific (‘sustainable’) sheep density levels may be quantified. The focus on assessment related to different levels of sheep density on alpine ranges will be the main interdisciplinary denominator of the project.