Restoring ecosystem function: Which functions and how much is enough?

In ecology it is generally assumed that there are certain ecosystem ‘functions' or ‘dynamic attributes' that are essential for the self-maintenance of a system. Such attributes include biotic components, abiotic components, material and energy flows, ecosystem architecture. In the case of degraded ecosystems it seems logical that these functions need to be restored to such a level that the ecosystem can function normally. The present paper will explore to what level what attributes need to be restored. Also the question will be addressed whether the optimal levels differ under different land-use intensity degrees. Next I will investigate the question which attribute should be prioritized under non-optimal conditions. Finally I will explore whether there exists any evidence that prioritizing different attributes will lead to alternative stable states.