The term open-space structure refers to the quantitative and qualitative pattern or distribution of land uses and functions in a near-natural state. It is one of the principles of spatial planning (Federal Spatial Planning Act – Section 2 (2) No.3) that the open-space structure of the national territory be protected and developed. The importance of open spaces for productive land use, the water balance, fauna and flora and for the climate is to be guaranteed or their function restored. Provision is to be made for economic and social uses of open spaces by taking their ecological functions into consideration. The designation of biosphere reserves and the concept of habitat network systems are ways to conserve open space structure.