Introducing SELS Sustainable development ensures that natural resources are conserved, managed and exploited in a manner that will guarantee equitable distribution of benefits among current and future generations. This goal should be an integrated component of decision-making regarding the development and utilization of ‘green and blue’ spaces. Essentially, the decision-making process comprises of evaluating a number of interests, including spatial and temporal. This should be carried out according to the principles of democratic decision-making, which consists of transparent criteria and clear procedures. Thus, a number of questions may arise, such as: which interests should be considered; how should they be assessed; which temporal and spatial scale should be used; and who should decide? The complexity of these sustainability questions is enhanced in the context of two opposing governance trends. On the one hand, globalization promotes the management of issues at an international level, e.g. the international convention on climate change. On the other hand, the trend of regionalization and democratization promotes a diverse range of stakeholders to participate in spatial planning negotiations. In the Netherlands, the current bill on spatial planning introduced the definition ‘territorial development’  that emphasizes decision-making processes with strong local orientation, cooperation between the government and private stakeholders, room for local creativity and initiatives, and a large role for local knowledge. This same trend can be observed in other democratic societies. In order for the governing complexity to do justice to natural resource management, knowledge on the functioning of these resources must be available in a convenient form for all relevant decision-making levels.             At landscape level, what are the important natural resources and why does the existing knowledge for practical implementation not meet the sustainability criteria? Ecosystems and mosaics of ecosystems (also known as landscapes) provide a great number of services that are essential to human-beings for wealth, health and wellbeing. However, this concept is difficult to quantify and apply to territorial development. Therefore, spatial planning decision-making processes at the various levels do not or rarely take the services provided by ecosystems and landscapes into account. For that reason investments in green-blue environments cannot be assessed on their economical and/or socio-cultural added-value. Therefore the various territorial development actors cannot discern the benefits gained by investing in spatial quality, in terms of wealth, health and wellbeing. In metropolitan landscapes (urban landscapes and rural landscapes within urban atmospheres), these public values are concentrated in a limited part of the landscape, located in areas that are not used for food production, residence or employment. The interests of these areas are connected to the residents and businesses of that particular area, the adjacent areas and other areas at greater distance. In rural landscapes beyond urban atmospheres and in landscapes where the natural processes are dominant, values and interests may be distributed differently spatially. As a result stakeholders that invest are not always the ones that make use of the service: the beneficiaries of the green-blue investment may be located a great distance away. The quantification of ecosystem and landscape services should include functions that provide services, the investments in these functions (by the investors), as well as making the benefits (in relation to the beneficiaries) measurable. In this instance, a function can only be considered a service, if it can be linked to the interests of a beneficiary or consumer.         Ecosystems and landscapes functions are connected to physical structures. Therefore, to gain the desired level of service, variables such as type, surface, quality, and spatial classification should be important components of spatial planning decision-making. Decision-makers of territorial development should connect the desired level of ecosystem- and landscape services in the region to the conditions needed to achieve these functions. In other words: each function requires a spatial design that supports its services. Spatial planning and policies need to be accompanied by appropriate investment plans that consider costs (cost effectiveness), benefits (cost-benefit analysis) and financial arrangements. In the context of spatial planning and design, this should be negotiated among interest groups and the desired level of functioning should be based on achievable conditions. This is usually achieved through a cyclical planning process; in which each phase has different needs with regard to the form the knowledge is provided.