Spatial optimisation of urban ecosystem services through integrated participatory and multi-objective integer linear programming

Urban ecosystem services (UES) are the benefits supplied by nature to people in urban systems. The supply of UES is threatened because of widespread increasing urbanisation. Modelling scenarios that optimise UES supplies can support sustainable urban planning processes. UES are linked to land use/land cover (LULC) types, which enables the optimisation of UES supply to be based on LULC configurations. However, current modelling approaches are not suitably adapted to the link between UES optimisation and LULC configurations. One possibility to target UES optimal supply is to use mathematical optimisation methods. The objective of this study is to test the combined use of participatory modelling and optimisation models to deliver spatial solutions that maximise UES by optimal urban LULC configurations. An integrated model is built using a multi-objective integer linear programming (MOILP) model along with LULC performance scores to maximise a set of locally supplied UES. This is illustrated with a case study of Lisbon (Portugal) involving the participation of key stakeholders to validate and benchmark the selection of optimisation constraints. Results show land optimally allocated to land cover types with high UES functions combined with a reshuffling and densification of residential land. Thus, the new LULC configuration increased multiple UES supplies while maintaining a level of housing capacity. The model shows clear implications of increasing land cover types whose UES functions are high compared to most other LULC classes. Moreover, incorporating stakeholder participatory modelling offers a transdisciplinary and interdisciplinary scientific contribution intersecting mathematical optimisation, UES, and urban planning.