Natural capital concepts and participatory methods both govern national and international environmental policy. Synergies and trade-offs between these concepts present opportunities and threats to policy success. Yet an explicit understanding of how natural capital and participatory methods work together within urban river contexts has had little attention. This thesis presents research where two theories, natural capital and participation, combine, resulting in the novel use of logic chains of natural capital to support decision making in collaborative urban river restoration. Logic chains are an operational application of natural capital thinking, creating pathways between ecosystem assets and benefits to people. This method therefore benefits from participation to allow natural capital to move beyond economic interpretations of natural assets and improve socio-ecological understanding.

This thesis comprises of four chapters: Firstly, a systematic map, reviewing case studies which combine participatory methods with natural capital analysis for environmental decision making. Secondly, participatory natural capital workshops that apply natural capital assessment and decision making to an urban river catchment, using logic chain pathways. Thirdly, a novel evaluation framework for assessing the contribution of natural capital to participatory decision making in river catchment management. Fourthly, interviews with key informants to assess the application of participatory natural capital thinking within wider urban river catchment management.

The analysis demonstrates participatory applications of natural capital thinking facilitate pluralistic interpretations of natural capital. By using logic chains of natural capital, catchment issues can be solved by improving the state of nature to use the socio-ecological system that facilities a flow of benefits from nature to society. A novel evaluation framework identified the contributions of conceptual natural capital for participatory catchment assessments. Logic chains justify integrating natural capital thinking with participation decision making as they enable solutions to environmental issues to be solved by improving by flows between natural assets and society.