This thesis makes a contribution to the growing body of literature examining the institutional dimension of human-environment interactions. It has been guided by an interest in the problem of loss of terrestrial biodiversity in the state of Queensland, Australia and its institutional determinants. The study explored two research questions: • How to conceptualise and evaluate the effectiveness of institutions contributing to the resolution of environmental problems? • How effective is the Queensland land use planning and development assessment system in achieving biodiversity protection outcomes? The first part of the study established a theoretical and analytical foundation for the effectiveness assessment of institutional environmental performance, by examining a wide range of theoretical, conceptual and analytical questions regarding the conceptualisation of institutions, their causal role and evaluation. The study was built on an understanding of institutions as systems of rules that structure social interactions, and it defined institutional ‘performance’ as an institutional influence on, or contribution to, the behavioural response of targeted actors. It argued that institutions play a significant role in social interactions, and are an important explanatory factor for many behavioural phenomena. Building on the literature review, the study established that biodiversity protection is a highly complex and multi-faceted problem. Institutional designs are required to address a range of problem attributes, such as the existing knowledge base, value and incentive systems, distribution of decision-making authorities, and coordination of interactions among a large number of actors. In this context, the study examined two analytical problems. The first was how to approach a large diversity of problem attributes that may contribute to the resolution or creation of complex environmental problems. The second was how to examine diverse and complex institutional designs.