Biodiversity and ecosystem services in strategic environmental assessment: evaluating outcomes, challenges, and opportunities

As human activity is the main driver of declines in biodiversity, ecosystem function and services, preventing irreversible losses of biodiversity and ecosystem services will depend on careful management of human impacts on the environment. A common approach used by governments around the world to regulate human impact is environmental impact assessment (EIA), which is applied to predict and manage the potential environmental impact of development proposals. Because of its restricted scope to individual projects, EIA can be limited in accounting for the cumulative effects that different development activities may have on the environment and their significance at larger spatial and temporal scales. An alternative approach that is increasingly being adopted around the world is strategic environmental assessment (SEA). SEA is a framework consisting of different approaches to support the development of environmentally sustainable strategic initiatives, including policies, plans and programs (Fischer and González, 2021). SEA aims for development across a landscape that is planned and implemented in such a way that negative effects on the environment, including biodiversity, are minimised. By ensuring that environmental impacts and alternatives are considered early in the decision-making process and addressing cumulative and large-scale effects, SEA has the potential to overcome some of the limitations of project-level EIA. SEA is being adopted and implemented by an increasing number of jurisdictions. Despite its growing use worldwide, knowledge on how SEA plays out in practice is limited and evaluating its effectiveness remains an important research need. Through case study research and mixed methods, this thesis investigates how effectively biodiversity and ecosystem services have been incorporated into SEA, and explores the challenges and opportunities for improving the capacity of SEAs to account for these matters in a range of contexts.  This thesis investigates these issues using a series of case studies in Australia and Mexico. Australia has more than a decade of experience conducting SEAs that have a strong focus on biodiversity matters. Mexico has limited experience and no legislation addressing SEA, but where SEA has been suggested as a promising approach to adopt. More specifically I undertake the following: (i) develop a framework to evaluate the integration of biodiversity and ecosystem services in the assessment stage of SEA and apply it to the six urban planning SEAs endorsed to date in Australia; (ii) investigate the implementation stage of a flagship Australian SEA, the Melbourne Strategic Assessment, to investigate the challenges of implementing biodiversity conservation interventions for critically endangered ecosystems and the potential improvements to achieve conservation objectives more effectively; (iii) examine the first attempt in Mexico of applying SEA to city-wide urban development plans, the Puerto Vallarta SEA, to identify contextual factors to consider when implementing SEA in Mexico and similar countries of the Global South to address biodiversity and ecosystem services effectively; and (iv) explore how the supply and benefit of an ecosystem service relevant for urban planning SEAs, heat mitigation, can be quantitatively assessed to enhance the contribution of SEA to strategic decision-making.     The research reveals that critical improvements are needed to ensure that SEA addresses biodiversity and ecosystem services considerations effectively and offers insights into the changes that could be adopted. At the assessment stage of SEA, biodiversity conservation objectives are oftentimes too broadly defined, which complicates their implementation, and evidence in this thesis suggests that the mitigation hierarchy is weakly applied. These limitations could be improved by defining reference scenarios to measure progress towards achieving no net loss objectives and providing evidence to demonstrate the application of previous steps of the mitigation hierarchy. I also find there is a low integration and weak analysis of ecosystem services at the assessment stage of SEA and that opportunities to obtain more substantial benefits from SEA are currently being missed, particularly those relating to human wellbeing. Decision-making under SEA would benefit from explicit and quantitative assessments of ecosystem services, and I demonstrate how such assessments could be conducted in urban planning SEAs for the service of heat mitigation in a way that considers both service supply (in terms of reduced temperature increases) and benefit (represented as energy costs borne by residents).  At the implementation stage of SEA, I identified flaws preventing the achievement of biodiversity conservation objectives including questionable funding and enforcement arrangements. Improvements that could help overcome these limitations include funding biodiversity conservation measures prior to implementing policies, plans or programs assessed under SEA and setting more explicit legal provisions for enforcing the implementation of biodiversity conservation interventions and objectives.  This research also offers insights regarding the implementation of SEA in Mexico and other countries of the Global South that, like Mexico, currently lack legislation for SEA. Implementing SEA effectively in these jurisdictions will require strengthening the capacity of environmental agencies that will regulate and enforce SEA. Furthermore, to ensure SEA makes valuable contributions to decision-making in such countries, training and guidance in SEA would need to be provided, including processes for conducting robust biodiversity and ecosystem services assessments. The research in this thesis reveals major problems in SEA practice and its current capacity to deliver genuine benefits to biodiversity and ecosystem service provision and suggests key improvements that are required to enhance its effectiveness. It remains to be seen whether jurisdictions around the world will be capable of implementing the reforms suggested by this research. However, only by improving current practice will SEA serve its intended purpose of improving strategic decision-making and help in the delivery of policies, plans, and programs that are less harmful to biodiversity and which provide enhanced benefits to people derived from ecosystem services.