Beyond compliance: Enhancing biodiversity through transformative mitigation strategies in spatial planning related SEAs and EIAs

The global biodiversity crisis underscores the need for transformative change in how development impacts are managed, and biodiversity is preserved. This study explores the integration of Strategic Environmental Assessment (SEA) and Environmental Impact Assessment (EIA) within spatial planning and infrastructure projects, emphasizing their evolving role in promoting both mitigation and enhancement of impacts. Traditionally, SEAs and EIAs have focused on minimizing negative impacts through the mitigation hierarchy; however, this research advocates for a broader, proactive application that includes enhancement measures to achieve net-positive biodiversity impacts. Using a collection of 200 SEA and EIA reports from Denmark, Spain, Portugal, and Germany, analyzed within the BioValue research project, this study examines how these assessments apply the mitigation and enhancement hierarchy to promote positive outcomes. The findings reveal significant variability in the practical application of SEAs and EIAs, highlighting both strengths and gaps in integrating enhancement measures. By focusing on enhancement as a formal requirement and strengthening the ‘avoidance’ step in the mitigation hierarchy, this paper argues that SEA and EIA can transition from reactive assessments to proactive instruments in environmental governance and add value to spatial planning developments. The study concludes with recommendations for embedding enhancement into regulatory frameworks, encouraging a shift towards transformative environmental assessment practice.