Leon Bennun, Claire Fletcher, Aonghais Cook, David Wilson, Ben Jobson,Rachel Asante-Owusu, Annie Dakmejian, Qiulin Liu About IUCN IUCN is a membership Union uniquely composed of both government and civil societyorganisations. It provides public, private and non-governmental organisations with theknowledge and tools that enable human progress, economic development and natureconservation to take place together. Created in 1948, IUCN is now the world’s largest and most diverse environmental network,harnessing the knowledge, resources and reach of more than 1,400 Member organisationsand some 16,000 experts. It is a leading provider of conservation data, assessmentsand analysis. Its broad membership enables IUCN to fill the role of incubator and trustedrepository of best practices, tools and international standards. IUCN provides a neutral space in which diverse stakeholders including governments,NGOs, scientists, businesses, local communities, Indigenous Peoples' Organisations andothers can work together to forge and implement solutions to environmental challengesand achieve sustainable development. Working with many partners and supporters, IUCNimplements a large and diverse portfolio of conservation projects worldwide. Combiningthe latest science with the traditional knowledge of local communities, these projects workto reverse habitat loss, restore ecosystems and improve people’s well-being. www.iucn.orghttps://x.com/IUCN/ About The Biodiversity Consultancy The Biodiversity Consultancy is a specialist consultancy in biodiversity risk management.We work with sector-leading clients to integrate nature into business decision-makingand design practical environmental solutions that deliver nature-positive outcomes. Weprovide technical and policy expertise to manage biodiversity impacts at a project level andenable purpose-driven companies to create on-the-ground opportunities to regenerate ournatural environment. As strategic advisor to some of the world’s largest companies, we leadthe development of post-2020 corporate strategies, biodiversity metrics, science-basedtargets, and sustainable supply chains. Our expertise is applied across the renewableenergy sector, including hydropower, solar, wind, and geothermal, where we specialise inthe interpretation and application of international finance safeguards. Guidance on biodiversitycumulative impact assessmentfor wind and solar developmentsand associated infrastructure Leon Bennun, Claire Fletcher, Aonghais Cook, David Wilson, Ben Jobson,Rachel Asante-Owusu, Annie Dakmejian, Qiulin Liu The designation of geographical entities in this publication, and the presentation of the material, do not implythe expression of any opinion whatsoever on the part of IUCN or other participating organisations concerningthe legal status of any country, territory, or area, or of its authorities, or concerning the delimitation of itsfrontiers or boundaries. The views expressed in this publication do not necessarily reflect those of IUCN or other participatingorganisations. IUCN is pleased to acknowledge the support of its Framework Partners who provide core funding: Ministryof Foreign Affairs, Denmark; Ministry for Foreign Affairs, Finland; Government of France and the FrenchDevelopment Agency (AFD); Ministry of Environment, Republic of Korea; Ministry of the Environment, Climateand Sustainable Development, Grand Duchy of Luxembourg; the Norwegian Agency for DevelopmentCooperation (Norad); the Swedish International Development Cooperation Agency (Sida); the Swiss Agencyfor Development and Cooperation (SDC); and the United States Department of State. This publication has been made possible in part by funding from EDF Renouvelables, Électricité de France(EDF), Energias de Portugal (EDP), Eni S.p.A, Equinor ASA, Iberdrola Renovables International SAU, ShellInternational Petroleum Mij Bv – Holland, and Total SE. Tabl e o f contents List of boxes, figures, and tablesExecutive summaryAcknowledgementsAcronymsGlossary vvixxixii 1Introduction1 1.1The renewable energy transition11.2Terminology41.3The importance of cumulative impacts for wind and solar development7 2About this guidance11 2.1Scope2.2Intended users 1212 3Practical steps for cumulative impact assessment 14 3.1Government-led cumulative impact assessment143.2Project-led cumulative impact assessment163.3Key steps183.3.1Set spatial and temporal boundaries for cumulative impact assessment183.3.2Identify valued environmental components193.3.3Determine valued environmental components trends, targets,and thresholds213.3.4Define approach to apportioning allowable impacts on valuedenvironmental components amongst future projects263.3.5Stakeholder engagement263.3.6Data sharing and dissemination27 4Technical methods supporting threshold setting 28 4.1Species distribution modelling and assessment of connectivity284.2Environmental laws and policies considering human migrations284.3Potential biological removal304.4Popula