Tiering in impact assessment has been advocated for mainstreaming environmental goals into different levels of planning. Likewise, the ecosystem services concept has been receiving increased attention for its potential
contribution to the difficult mission of integrating the fragmented views of society’s dependence on nature when
taking decisions about development proposals and public policies. Using the tiered planning of transportation
infrastructure in S\u02dcao Paulo, Brazil, this paper examines the use of the ecosystem services concept as a thread to tiering in impact assessment from the strategic to the project level. By exploring a particular case in the transportation infrastructure sector, we aim at advancing knowledge and drawing lessons about the contribution of ecosystem services as an integrative tool to knit the analysis of impacts at successive levels of planning. The
highway affects forest lands and watersheds that provide invaluable services for a large population. By analyzing
strategic and project environmental assessments, we found that although ecosystem services underpin three out of five key strategic issues, they were addressed mostly implicitly, both at the strategic and at the project levels, missing an opportunity to integrate societal concerns into the assessment. The explicit and upfront consideration of ecosystem services is necessary to support an integrated assessment and the structured consideration of socioecological systems in decision-making and to reveal trade-offs that are usually hidden in piecemeal assessments.<\/p>\n\n\n\n