ABSTRACT
This chapter explains some important definitions and concepts to provide a basis for considering impacts on ecosystem services and human wellbeing. These have a bearing on preferred approaches and methods, with some divergence between those preferring to interpret impact significance in quantitative terms and those taking a more qualitative approach. Available guidance on incorporating ecosystem services in Environmental and Social Impact Assessment (ESIA) is also summarised. Appropriate consideration of ecosystem services in ESIA therefore requires a more collaborative mindset, with active engagement between "specialist" dimensions. Economic valuation techniques attempt to elicit preferences for changes in ecosystems (impacts) in monetary terms. Payments for Ecosystem Services (PES) are a mechanism for people who manage ecosystems to benefit from generating ecosystem services that are used or enjoyed by others. Ecosystem service use is the level of a particular ecosystem service actually consumed or enjoyed by beneficiaries.
