Ecosystem Services and ESIA: moving forward

13th March 2015

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Elizabeth Collett

Environment specialist Fraser Paterson at Xodus considers how ecosystem services is being considered in environmental and social impact assessments for international projects.

Ecosystem services (ES) are being increasingly addressed in international impact assessments, particularly for major infrastructure and extractive industry projects. This follows the International Finance Corporation’s (IFC) inclusion of ES criteria in the 2012 versions of its performance standards, which are widely applied by development finance institutions and Equator Principles adherents to their funding clients. Consequently, any project which has to meet the environmental and social standards of participating financial institutions to secure funding must address ES requirements.

The IFC’s guidance on the performance standards provide some additional information on requirements and offer useful clarifications. However, as the guidance is divided between the assessment and management, biodiversity and community health and safety documents, IFC requirements appear a little disjointed and there is no recommended assessment methodology.

Also, at the same time the IFC introduced its ES criteria, it made significant changes to its complex requirements for protecting and conserving biodiversity. The aim of “no net loss” to biodiversity obliges projects to categorise the habitats they might affect, and determine whether there are any impacts on “critical habitat”, which either hosts at-risk species, ecosystems or key evolutionary processes, or consists of protected or designated land. Consequently, biophysical practitioner focus on mainstream biodiversity changes may have resulted in a less thorough consideration of all ES aspects.

The World Resources Institute (WRI) addressed the methodology gap through its document Weaving Ecosystem Services into Impact Assessment; a Step-by-Step Method in 2013. This proposes the following six steps to incorporating the institute’s ecosystem services review (ESR) approach into the scoping, baseline, assessment and mitigation stages of the environmental and social impact assessment (ESIA) process:

  1. Identification of relevant ES.
  2. Prioritisation of ES.
  3. Definition of scope and identification of information requirements for assessment.
  4. Establishing the baseline for priority ES.
  5. Assessment of project impacts and dependency upon priority ES.
  6. Mitigation and management of priority ES impacts and dependencies.

ESIA treatment of ES departs from the traditional source-pathway-receptor model to take account of impacts on biophysical receptors that, in turn, affect dependent socioeconomic ‘beneficiaries’ (that is, source-pathway1-receptor1-pathway2-receptor2). Accordingly, the WRI’s six steps are applied to both impact assessment and dependency assessment strands of that methodology and – consistent with the complexity of this evolving discipline – there are also multiple sub-steps.

The technical appendix of the WRI’s methodology publication is aimed at ESIA practitioners; it includes suggested significance criteria and illustrates the stepped approach through a worked case study, tools and examples of the output from each of the main steps.

The WRI’s methodology is still to filter widely into publicly available ESIA reports, so it is premature to judge practitioner take-up or assess its potential for guiding UK environmental impact assessment (EIA) studies. Nevertheless, though there are marked differences between ESIA and EIA, the challenges for practitioners are broadly similar and, given the lack of professional training on this subject, some lessons from recent experience may help practitioners.

  • All-inclusive assessment of every feasible impact and dependency on each ES is beyond the scope (and budget) of many assessments.
  • Project nature, location, area of influence (AoI)and ecosystem context are critical determinants (a small brownfield project may not affect ES, for example).
  • Plan ES assessments early and carefully. The ESIA manager needs to recruit biophysical and socioeconomic experts and consider team training and capacity building needs.
  • Using the WRI’s technical appendix’s tables on ES by habitat type and ES by land cover class can simplify scoping, but apply the precautionary principle where there are information gaps and limitations.
  • Start targeted stakeholder engagement as soon as practicable, as it may be the only way to identify beneficiaries and quantify dependency levels (to differentiate between continual, seasonal or one-off wild foods foraging, for example).
  • Baseline information needs to establish the current condition of the ES, as well as trends and/or external threats, in and around the project AoI.
  • Always focus assessment on priority ES that are under direct control of the project and which may result in significant adverse impacts upon human health, safety, livelihoods or cultural heritage.
  • Standard EIA significance criteria can be used for assessment but should reflect:
  • the level of beneficiaries’ dependence
  • the resilience of ecosystems and their beneficiaries to change
  • the extent, duration, reversibility and frequency of the anticipated impacts on beneficiaries.
  • Wider regional or global ES, such as carbon storage, should be addressed in the cumulative impact or relevant technical sections of the report.
  • Avoid any consideration of economic valuation and payments for ES, unless there are applicable compliance obligations and/or relevant ongoing initiatives.


  1. International Finance Corporation, 2012 (

a. Performance Standard 1: Assessment and Management of Environmental and Social Risks and Impacts

b. Performance Standard 4: Community Health and Safety

c. Performance Standard/Guidance Note 6: Biodiversity Conservation and Sustainable Management of Living Natural Resources

  1. World Resources Institute, 2013 (

a. Weaving Ecosystem Services into Impact Assessment; a Step-by-Step Method (Version 1.0)

b. Weaving Ecosystem Services into Impact Assessment: Technical Appendix (Version 1.0)

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