The EIA process should ideally follow the stages outlined below. This is the basic best-practice method of conducting an EIA as published by the IAIA. Use the links to find further information below.
- to determine whether or not a proposal should be subject to EIA and, if so, at what level of detail.
- to identify the issues and impacts that are likely to be important and to establish terms of reference for EIA.
- Examination of alternatives
- to establish the preferred or most environmentally sound and benign option for achieving proposal objectives.
- Impact analysis
- to identify and predict the likely environmental, social and other related effects of the proposal.
- Mitigation and impact management
- to establish the measures that are necessary to avoid, minimize or offset predicted adverse impacts and, where appropriate, to incorporate these into an environmental management plan or system.
- Evaluation of significance
- to determine the relative importance and acceptability of residual impacts (i.e., impacts that cannot be mitigated).
- Preparation of Environmental Impact Statement (EIS) or report
- to document clearly and impartially impacts of the proposal, the proposed measures for mitigation, the significance of effects, and the concerns of the interested public and the communities affected by the proposal.
- Review of EIS
- to determine whether the report meets its terms of reference, provides a satisfactory assessment of the proposal(s) and contains the information required for decision making.
- to approve or reject the proposal and to establish the terms and conditions for its implementation.
- to ensure that the terms and condition of approval are met; to monitor the impacts of development and the effectiveness of mitigation measures; to strengthen future EIA applications and mitigation measures; and, where required, to undertake environmental audit and process evaluation to optimise environmental management.
NB: monitoring, evaluation and management plan indicators should be designed so they also contribute to local, national and global monitoring of the state of the environment and sustainable development wherever possible.
Operating Principles for biodiversity-inclusive EIA
Use biodiversity inclusive screening criteria to determine whether important biodiversity resources may be affected. Biodiversity screening "triggers" for IA should include:
- Potential impacts on protected areas and areas supporting protected species.
- Impacts on other areas that are not protected but are important for biodiversity.
- Activities posing a particular threat to biodiversity (in terms of their type, magnitude, location, duration, timing, reversibility).
- Areas that provide important biodiversity services including extractive reserves, indigenous peoples' territories, wetlands, fish breeding grounds, soils prone to erosion, relatively undisturbed or characteristic habitat, flood storage areas, groundwater recharge areas, etc.
Encourage development of a biodiversity screening map indicating important biodiversity values and ecosystem services. If possible, integrate this activity with the development of a National Biodiversity Strategy and Action Plan (NBSAP) and/or biodiversity planning at sub-national levels (e.g., regions, local authorities, towns) to identify conservation priorities and targets.
Scoping leads to Terms of Reference for IA, defining the issues to be studied and the methods that will be used. Use scoping as an opportunity to raise awareness of biodiversity concerns and discuss alternatives to avoid or minimize negative impacts on biodiversity. It is good practice to produce a scoping report for consultation. This should address the following issues (on the basis of existing information and any preliminary surveys or discussions):
- The type of project, program, plan or policy, possible alternatives and a summary of activities likely to affect biodiversity
- An analysis of opportunities and constraints for biodiversity (include "no net biodiversity loss" or "biodiversity restoration" alternatives)
- Expected biophysical changes (in soil, water, air, flora, fauna) resulting from proposed activities or induced by any socio-economic changes
- Spatial and temporal scale of influence, identifying effects on connectivity between ecosystems, and potential cumulative effects
- Available information on baseline conditions and any anticipated trends in biodiversity in the absence of the proposal
- Likely biodiversity impacts associated with the proposal in terms of composition, structure and function
- Biodiversity services and values identified in consultation with stakeholders and anticipated changes in these (highlight any irreversible impacts)
- Possible measures to avoid, minimize, or compensate for significant biodiversity damage or loss, making reference to any legal requirements
- Information required to support decision making and summary of important gaps
- Proposed IA methodology and timescale
For practical use, develop in-country (sectoral) guidance translating this generic scoping sequence into tools, such as guidelines and sample Terms of Reference.
Impact study and preparation of EIS
Address biodiversity at all appropriate levels and allow for enough survey time to take seasonal features into account. Focus on processes and services which are critical to human well-being and the integrity of ecosystems. Explain the main risks and opportunities for biodiversity. Questions to ask:
- At the gene level, to what extent will the proposal have significant effects on:
- Genetic diversity of species, particularly rare and declining species and those with identified as priorities in NBSAPs and/or sub-national biodiversity plans?
- Opportunities for species populations to interact, e.g., by increasing habitat fragmentation and isolation?
- Risk of extinction?
- Persistence of locally-adapted populations?
- At the species level, to what extent will the proposal:
- Alter the species-richness or species-composition of habitats in the study area?
- Alter the species-composition of communities?
- Cause some species to be lost from the area?
- Affect species identified as priorities in NBSAPs and/or sub-national biodiversity plans?
- Increase the risk of invasion by alien species?
- At the ecosystem level, to what extent will the proposal:
- Change the amount, quality or spatial organization of habitat?
- Affect plans to enhance habitat availability or quality?
- Damage ecosystem processes and services, particularly those on which local communities rely?
- If habitats will be lost or altered, is alternative habitat available to support associated species populations?
- Are there opportunities to consolidate or connect habitats?
Take an ecosystem approach and involve relevant stakeholders (including local communities). Consider the full range of factors affecting biodiversity. These include direct drivers of change associated with a proposal (e.g., land conversion and vegetation removal leading to loss of habitat: a key driver of biodiversity loss, emissions, disturbance, introduction of alien and genetically modified species, etc.); and indirect drivers of change which are harder to quantify, including demographic, economic, socio-political, cultural and technological processes or interventions.
Evaluate impacts of alternatives with reference to the baseline situation. Compare against thresholds and objectives for biodiversity. Use NBSAPs, sub-national biodiversity plans and other conservation reports for information and objectives. Take into account cumulative threats and impacts resulting either from repeated impacts of projects of the same or different nature over space and time, and/or from proposed plans, programs or policies.
Biodiversity is influenced by cultural, social, economic and biophysical factors. Cooperation between different specialists in the IA team is thus essential, as is the integration of findings which have bearing on biodiversity. Provide insight into cause-effect chains. If possible, quantify the changes in quality and amount of biodiversity. Explain the expected consequences of any biodiversity losses associated with the proposal, including the costs of replacing biodiversity services if they will be damaged by a proposal.
How do these relate to relevant biodiversity priorities and objectives or any legal obligations? Indicate the legal issues that create the boundary conditions for decision making.
Remedial action can take several forms, i.e., avoidance (or prevention), mitigation (including restoration and rehabilitation of sites), and compensation. Apply the "positive planning approach", where avoidance has priority and compensation is used as a last resort measure. Avoid "excuse"-type compensation. Look for opportunities to positively enhance biodiversity. Acknowledge that compensation will not always be possible; there will still be cases where it is appropriate to say "no" to development proposals on grounds of irreversible damage to biodiversity.
Review for decision-making.
Peer review of environmental reports with regard to biodiversity should be undertaken by a specialist with appropriate expertise, where biodiversity impacts are significant. Depending on the level of confidentiality of public decision-making, consideration should be given to the involvement of affected groups and civil society.
Avoid pitting conservation goals against development goals; balance conservation with sustainable use for economically viable, and socially and ecologically sustainable solutions. For important biodiversity issues, apply the precautionary principle where information is insufficient and the no net loss principle in relation to irreversible losses associated with the proposal.
Management, monitoring, evaluation and auditing
It is important to recognize that all prediction of biodiversity response to perturbation is uncertain, especially over long time frames. Management systems and programs, including clear management targets (or Limits of Acceptable Change (LC)) and appropriate monitoring, should be set in place to ensure that mitigation is effectively implemented, unforeseen negative effects are detected and addressed, and any negative trends are detected. Provision is made for regular auditing of impacts on biodiversity. Provision should be made for emergency response measures and/or contingency plans where upset or accident conditions could threaten biodiversity.