Project Description

Ecological Impact Assessment

Ecological Impact Assessment (EcIA) is the process of identifying, quantifying and evaluating the potential effects of proposed development on habitats and species. EcIA can be used to provide the ecological component of an Environmental Impact Assessment (EIA) or it can be applied to any development project to identify significant ecological impacts. EcIA should be an iterative process, which means that the results of the surveys should advise the development design, to avoid significant harm to biodiversity.

It is important that all disciplines are involved in the project at an early stage to ensure that all potential impacts are taken into account when designing ecological surveys.


At the initial scoping stage we gather information on the proposed development, the ecology of the site and any relevant legislation and policies. A desk study draws on published material and databases held by relevant local organisations. The scoping stage is used to inform the content of the full EcIA.

Ecological Surveys

An extended Phase 1 habitat survey provides information on the main habitat types and considers through careful evaluation, the potential of the development site to support important habitats and species.

Detailed ecological surveys will be required if the initial scoping stage indicates that the development is likely to affect sensitive or protected habitats or species. Many surveys are seasonally constrained to ensure that the results are robust for the reports to be relied upon at the planning stage.

Determining Importance

The information collated at the scoping stage and during the detailed ecological surveys is cross referenced against published guidelines to determine the level of value ensuring that statutory requirements and policy objectives for biodiversity are followed. The identified important ecological features are then carried forward to the impact assessment.

Impact Assessment

Potential impacts (positive and negative) on the important ecological features are identified and characterised. The significance of potential impacts is assessed with reference to the value of the feature. Mitigation measures are proposed to reduce or compensate any identified impacts. Once the mitigation measures have been applied, the effect of the development on biodiversity is then reassessed to determine the final residual impact.

ESL frequently produce ecology chapters, from experience we have found it very important to liaise very closely with other disciplines to ensure that the EcIA is consistent throughout.