Many environmental practitioners will be familiar with the ‘Ecological Impact Assessment:
EIANZ guidelines for use in New Zealand: terrestrial and freshwater ecosystems’ (EcIA
Guidelines). The purpose of the guidelines is the provision of a consistent framework for
assessing the effects of resource management and use on the ecosystems and their values in New Zealand.

This explanatory note provides additional guidance on applying the Ecological Impact Assessment (EcIA) Guidelines for use in New Zealand: terrestrial and freshwater ecosystems, with a particular focus on the interpretation of spatial scale when assessing ecological values and the magnitude of ecological effects.

Developed through EIANZ’s New Zealand Chapter, the note responds to practitioner feedback about how scale is being interpreted and applied in ecological impact assessment. It clarifies that, in general, the magnitude of an effect should be assessed at the same spatial scale as the ecological value assessment, with wider ecological context informing rather than replacing that assessment.

Using freshwater and terrestrial ecology examples, the note highlights how changing the assessment scale can inadvertently minimise or amplify ecological effects and influence subsequent consideration of avoidance, minimisation, remediation, mitigation, offsetting, compensation and monitoring. It also provides practical guidance for practitioners on clearly identifying and explaining the spatial scales used in an assessment.