How can the biodiversity footprint of linear infrastructure projects such as gas pipelines be assessed? How do such assessments link to existing environmental impact assessments (EIA) and regulatory mitigation hierarchy measures? A case study was conducted based on the construction of a gas pipeline, looking both at the impacts from steel production and regulatory biodiversity offset measures.   🔍 The pilot, conducted by CDC Biodiversité, and involving both GRTgaz and the Groupe Caisse des Dépôts as a shareholder of the energy company, is summarised in a 6 page document, starting with a standardised summary sheet (8 other case studies are available on CDC Biodiversité’s website). Data on land use changes, GHG emissions, pipeline materials and biodiversity offset land use changes extracted from the EIA and collected through exchanges with GRTgaz and the team in charge of the offset measures were used to assess the impacts on one aspect of #biodiversity, ecosystem integrity, using the #GlobalBiodiversityScore (GBS) tool and the #MeanSpeciesAbundance (MSA) metric.   💡 A result which surprised the persons involved was that during the construction, the most significant periodic loss was caused not by the land use changes associated to the construction but by the climate change pressure generated by the production of steel required for the pipelines.   🌳 This case study showcases the application of the GBS to assess and forecast positive impacts of biodiversity offset measures in terms of functional biodiversity (here between 0 and 0.35 MSA.km2 of gains, with significant uncertainties as the success of the offset measures is not guaranteed), besides the expected gains of those measures for species populations and their habitat. It is very important to stress that assessing the ecological integrity footprint of such a pipeline comes as a complement to the usual impact assessment conducted during an EIA. It does NOT replace it at all and achieving a low negative footprint and large positive gains expressed in MSA.km2 does NOT mean a project has achieved no net loss with regards to the habitats of protected or endangered species (and vice-versa). A company needs to achieve both no net loss through the regulatory mitigation hierarchy with its focus on species’ habitats and a low ecological integrity footprint.   Linear infrastructure projects are especially difficult to assess using ecosystem integrity metrics and I’d be curious to hear from the assessment of other projects (e.g. road, rail or other energy infrastructures) you may know!