Population abundance should be an Essential Biodiversity Variable in infrastructure impact assessment

Roads, railways, power lines, and other linear infrastructure benefit the growing economy but also impact biodiversity. Environmental Impact Assessments (EIAs) are a key process that should guarantee that biodiversity loss is avoided or mitigated on linear infrastructure projects. Long-term population persistence can be compromised near infrastructure if their impacts are reducing population abundance. This is why the mere presence of an animal population near an infrastructure is not enough to infer that this infrastructure is or is not having an impact and there is a need to monitor population abundance trends. However, population-oriented approaches are rare in studies focused on the impacts of linear infrastructure. We suggest that the best way to evaluate genuine impacts is to include wildlife population abundance among the metrics to be measured in EIAs and monitored in follow-up studies. Population abundance and its trend are good proxies to evaluate the impact of linear infrastructure on the health of local populations and their persistence probability. • Linear infrastructure cause many impacts on wildlife. • To effectively mitigate them we must know their effects on population abundance. • The ultimate goal should be guaranteeing wildlife population persistence.