Ecological compensation: From general guidance and expertise to specific proposals for road developments

The main scientific bibliography addressing the rationale behind ecological compensation is reviewed in order to examine general guidelines. This contains interesting general guidance on how to implement compensation, and provides the basis for future developments in compensation practice. On this basis, we propose a further step in compensation practice, advancing compensation proposals or rules for specific kinds of projects and contexts, focusing on road projects in the Spanish Environmental Impact Assessment (EIA). Three main residual impacts of roads are identified which usually remain uncompensated for: the loss of natural and semi-natural land use, the increase in emissions resulting from any new road, and the fragmentation, severance or barrier effect on the landscape and its wildlife. To counteract these, four proposals, or "rules", are advanced: conservation of natural and semi-natural land use area, conservation of dominant plant species physiognomy, compensation for emissions, and the rule of positive defragmentation. -- Highlights: • Ecological compensation theory does not specify guidelines for types of projects. • EIA practitioners lack valuable specific guidance on how to implement compensation. • Specific guidance for road project ecological compensation is proposed. • Compensation proposals should have in mind present-day compensation practice level. • Specific ways to compensate for habitat loss, emissions, and fragmentation are shown