The Human Pressure Index (HPI)

Effective ecosystem assessment and environmental planning require spatially explicit indices capturing how human-driven stressors affect ecosystems. Global assessments, including IPBES, identify land-use change, pollution, and invasive alien species (IAS) as major drivers of biodiversity loss. Yet these pressures remain insufficiently operationalised within ecosystem accounting frameworks such as SEEA-EA, limiting their direct policy application. To bridge this gap, we propose a pressure-based conceptual framework aligned with the hierarchical structure of SEEA-EA ecosystem condition, which explicitly distinguishes anthropogenic pressures from ecosystem state variables and enables their systematic representation within ecosystem accounting. We operationalise this framework through the Human Pressure Index (HPI), a harmonised and spatially explicit composite index for European terrestrial ecosystems. HPI integrates 16 pressure indicators into three modular pressure-specific indices aligned with the IPBES drivers (land-use, pollution, and IAS), enabling both cumulative and driver-specific analyses. HPI shows a strong negative association with the Biodiversity Intactness Index (BII), with pollution emerging as the strongest correlate of BII variation. A GAM–Beta model captures nonlinear biodiversity responses along the pressure gradient, explaining 40% of deviance and revealing saturation effects at high pressure levels. Comparisons with the Global Human Modification (GHM) index highlight complementarities between structural modification (GHM) and diffuse functional pressures (HPI). Overall, this study provides a scalable and transferable pressure-based framework for the systematic integration of anthropogenic pressures within ecosystem condition assessment. HPI offers a policy-ready, spatially explicit tool for mapping cumulative pressures across ecosystems and supports environmental monitoring, policy evaluation and strategic planning across governance levels.