PlanWise4Blue (PW4B) assesses the cumulative effects of human activities and pressures on nature values. Each nature value is a spatial layer showing its distribution, suitability, probability of occurrence, biomass, habitat area or another relevant unit. Human activities and pressures are spatial layers scaled as intensity values from 0 to 1, where 0 means the pressure is absent in a grid cell and 1 means the pressure intensity is highest according to the available data.

How the assessment works

PW4B combines these layers with effect sizes describing how strongly individual pressures, and combinations of pressures, affect each nature value. Where possible the effect sizes come from meta-analysis of published scientific studies and empirical datasets; where evidence is missing or insufficient, structured expert assessment is used. The assessment is therefore primarily evidence-based but can still include important pressure–nature value relationships for which published data are limited.

For each grid cell the tool calculates the effect of a single pressure, or the combined effect of several. Where evidence does not support interaction terms the individual contributions are summed. Pressures do not always act independently, so interactions are included where evidence supports them: a combined effect may be stronger than expected (synergistic) or weaker (antagonistic). For practical reasons the model includes interactions involving no more than three pressures, although an assessment may include more than three individual pressures.

The current baseline

Results are always expressed as change relative to the current baseline, not as an absolute environmental state. PW4B stores the best available information on current human pressure intensities and uses those layers as the default baseline for comparison with user-defined scenarios. Where more detailed and reliable local pressure data are available, you can compare your scenario against a refined local baseline instead – set it as the reference scenario on the Human pressures tab.

Working through an assessment

1. Create a user account and log in.
2. Check which nature values and human activity layers cover your area of interest.
3. Create a workspace in the Cumulative Effects Assessment section.
4. Define the extent of the scenario.
5. Select and edit human pressures.
6. Select nature values and run the model.
7. Read the results as maps and tables.

Built-in data

The tool currently contains nearly 1,500 spatial layers representing species, habitats and selected ecosystem services, including pan-European datasets such as EUNIS habitats, Habitats Directive habitat types and CORINE Land Cover, alongside national datasets. Built-in nature value and pressure layers are continuously updated and expanded, so check the current availability for your area of interest directly in the tool. Where suitable locally validated datasets exist, you can request that they be added.

User manual

The full user manual describes the method, the built-in data layers and every step in detail, including the evidence base behind the effect sizes. Download the PW4B user manual (Word)

Support

For questions, or to ask about adding local data layers, contact bluebiosites@ut.ee. For new accounts the confirmation email may take up to two days.