5. OSPAR Tackles Cumulative Pressures

Quantifying pressures and assessing their cumulative effects across entire ecosystems has been a goal of OSPAR since the QSR 2000. Examination of the data on cumulative pressures presented in previous Quality Status Reports reveals how each successive QSR tells a richer and more complex story.

For The Quality Status Report 2000 (QSR 2000), experts were able to look at multiple pressures within one Region of the OSPAR Maritime Area (the North Sea) for the first time, and these were ranked according to their relative impacts using an assessment process involving structured expert judgement and taking into account severity, spatial scale and recovery time.

For the QSR 2010, building on expert opinion, OSPAR was able to rank the pressures on four species groups and four habitat types, according to their potential impact across three of the five OSPAR Regions.  This time, more information was available on the geographic distribution of human activities and the spatial and temporal extent, intensity and frequency of the pressures resulting from these activities. The criteria for estimating the impacts of these pressures on ecosystem components were further refined, and an attempt was made to summarise the total impact on each ecosystem component as well as the total impact per pressure across ecosystem components, using a structured scoring and weighting system. As previously for the QSR 2000, the level of consensus among experts was recorded.

In this latest QSR 2023, the Thematic Assessments on human activities, pressures, and biodiversity have presented information according to the DAPSIR framework. Working with this fuller understanding of how pressures affect state, the experts assessing biodiversity were able to begin ranking the relative importance of pressures on biodiversity. These rankings were then presented in a holistic way for five of the biodiversity themes assessed (marine birds, marine mammals, fish, benthic habitats, and pelagic habitats) in the form of Sankey diagrams. These diagrams show the estimated contribution of various pressures from human activities on the state of marine ecosystem components and the resulting expected changes in ecosystem service delivery at the North-East Atlantic scale.

The example below shows the array of human activities and pressures affecting pelagic habitats and their expected impact on ecosystem service delivery.

These 'weighted' outputs demonstrating the interrelationship between pressures, impacts on state, and the ultimate effect on ecosystem services delivery are shown in Sankey diagrams created for each of these five Thematic Assessments. Additional work to include the persistence of pressures and the resilience of the ecosystem to changes was initiated but requires further analysis. Future work will also consider the differences between OSPAR Regions and improve the presentation of outputs by using maps.

Figure 5.1: Impact Potential of Pelagic Habitats under exposure to pressures from human activities in the North-East Atlantic. Columns left to right: Activity, Pressure, State, Environmental Impact, Ecosystem Service. Derived from Exposure score (Extent x Frequency of pressure) x Degree of Impact score (in terms of whether impact is Acute or Chronic). Pressures with a low Degree of Impact score have been removed for clarity. ‘Impact’ in this context does not consider the persistence of the pressure or the resilience of the ecosystem associated with that pressure. If these parameters were included, the relative contribution for some pressures would most likely increase and score higher in the relative ranking. Links are weighted to indicate relative contribution to impact. A wider link = greater potential for impact.

It should be noted that the Sankey plots and associated narratives in this thematic assessment are an illustrative representation of a complex set of interactions between DAPSIR components at the coarse North-East Atlantic scale and should be considered and interpreted alongside the supporting full thematic assessment narrative. The Sankey plots should thus be applied with caution and not considered or used as the sole basis for management decisions.