Marine Birds Thematic Assessment

Cumulative effects assessment for marine birds

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 therefore be applied with caution and not considered or used as the sole basis for management decisions.

A range of human activities contribute pressures with the cumulative potential to affect the state of marine birds and associated ecosystem services. The predominant pressures on marine birds are prey depletion caused by prevailing environmental conditions (e.g., climate change), fishing and shellfish harvesting; mortality from fishing (incidental by-catch) and climate change (e.g., storm ‘wrecks’) and other activities (e.g., collisions with wind turbines); and disturbance caused by multiple activities. Other important pressures are habitat loss, physical disturbance of the seabed, non-indigenous species (NIS), input of other substances and input of litter. Following a Driver-Activity-Pressure-State-Impact-Response (DAPSIR) framework and a weighting exercise, an indicative assessment of cumulative effects has been undertaken (see: CEMP Guideline for details) as a first step to describing the potential pathways of the cumulative causes and consequences of change in the ecosystem, linking these to impacts on ecosystem services. 

The Marine Birds Thematic Assessment describes the connectivity between the relevant DAPSIR components. The bow-tie analysis provides a schematic of potential pathways describing cumulative causes and consequences of change in the ecosystem, demonstrating that multiple human activities are contributing to multiple pressures which can lead to multiple impacts on the state of marine birds and the associated ecosystem services. A better understanding of this complexity in the causes and consequences of cumulative effects from human activities on ecosystem state and ecosystem services is critical in order to explicitly apply the ecosystem approach so as to target management measures appropriately.

The evidence underpinning the analyses described in this section is drawn from the Driver, Activity, Pressure, State, Impact and Response sections of this thematic assessment, and thus should be read and interpreted alongside the extended narratives provided therein. The Human activities and Pressures sections of this thematic assessment provide details of the threats that the left-hand side of the Sankey plot (Figure CE.1) pose to marine birds. The State section of this Thematic Assessment provides details of ecosystem state, shown in the centre of the Sankey plot (Figure CE.1), illustrated for marine birds. The right-hand side of Figure CE.1 incorporates the scores for impact on ecosystem services in order to present the Activity, Pressure, State and Impact components of the marine birds ‘ecosystem’ in a single plot. This is consistent with the aim of NEAES operational objective S7.O3 on ecosystem services and natural capital, “to recognise, assess and consistently account for human activities and their consequences in the implementation of ecosystem-based management”.

Figure CE.1 shows the complex combinations of human and pressures on state changes (left-hand side) and of state changes on ecosystem services (right-hand side). However, there is currently insufficient understanding and evidence to be able to directly track from left to right, hence the single bar in the centre. This should be a focus of study to inform future assessments. 

Overall, confidence in the evidence for the weighted bow-tie analysis outputs presented in this marine bird thematic assessment is described as medium for evidence and medium for degree of agreement. Additionally, separate confidence assessments have been applied to each module.

Figure CE.1: Impact potential of marine birds to 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. Were these parameters to be 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.

Figure CE.1 demonstrates the complex relationships between the collective pressures from human activities and the quality status of marine birds. This complexity suggests that while single-issue responses may be effective, in order to fully apply ecosystem-based management OSPAR needs to consider the causes and consequences of changes in ecosystem state more holistically, by 

• recognising that any measures to reduce impacts whilst critical to ecosystem health could have potential consequences for our ability to maintain ecosystem services to meet society’s needs, which in turn has consequences for the viability of human activities in the North-East Atlantic;
• recognising that pressures may have additive, multiplicative, synergistic or antagonistic interactions when combined, which has implications for the nature of the threats posed to marine birds and how best to manage those threats.

Methodology

A modified bow-tie analysis (Cormier et al., 2018, Cormier et al., 2019) was developed to identify and connect all the DAPSIR components, integrating these into either a pressure- (e.g., underwater sound, litter, hazardous substances, eutrophication) or a biodiversity receptor-focused analysis of the causes and consequences of change (e.g. pelagic habitats, benthic habitats, fish, marine birds, marine mammals). For the biodiversity assessments, the APS connections are weighted to determine which are the most important, using an adaptation of the ODEMM pressure assessment (Robinson et al., 2013; Knights et al., 2015) focusing on:

1. Exposure module: spatial extent and frequency for all activity pressure combinations on state, to generate exposure weightings;
2. Impact potential module: spatial extent, frequency of occurrence and impact potential for all activity pressure combinations on state, to generate impact potential weightings;
3. Risk module: spatial extent, frequency of occurrence and impact potential for all activity pressure combinations on state, combined with pressure persistence and ecosystem resilience, to generate risk weightings.

The SI (ecosystem services) connections are weighted to determine which are the most important (Cornacchia, 2022).

The impact potential and ecosystem services outputs are combined and presented in Sankey diagrams (Figure CE.1).

The confidence in this weighted bow-tie analysis for marine birds has been assessed following the QSR 2023 Guidance Document. Confidence is based on two criteria to communicate the degree of uncertainty in the key findings: (i) level of evidence and (ii) degree of agreement.

Exposure module:

Confidence Assessment: Evidence – Medium; Consensus – Medium

Pressures from human activities have been demonstrated in the assessments for this QSR to be widely distributed in the OSPAR Maritime Area. The presence of pressures does not automatically lead to adverse impacts. However, in the first instance, consideration of the spatial and temporal extents of pressures provides a useful basis for consideration of cumulative effects within a risk-based approach (in line with North-East Atlantic Ecosystem principle and strategic approach). 

The exposure module describes the amount of pressure from human activities in the North-East Atlantic. It considers the spatial extent and frequency of human activity / pressure combinations which have been identified as important for marine birds (derived from spatial extent score multiplied by the frequency score). Exposure only relates to the Pressure cell in the DAPSIR schema (Figure CE.1). Consideration of exposure in isolation provides a coarse cross-cutting assessment to provide an early identification which allows OSPAR to develop management strategies for pressures to prevent / minimise impacts.

The thematic assessments for Hazardous Substances, Marine Litter, Underwater Noise, Offshore Industry, Human Activities and Climate Change and the Ocean Acidification Other Assessment describe pressures on marine birds. The Radioactive Substances Thematic Assessment identifies inputs of radionuclides from a range of human activities but has concluded that there are no significant radiological impacts from the current levels of radionuclides on biodiversity.

The highest exposure scores relate to climate change, disturbance of species; habitat loss; extraction, mortality or injury of wild species; prey depletion; input of litter; input of radionuclides; physical disturbance of the seabed; input of substances and input or spread of NIS, thus demonstrating the ubiquitous nature of these pressures in the North-East Atlantic.

Climate Change pressures have been identified as important for marine birds. Multiple activities disturb bird species by their physical presence both at sea and on land. It should be noted that the intensity of the activities, and therefore of the exposure, will vary depending on location in the OSPAR area and on species group. Habitat loss and extraction or mortality / injury of birds will show considerable variation in levels of activities and in the subsequent intensity of this pressure across the OSPAR area. Habitat loss relates to the loss of nesting sites and loss of or displacement from feeding areas. Extraction of or mortality / injury to wild species is linked to either intentional extraction in the form of hunting and culling (in specific areas) or unintentional injury and mortality through incidental by-catch and collisions (e.g. with energy infrastructure such as wind turbines). Inputs of radionuclides, litter and other substances are also notable and unsurprising, given that these pressures and the associated human activities are widespread in the North-East Atlantic.

The exposure scores support the importance that OSPAR places on these pressures under the North-East Atlantic Environment Strategy:

• Strategic Objectives 10 to raise awareness of climate change and ocean acidification; 11 to facilitate adaptation to the impacts of climate change and ocean acidification; and 12 to mitigate climate change and ocean acidification;
• Strategic Objective 2 to prevent pollution by hazardous substances (and the work of the Hazardous Substances and Eutrophication Committee) ( Hazardous Substances Thematic Assessment );
• Strategic Objective 3 to prevent pollution by radioactive substances (and the work of the Radioactive Substances Committee ( Radioactive Substances Thematic Assessment ); 
• Strategic Objective 4 to prevent inputs and significantly reduce marine litter (Marine Litter Thematic Assessment) (and the work of the Environmental Impacts of Human Activities Committee ( Human Activities Thematic Assessment ); 
• Strategic Objective 5 to protect and conserve marine biodiversity and ecosystems (this Marine Birds Thematic Assessment and the work of the Biodiversity Committee, including the other biodiversity thematic assessments ( Pelagic Habitats Thematic Assessment , Benthic Habitats Thematic Assessment , Fish Thematic Assessment , Marine Mammals Thematic Assessment , Food Webs Thematic Assessment ).
• Strategic Objective S7.02 to develop a coordinated management approach to ensure that the number of non-indigenous species introduced via human activity is minimised and where possible reduced to zero; 
• Strategic Objective 9 to safeguard the structure and functions of the seabed/marine ecosystems by preventing significant habitat loss and physical disturbance (this Marine Birds Thematic Assessment and the work of the Biodiversity Committee, including the Benthic Habitats Thematic Assessment ).

Multiple human activities have been identified as exerting these pressures in the North-East Atlantic. Any actions to manage these pressures in order to prevent or reduce impacts either individually or cumulatively (collectively) will need to consider if and how these human activities might best be targeted (and the consequences for the associated drivers and ecosystem services) within an Ecosystem Approach.

Impact potential module:

Confidence Assessment: Evidence – Medium; Consensus – High

The impact potential is incorporated with the exposure module (spatial extent and frequency) of pressures from specified human activities (derived from the aggregated exposure score multiplied by the degree of impact score). Degree of impact here relates to the generic interaction in terms of a pressure’s likely effects on the ecological component, in the categories of low potential for significant impact, chronic impact or acute impact (Robinson et al., 2013). Figure CE.1 shows the combined weighted scores for exposure and impact potential. 

Any activity-pressure combinations with a Degree of Impact score of Low was filtered out, following discussion with the expert groups. For example, the input of radionuclides has been filtered out based on the conclusions in the Radioactive Substances Thematic Assessment as these have been demonstrated to have a low potential for significant impact, based on the available evidence.  Other pressures filtered out as having low potential for significant impact are the inputs of other forms of energy from the extraction of oil and gas and from physical disturbance of the seabed by transport – shipping.

The relative ranking of pressures changes when impact is considered. Climate change, leading to prey depletion and habitat loss pressures, ranks highly (see the Climate Change Thematic Assessment for detail on contributing human activities). The importance of climate change pressures on marine birds is described in the Climate Change section of this thematic assessment. Extraction, mortality and injury of species (predominantly from fisheries incidental by-catch) and disturbance of species (from multiple activities) pressures also rank highly in terms of impact. Habitat loss and physical disturbance of the seabed associated with a range of human activities rank highly; the latter contributes to prey depletion. Input and spread of NIS, inputs of other substances (chemical contaminants) and litter from multiple human activities were also shown to be important for marine birds.

Risk module:

Confidence Assessment: Evidence – Low; Consensus – Low

Given the low confidence scoring, the outputs from the risk analyses have not been included in this thematic assessment for QSR 2023. Nevertheless, it is beneficial to consider the agreed outputs of the persistence weightings. Details of the criteria applied in the risk module are described in the CEMP Guideline.

Regional summary of likely cumulative effects:

Confidence Assessment: Evidence – High; Consensus – Medium

While the weighted bow-tie analyses displayed in the Sankey diagrams have been produced at the North-East Atlantic scale, consideration can be given to where regional differences may arise by cross-referencing other assessments in QSR 2023.

The marine bird Thematic Assessment identifies the cumulative pressures on marine birds in terms of both exposure and impact (but no regional breakdown of pressures is attempted here).

The list below summarises the main pressures impacting marine birds, with information on associated activities. The activity-pressure combinations scored as low impact based on the current available evidence have been filtered out from the relevant Sankey diagram. However, the activity-pressure links listed below relate to the unfiltered outputs used in the Exposure assessment.

• Prey depletion from: fishing activities and the effects of climate change; 
• Extraction of or mortality / injury to wild species from: fishing activities (by-catch); hunting; climate change (e.g., storm ‘wrecks’); renewable energy generation (collisions); transport – shipping (collisions); extraction of minerals (aggregates) and extraction of oil and gas; 
• Disturbance of species from: renewable energy generation; extraction of oil and gas; tourism and leisure infrastructure and activities; land claim; coastal defence and flood protection; transport infrastructure; offshore structures; extraction of minerals (aggregates); fishing activities; military operations; transport – shipping; 
• Habitat loss from: climate change (e.g., ‘coastal squeeze’); renewable energy generation; extraction of oil and gas; tourism and leisure infrastructure; land claim; subsea cables; coastal defence and flood protection; transport infrastructure; offshore structures; extraction of minerals (aggregates); fishing activities; military operations; tourism and leisure activities; non-renewable energy generation (nuclear); 
• Input or spread of NIS (mainly invasive predatory mammals e.g., rats, American mink, feral cats) from: urban uses; tourism and leisure activities; transport – shipping; 
• Input of litter from: tourism and leisure activities; transport – shipping; industrial uses; urban uses; fishing; aquaculture; 
• Physical disturbance of the seabed from: extraction of oil and gas; tourism and leisure infrastructure; land claim; subsea cables; coastal defence and flood protection; transport infrastructure; offshore structures; extraction of minerals (aggregates); fishing activities; military operations; tourism and leisure activities; transport – shipping; with direct effects on supply of benthic prey or indirect effects on prey further up the food chain;
• Input of other substances from: extraction of oil and gas; military operations; non-renewable energy generation (nuclear); research, survey and educational activities; industrial uses; urban uses; 
• Input of other forms of energy from: transport – shipping; renewable energy generation; 
• Input of anthropogenic sound from shipping and industrial uses. 

OSPAR does not have evidence on all human activities, but a regional breakdown of the relative intensities of Aquaculture; Extraction of minerals (aggregates); Oil and Gas; Nuclear; Renewable Energy; Fisheries; Shipping and Tourism has been extracted from the supporting evidence for QSR 2023 and is summarised below. The direct influence of the cumulative pressures from these activities on marine birds is likely to follow similar trends in intensity within these Regions. The pressures spread beyond the spatial extent of e human activities, but insufficient evidence is currently available, and so trends in indirect cumulative pressures have not been considered.

The Offshore Industry Thematic Assessment describes:

• low relative intensity of Oil and Gas sector activity in the Bay of Biscay and Iberian Coast (Region IV) and Wider Atlantic (Region V);
• moderate relative intensity of Oil and Gas sector activity in the Arctic Waters (Region I) and Celtic Seas (Region III);
• high relative intensity of Oil and Gas sector activity in the Greater North Sea (Region II).

The Human Activities Thematic Assessment describes:

• low relative intensity of Aggregate Extraction sector activity in the Arctic Waters (Region I) and Wider Atlantic (Region V);
• moderate relative intensity of Aggregate Extraction sector activity in the Celtic Seas (Region III) and Bay of Biscay and Iberian Coast (Region IV);
• high relative intensity of Aggregate Extraction sector activity in the Greater North Sea (Region II);
• moderate relative intensity of Aquaculture sector activity in the Celtic Seas (Region III) and Bay of Biscay and Iberian Coast (Region IV);
• high relative intensity of Aquaculture sector activity in the Arctic Waters (Region I) and Greater North Sea (Region II);
• low relative intensity of Fisheries sector activity in the Wider Atlantic (Region V);
• moderate relative intensity of Fisheries sector activity in the Bay of Biscay and Iberian Coast (Region IV);
• high relative intensity of Fisheries sector activity in the Arctic Waters (Region I), Greater North Sea (Region II) and Celtic Seas (Region III).
• low relative intensity of Offshore Renewable Energy sector activity in the Bay of Biscay and Iberian Coast (Region IV);
• moderate relative intensity of Offshore Renewable Energy sector activity in the Celtic Seas (Region III);
• high relative intensity of Offshore Renewable Energy sector activity in the Greater North Sea (Region II).
• low relative intensity of Tourism sector activity in the Arctic Waters (Region I) and Wider Atlantic (Region V);
• moderate relative intensity of Tourism sector activity in the Celtic Seas (Region III);
• high relative intensity of Tourism sector activity in the Greater North Sea (Region II) and Bay of Biscay and Iberian Coast (Region IV).
• low relative intensity of Transport and Shipping sector activity in the Wider Atlantic (Region V);
• moderate relative intensity of Transport and Shipping sector activity in the Arctic Waters (Region I);
• high relative intensity of Transport and Shipping sector activity in the Greater North Sea (Region II), Celtic Seas (Region III) and Bay of Biscay and Iberian Coast (Region IV).

The Radioactive Substances Thematic Assessment describes:

• no Nuclear sector activity in the Wider Atlantic (Region V);
• low relative intensity of Nuclear sector activity in the Arctic Waters (Region I);
• moderate relative intensity of Nuclear sector activity in the Bay of Biscay and Iberian Coast (Region IV);
• high relative intensity of Nuclear sector activity in the Greater North Sea (Region II) and Celtic Seas (Region III).

Regional evidence for trends in the intensity of other human activities or for climate change and ocean acidification were not available in sufficient detail to be utilised in this assessment.