NatureScot Research Report 1273 - Development of Marine Bird Sensitivity Assessments for FeAST

Arctic skua

Stercorarius parasiticus

Arctic tern

Sterna paradisaea

Atlantic puffin

Fratercula arctica

Black-headed gull

Chroicocephalus ridibundus

Black-legged kittiwake

Rissa tridactyla

Black guillemot

Cepphus grylle

Common gull

Larus canus

Common guillemot

Uria aalge

Common tern

Sterna hirundo

European storm petrel

Hydrobates pelagicus

European shag

Phalacrocorax aristotelis

Great cormorant

Phalacrocorax carbo

Great black-backed gull

Larus marinus

Great skua

Stercorarius skua

Herring gull

Larus argentatus

Leach's storm petrel

Oceanodroma leucorhoa

Lesser black-backed gull

Larus fuscus

Little gull

Hydrocoloeus minutus

Little tern

Sternula albifrons

Manx shearwater

Puffinus puffinus

Northern fulmar

Fulmarus glacialis

Northern gannet

Morus bassanus

Razorbill

Alca torda

Sandwich tern

Thalasseus sandvicensis

Black-throated diver

Gavia arctica

Common scoter

Melanitta nigra

Common eider

Somateria mollissima

Common goldeneye

Bucephala clangula

Goosander

Mergus merganser

Great northern diver

Gavia immer

Long-tailed duck

Clangula hyemalis

Red-breasted merganser

Mergus serrator

Red-throated diver

Gavia stellata

Greater scaup

Aythya marila

Slavonian grebe

Podiceps auritus

Velvet scoter

Melanitta fusca

Definition

Full recovery expected within 10-25 years.

Full recovery expected within 2-10 years.

Full recovery expected within 2 years.

Lifespan

Long- lived (10 years +)

Moderate lifespans (5-10 years)

Short-lived (up to 5 years)

Age at first maturity

Deferred maturity (first breeds when more than 3 years old)

First breeds when 2-3 years old

First breeds at one year of age

Adult mortality rate

Low natural mortality (<15%)

Moderate natural mortality rate (15-25%)

High natural annual mortality (>25%)

Fecundity / reproductive success

Low reproductive output (<2 chicks per pair per annum)

Moderate reproductive output (2-5 chicks per pair per annum)

High reproductive output (>5 chicks per pair per annum)

None

A severe decline (>50%) in the estimated size of the local population as a result of increased mortality, reduced reproductive success, displacement or any other mechanism

Low

A significant decline (>10 and ≤50%) in the estimated size of the local population as a result of increased mortality, reduced reproductive success, displacement or any other mechanism.

Medium

A moderate decline (loss of up to 10%) in the estimated size of the local population as a result of increased mortality, reduced reproductive success, displacement or any other mechanism.

High

No population decline is expected. Effects affecting key functional and physiological attributes of the species (e.g. food intake rate, energy expenditure rate) may occur but are buffered from feeding through to changed rates of reproduction or mortality and hence population size by virtue of species’ flexibility to respond to the pressure e.g. by redistribution, dietary shifts, increased foraging effort, etc.

Very Low* Recovery

High

High

Medium

Low

Low Recovery

High

High

Medium

Low

Medium Recovery

Medium

Medium

Medium

Low

High Recovery

Medium

Low

Low

Not Sensitive

High

A feature is assessed as having high sensitivity where the pressure causes severe or significant mortality of a species population. If recovery is possible, the feature is anticipated to have a recovery of low or very low.

Medium

Features with medium sensitivity are those characterised by medium tolerance and no to low recovery or no to low tolerance and medium to high recovery.

Low

Features with low sensitivity are those with high tolerance or where recovery from any impacts caused by pressure is high and tolerance is low or medium.

Sensitive

Not enough information is available to complete one of the sensitivity assessment stages to give a final score, but due to concern over potential impacts on feature it has been assessed as sensitive.

Not Sensitive

Features with high tolerance and high recovery from the impacts caused by pressure are considered Not Sensitive at the benchmark described.

Not Assessed

Where the evidence available with which to undertake a sensitivity assessment is extremely limited, poorly understood or completely absent. There may still be an obvious pathway for interaction/impact OR the pressure description is not applicable to the feature and no obvious pathway of interaction exists - explained further in evidence.

High

Based on Peer Reviewed papers (observational or experimental) or grey literature reports by established agencies on the feature

Score = 5

Assessment based on the same pressures arising from similar activities, acting on the same type of feature in comparable areas (i.e. Ireland, UK)

Score = 5

Evidence agrees on the direction and magnitude of impact

Score = 5

Medium

Based on some peer reviewed papers but relies heavily on grey literature or expert judgement on feature or similar features

Score = 3

Assessment based on similar pressures on the feature in other areas

Score = 3

Evidence agrees on direction but not magnitude of impact

Score = 3

Low

Based on expert judgement, which is not clearly documented

Score = 1

Assessment based on proxies for pressures, e.g. natural disturbance events

Score = 1

Evidence does not agree on concordance or magnitude

Score = 1

Low confidence in Recovery score

Low

Low

Low

Medium confidence in Recovery score

Low

Medium

Medium

High confidence in Recovery score

Low

Medium

High

Literature searches

Use of one search engine for literature searches.

It was originally proposed that two different search engines would be used to carry out the literature searches (Google Scholar and one other), upon reflection following the first three species two search engines were no longer deemed necessary. For the pilot species, literature searches were first conducted using Science Direct, and then repeated using Google Scholar for each species and pressure combination.

However, Science Direct only provided a narrow range of references and these were subsequently also found using Google Scholar. Google Scholar provides a wider literature search and highlights relevant grey literature as well as peer reviewed literature.

Literature searches were carried out using Google Scholar only.

Evidence bases

Addition of summary statements of recovery and tolerance score at the end of evidence bases.

After the evidence bases were compiled for the initial three species it was decided a summary sentence would be added at the second QA stage, by the expert ornithologist. These would explain how the tolerance score had been decided given the evidence. In addition, the recovery score would be outlined in text as well as in the recovery score column.

A summary sentence outlining tolerance score and recovery score were included at the bottom of the evidence base.

Ability to assess tolerance

Use of evidence from proxy species and general seabird statements if insufficient species-specific evidence was found for a pressure.

For the initial three species, if insufficient species-specific information was found, the pressure was marked as “NA – not enough evidence to assess”. On discussion with NatureScot, MS, and JNCC it was agreed that evidence from proxy species or any statements about general seabird/waterfowl species would be applied to these pressures. This would allow a tolerance score to be assessed for as many pressures as possible. If a proxy species, or general statements, were used a lower confidence score was assigned.

Statements from proxy species or general statements for seabird/waterfowl species were included in the evidence bases to pressures with very limited species-specific information. This would allow tolerance scores to be assigned. If proxy or general statements were used the confidence score was assigned as low.

Indirect pressures – review

No pressures that were scoped as having indirect effects for marine birds were assessed. During the assessments, the assessors determined if a pressure only acted on the feature in an indirect way, via their prey species.

The pressures deemed to be indirect by draft scoping from NatureScot/JNCC were reviewed and in agreement were assessed as having an indirect effect on marine birds. During the assessment of the initial three species no evidence was found to suggest the following pressures exerted direct effects on the three pilot species:

• Emergence regime changes (local)
• Siltation rate changes (heavy)
• Temperature changes (regional / national); the majority of evidence relates to the relationship between prey availability and temperature, although there are some references related to extreme heat waves.
• Water flow (tidal current) changes (local)
• Water clarity changes

In discussion with the PSG it was agreed that these pressures might have direct effects on other species/guilds included in the assessment but not assessed during the pilot stage. Therefore, these pressures were not included in the list of indirect pressures.

Pressures deemed to have indirect effects on marine birds by NatureScot/JNCC were kept. No other pressures were added to the indirect pressure list after the assessment of the three pilot species. During the assessments, the assessors determined if any pressure (scoped to have a direct effect) only acted on the feature in an indirect way, via their prey species.

Indirect pressures – evidence bases

Addition of evidence base statements for indirect pressures, highlighting prey species and linking to the ‘Reduction in prey’ pressure.

No literature searches were performed for indirect pressures. Text from FeAST assessments for all prey species was not possible and this would change in the future. Text included in the evidence base for these pressures needed to include information on prey species and a link to the reduction in prey pressure.

Prey species of the feature were identified from the BTO’s Bird Facts website (Robinson, 2005) and results of a literature review of diets of wintering waterfowl undertaken by the BTO (Woodward & Humphreys, 2018) for NatureScot. Sentences highlighting prey species, linking to the ‘Reduction in prey’ pressure and if appropriate, links to sandeel FeAST assessment were included for all indirect pressures.  

Benchmarks

Assessment of pressures by qualitative benchmarks.

Whilst carrying out the Sensitivity Assessments for the initial three species, it was determined that for several pressures the benchmarks were deemed too quantitative and specific to be easily assessed against, for example (see Annex 5 – Benchmarks for full list):

• Emergence regime changes (local) = A 1-hour change in the time covered or not covered by the sea for a period of 1 year.
• Radionuclide contamination = An increase in 10µGy/h above background levels
• Siltation rate changes (heavy) = Heavy deposition of more than 5 cm and up to 30 cm of fine material added to the habitat in a single discrete event or continuous deposition of fine material.
• Temperature changes = 1.5-4ºC change in sea temperature by 2100 (from UK Climate Impacts Project 2009 predictions).
• Underwater noise = Over 20% of days within a calendar year, over 20% of the habitat occupied by the individual in which anthropogenic sound sources that exceed levels that elicit a response from an individual, in terms of movement away, or cessation of feeding.

For the initial three species assessed it was very difficult to find evidence which refers to the benchmark level for these pressures.

A qualitative interpretation on the benchmark was adopted for these pressures, i.e., an emergence or presence of the pressure within the environment. This approach allowed for sensitivity scores to be given to pressures which at a quantitative benchmark may not be able to be assessed due to insufficient evidence.

Subjectivity of tolerance scores

Assessment of tolerance was based on perceived severity of the pressure to the feature’s population if no specific evidence on population decline was available in the literature. A precautionary approach was taken for assessment of the Tolerance and Sensitivity scores, assuming the worst-case scenario.

For the initial three species it was not always possible to find references which specifically referred to a percentage population decline. Therefore, for the majority of pressures expert judgement was used to assess the Tolerance score based on the perceived severity of the pressure to the feature population rather than referring to a specific percentage decline. For instances where evidence did not explicitly state breeding or survival consequences it was agreed with NatureScot, MS and JNCC that the impact was reviewed by assessing how the pressure acts on the species, e.g. by displacement from suitable habitat, by influencing breeding and survival, or by increasing energetic costs or reducing foraging time. A precautionary approach was taken, and the worst-case scenario was assumed.

Tolerance was assessed on perceived severity of the pressure to the feature population, if no specific evidence on population decline was found. A precautionary approach was taken for the tolerance score assessment, assuming that the worst-case scenario of the pressure in the environment.

Pressure: Climate Change

This pressure is assessed following a modified MarLIN methodology. Splitting the evidence by the five categories (sea surface temperature (SST) and air temperature, ocean acidification, sea level rise, storms and waves and freshwater input and salinity) plus an “Indirect - prey” category for evidence related to changes in prey availability. Colour coding the evidence base to allow for possible future separation of the categories.

For the initial three species, the climate change pressure was assessed following a modified MarLIN methodology (Garrard & Tyler-Walters, 2020) and investigating the possible direct effects of the five categories of sea surface temperature (SST) and air temperature, ocean acidification, sea level rise, storms and waves and freshwater input and salinity. The evidence base included the available evidence for all sub-pressures and one overall score was provided for the pressure.  This approach was suitable for this pressure and was agreed to be used for all species. The evidence base was colour coded to reflect these different sub-pressures and to facilitate future separation of these categories should that be required. For the initial three species, evidence was only found for the temperature and storms and waves categories of this pressure. Ocean acidification, sea level rise and freshwater input and salinity are likely to be less relevant to pelagic seabirds and may only have an indirect effect. Therefore, a sub-pressure for indirect-prey was included, as the vast majority of evidence related to temperature is linked to changes in prey availability.

Evidence for the climate change pressure was split into six categories. Five categories from the MarLIN method plus an “Indirect effect” to cover the evidence for changes in prey availability.

Pressure: Removal of target species

Assessment of the tolerance pressure including evidence from UK and non-UK/EU areas.

In the previous assessments, the removal of target species pressure was assessed as low tolerance, as there would be a large impact on the population if the species is being hunted. However, although hunting only occurs for a few of the listed species, this pressure was still assessed as it may be relevant to species that are hunted as pests or recreationally. Evidence from UK and non-UK/EU areas was included, and the tolerance was assessed with all the evidence, taking the location of evidence into account. 

This pressure was assessed and evidence from UK and non-UK/EU areas was included, and the tolerance was assessed with all the evidence, taking the location of evidence into account. 

Pressure: Introduction of other substances

No literature search was undertaken for this pressure and “Not Assessed” was assigned.

A specific literature search was not carried out for the pressure “other substances”, as it is not within the scope of this work to carry out a literature review of all potentially harmful substances to all species. On reflection with NatureScot, MS and JNCC, if evidence was found on a range of new emerging contaminants which could be harmful to seabirds and waterfowl, these emerging substances will be noted in this final report (discussed in Literature search section) as possible pressures to consider in future assessments.

Any evidence of new emerging contaminants which could be harmful to marine birds these substances will be included in the this report (discussed in Literature search section) as possible pressure to consider in future assessments.

Barrier to species movement

Surface/sub-surface, benthic and water column feeders can be directly impacted by artificial structures above water causing an alteration of migration flyways or local flight passes and/or within the marine habitat (e.g. tidal developments or underwater structures) causing alteration to underwater movement, e.g. between breeding and feeding habitat and access to loafing/rafting areas. This pressure may cause increased energy expenditure (negative impact on energy budget) and additionally impact birds by prevention of access to prey resource where barrier is effectively a block.

barrier, windfarm, renewable, dredging, tidal energy, wave energy,

2019

Death or injury by collision below water

Water column and benthic feeders are the most vulnerable guilds and can be directly impacted by death or injury by collision with artificial structures. Water column feeders, such as guillemot, may be directly impacted by wave devices and vulnerable to collision with tidal turbines. Surface feeding species show only low (e.g. tern species) or very low (e.g. fulmar, kittiwake, shearwaters) vulnerability to colliding with submerged or floating structures like tidal stream turbines and wave energy devices.

wave energy, tidal

2019

Death or injury by collision above water

Marine bird species can be directly impacted by death or injury by collision with artificial structures.  Collisions have been recorded at offshore wind farms for several species. Species that fly higher above the surface of the sea (e.g. gulls, gannet) are considered most vulnerable to collision with wind turbines, but lower structures and mobile structures (e.g. shipping) can be hazards to birds flying at lower heights above sea (e.g. auks, divers, sea duck). Lighting on structures can affect collision risk especially in poor visibility.

windfarm, renewable, collision

2019

Emergence regime changes - local

Emergence regime changes have the potential to change the temporal availability of certain habitat types (flooding versus exposure of mudflats and sandbanks etc.). This pressure acts through access to prey. Water birds may make use of intertidal habitat as foraging and/or roosting habitat.

regime change

2019

Introduction of light or shading

Shading is not likely to be an important pressure for seabirds, at least not directly. Introduction of lighting could mean 24 hour foraging opportunities for some (gulls in harbours for example). Lights can also influence attraction to structures (see collision above water). Boats and lighthouses have recorded high numbers of collisions which are associated with poor visibility and attraction to light. Red coloured and flashing light have been found to be less attracting than constant and white light. Petrels and Shearwaters (very nocturnal on land) have been found to be most vulnerable to light attraction. See also Visual Disturbance pressure.

Light, boat, lighthouse

All

Introduction of microbial pathogens (disease), viruses or parasites

This pressure acts through direct mortality due to disease (or possibly loss of prey resource through the same). Several marine bird guilds, including water column, benthic and surface feeding gull and tern species, are potential reservoirs of microbial pathogens such as Avian Influenza Viruses and are reported to be susceptible to the virus, and therefore may be threatened by future outbreaks.

bird flu, disease, virus, parasite, bacteria,  H5N1, infection, botulism, land-fill, influenza

2019

Introduction or spread of non-indigenous species & translocations (competition)

Mainly effective through actions of introduced predator or species competing for the same prey resource. The greatest impact on all marine bird guilds mainly occurs during the breeding season where predation on eggs and chicks by, e.g. rats, could take place. Cliff nesting species may be less vulnerable than ground nesting species to chick and egg predation.

non-indigenous, non-native, mink, squirrel, rat, stoat, cat, mouse, mice, invasive, alien

2019

Nitrogen & phosphorus enrichment

There is evidence that algal blooms (as a result of N and P enrichment) which produce toxins can have a direct impact on birds. This pressure may also indirectly affect the feature under consideration through effects on the feature’s supporting habitat. N and P enrichments can result in, for example, algal blooms which can reduce provisioning efficiency resulting in reduced adult survival or poor body condition of surviving birds with subsequent impacts on breeding success; see Reduction in Prey pressure.

nitrogen, phosphorus, eutrophication

2019

Litter

This pressure can cause direct mortality to birds, or sub-lethal effect leading to reduced fitness. Records of birds ingesting marine litter and records of direct deaths as a result of nest incorporation of litter (mostly ghost-fishing gear) in both adults and chicks. Evidence of ingestion and entanglement in active fishing gear is covered under the ‘Removal of non-target species (lethal)’ pressure. Micro-plastics and ghost fishing gear are included within this pressure.

litter, waste, plastic, ghost net, debris

2019

Transition elements and organo-metal (e.g. Chromium, Copper, TBT) contamination. Includes those priority substances listed in Annex II of Directive 2008/105/EC.

There is potential for accumulation of transitional elements and organo-metals to contaminate marine birds, leading to direct effects on reproduction and survival and well as more chronic deterioration of fitness due to effects on body condition. For example, a high contaminant burden of mercury in birds can act as a neurotoxin, which can lead to decreased reproduction.  

mercury, Chromium, copper, metal, transition element

2019

Hydrocarbon & PAH contamination (Includes those priority substances listed in Annex II of Directive 2008/105/EC).

This pressure is assumed a general relevance for all bird guilds. Surface and benthic feeding species are likely more vulnerable to oil and PAH contamination, as the species spend a high proportion of time on the water surface, than plunge-diving such as gannets. Some water-column foragers, like guillemots, also spend a large amount of time on the water surface and will be impacted by oil. Although evidence strongly suggest that hydrocarbon and PAH compound levels associated with oil spills will severely affect birds, the evidence base is not considered to be developed enough for assessments to be made of sensitivity at the benchmark pressure level.

oil, pollution, hydrocarbon

2019

Physical loss (to land or freshwater habitat)

This pressure can cause direct displacement of birds. Sheltered bays for example may be used as safe places to moult or to raft and rest (i.e. other activities other than just foraging). For example, a fish farm or a new port development could decrease marine water available to birds potentially directly displacing birds from some of these sheltered bays. See Barrier to species movement for information on displacement from loss of marine habitat.
This pressure may also indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Physical loss of existing marine habitat can have a negative impact on the abundance of prey species and marine foraging habitat resulting in reduced adult survival or poor body condition of surviving birds with subsequent impacts on breeding success; see Reduction in Prey pressure.

flood, inundation, sea-level, salt marsh, waste, landfill, habitat loss

2019

Radionuclide contamination

This pressure can cause direct mortality to birds, or sub-lethal effect leading to reduced fitness.

radionuclide, contamination

All

Reduction in availability or quality of prey

This pressure can impact through multiple effects causing lower productivity and body condition and ultimately decline of populations.

prey availability, prey quality, prey

All

Removal of non-target species (including lethal)

The effect of this pressure is increased mortality. Benthic and water column feeders represent the species guilds most susceptible to entanglement in gillnets due to their foraging strategies. Surface feeding species, e.g. Fulmar, kittiwake, terns, are also reported victims of by-catch by entanglement during net hauling or setting or can be trapped when scavenging a net drifting at the surface.

bycatch, drown, net, entangle, windfarm, renewable, static gear, seine, aquaculture, longline

2019

Removal of target species (including lethal)

Hunting or alternative removal of all species guild will directly remove individuals from a population, therefore there is potential for a direct negative effect, depending on the state of the population impacted and whether the additional mortality can be sustained. Long-lived species, like surface feeding seabirds are especially vulnerable to adult mortality. Taking of eggs is allowed in Scotland, England and Wales under the licensing regimes.

harvest, egg collection, persecution, cull, hunt, trap, exploit

2019

Siltation rate changes (heavy)

This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. High siltation can completely smother prey habitat. Siltation can have a negative impact on the abundance of prey species resulting in reduced adult survival or poor body condition of surviving birds with subsequent impacts on breeding success. Sandeel is an important prey species for water column feeders. Sensitivity of sandeel to this pressure is High. See Reduction in Prey pressure.

Evidence for the potential direct impact of siltation on the visual bird forager’s ability to detect prey, e.g. shag, is incorporate under the Water clarity changes pressure.

siltation, smother

2015

Synthetic compound contamination (inc. pesticides, antifoulants, pharmaceuticals) Includes those priority substances listed in Annex II of Directive 2008/105/EC.

There is potential for bioaccumulation of ingested synthetic compounds leading to direct fecundity and/or mortality impacts on marine birds as well as potential effects on productivity. Effects may include immunosuppression, decreased egg viability, hormonal effects, oxidative stress level changes, decreased body condition.

organochlorine, pesticide, antifoulant, pharmaceutical

2019

Temperature changes - regional/national

This pressure is likely to influence species differently, with some being influenced positively and others negatively. The pressure may have population level effects on numbers and distribution of species. It may cause increased energy expenditure from changes to thermoregulation needs or changes to access to suitable habitats for breeding or foraging.

temperature, phenology, migration, short-stopping

2019

Underwater noise

Underwater noise may directly affect benthic and water column feeders, being submerged for comparable long periods when diving in search for prey on the seabed. Cormorants have also been shown to be sensitive to noise in experimental conditions, and therefore it is expected that shags could be too since they are in the same family. There could be direct effects of underwater noise on surface feeding birds, e.g. fulmar or terns, but as the bulk of their food is taken from the water surface any potential affect may be minor.

noise, decibel

2019

Visual disturbance (behaviour)

Marine bird species can be directly impacted by visual disturbance from a variety of sources. Human disturbance has been linked with declines in breeding success of cliff-nesting birds and cause abandoning of nest and chicks and/or increase the risk of eggs and chicks being predated while breeding adults are absent due to disturbance. Benthic feeders are reported as the species guild showing highest vulnerability to disturbance and/or displacement from their marine foraging habitat. The impact of this pressure is measured by disturbance effects to birds causing change in energy budget, abandonment of preferred feeding or breeding area etc.

visual disturb, human, boat, recreation, tourism, vehicle

2019

Water clarity changes

This pressure affects the bird’s ability to detect prey and/or prey density leading to reduced prey availability. Water column, benthic and surface feeders are potentially impacted by water turbidity in terms of foraging success. There is some variation between species of the water column feeding guild as divers, grebes and seaducks are more vulnerable than gannets and auks. Manx shearwaters have very low sensitivity to increased water turbidity in response to dredging operations and guillemots, razorbills and puffins are moderately sensitive. Sensitivity is particularly reported in surface feeding tern species foraging visually.

water clarity

2019

Water flow (tidal current) changes - local

This pressure affects energy budget or foraging efficiency. Increases in flow could increase energy expenditure of resting birds on the water surface or birds diving for prey This could reduce body condition and therefore give rise to direct impacts. Surface feeders can be affected by water flow changes, as this affects the availability of prey items at or close to the water surface.

water flow, water current

2019

Wave exposure changes - local

This pressure affects the bird’s ability to detect or capture prey. Local changes in wavelength, height and frequency can directly affect surface feeder; directly affecting the ability of the bird to capture prey when it is present. There is also the potential negative affect for surface feeding species (plunge diving), due to birds finding it more difficult to predict the position of fish below the surface. This pressure covers changes due to extreme weather events.

wave, roost

2019

Climate change

(Pressure not currently in FeAST)

Climate change pressure assessed following the MarLIN methodology and investigating the possible direct effects of the five categories of sea surface temperature (SST) and air temperature, acidification, sea level rise, storms and waves and freshwater input and salinity. Indirect effects via prey species are also highlighted. The evidence base is categorised in colour for the different categories:
- SST & air temp (red);
- Acidification (blue),
- Sea level rise (orange);
- Storms & waves (green);
- Freshwater input & salinity (purple),
- Indirect – prey (grey)

climate change, sea surface temperature, air temperature, acidification, sea level rise, storm, waves, freshwater input, salinity

All

Physical change (to another seabed type)

This pressure may indirectly affect marine birds through effects on the feature’s supporting habitat. Loss of preferred seabed habitat can have a negative impact on the abundance of some key prey species resulting in potential reduction in adult survival or poor body condition of surviving birds with subsequent impacts on breeding success. New prey species may colonise the new habitats but these may be of poorer dietary quality or harder to catch to the preferred key prey species; See Reduction in Prey pressure.

2015

Physical removal (extraction of substratum)

This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Loss of preferred seabed habitat can have a negative impact on the abundance of some key prey species resulting in potential reduction in adult survival or poor body condition of surviving birds with subsequent impacts on breeding success. New prey species may colonise the new habitats but these may be of poorer dietary quality or harder to catch to the preferred key prey species; See Reduction in Prey pressure.

2015

Sub-surface abrasion/penetration

This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Damage to preferred seabed habitat can have a negative impact on the abundance of some key prey species resulting in potential reduction in adult survival or poor body condition of surviving birds with subsequent impacts on breeding success. New prey species may colonise the new habitats but these may be of poorer dietary quality or harder to catch to the preferred key prey species. Sandeel is an important prey species for water column feeders. Sensitivity of sandeel to this pressure is High. See Reduction in Prey pressure.

2015

Surface abrasion

This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Damage to preferred seabed habitat can have a negative impact on the abundance of some key prey species resulting in potential reduction in adult survival or poor body condition of surviving birds with subsequent impacts on breeding success. New prey species may colonise the new habitats but these may be of poorer dietary quality or harder to catch to the preferred key prey species. Sandeel is an important prey species for water column feeders. Sensitivity of sandeel to this pressure is Medium. See Reduction in Prey pressure.

2015

Organic enrichment

This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Increased organic enrichment can have a negative impact on the abundance of prey species and reduced visibility for pursuit feeders, resulting in reduced adult survival or poor body condition of surviving birds with subsequent impacts on breeding success); See Reduction in Prey pressure.

2015

De-oxygenation

This pressure may indirectly affect marine birds through effects on the feature’s supporting habitat. De-oxygenation can have a direct negative impact on the abundance of prey species resulting in reduced adult survival or poor body condition of surviving birds with subsequent impacts on breeding success. See Reduction in Prey pressure.

2015

Salinity changes - local

This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Changes in salinity can have a negative impact on the abundance of prey species resulting in reduced adult survival or poor body condition of surviving birds with subsequent impacts on breeding success; See Reduction in Prey pressure.

2015

Electromagnetic changes

This pressure may indirectly effect marine birds through effects on the feature’s supporting habitat.  Whilst there has not been studies specifically relating to marine birds and underwater electro magnetic fields (EMF), evidence suggests that EMF can cause fish and invertebrate species on the seabed to move away from the magnetic field. This effect on prey species is particularly relevant for benthic feeders. See Reduction in Prey pressure.

2015

Siltation rate changes (light)

This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Siltation rate changes affect prey habitat which can have a negative impact on the abundance of prey species resulting in reduced adult survival or poor body condition of surviving birds with subsequent impacts on breeding success. Sandeel is an important prey species for water column feeders. Sensitivity of sandeel to this pressure is Medium. See Reduction in Prey pressure.

2015

Temperature changes - local

This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Change in water temperature locally can have a negative impact on the abundance of some key prey species resulting in potential reduction in adult survival or poor body condition of surviving birds with subsequent impacts on breeding success. New prey species may colonise the new habitats but these may be of poorer dietary quality or harder to catch to the preferred key prey species. Sandeel is an important prey species for water column feeders. Sensitivity of sandeel to this pressure is High. See Reduction in Prey pressure.

2015

The mechanism through which an activity has an effect on any part of the ecosystem. The nature of the pressure is determined by activity type, intensity, and distribution.

The standard descriptor of the pressure defined in terms of the magnitude, extent, duration, and frequency of the effect.  Benchmarks may be quantitative or qualitative.

Barrier to species movement

Benchmark: Barrier to species movement.

For marine birds the impact is increase in energy expenditure and loss of access to (foraging) habitat. The level at which this would cause mortality is not understood but modelling in Forth and Tay shows mortality expected when multiple barriers to access exist. Metric required will be % increase in energy expenditure to perform current actions, translated to % area of current foraging sites unavailable or % increase in flight distance required to maintain current foraging activity.

Description: The physical obstruction of species movements including local movements (within & between roosting, breeding, feeding areas) and regional/global migrations (e.g. birds, eels, salmon, and whales).

Includes upriver movements (where tidal barrages & devices or dams could obstruct movements) or movements across open waters (offshore wind farm, wave or tidal device arrays, mariculture infrastructure or fixed fishing gears).  It is acknowledged that aquaculture and fixed fishing gears represent very low scale barriers.

Note: entanglement is included under ‘Removal of non-target species’ pressure.

De-oxygenation

Benchmark: Compliance with WFD criteria for good status: fully saline waters is 4mg/l and within estuaries, the WFD standard for good status is 5-(0.028xsalinity).

Description: The lowering, temporarily or more permanently, of oxygen levels in the water or substrate due to anthropogenic causes. Pressure is closely related to the ‘N and P enrichment’ pressure. The water

column immediately above the seabed can have lower oxygen levels than the general water column, and this is closely linked to the ‘Organic enrichment’ and ‘Siltation’ pressures. Compliance with WFD criteria for good status. In offshore waters oxygen status can be assumed to be high as there are no significant pressures. For fully saline waters, the WFD standard for good status is 4mg/l, compared to a suggested level of 5mg/l in WQTAG 088e. However, all fully saline waters already meet high status (>5.7mg/l). Within estuaries, the WFD standard for good status is 5-(0.028xsalinity) compared to a suggested level of 6- (0.028xsalinity) in WQTAG088e. The latter standard is more precautionary as it also seeks to protect migratory fish, which are likely to be the most sensitive element. Note1: where deoxygenation is being considered for features present within estuaries or in relation to mobile species, additional consideration should be given. Note 2: Assume existing EQS will ensure Not Sensitive unless evidence to suggest otherwise, however if the standards were breached then this pressure would need to be reconsidered.

Death or injury by collision below water

Benchmark: Death or injury by collision below water*

Description: Injury or mortality from collisions of biota with both static &/or moving structures. Examples include: collision with rigs (e.g. birds) or screens in intake pipes (e.g. fish at power stations) (static) or

collisions with wind turbine blades, fish & mammal collisions with tidal devices and activities involving shipping (moving).

Death or injury by collision above water

Benchmark: Death or injury by collision above water*

Description: Injury or mortality from collisions of biota with both static &/or moving structures above the surface of the water. Collision at night may be associated with 'Introduction of light' pressure that may attract some birds.

Electromagnetic changes

Benchmark: Local electric field of 1 volt per meter, or Local magnetic field of 10 telsa (μT) due to anthropogenic means.

Description: Localized electric and magnetic fields associated could alter behaviour (e.g. attract or repel) and migration patterns of sensitive species. Elasmobranch species (sharks, skates and rays) are relatively sensitive to electric fields, and diadromous species are expected to have relatively higher sensitivity to magnetic fields.

Emergence regime changes - local

Benchmark: A 1 hour change in the time covered or not covered by the sea for a period of 1 year. Description: Changes in water levels may reduce the intertidal zone (and the associated/dependent habitats) by changing either the spatial area and or duration of immersion/exposure during tidal cycles. Changes in tidal flushing can change sediment dynamics that may lead to changing patterns of deposition and erosion and extent of tidal immersion. Impacts include reduced habitats, resources, and feeding times, exposure, desiccation,

Impact on bird species that forage in the intertidal area either when covered or uncovered.

Genetic modification & translocation of indigenous species

Benchmark: Translocation of indigenous species and/or introduction of genetically modified or genetically different populations of indigenous species that may result in changes in genetic structure of local populations, hybridization, or change in community structure.

Note: Aquaculture species only - Translocation outside of geographic area or introduction of hatchery-reared juveniles outside of geographic area from which adult stock derives. Note that issues of salmon or halibut escapes are not included as these do not pose any impacts on MPA protected features.

Description: Moving of indigenous or genetically modified species to different areas may cause competition with local populations of species with different genetic make ups, alter the community of the receiving habitat, or provide the opportunity for hybridization between similar species (e.g. Spartina spp. and Mytilus spp.).

Introduction of light or shading

Benchmark: Change in incident light via anthropogenic means.

Description: Introduction of light on structures may disorientate, repel or attract species (affecting e.g. migration routes), increase algal growth, change communities or species present. Shading from structures may reduce growth, feeding or change communities/species present.

Introduction of microbial pathogens (disease), viruses or parasites

Benchmark: The introduction of relevant microbial pathogens, metazoan disease vectors or parasites to an area where they are currently not present or likely to cause a significant increase in levels compared to background levels.

Description: The introduction or increase in levels of pathogens, disease vectors or parasites from anthropogenic activities.

Introduction of Other Substances (Solid, Liquid or Gas)

Benchmark: Compliance with all Average Annual Environmental Quality Standards, conformance with Probable Effect levels, Environment Assessment Criteria, Effects Range - Low, and any introduction of other solid debris without EQS that may cause changes to species or habitats.

Description: The 'systematic or intentional release of liquids, gases ' (from MSFD Annex III Table 2) is considered e.g. in relation to produced water from the oil industry. It should, therefore, be considered in parallel with the other chemical contaminants. Other solid debris such as shellfish shells and seaweed debris may also have detrimental effects which are not covered in other pressures.

Introduction or spread of non- indigenous species & translocations (competition)

Benchmark: A significant pathway exists for introduction of one or more Invasive non-indigenous species (INIS) (also referred to as Invasive Non-Native Species (INNS))**

Description: The direct or indirect introduction of invasive non-indigenous species, e.g. Chinese mitten crabs, slipper limpets, Pacific oyster and their subsequent spreading and out-competing of native species.

Sensitivity assessment will be made against a prescribed list of INIS based on the GB Non-native Species Information Portal list of potentially invasive species.

Nitrogen & phosphorus enrichment

Benchmark: Compliance with WFD criteria for good status (or increases in nutrient loading over background levels if information available)***

Description: Increased levels of the elements, nitrogen, phosphorus, silicon (and iron) in the marine environment compared to background concentrations. Ideally, the pressure would be assessed in terms of increases in nutrient loading over background. However, such information is not readily available. As a surrogate, it could be possible to use information from WFD and CEMP assessments in relation to winter concentrations of DIN (a measure of state) and compare these to WFD standards and status classification outputs. Adverse environmental effects include deoxygenation, algal blooms, changes in community structure of benthos and macrophytes. Note: closely linked with de-oxygenation pressure.

Litter

Benchmark: Introduction of man-made objects able to cause physical harm (surface, water column, sea floor and/or strandline).

Description: Marine litter is any manufactured or processed solid material from anthropogenic activities discarded, disposed or abandoned (excluding legitimate disposal) once it enters the marine and coastal environment including plastics, metals, timber, rope, fishing gear etc. and their degraded components, e.g. microplastic particles.

Transition elements & organo-metal (e.g. Chromium, Copper, TBT) contamination. Includes those priority substances listed in Annex II of Directive 2008/105/EC.

Benchmark: Compliance with all average annual Environmental Quality Standards, or conformance with Probable Effect levels, Environment Assessment Criteria, Effects Range - Low.

Description: These standards provide good levels of protection for all living organisms where standards are adhered to.  For marine sediments the main elements of concern are Arsenic, Cadmium, Chromium, Copper, Mercury, Nickel, Lead and Zinc Organo-metallic compounds such as the butyl tins (Tri butyl tin and its derivatives) can be highly persistent and chronic exposure to low levels has adverse biological effects, e.g. Imposex in molluscs.

Note: all transition elements should be considered under this pressure, but the transition element should be clearly identified in the evidence base.

Hydrocarbon & PAH contamination. (Includes those priority substances listed in Annex II of Directive 2008/105/EC).

Benchmark: Compliance with all average annual Environmental Quality Standards, or conformance with Probable Effect levels, Environment Assessment Criteria, Effects Range – Low****

Description: These standards provide good levels of protection for all living organisms where standards are adhered to. Exceeding EQS may occur (e.g. for accidental spills or bioaccumulation) and the potential ecological consequences include lethal and non-lethal effects, physiological changes. These are naturally occurring compounds, complex mixtures of two basic molecular structures: straight chained aliphatic hydrocarbons (relatively low toxicity and susceptible to degradation) and multiple ringed aromatic hydrocarbons (higher toxicity and more resistant to degradation). Ecological consequences include tainting, some are acutely toxic, carcinomas, growth defects.

Note: the distinction between chronic level pollution and accidental spills/bioaccumulation should be clearly identified in the evidence base.

Organic enrichment

Benchmark: A deposit of 100gC/m2/yr.

Note: Further discussion on benchmarks warranted by FeAST working group, as organic enrichment doesn’t have an EQS as such.

Description: This pressure is referring to particulate organic matter and is therefore closely associated with the Siltation pressures. Dissolved organic matter is not covered directly by other pressures, but N and P enrichment pressure addresses the key enrichment factors.

Adverse environmental effects include deoxygenation, algal blooms, changes in community structure of benthos and macrophytes.

Note: overlap with siltation and Nitrogen and Phosphorous enrichment pressures, but organic enrichment also has its own effects. Level of organic enrichment at which community structures changed are likely to have indirect effect. Level at which algal blooms (toxic algae) may be direct effect.

Physical change (to another seabed type)

Benchmark: The permanent change of one marine habitat type to another marine habitat type, through the change in substratum, including to artificial (e.g. concrete mattresses, rock dumping).

Description: Two separate possibilities 1) Change in sediment type by one Folk class, 2) Change from sedimentary or soft rock substrata to hard rock or artificial substrata or vice-versa. A change from sediment to hard rock (or vice versa) would affect all types of substratum, and all habitats would be assessed as highly sensitive. This pressure concerns disposal or the deposit of material, whilst the removal of material is covered under sub-surface abrasion and physical removal pressures.

Physical loss (to land or freshwater habitat)

Benchmark: Permanent loss of existing marine habitat (to land or coastal infrastructure).

Description: The permanent loss of marine habitats by activities or infrastructure that encroaches on the marine area so as to move the MHWS mark seawards. Coastal features assumed to be highly sensitive to loss of their habitat.

Physical removal (extraction of substratum)

Benchmark: Extraction of sediment to 30cm.

Description: This pressure relates to extraction of sediment substrate.

Radionuclide contamination

Benchmark: An increase in 10µGy/h above background levels.

Description: Introduction of radionuclide material, raising levels above background concentrations.

Reduction in availability or quality of prey

Benchmark: Reduction in prey availability or quality of prey*****

Description: Reduction in prey availability or quality of prey could be caused by competition (with e.g. other marine predators) or from pressures that affect prey species. Temporary or longer-term impacts can arise from construction, operational and decommissioning phases of infrastructure developments. Consequences include starvation, a poorer diet with knock on effects on energy budget, breeding etc. and ultimately decline in populations.

Removal of non-target species (including lethal)

Benchmark: Accidental or incidental removal of features through pursuit of a target fishery, or harvesting or other extractive activity (commercial, recreational or artisanal scale), including through accidental entanglement with nets or ropes e.g. aquaculture nets, mooring lines or creels.

Mainly a synonym for bycatch.

Description: Any damage, loss or removal of species through accidental or incidental catch (or by-catch) associated with fishing, harvesting and extraction activities, including extraction of substrate or water. Also includes accidental entanglement in ropes or lines associate with various activities.

Note: ghost-fishing gear is covered under the ‘litter’ pressure;

Removal of target species (including lethal)

Benchmark: Removal of target species that are features of conservation importance or sub-features of habitats of conservation importance at a commercial, artisanal or recreational scale.

Description: Ecological consequences include the sustainability of populations, impacting energy flows through food webs and the size and age composition within populations, alteration to habitat structure, biodiversity or function.

Note: at sea hunting of marine birds rarely (if ever) now occurs in Scotland. An offence under the NC (Scotland) act 2004 so would be legal matter - unless licenced (whereby activity is regulated).

Salinity changes - local

Benchmark: Increase from 35 to 38 units for one year or Decrease in salinity by 4-10 units for a year.

Description: Activities have the potential to increase or decrease local salinity through either input of fresh water or physical changes that may alter water exchange and therefore salinity.  Changes to salinity can impact growth, respiration, behaviour, and reproduction, and may ultimately alter communities/habitats, particularly if combination with other stresses such as temperature.

Siltation rate changes (heavy)

Benchmark: Heavy deposition of more than 5cm and up to 30cm of fine material added to the habitat in a single discrete event or continuous deposition of fine material.

Description: Siltation (or sedimentation) is the settling out or deposit of silt or sediments suspended in the water column to the seabed. Changes relate to those over natural siltation and those above 5 cm (less than this depth is covered by different pressure), or where a high level of deposition is continuous (e.g. fish farming). Siltation of this level can completely smother species and habitats, particularly sessile organisms. Impacts are mainly from hypoxia, inability to feed or photosynthesise and potentially death unless tolerance species or species that can re-emerge.

Siltation rate changes (light)

Benchmark: Light deposition of up to 5cm of fine material added to the seabed in a single event or continuous deposition of fine material.

Description: Siltation (or sedimentation) is the settling out or deposit of silt or sediments suspended in the water column to the seabed. Changes relate to those over natural siltation and up to 5 cm (more than this depth is covered by different pressure), or where a light level of deposition is continuous (e.g. shellfish farming). Siltation of this level may completely smother smaller species and habitats, particularly sessile organisms. Effects can be hypoxia, physical difficulties in feeding, reproduction, reduction in photosynthesis and potentially death for more sensitive species.

Sub-surface abrasion/penetration

Benchmark: Damage to species or habitats below the surface of the seabed.

Description: Abrasion damage involving some degree of physical penetration to the seabed or disturbance of habitats or species below the surface of the seabed. Penetration and damage to the soft rock substrata are considered, however, penetration into hard bedrock is deemed unlikely.

Surface abrasion

Benchmark: Damage to species or habitats living on the seabed. Damage to surface features (e.g. species and physical structures within the habitat).

Description: Abrasion damage at the surface of the substratum in sedimentary or rocky habitats e.g. epiflora and epifauna.

Synthetic compound contamination (inc. pesticides, antifoulants, pharmaceuticals). Includes those priority substances listed in Annex II of Directive 2008/105/EC.

Benchmark: Compliance with all average annual Environmental Quality Standards, or conformance with Probable Effect levels, Environment Assessment Criteria, Effects Range - Low.

Description: The EQS standards provide good levels of protection for all living organisms where standards are adhered to. See separate pressures where exceeding EQS may occur and the potential ecological consequences include lethal and non-lethal effects, physiological changes (e.g. growth defects, carcinomas).

The sub-pressure ‘Synthetic compound contamination from pollution incidents/accidental spills or bioaccumulation’ considers synthetic compound contamination where spills, accidents or bioaccumulation are significant.

Note: EQS benchmark suitable for categories that are not accidental spill. Spills will (always) trigger assessment. Impacts at 100m from point source unlikely to lead to population level impacts. Impacts around fish farm sites (i.e. fish farm footprint plus 100m) would be worthy of consideration, especially in cumulative situation.

Temperature changes - local

Benchmark: A 5°C change in temp for a one month period, or 2°C for one year.

Description: Events or activities increasing or decreasing local water temperature. This is most likely from thermal discharges, e.g. the release of cooling waters from power stations. This pressure only applies within the thermal plume generated by the pressure source.

An emergence or presence of the pressure within the environment.

Temperature changes – regional/national

Benchmark / Description: 1.5-4ºC change in sea temperature by 2100 (from UK Climate Impacts Project 2009 predictions).

Sea temperature change will have greater impact at same scale compared to air temperature change. General increase of 0.5 deg C would have significant effect on prey, greater increases in water temperature change will be accompanied by air temperature change. Appropriate to deal with effects through 'climate change' pressure.

An emergence or presence of the pressure within the environment.

Underwater noise

Benchmark: Over 20% of days within a calendar year, over 20% of the habitat occupied by the individual, in which anthropogenic sound sources that exceed levels that elicit a response from an individual, in terms of movement away, or cessation of feeding (for disturbance, or exposure which leads to auditory injury.

Need evidence from behavioural changes of birds to set an appropriate benchmark. Cetacean appropriate benchmark probably would also be precautionary for diving birds.

Description: Anthropogenic sounds may be of short duration (e.g. impulsive such as from seismic surveys and piling for wind farms and platforms, as well as explosions) or be long lasting (e.g. continuous such as dredging, shipping and energy installations) affecting organisms in different ways. Marine mammals are most susceptible, however fish and other benthic species including invertebrates may also be affected, although literature is limited.

An emergence or presence of the pressure within the environment.

Visual disturbance (behaviour)

Benchmark: The visual disturbance of biota by anthropogenic activities.

Disturbance such that birds are prevented from accessing nest sites for more than 1 hour, or accessing (local) feeding areas for 1 day.

Description: Visual disturbance is only relevant to species that respond to visual cues, for hunting, behavioural responses or predator avoidance, and that have the visual range to perceive cues at distance. It is particularly relevant to fish, birds, reptiles and mammals that depend on sight but less relevant to benthic invertebrates. The cephalopods are an exception but they are only likely to respond to a visual disturbance at close range (from e.g. divers). Audio disturbance is relevant to species that respond to in-air noise, for example aircrafts. Not including introduction of light as this is addressed by separate pressure.

Water clarity changes

Benchmark: A change in one rank on the WFD (Water Framework Directive) scale, e.g. from clear to intermediate for one year. (Ranks are mean suspended particulate matter in units of mg/c: >300 - very turbid; 100-300 - medium turbidity; 10-100 - intermediate; <10 - clear).

Description: Changes in water clarity (or turbidity) due to changes in sediment & organic particulate matter and chemical concentrations. It is primarily related to activities disturbing sediment and/or organic particulate matter and mobilizing it into the water column. Particle size, hydrological energy (current speed & direction) and tidal excursion are all influencing factors on the spatial extent and temporal duration.

Salinity, turbulence, pH and temperature may result in flocculation of suspended organic matter. Changes in suspended sediment loads can also alter the scour experienced by species and habitats. Therefore, the effects of scour are also addressed here.

Note: links with sediment deposition and organic enrichment pressures.

An emergence or presence of the pressure within the environment.

Water flow (tidal current) changes - local

Benchmark: Peak mean spring tide flow change of greater than 0.1m/s over an area >1km2 or 50% of width of water body for > 1 year.

Description: Changes in water movement associated with tidal streams (the rise and fall of the tide, riverine flows), prevailing winds and ocean currents.  The pressure extremes are a shift from a high to a low energy environment (or vice versa), which can alter the biota, substratum, sediment transport and seabed elevation.

The potential exists for profound changes (e.g. coastal erosion/deposition) to occur at long distances from responsible activity, with complex interactions.

An emergence or presence of the pressure within the environment.

Wave exposure changes - local

A change in nearshore significant wave height >3% for one year.

An increase to the lower threshold of this benchmark would be appropriate, although no value to suggest. At 25% effects much more likely, whereas assessing impact at 3-5% would be difficult.

Description: Exposure on open shore determined by local changes in wavelength, height and frequency. Significant wave height = the average height of the highest one third of waves and is dependent upon the distance of open sea water over which wind may blow to generate waves (the fetch) and the strength and incidence of winds, and topography; generally significant wave height is <1.2m but can be up to 3m around UK coast.

Recovery scoring

The descriptors for resistance and resilience, relating to birds, fish and mammals, developed by Natural England (Perez-Dominguez et al., 2016)11 have been further revised for marine birds to align as far as possible with current FeAST scoring for tolerance and recovery. The 2015 and 2019 draft Sensitivity Assessments used the definitions of tolerance (resistance) and recovery (resilience) used by Natural England but used the FeAST sensitivity score matrix.

The Natural England scoring system for recovery is based on life-history traits. Based on this scoring criteria, it was decided that recovery potential should be scored as ‘Low’ in all seabird assessments updated in 2019 for the SSCS. This is a generic approach to recovery scoring for seabird species was used in the 2019 assessments in the absence of any other evidence.

The same matrix should be used for marine waterfowl assessments; some may score medium but all seabirds should be kept at a low recovery score due to life history traits (long-lived).

In the 2021 assessments, recovery was assessed on life-history traits (Table 2), all marine seabird species were assessed as low recovery, except 2 divers, a grebe and 2 seaducks which were assessed as medium recovery.  

Sensitivity scoring

For seabirds the variation in the sensitivity score is mainly based on the tolerance score because most seabirds would have a generic ‘low’ recovery potential (see Table 4).

Hydrocarbon & PAH contamination pressure

This pressure is aimed at chronic pollution with benchmarks set at ‘compliance with all relevant environmental quality standards (EQS)’. If the concentration at EQS standard level is achieved, it should prevent harm to bird species. As a result, all species are technically considered to be ‘Not sensitive’ at the benchmark level.

It is important that a review of evidence relating to oil spills (and catastrophic contamination of any sort) is undertaken separately under this pressure and a clear distinction is made from chronic pollution levels. To take into account the possibility of accidental spills or other pollution incidents and the possibility of bioaccumulation of contaminants up the food chain in top predators, FeAST has handled this by providing indicative scores for tolerance, recovery and overall sensitivity. These scores are based on the species sensitivity to contaminants in the event of an accident happening, along with supporting evidence to inform situations where, for example EQS may be exceeded, compounds are accidentally spilled or where bio- accumulation occurs.

The mobile species assessments for cetaceans, seals and fish have tackled this by using the following statement:

‘In practice, the benchmark for this pressure assumes compliance with all AA EQS and conformance with PELs, EACs and ER-Ls which, if achieved, will prevent harm to this species. Even so, indicative scores for tolerance, recovery and sensitivity are provided, along with supporting evidence, to inform situations where, for example, EQS may be exceeded, compounds are accidentally spilled or where bio- accumulation occurs.’

Followed by the evidence base to support the assessment for impact on the feature when EQS is exceeded due to accidental spills and bioaccumulation.

Furthermore, the transition element is clearly identified in the evidence base so that if in the future it is decided to separate these out, it can be done so relatively easily.

This approach was used for marine birds for consistency. For greater clarity the following statement was used in the evidence bases for this pressure: “In practice, the benchmark for this pressure assumes compliance with all Annual Average Environmental Quality Standards (AA EQS) and conformance with Permissible Exposure Limits (PELs), Environmental Assessment Criteria (EACs) and Effects Range-Low (ER-Ls) which, if achieved, will prevent harm to this species. Even so, indicative scores for tolerance, recovery and sensitivity are provided, along with supporting evidence, to inform situations where, for example, EQS may be exceeded, compounds are accidentally spilled or where bio- accumulation occurs”.

Displacement

Displacement of birds is considered under the barrier effect pressure rather than the physical loss (marine habitat) pressure.

These pressures have the potential to be easily confused and it was felt that it is important to align FeAST with how advice is provided in casework. The justification behind this decision to deal with evidence of displacement under the barrier effect pressure is provided by the definitions below on displacement, barrier effect and physical (habitat) loss:

Displacement

When a bird can no longer use an area that it did previously, we usually term that as it being displaced. This is typically a behavioural response to an anthropogenic disturbance; in offshore development casework this is normally expected as a consequence of an area of sea being occupied by a development that birds will avoid.

Barrier

In other cases the birds will not have utilised the marine habitat in the area that is developed, but would have gone beyond – or travelled through- the area to reach other parts of the sea, for example a commuting route to a foraging area or a migratory route. Some birds will travel a greater distance around the development to still reach the area that they originally would have, others may turn back and be prevented from accessing the area they would have previously reached.

Physical Loss

When an area of marine habitat is changed from sea to e.g. land or freshwater. This will cause birds to no longer use the area.  It is possible that if the area is between a colony and a foraging site the changed habitat could act as a barrier in the same way as above. Under the FeAST definition, it does not include a change of one marine habitat type to another marine habitat type.

Climate change

For the assessment of marine birds in 2021 this pressure was included. The pressure was divided into six sub-pressures. Five from the MarLIN methodology (Garrard & Tyler-Walters, 2020):  sea surface temperature (SST) and air temperature, acidification, sea level rise, storms and waves and freshwater input and salinity. A sixth sub-pressure, indirect – prey, was added to be able to distinguish literature that suggested an indirect impact by climate change on the feature. An overall Tolerance and Sensitivity score for this pressure was assigned.

Literature for each sub-pressure were colour coded in the evidence base to ensure the different sub-pressures could be easily separated if required at a later date.

Micro-plastics and ghost fishing gear

For the assessment of marine birds in 2021, the issue of micor-plastics and ghost fishing gear were included within the litter pressure. The litter pressure’s justification was updated as: “This pressure can cause direct mortality to birds, or sub-lethal effect leading to reduced fitness. Records of birds ingesting marine litter and records of direct deaths as a result of nest incorporation of litter (mostly ghost-fishing gear) in both adults and chicks. Evidence of ingestion and entanglement in active fishing gear is covered under the ‘Removal of non-target species (lethal)’ pressure. Micro-plastics and ghost fishing gear are included within this pressure.”

Indirect pressures

Indirect sensitivity is only applied where there is evidence of sensitivity for the prey or supporting habitat of the feature. The evidence base starts with a clear statement that there is ‘No direct sensitivity’ to the pressure. The evidence base then describes the links / interactions that exist between the pressure and the feature via changes in prey. No high, medium or low score is provided for indirect sensitivity, but the sensitivity score for the prey or supporting habitat to the pressure is provided in the evidence base. For example, ‘FEAST sensitivity assessment for sandeel to this pressure is high’.

Evidence is then provided under the ‘reduction in availability or quality of prey’ pressure on the impact that changes in prey has or may have on the marine bird species in question.

In instances where the feature is also directly sensitive to the pressure, a score is given to reflect this using the tolerance and recovery scores in the usual way and any indirect sensitivities explained in the evidence base too (but not scored).

Whilst there are few examples where any marine bird species is reliant on single prey species, it is not necessarily true that marine birds will thrive eating any prey types in sufficient quantities.  Differences in the quality of prey are likely to be as important to marine bird species as the quantity of prey. Consequently, indirect effects are complex and often difficult to assess using the typical sensitivity assessment methodology. In addition, literature may not explicitly provide the links / interactions between the pressure and feature by the prey, in these cases expert judgement is used to decide on the indirect aspect of the pressure.

Pressures with a terrestrial influence

For these pressures, the marine focus remains the priority. Evidence is first included for the pressure in terms of marine impacts, but then also any terrestrial impacts to breeding/roosting areas are included.

More than one sub-pressure under one pressure

If there is more than one sub-pressure, for example under the non- synthetic compound pressure ‘transition elements and organo-metals’ there may be studies addressing two different heavy metals, then:

Use the score with the lowest tolerance across the sub pressure. (i.e. go with the most detrimental sub-pressure).

This scoring should be indicated in the notes.

[Note: if there is no evidence for other sub-pressures it does not mean automatically that they might not be important]

Pressure only occurs abroad

To future proof FeAST, tolerance assessments should be applicable regardless of location.

Example: removal of target species (hunting). Depends on legislation of country.

Conclusion: even if hunting is not allowed in Scotland at the moment, tolerance should be low unless evidence suggests otherwise.

Evidence base structure

To provide a more user-friendly tool, the current text used in each draft sensitivity assessment has been reviewed and differentiation is made between:

Generic text – relevant to all marine birds

Guild specific text – (surface feeders, benthic feeders, water-column feeders and/or family i.e. terns, divers)

Species specific text – relevant to the named species

Where it is legitimate to use similar species as the evidence base for a different species this has also been done. For example, evidence available for Arctic tern is appropriate for using as evidence for common tern but less so for little tern.

For additional clarity, all the evidence bases include an additional summary sentence at the bottom stating ‘Tolerance is assessed as x and Recovery as x’.

More than one piece of evidence per species and pressure

To come to a joint conclusion on the tolerance to the pressure, the following rules were developed:

Evidence with higher confidence levels will have priority.

If several pieces of evidence have comparable confidence levels, a precautionary approach should be taken, and the lowest tolerance described between the publications should be used.

Evidence could fall under different pressures

Do not include all possible pressures, but mainly the ones immediate to the human induced pressure.

Example: algae blooms could be recorded under pathogens, interspecific interaction, climate change, non-synthetic compound.

Conclusion: depending on the evidence, e.g. climate change or possibly organic enrichment, if that is mentioned as a cause.

Keywords

‘Interspecific interaction’ and ‘Displacement’ for pressures should be included in the literature review part of this contract, additionally to the keywords currently used for the draft assessments.

Note: ‘interspecific interaction’ was included as a FeAST pressure but was used in the 2019 assessments as a pressure; this means that in the 2019 assessments that any relevant information will need to be moved from this pressure to another FeAST pressure. E.g. some

literature on mammalian predators came under this pressure, which would now need moving to the non-native species pressure.

Breeding (Br)/non- breeding (NBr) assessments

2015 draft assessments provided Br and NBr in separate spreadsheets. 2019 draft assessments included a column to indicate which season (Br and/or NBr) the pressure was apparent. Where the pressure was present in both seasons ‘all’ was attributed.

It was concluded that most pressures listed in FeAST are exerted during both Br and NBr seasons and therefore as a pragmatic approach the approach used in the 2019 assessments will be adopted for developing the final sensitivity assessments. Seasons should be combined into one assessment spreadsheet and the season when the pressure is acting and attributed as Br/NBr/all with nuances are described within the evidence text.

The approach for 2019 assessments were also taken for the 2021 marine bird assessments.

Barrier to species movement, Collision above water

Guillemot, Kittiwake, Puffin, Razorbill

Searle, K.R., Butler, A., Mobbs, D.C., Trinder, M., Waggitt, J., Evans, P. and Daunt, F., 2019. Scottish Waters East Region Regional Sectoral Marine Plan Strategic Ornithology Study: final report. Marine Scotland/SEANSE, CEH Ref: NEC07184

Climate Change

Eider

Dey, C.J., Semeniuk, C.A., Iverson, S.A., Richardson, E., McGeachy, D. and Gilchrist, H.G., 2018. Forecasting the outcome of multiple effects of climate change on northern common eiders. Biological Conservation, 220, pp.94-103.

Climate change

Guillemot and Kittiwake

Sadykova, D., Scott, B.E., De Dominicis, M., Wakelin, S.L., Wolf, J. and Sadykov, A., 2020. Ecological costs of climate change on marine predator–prey population distributions by 2050. Ecology and evolution, 10(2), pp.1069-1086.

Climate change, Temperature change

Great skua

Oswald, S.A., Bearhop, S., Furness, R.W., Huntley, B. and Hamer, K.C., 2008. Heat stress in a high‐latitude seabird: effects of temperature and food supply on bathing and nest attendance of great skuas Catharacta skua. Journal of Avian Biology, 39(2), pp.163-169.

Collision below water

Manx shearwater

Shoji, A., Dean, B., Kirk, H., Freeman, R., Perrins, C.M. and Guilford, T., 2016. The diving behaviour of the Manx Shearwater Puffinus puffinus. Ibis, 158(3), pp.598-606.

Light or shading

European storm petrel

Miles, W., Money, S., Luxmoore, R. and Furness, R.W., 2010. Effects of artificial lights and moonlight on petrels at St Kilda. Bird Study, 57(2), pp.244-251.

Non-indigenous species

European storm petrel

Ratcliffe, N., Mitchell, I.A.N., Varnham, K., Verboven, N. and Higson, P., 2009. How to prioritize rat management for the benefit of petrels: a case study of the UK, Channel Islands and Isle of Man. Ibis, 151(4), pp.699-708.

Transition elements and organo-metal contamination

Common Scoter

Takekawa, J.Y., Wainwright-De La Cruz, S.E., Hothem, R.L. and Yee, J., 2002. Relating body condition to inorganic contaminant concentrations of diving ducks wintering in coastal California. Archives of Environmental Contamination and Toxicology, 42(1), pp.60-70.

Transition elements and organo-metal contamination

Manx shearwater

Thompson, D.R., Furness, R.W. and Walsh, P.M., 1992. Historical changes in mercury concentrations in the marine ecosystem of the north and north-east Atlantic Ocean as indicated by seabird feathers. Journal of Applied Ecology, pp.79-84.

Underwater noise

Great skua

Cramp, S., Simmons, K.L.E., Brooks, D.C., Collar, N.J., Dunn, E., Gillmor, R., Hollom, P.A.D., Hudson, R., Nicholson, E.M., Ogilvie, M.A. and Olney, P.J.S., 1983. Handbook of the birds of Europe, the Middle East and North Africa. The birds of the Western Palearctic: 3. Waders to gulls.

Underwater noise

Common Scoter

Hansen, K.A., Hernandez, A., Mooney, T.A., Rasmussen, M.H., Sørensen, K. and Wahlberg, M., 2020. The common murre (Uria aalge), an auk seabird, reacts to underwater sound. J. Acoust. Soc. Am, 147, pp.4069-4074.

Visual disturbance

Black-headed gull, common gull, herring gull

Goodship, N. & Furness, R.W. 2019. Seaweed hand-harvesting: literature review of disturbance distances and vulnerabilities of marine and coastal birds. Scottish Natural Heritage Research Report No. 1096.

Visual disturbance

Black-throated Diver, Great northern diver, Red-throated diver

O'Brien, S., Ruffino, L., Lehikoinen, J.P., Lewis, M., Petersen, A., Petersen, I.K., Okill, D., Väisänen, R., Williams, J. and Williams, S., 2018. Red-Throated Diver Energetics Project: 2018 Field Season Report.

Water clarity changes

Velvet scoter

Wilson, B., Batty, R.S., Daunt, F. and Carter, C., 2006. Collision risks between marine renewable energy devices and mammals, fish and diving birds: Report to the Scottish executive.

Emergence regime changes

Change to prey

Change to prey

Change to prey

NO DIRECT EFFECTS. This pressure may only indirectly affect the feature under consideration through effects on the feature’s supporting habitat. Changes in water levels may reduce the intertidal zone (and the associated/dependent habitats) by changing either the spatial area and or duration of immersion/exposure during tidal cycles. Changes in tidal flushing can change sediment dynamics that may lead to changing patterns of deposition and erosion and extent of tidal immersion. Impacts include reduced habitats, resources, and feeding times, exposure, desiccation.