Displacement Assessment: ASSESSMENT DURING THE BREEDING SEASON - - PowerPoint PPT Presentation

Displacement Assessment: ASSESSMENT DURING THE BREEDING SEASON Francis Daunt Marine bird impact assessment guidance workshop 20 February 2020

Acknowledgements

• Kate Searle (CEH), Adam Butler (BioSS) and Deena Mobbs (CEH)
• Funded projects from Marine Scotland
• Project Steering Group members: MS, SNH, JNCC, NE, RSPB

Displacement in the breeding season

• Breeding seabirds may be displaced from favoured foraging habitats

by Offshore Renewable Developments

• Potential for negative consequences on SPA populations

Displacement Matrix

Joint Statutory Nature Conservation Bodies (SNCB) Interim Displacement Advice Note (2017)

Density in footprint x Displacement rate x Mortality rate

Displacement Matrix calculation

SeabORD

Sub-lethal effects

Driver Behaviour Energetics Demographic rates Population size Sub-lethal

SeabORD Individual-based model

• Simulate foraging behaviour of individuals in accordance with seabird behaviour and
• ptimal foraging theory (maximising energy intake / minimising time spent foraging)
• Displacement: individuals relocate and experience patch depletion and competition

effects whilst foraging in a location

• Barrier effects: Individuals incur additional flight costs
• Fate of individual birds experiencing displacement and barrier effects:
• Effects on adult survival (via changes in body mass)
• Effects on productivity

SeabORD Inputs

• Bird utilisation distribution
• Prey distribution
• Displacement and barrier rate
• Footprint shapefiles
• ‘border’ width (km) to be added for OWF footprints
• ‘buffer’ width (km) to be added to OWF footprints
• Species-specific parameters:
• Adult and chick body mass
• Adult and chick critical body mass
• Length of season
• Adult DEE and chick energy requirement
• Activity costs
• Intake rates

SeabORD flight lines

SeabORD Worked Example

SeabORD Worked Example

SeabORD Worked Example

• Generates adult and chick masses and

number of foraging flights per day

• Generates time budgets (time spent

foraging and flying)

SeabORD Worked Example

SeabORD Limitations

• Chick-rearing period only
• Simple flight lines
• Only currently parameterised for 4 species: kittiwake, guillemot, razorbill, puffin
• Processing time to run can be long
• Requires initial calibration to set baseline conditions appropriately in line with

empirical observations of adult mass loss and productivity

How to use SeabORD in assessments

• Where you have a defensible Utilisation Distribution of breeding birds:
• Run SeabORD
• Where this is absent:
• Run SeabORD emulator to estimate mortality rate
• Run SeabORD using a 'generic' bird UD (e.g. derived from models of

seabird distribution) to estimate mortality rate

• Use mortality rate in displacement calculation:

density x displacement rate x mortality rate

SeabORD emulator

• Explanatory variable: mortality rate per individual in footprint
• Covariates (available everywhere)
• Footprint distance to colony
• Footprint alignment to colony
• Density in footprint
• Survival
• Productivity
• Run SeabORD across the full range of each input to derive regression equation
• Use regression equation based on known covariates

How to use SeabORD in assessments

Mean abundance of birds in footprint From local at-sea surveys From UD and colony count SeabORD with UD derived from good local GPS with UD derived from multi-site modelling of GPS data (e.g. Wakefield et al., 2017) with UD derived from MERP at-sea survey maps & SNH apportioning SeabORD Emulator n/a

SeabORD: integration of Collision

Driver Behaviour Energetics Demographic rates Population size Sub-lethal

Density in footprint x Displacement rate x Mortality rate

Contribution of SeabORD to summer assessments

• Current approaches use expert judgement to estimate

mortality rate of displaced birds

• SeabORD estimates mortality of displacement based
• n biological realism
• SeabORD is flexible in how it can be used, dependent
• n the availability of input data
• Key pointers on data gaps
• New version of SeabORD (available March) will

integrate collision and displacement effects