Beth ScottUniversity of Aberdeen

Impact Assessment: Research methods for assessing impacts on birds

Seabirds and Renewables Not a trade off!

Using knowledge of behaviour and preferred habitats to ensure rapid and sensible development

Beth Scott b.e.scott@abdn.ac.uk

&

What we need to KNOWWill renewable developments affect

seabird populations?• Can devices cause direct Mortality?

• collision, entrapment, pollution, etc

• Can devices cause Displacement?• Displacement from feeding / reproducing / resting locations leads

to increase energy use / time away from nest (adult condition, chick mortality)

• Can devices cause changes to Habitats?• Bio-physical changes to feeding / reproducing / resting habitats

in particular influence foraging success via affects on presence/abundance/behaviour of PREY

Direct Mortality?Most diving species will come into contact with area of

moving parts of tidal devices.

Langton R, Scott BE, Davies IM (in prep)

• METHODS:

• Direct observation - Acoustic (multi-frequency)?

• Pressure depth tags?

Displacement / Energy Use METHODS: Tagging (GPS, etc) / Radar

RSPB photo Ellie Owen

GPS tags

• Rapid knowledge of foraging locations, understanding of routes and time budgets - allows modelling of energy use & population consequences – links to SPA.

• High individual variance within populations – but also evidence of foraging site fidelity (*low numbers)

Feeding locations Most effort so far into Distribution

• http://www.jncc.gov.uk/default.aspx?page=4564

• Know where birds are – but not why?

• SO can not be predictive or explanatory of annual /seasonal differences in distribution or changes in breeding or winter mortality.

Suggested at-sea methods for defining (bio-physical) feeding areas.

Tested in multi-disciplinary EU project - led by K. Camphuysen

Continuously Record• SEABIRD BEHAVIOUR

(actively feeding vs flying through)

• BIO-PHYSICAL (water column characteristic)

• PREY - Fisheries Acoustics

All foraging animals grouped as one predator Abundance high in areas of higher sub-

surface chl

What causes these patches of chl and can renewable devices effect primary production (+ or -)?

Scott et al 2010 (MEPS 408: 207–226)

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Longitude (Latitude 56.25)

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Sub surface Chlorophylllmaximum

Cholorophyll depth averaged

Total Weighted Abundance

Large numbers foraging only during maximum ebb, only on bank edge, when PREY are closer to surface.

Understanding daily/seasonal/inter-annual variance in counts!

Embling et al., submitting to JAE.

Shear

Fast Flow

Upwelling

Standing waves

Suggested near-shore High Tidal Speed methods• Define Habitat Characteristics and tidal

speeds /directions to quantify species foraging habitat

location of shear

predators

Artic Tern Surface feeder

(only during ebb tides and in upwelling habitat 3 & shear 1) 10

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Black Guillemot Diving bird

(over more tidal speeds and within Fast flow (2) and

downstream of upwelling (4)

Mean number of actively foraging birds

IE MaxE DE IF MaxF DF

Scott et al (in prep)

Methods that will rapidly prove if & how renewables affect seabird populations!

• Can devices cause direct mortality? • Need to direct observations

• Can devices cause Displacement? Or changes to Habitat?

• Need to understand WHY birds use that habitat to be able to predict : Device effect vs climate / annual prey effect

• Seabird foraging behaviour – indicators of water column characteristics.

• Putting devices in for next 20-50 years – need to work together to make a win-win situation

Foraging seabirds predictably in areas of different levels of tidal mixing (log10(h/U3))

Identify preferred habitat via bathymetry & tides

High 4.5

Low 3.2

Intermediate stratification

More mixed

Isle of May

More stratified