3 November 2014

Using Particle Modeling for Ecological

Questions Case Study Birds Dispersion in

the North Sea Transportmodelling of Common Guillemot and Razorbill in

the North Sea

Steve Geelhoed (IMARES)

Marc Weeber ; Mathieu Chatelain (Deltares)

Setup

1. Introduction

2. Background information

3. Modelling

4. Results

5. Surveys

6. Conclusion

Introduction

• Project “Aanvullende Beschermde

Gebieden”

• Potential NATURA 2000 areas

• Brown Ridge is currently not

protected. However, aggregation of

bird species at the Brown Ridge

• What could be the reason?

• Good feeding grounds (more

fish available)

• Effect of hydrodynamics

Background information

Common Guillemot Razorbill

Location Common Guillemot Razorbill

Seaborne June September

Brown Ridge November-February January-March

Background information

Common Guillemot Razorbill

Background information

August-September December-January

Modelling

Research question:

- Can the effect of the hydrodynamics

explain why these bird species aggregate

at the Brown Ridge?

Approach:

- Model the bird species as floating

particles in the North Sea.

- Assume that flying has no effect on their

distribution

11 november 2014

Forward:

Where do particles go to after

release from the central North

Sea?

Backward:

Where do particles that end up at

the Brown Ridge come from?

Modelling

Hydrodynamics:

2003 – 2004 (average wind / high peaks)

2005 – 2006 (average wind / low peaks )

2006 – 2007 (high wind)

Wind:

Yes / No

Release period:

Forward Backward

15 Jul 15 Dec

1 Aug 15 Jan

15 Aug 15 Feb

1 Sep 15 Mar

Results

Forward

15 Aug 2005

Results

Forward

-Hydrodynamics:

- First days remain in place due to tide.

- Eventually moves out of the North model boundary along the Danish coast.

-Wind:

- Particles move out of the North model boundary more quickly with wind

influence.

- The amount of particles that get stuck along the Dutch and Danish coast

increases with wind influence.

-Release period:

- The amount of time that the particles remain in the model is overall longest when

released on 15 July. Probably due to lower wind velocities.

-Period:

- The periods 2005-2006 and 2006-2007 look alike (end at North model boundary)

- The period 2003-2004 deviates as in two release periods some particles end up

along the English coast.

Results

Backward

15 Dec 2003

Results

Backward

-Hydrodynamics:

- Particles are originating from the English Channel and the English South East

coast.

-Wind:

- With wind particles can also be originating from the English North East coast.

- With wind it is less likely that particles are originating from outside the model

boundary of the English Channel.

-Release period:

- Period of release and place of origination doesn’t has a consistent effect in the

different periods

-Period:

- In the periods 2003-2004 and 2005-2006 particles can originate from the English

North East coast.

- In the period 2005-2006 there are no particles orginating from the English

Channel.

Results

Surveys: distribution Common Guillemot

Surveys: distribution Razorbill

Conclusion

Forward:

•The forward simulation corresponds with the distribution of Common

Guillemot and Razorbill up to September (moulting).

Backward:

•For Common Guillemot it is likely that part of the individuals that end

up at the Brown Ridge make use of the currents (English Channel,

English East Coast). Most distribute by active transport.

•For Razorbill it is unlikely that they make use of the currents to end

up at the Brown Ridge. Active transport by flying.

Conclusion

Overall:

•Both Common Guillemot as Razorbill need active movement to end

up at the Brown Ridge within the modelled time span.

•Both species need active movement to maintain at the Brown Ridge.

Concluding : Hydrodynamics are not (solely) responsible for high

aggregation at the Brown Ridge. Common Guillemot

and Razorbill specifically move towards the Brown

Ridge.

Thank you

Thank you for your attention.

Questions?