management in white dunes

07-10-2015,

Leon Terlouw; PWN

Maaike Veer; Waternet

Project Noordwest Natuurkern - part of Life Project Dutch Dune Revival

Management of white dunes

The answer blowing in the wind?

Where?

Natura2000 Kennemerland-Zuid Nr. 88

Dunes were very much stabilized

Causes of

stabilisation

Sea-defence

>CO2; >temperature

and >rain

1998 Era of new management: dynamic dune management

several large scale experiments

Reactivating moving dunes

2009

Lessons of reactivating large scale movingdunes in the innerdunes

• Large scale projects are active for at least 10 years

• Stabilisation by remainssprouting from roots

• Follow up management is necessary to remove theremnants of formermanagement

• New formation of wet duneslacks is successful

Importance of frontdunes dynamics

• Living dunes at the seaside

• Dynamics (wind, salt, sand) from seaside to innerdunes

• Shower of lime to innerdunes

• Start of dune formation

• Necessary for conservation of Grey and White dunes

Availability of sand is important

Fresh sand from the beach is

blown through the gullies into

the dunes

Results

2012

2013

2014

2015

Houtglop

Before

After

2013From the westside

of the dune fresh

sand is blown out

of the dune slack

2015Valleyfloor adapted to

current groundwatertable

2013

2015

In the deposition zone fresh sand can reach

large distances (500-1000 m) to rejuvenate

and fight acidification of grey dunes

Dynamic dunes, especially small

scale blowouts are necessary for

biodiversity and healthy grey dunes

Future management strategy:

reactivation of small blowouts

throughout the entire dune system

Vlaggenduin near Katwijk, 15-4-2015

Bas Arens

Barren

Little Rubus growth

Some Rubus growth

Much Rubus growth

Few roots

Many roots

Little Ammophila

Some Ammophila

Much Ammophila

Other vegetation

westGulliesin most western

dunes

Because of high

dynamics little

management

needed

High dynamicsKattendel Summer 2008

Dec. 5; 2013 Jan 19; 2015

Follow-up management by weeding

To remove previous stabilization influence of man

Regrowth of Rubus caesius from old roots

Parabolic dunes:

We tried different kinds of follow up management

Steep slopes weeded by volunteers

(Mechanical) removal of roots

and vegetation should be

repeated several times to be

effective

Hopefully effective!Rubus caesius can have roots up to 1.7 m deep

Untill now 3 different treatments done…..

Do these dunes stay mobile on the long run in current climaticconditions?

The answer is blowing in the wind!