restoration of drift sands - european commission...podd duration (days) recommendations drift sands...

restoration of drift sands Eva Remke

Bargerveen Foundation &

Radboud University Nijmegen

[email protected]

With contributions from …. …Marijn Nijssen (Bargerveen)

… Michel Riksen (WUR) …Bart Wouters (Bargerveen/BTL)

coastal dunes: young (late middle age) old (early middle age or older) inland dunes and river dunes: young (holocene) old (before holocene) windborne sand deposits: young deposits (± 12.000-20.000 years old) old depostis before the last ice age (> 60.000)

geological background coastal/ inland dunes - The Netherlands -

Drift sands are aeolian deposits which developed during the late holocene. In NW-Europe older sand deposits were reactivated due to human impact and climate change.

geological background drift sands

european sand-belt (Koster, 2005. The physical Geography of Western Europe. Oxford University press)

• age of sands – mostly older deposits • sand nourishment – amount of sand is

mostly limited • climate – less humid & less wind

differences coastal dunes – inland dunes

• only reactivation if area is large enough • start in the SW – drift sand is growing

towards the wind!

recommendations drift sands

• Grow against the wind, thus to the south-west (NL)

• Longitudinal cells in a south-west to north-east direction

Growth of drift sands

• Grow against the wind, thus to the south-west (NL)

• Longitudinal cells in a south-west to north-east direction

• Wind velocity is hampered in zone about 20 x the height of the adjacent forest: trees ca. 12-15 m -> drift sands at least several hundred meters long for sufficient aeolian activity

Growth of drift sands


towards the wind!



towards the wind! • depending on aim – get rid of organic

matter




matter • organic matter content < 0.4% -> risk of

rapid recolonization is minimal


disc harrow

before after

drift sand cleaner

digger



matter • organic matter content < 0.4% -> risk of

rapid recolonization is minimal • at least 40-60% open sand in area to keep

it going and space for every element and species


• special adapted species – escape harsh conditions

• special thermophilic species – need for warm & dry conditions

Tree grayling (Hipparchia statilinus)

‘Sand earwing’ (Lapidura riparia)

Snow flea (Boreus hyemalis)

drift sand fauna

Importance of microclimate for development of animals

Example coastal dunes – grashopper experiment

Blue-winged grasshopper (Oedipoda caerulescens)

Common field grasshopper (Chorthippus bruneus)

Mottled grasshopper (Myrmeleotettix maculatus)

Importance of microclimate for development of animals

Temperature 3 cm below soil surface

0

10

20

30

40

50

60

Time (march-july)

Tem

pera

ture

(°C

)

sandy dunegrasslandencroacheddune grassland

Egg development grasshoppers and microclimate

Post diapauze development (PoDD) duration Chorthippus brunneus

y = 0.9273x2 - 42.745x + 514.75R2 = 0.9984

2.5

12.5

22.5

32.5

42.5

52.5

62.5

72.5

15 16 17 18 19 20 21 22 23

Temperature (°C)

PoD

D d

urat

ion

(day

s)

(F=305.62; p=0.04)

Simulated hatching date

• ± 50 days delay in development between sandy and encroached dune grasslands

• thermophylic species -> longer post diapauze development

• total days larvae-adult-reproduction = 130 days

Impossible to complete lifecycle

Temperature 3 cm below soil surface

0

10

20

30

40

50

60

Time (march-july)

Tem

pera

ture

(°C)

sandy dune grassland

encroached dunegrassland

Post diapauze development (PoDD) duration Chorthippus brunneus

y = 0.9273x2 - 42.745x + 514.75R2 = 0.9984

2.5

12.5

22.5

32.5

42.5

52.5

62.5

72.5

15 16 17 18 19 20 21 22 23

Temperature (°C)Po

DD

dur

atio

n (d

ays)


• only large scale reactivation reactivation in areas of several ha’s

• depending on aim – get rid of organic matter • Specially adapted species need extreme climates

discussion points

Large scale – small scale dynamic restoration: do we know what to do when and where? Mosaic and dynamic pattern of dune landscapes contrast with adminstrative culture of national legislation and Natura 2000. Basic research before restoration start and monitoring of measures are labour intensive and expensive, though more than needed.

Vanaf hier extra slides als er vragen zijn …. ;-) … misschien red ik het nog deze te vertalen

Kenschets van stuifzanden

• Arm aan nutriënten en mineralen

• Extreem microklimaat

• Zeer dynamische tot stabiele biotopen

• Relatief arm aan planten- en diersoorten

• Zeer karakteristieke soortensamenstelling

Biotooptypen binnen stuifzanden

dynamisch stabiel onvoorspelbaar voorspelbaar extreem microklimaat gebufferd microklimaat voedselarm matig voedselrijk

open zand, verstuiving


pionier Buntgras


Ruig Haarmos




lichensteppe



stuifzandheide


Grijs Kronkelsteeltje



Hoog gras



Vegetatiesuccessie stuifzanden

Kaal zand

Buntgras en

haarmos

Korstmossen en grasland

Bos Grijs

kronkelsteeltje en

grasland

Heide

5-15 jaar

20-50 jaar 30-100 jaar

herstelbeheer

Zandoorworm

Beperkt tot open zand en pionier Buntgras vegetatie

0

50

100

150

200

250

300

3Z 2B 3B 4B 1H 2H 3H 4H 5H 8H 1K 2K 3G 4G 7G

potvalserie

aant

al in

d. vrouwmannymf

biotoop zand Buntgras Ruig Haarmos Grijs Kronkelsteeltje gras

• Ingraven overwintering en voortplanting gebonden aan los open zand

• Zeer mobiel: vliegend en lopend • Twee generaties per jaar

ontsnappen dynamiek en kolonisatie nieuwe plekken • Broedzorg voor eerste larvestadium • Overdag ingegraven • Nachtactief aan de oppervlakte ontsnapping aan extreem klimaat

Zandoorworm

Sneeuwspringer

• Larven leven van rhizomen van mossen, adulten van mosblad Beperkt tot Ruig Haarmos vegetatie

• Larve weinig mobiel, ontwikkeling duurt 2 jaar

Kan met lage voedselkwaliteit omgaan

• Adulten leven in november – februari, voortplanting in winter ontsnapping aan heet en droog klimaat

• Adulten vrij mobiel door springen

kolonisatie nieuwe vegetaties

Kleine Heivlinder

• Larven op Buntgras, maar weinig mobiel gebonden aan stabiele vegetatie (haarmos-lichenesteppe)

• Popstadium juli-august • Mobiele adulten august-september

ontsnapping meest extreme klimaatomstandigheden

• Larven eten pas vanaf voorjaar • Adulten al eitjes bij uitsluipen popstadium geen voedsel nodig wanneer niet voorhanden

Dianummer 1Dianummer 2Dianummer 3Dianummer 4Dianummer 5Dianummer 6Dianummer 7Dianummer 8Dianummer 9Dianummer 10Dianummer 11Dianummer 12Dianummer 13Dianummer 14Dianummer 15Dianummer 16Dianummer 17Dianummer 18Dianummer 19Dianummer 20Dianummer 21Dianummer 22Dianummer 23Dianummer 24Dianummer 25Dianummer 26Dianummer 27Dianummer 28Dianummer 29Dianummer 30Dianummer 31Dianummer 32Dianummer 33Dianummer 34Vegetatiesuccessie stuifzandenDianummer 36Dianummer 37Dianummer 38Dianummer 39

restoration of drift sands - european commission...podd duration (days) recommendations drift sands...

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