Population dynamics of Large Copper Time for a

Population dynamics of Large Copper
Time for a smile
Henk de Vries
With contributions of Isabel Silva, Sicco Ens, Satu Kujala,
Mathilde Groenendijk, Menno Venema, Gerrit Padding,
Jeroen Bredenbeek, Henk Ruiter, Geert Kooijman, Hester
Soomers, Monique van Kessel, Daniel Goedbloed, Nico
Steiner, Ivo Lustenhouwer & Angelique Hofman
Present and past populations
Monitoring populations Large Copper:
Adults Eggs Caterpillars
Monitoring of four areas
•
•
•
•
Weerribben since 1997
Rottige Meente since 1999
De wieden since 2001
Brandemeer since 2007
Trends in populations of Large Copper
Ln ( Average number + 1 )
6
5
4
3
2
1
0
1997
1998
1999
2000
2001
Weerribben
De Wieden
2002
2003
2004
2005
2006
Rottige Meente
Brandemeer
2007
Time for a smile
Trying to explain distribution of Large Copper:
• Vegetation surveys (Water Dock)
• Modelling hydrological isolation
Acid – base gradients indicated by Cottongrass
Modelling population dynamics
1 % better survival makes big differences!
• Normal survival rates are
between 3 and 9%
• Mowing during winter or
summer seems to make
large differences
Three treatments:
Preliminary results:
Average survival rates of 13%!
How many eggs on one plant?
plant 1 ribbe 2004
120
100
80
60
40
20
0
13-jul
17-jul
22-jul
2-aug
dicht
10-aug
open
16-aug
totaal corr
26-aug
rups
1-sep
totaal
Correction of 1,84 to open eggs
9-sep
16-sep
Diapausing larvae: where are they?
Number found
10
8
6
4
2
0
0-10
10-20
20-30
height (cm)
30-40
40-50
Natural enemies
?
Predators:
Picromerus bidens
Observed: Stenus spec.
Parasitoids
Trichogramma
semblidis
(Hymenoptera,
Trichogrammatidae)
Hyposoter placidus
(Hymenoptera,
Ichneumonidae)