What are the combined effects of global climate change and biological

invasions on insect community structure?

Components of global change

Habitat loss

Elevated CO2 Climate change

Invasive species

Insects

Invasions Elevated CO2

Insects

Invasions Elevated CO2

What are the combined effects

of elevated CO2 & plant

invasions on insect community structure?

0

10

20

30

40

Elevated [CO2] (n=2) Ambient [CO2] (n=3)

Inse

ct r

ich

nes

s

t=-9.91, df=3, p=0.002

0

10

20

30

40

50

60

Elevated [CO2] Ambient [CO2]

Inse

ct a

bu

nd

ance

t=-2.61,df=2,p=0.12

Role of plant communities?

1. Plant quality?

C:N ratios herbivory

0

5

10

15

20

25

30

35

Box elder Goldenrod Blackberry Nepal grass Honeysuckle

C:N

rat

io

*

0

5

10

15

20

25

30

35

Her

biv

ory

(%

)

Box elder Goldenrod Blackberry Nepal grass Honeysuckle

*

Role of plant communities?

1. Plant quality

C:N ratios herbivory

2. Diversity

0

2

4

6

8

10

12

Elevated [CO2] Ambient [CO2]

Pla

nt

rich

nes

s

t=1.06,df=1.07,p=0.48

0

10

2030

40

50

0 5 10 15 20

Plant richness

Inse

ct r

ich

nes

s Elevated

Ambient

Role of plant communities?

1. Plant quality

C:N ratios herbivory

2. Diversity

3. Invasives

0

10

20

30

40

50

60

70

Elevated [CO2] Ambient [CO2]

Ho

ney

suck

le c

ove

r (%

)df=1,t=1.79,p=0.32

0

10

20

30

40

50

0 20 40 60 80 100

Honeysuckle cover (%)

Inse

ct r

ich

nes

sR2=0.25, p=0.02

Insects

Invasions Elevated CO2