1

Invasive plants and Native anurans

A tale of two interactions

2

Amphibian declines

• ~7000 spp.• ~1/3 threatened• ~160 presumed

extinct recent times

3Habitat loss/degradation

Why?

4

Loss vs. Degradation

5

Invasive plants

• 4,000+ non-native plants outside cultivation

• 79 plants cost US $97B per year

• Contribute to nearly half of threatened native spp.

6

But…what do plants have to do with frogs?

Physical structure

(Invertebrate) Community

(Water) Chemistry

Invasive plants

7

Invasive plants

Phragmites australis Typha angustifolia

8

Three basic questions

• Are there differences in water quality among invaded and non-invaded wetlands?

• If there are differences, do they affect the growth and survivorship of tadpoles?

• Do invasive plants affect the behavior of adult frogs?

9

Hypothesis 1 methods

• Natural wetlands- 2007, 2008, 2011– Tested weekly over summer– P. australis, T. angustifolia, non-invaded

(doubly invaded in 2007)– LabPro datalogger

10

Water quality

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

8 9 10 11 12 13 14 15 16

Weeks

Am

mo

niu

m (

mg

/L)

Typha angustifolia

Phragmites australis

Non-invaded

Doubly invaded

Ammonium

11

Water quality

Dissolved Oxygen

4

4.5

5

5.5

6

6.5

7

7.5

8 9 10 11 12 13 14 15 16Weeks

Dis

solv

ed o

xyg

en (

mg

/L)

Typha angustifolia

Phragmites australis

Non-invaded

Doubly invaded

12

Water quality

Nitrate

0.1

0.2

0.3

0.4

0.5

0.6

0.7

8 9 10 11 12 13 14 15 16Weeks

Nit

rate

(m

g/L

)

Typha angustifolia

Phragmites australis

Non-invaded

Doubly invaded

13

Water quality

Temperature (2008)

5

10

15

20

25

30

1 2 3 4 5 6 7 8 11 12 13 14 15 16 17 18 19

Weeks

Tem

per

atu

re (

Cel

siu

s)

Typha angustifolia

Phragmites australis

Non-invaded

14

Lithobates clamitansLithobates catesbeianus

15

Larval growth and survival

• Natural wetlands- 2008, 2011– Tested weekly over summer– P. australis, T. angustifolia, non-invaded – Small enclosures with separate individuals

16

17

Larval survival

0

5

10

15

20

25

30

35

140

147

154

161

168

175

182

189

196

203

210

217

224

231

238

245

252

259

266

Day of Year

Ind

ivid

ua

ls p

er

en

clo

sure

Typha angustifolia

Phragmites australis

Non-invaded

Survival

18

Larval length:

0

5

10

15

20

25

30

35

140

147

154

161

168

175

182

189

196

203

210

217

224

231

238

245

252

259

266

Day of Year

Le

ng

th (

mm

)

Typha angustifolia

Phragmites australis

Non-invaded

Length

19

Adult behavior

• Adult behavior arenas

• Stem density mimicking natural setting

• Acclimation 15 minutes

• 15 minute trial

• Rest

• Repeat with all plants

20

Hypothesis 3 results

Lithobates clamitans

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

Individual Lithobates clamitans

To

tal

tim

e m

ovi

ng

Typha angustifolia

Phragmites australis

Non-invaded

T

P

N

21

Hypothesis 3 results

Lithobates clamitans

0

2

4

6

8

10

12

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

Individual Lithobates clamitans

Nu

mb

er o

f m

ove

men

ts

Typha angustifolia

Phragmites australis

Non-invaded

P

T

N

22

Hypothesis 3 results

Lithobates catesbeianus

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Individual Lithobates catesbieanus

To

tal

tim

e m

ovi

ng

Typha angustifolia

Phragmites australis

Non-invaded

T

P

N

23

Hypothesis 3 results

Lithobates catesbeianus

0

2

4

6

8

10

12

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Individual Lithobates catesbeianus

Nu

mb

er o

f m

ove

men

ts

Typha angustifolia

Phragmites australis

Non-invaded

T

P

N

24

Hypothesis 3 results

Lithobates catesbeianus

0

1

2

3

4

5

6

7

8

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Individual Lithobates catesbeianus

Nu

mb

er o

f "h

ang

-up

s"

Typha angustifolia

Phragmites australis

Non-invaded

T

P

N

25

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

Individual Lithobates clamitans

Tota

l dis

tanc

e

Typha angustifolia

Phragmites australis

Non-invaded

P

T

N

26

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Individual Lithobates catesbeianus

Tota

l dis

tanc

e

Typha angustifolia

Phragmites australis

Non-invaded

T

N

P

27

Acknowledgements

• Advisors- Oscar Rocha, Mark Kershner

• Committee- Ferenc de Szalay, Marilyn Norconk, Allison Smith

• Funding- Graduate Student Senate, Kent Environmental Council, Ohio Biological Survey, Ohio Native Plant Society, Society for the Study of Amphibians and Reptiles