1

Invasive plants and Native anurans

A tale of two interactions

2

3

Amphibian declines

• ~6000 spp.• ~1/3 threatened• ~160 presumed

extinct recent times

4Habitat loss/degradation

Why?

5

Loss vs. Degradation

6

Invasive plants

• 4,000+ non-native plants outside cultivation

• 79 plants cost US $97B per year

• Contribute to nearly half of threatened native spp.

7Area covered by 8 invasive plants in ONWR

8

But…what do plants have to do with frogs?

Physical structure

Invasive plants

9

But…what do plants have to do with frogs?

Physical structure

(Water) Chemistry

Invasive plants

10

But…what do plants have to do with frogs?

Physical structure

(Invertebrate) Community

(Water) Chemistry

Invasive plants

11

Invasive plants

Phragmites australis Typha angustifolia

12

13

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?

14

Three basic questions

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

15

Hypothesis 1 methods

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

(doubly invaded in 2007)– LabPro datalogger

16

Natural wetland complexes

17

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

18

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

19

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

20

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

21

Highlights

• In ammonium, non-invaded wetlands consistently lowest

• In dissolved oxygen, T. angustifolia-invaded wetlands consistently highest

• In nitrate, non-invaded wetlands consistently lower

• Temperature consistently highest in non-invaded, lowest in invaded wetlands

22

Water quality: summary

Ammonium Dissolved oxygen

Nitrate Temp.

T. angustifolia 2 1 1 2

P. australis 1 3,2 3 2

Non-invaded 3 2,3 3 1

Doubly-invaded 1 1 2

2007, 2008

23

24

Three basic questions

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

25

Lithobates clamitansLithobates catesbeianus

26

Larval growth and survival

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

27

28

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

29

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

30

Growth rate

-1

0

1

2

3

4

5

6

7

8

140 147 154 161 168 175 182 189 196 203 210 217 224 231 238 245 252 259 266

Weeks

Gro

wth

(m

m/w

ee

k)

Typha angustifolia

Phragmites australis

Non-invaded

Growth rate

31

Relative Growth rate

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

140 154 168 182 196 210 224 238 252 266

Weeks

Re

lativ

e G

row

th R

ate

Typha angustifolia

Phragmites australis

Non-invaded

Relative Growth Rate

32

Highlights

• Non-invaded consistently highest survival

• T. angustifolia consistently middle in length

• Non-invaded consistently highest in growth

• Non-invaded consistently highest in RGR

33

Summary of results

Survival Length Growth RGR

T. angustifolia 2 2 2 2

P. australis 2 3 3 2

Non-invaded 1 1 1 1

34

But…what do plants have to do with frogs?

Physical structure

Invertebrate community

Water chemistry

Invasive plants

35

36

Three basic questions

• Do invasive plants affect the behavior of adult frogs?

37

Adult behavior

• Adult behavior arenas

• Stem density mimicking natural setting

• Acclimation 15 minutes

• 15 minute trial

• Rest

• Repeat with all plants

38

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

39

Hypothesis 3 results

Lithobates clamitans

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

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

Individual Lithobates clamitans

Lo

ng

est

ind

ivid

ual

mo

vem

ent

Typha angustifolia

Phragmites australis

Non-invaded

P

T

N

40

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

41

Hypothesis 3 results

Lithobates clamitans

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

Individual Lithobates clamitans

Nu

mb

er o

f "h

ang

-up

s"

Typha angustifolia

Phragmites australis

Non-invaded

P

T

N

42

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

43

Hypothesis 3 results

Lithobates catesbeianus

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

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

Individual Lithobates catesbeianus

Lo

ng

est

ind

ivid

ual

mo

vem

ent

Typha angustifolia

Phragmites australis

Non-invaded

T

P

N

44

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

45

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

46

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

To

tal

dis

tan

ce

Typha angustifolia

Phragmites australis

Non-invaded

P

T

N

47

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

To

tal

dis

tan

ce

Typha angustifolia

Phragmites australis

Non-invaded

T

N

P

48

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

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

Individual Lithobates clamitans

Dis

tan

ce f

rom

sta

rt

Typha angustifolia

Phragmites australis

Non-invaded

PN

T

49

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

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

Individual Lithobates catesbeianus

Dis

tan

ce f

rom

sta

rt

Typha angustifolia

Phragmites australis

Non-invaded

T

NP

50

Highlights

• More movements in non-invaded wetlands

• More time moving in non-invaded wetlands

• More hang-ups in invaded wetlands

51

Summary of results

• Water chemistry different in invaded wetlands

• Generally higher growth and survival in non-invaded wetlands

• Differences in movement in invaded wetlands

52

Future research

• Compare other invasive plants

• Invertebrate community effects

• Comparison with native relatives?

53

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

54