sigma xi 2013
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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
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