spore reproduction of japanese climbing fern in florida as...
TRANSCRIPT
Spore Reproduction of Japanese Climbing Fern in Florida as a Function of
Management Timing
Greg MacDonald1, Candice Prince1, Kimberly Bohn2,
Ashlynn Smith1, and Mack Thetford1
1University of Florida, 2Pennsylvania State University
Photo Credit: Chris Evans, University of Illinois, Bugwood.org
Old world climbing fern
(Lygodium microphyllum)
Japanese climbing fern
(Lygodium japonicum)
Exotic climbing ferns in Florida
Keith Bradley, Atlas of Florida Vascular Plants Chris Evans, University of Illinois, Bugwood.org
Japanese climbing fern (Lygodium japonicum)
• Native to temperate and tropical Asia
• Climbing habit
• Early 1900s: introduced as an ornamental1
• Long-distance dispersal via wind, pine straw bales2,3
Chris Evans, University of Illinois, Bugwood.org Dennis Teague, U.S. Air Force, Bugwood.org
Impacts
• Smothers and displaces vegetation,
fire ladders
• Florida Exotic Pest Plant Council:
Category I species
• Florida Noxious Weed List
• Alabama Noxious Weed List (Class
B)
Chris Evans, University of Illinois, Bugwood.org
Chuck Bargeron, University of Georgia, Bugwood.org
Japanese climbing fern: life cycle “From Research in the Panhandle”
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Spore
bank
Gametophyte
stage
Sporophyte
Stage
Development of
fertile fronds Spores disperse
John Tiftickjian,
Delta State University Sigel Lab, University of
Louisiana at Lafayette
Previous research - Control
• Herbicide studies to control mature plants:
• Glyphosate, imazapyr, and metsulfuron
• Applications targeted during mid-September
• Glyphosate (2% v:v): best control over 2 years, but
metsulfuron also very effective
• However, observed increased spore production
following herbicide application
Previous research – Spore Development
• Herbicide Timing:
• Glyphosate and metsulfuron at
4 intervals from July – Sept
• Applications on individual plants
• Metsulfuron: better at limiting
gametophyte development
• Established in 8 southeastern states
• What’s up with Pennsylvania?!
• Present in much of Florida but most
prevalent in northern areas where it
dies back in winter and re-sprouts
from rhizomes
• Continues to move south
Distribution
USDA NRCS National Plant Data Team, 2016
Atlas of Florida Vascular Plants, Institute of Systemic
Botany, 2016
Current research:
• Two main objectives:
1. Determine if reduced gametophyte development
is similar when applications are made at the
landscape level – management scale treatments
2. Assess the effect of timing of herbicide
treatments on sites across Florida
• Two year project began in 2015
Herbicide application:
• Herbicide applications via backpack sprayer with a handgun. Plants
sprayed to wet.
Herbicide treatments:
1. Glyphosate – 2% (v/v)
2. Metsulfuron methyl – 0.5 g per liter
3. Glyphosate + metsulfuron methyl
4. Untreated Control
Western Panhandle sites - 2015
1. Blackwater River State
Forest (BRSF): upland
longleaf pine forest
2. Neal site in Blountstown:
hardwood forest
• Treatments applied to 10 ft.
x 20 ft. plots
Central Florida sites - 2015
1. Ocala National Forest:
upland longleaf pine/sand
pine
2. Lake County: hardwood
forest
• Treatments applied to
fern patches
Spore collection:
• Fertile fronds collected 4
weeks after herbicide
treatment
• Spores were separated from
fronds and weighed
• Spore yield = Total Spore Yield
Total Frond Weight
Spore germination and gametophyte development:
• Only BRSF and Ocala
• Spores mixed in water (0.015 g
spores to 20 mL water)
• 4 mL spread over pot surface
• Measured % cover after 5 weeks in
growth chambers:
• 25ºC
• 75% humidity
• 12 hour day
Results - 2015
Spore Yield - 2015
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
July Aug Sept
Spore
Yie
ld (
g/g)
BRSF
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
July Aug Sept
Spore
Yie
ld (
g/g)
Neal GlyMetGly+MetControl
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
July Aug Sept
Spore
Yie
ld (
g/g)
Ocala
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
July Aug Sept
Spore
Yie
ld (
g/g)
Lake County
Results: spore germination and gametophyte development
Blackwater River State Forest Ocala National Forest
Results 2015
• No significant relationship between herbicide
treatment and spore yield, in contrast to previous
studies.
• Metsulfuron provided much less control on large scale
treatments plots – BRSF
• Very low spore yield in the hardwood shaded sites -
Neal L&T, Lake County, minimal effect of herbicides
• Ocala site – the combination treatment was best
• Spore Germination – impact was seen in the later
application timings with all three herbicide treatments
Spore Germination
• Test spore viability directly
• % cover is somewhat subjective
Changes in Methodology
• Test spore viability directly
• Developed methodology for
spore germination on
microscope slides
• Measure % germination
instead of % cover
Studies - 2016
Florida sites - 2016
1. Blackwater River State
Forest (BRSF): upland
longleaf pine forest
2. Ocala National Forest:
upland longleaf pine/sand
pine
3. Hillsborough County:
hardwood forest
Herbicide application - 2016:
• Herbicide applications via backpack sprayer with a handgun. Plants
sprayed to wet.
Herbicide treatments:
1. Glyphosate – 2% (v/v)
2. Metsulfuron methyl – 0.5 g per liter
3. Glyphosate + metsulfuron methyl
4. Untreated Control
*Additional herbicide timing
0
5
10
15
20
25
30
35
40
Early July Late July Mid Aug. Early Sep.
Spo
re Y
ield
(m
g/g)
South Florida (Hillsborough)
Gly Met Gly +Met Control
0
10
20
30
40
50
60
70
80
90
100
Early July Late July Mid Aug. Early Sep.
Germ
inat
ion (
%)
South Florida (Hillsborough) Gly Met Gly +Met Control
c
abc abc
bc bc abc abc
ab ab ab
abc
ab
abc abc
abc
a
0
20
40
60
80
100
120
140
Early July Late July Mid Aug. Early Sep.
Spo
re Y
ield
(m
g/g)
Central Florida (Ocala)
Gly Met Gly +Met Control
0
10
20
30
40
50
60
70
80
90
Early July Late July Mid Aug. Early Sep.
Ger
min
atio
n (
%)
Central Florida (Ocala) Gly Met Gly +Met Control
0
10
20
30
40
50
60
70
80
90
100
Early July Late July Mid Aug. Early Sep.
Ger
min
atio
n (
%)
Panhandle (Waren) Gly Met Gly +Met Control
ef
bcde
abc
a
ef
def cdef
abcd
0
20
40
60
80
100
120
Early July Late July Mid Aug. Early Sep.
Spo
re Y
ield
(m
g/g)
Panhandle (Waren) Gly Met Gly +Met Control
RESULTS - 2016
• Hillsborough – low spore yields and minimal effect
of herbicide, no effect on spore germination
• Ocala – low spore yields and minimal herbicide
effects, appears to be some impact of metsulfuron
treatments on spore germination
• Warren – higher spore yields, even as early as July;
some impacts of herbicide on reducing spore yield;
all treatments lowered spore germination
Management Implications
• Although previous research suggested metsulfuron
was more effective than glyphosate at limiting spore
production, broadscale applications showed minimal
differences between herbicides.
• Spore formation occurs earlier than expected,
glyphosate seemed to work best earlier in season,
metsulfuron alone or in combination with glyphosate
for later season applications
Acknowledgements:
• Funding for all studies provided by the Florida Fish and Wildlife
Conservation Commission, Bureau of Invasive Species
Management
• USFS assistance at Ocala National Forest provided by Liz Ramirez,
SWFWMD – Mike Terry
• Site access at Blountstown provided by Neal Land and Timber Co.
• Field and technical support provided by: Justin McKeithen, Nathan
Mooers, Ashlyn Smith, and Heather Van Heuvlen
Thank you! Questions?
Chris Evans, University of Illinois, Bugwood.org