Spore Reproduction of Japanese Climbing Fern in Florida as a Function of Management Timing

Transcription

1 Spore Reproduction of Japanese Climbing Fern in Florida as a Function of Management Timing Greg MacDonald 1, Candice Prince 1, Kimberly Bohn 2, Ashlynn Smith 1, and Mack Thetford 1 1 University of Florida, 2 Pennsylvania State University Photo Credit: Chris Evans, University of Illinois, Bugwood.org

2 Exotic climbing ferns in Florida Old world climbing fern (Lygodium microphyllum) Japanese climbing fern (Lygodium japonicum) Keith Bradley, Atlas of Florida Vascular Plants Chris Evans, University of Illinois, Bugwood.org

3 Japanese climbing fern (Lygodium japonicum) Native to temperate and tropical Asia Climbing habit Early 1900s: introduced as an ornamental 1 Long-distance dispersal via wind, pine straw bales 2,3 Chris Evans, University of Illinois, Bugwood.org Dennis Teague, U.S. Air Force, Bugwood.org

4 Impacts Chris Evans, University of Illinois, Bugwood.org Smothers and displaces vegetation, fire ladders Florida Exotic Pest Plant Council: Category I species Chuck Bargeron, University of Georgia, Bugwood.org Florida Noxious Weed List Alabama Noxious Weed List (Class B)

5 Japanese climbing fern: life cycle From Research in the Panhandle John Tiftickjian, Delta State University Sigel Lab, University of Louisiana at Lafayette Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Spore bank Gametophyte stage Sporophyte Stage Development of fertile fronds Spores disperse

6 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

7 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

8 Distribution USDA NRCS National Plant Data Team, 2016 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 Atlas of Florida Vascular Plants, Institute of Systemic Botany, 2016

9 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

10 Herbicide application: Herbicide treatments: 1. Glyphosate 2% (v/v) 2. Metsulfuron methyl 0.5 g per liter 3. Glyphosate + metsulfuron methyl 4. Untreated Control Herbicide applications via backpack sprayer with a handgun. Plants sprayed to wet.

11 Western Panhandle sites 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

12 Central Florida sites Ocala National Forest: upland longleaf pine/sand pine 2. Lake County: hardwood forest Treatments applied to fern patches

13 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

14 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

15 Results

16 Spore Yield (g/g) Spore Yield (g/g) Spore Yield (g/g) Spore Yield (g/g) Spore Yield BRSF Neal Gly Met Gly+Met Control July Aug Sept 0 July Aug Sept 0.16 Ocala 0.16 Lake County July Aug Sept 0 July Aug Sept

17 Results: spore germination and gametophyte development Blackwater River State Forest Ocala National Forest

18 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

19 Spore Germination Test spore viability directly % cover is somewhat subjective

20 Changes in Methodology Test spore viability directly Developed methodology for spore germination on microscope slides Measure % germination instead of % cover

21 Studies

22 Florida sites Blackwater River State Forest (BRSF): upland longleaf pine forest 2. Ocala National Forest: upland longleaf pine/sand pine 3. Hillsborough County: hardwood forest

23 Herbicide application : 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 Herbicide applications via backpack sprayer with a handgun. Plants sprayed to wet.

24 Germination (%) Spore Yield (mg/g) South Florida (Hillsborough) 40 Gly Met Gly +Met Control Early July Late July Mid Aug. Early Sep. South Florida (Hillsborough) Gly Met Gly +Met Control ab ab ab ab a abc abc bc bc abc abc abc abc abc abc 40 c Early July Late July Mid Aug. Early Sep.

25 Germination (%) Spore Yield (mg/g) Central Florida (Ocala) 140 Gly Met Gly +Met Control Early July Late July Mid Aug. Early Sep. 90 Central Florida (Ocala) Gly Met Gly +Met Control Early July Late July Mid Aug. Early Sep.

26 Spore Yield (mg/g) Germination (%) 100 Panhandle (Waren) Gly Met Gly +Met Control 90 a 80 abc abcd ef bcde ef def cdef Early July Late July Mid Aug. Early Sep. 120 Panhandle (Waren) Gly Met Gly +Met Control Early July Late July Mid Aug. Early Sep.

27 RESULTS 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

28 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

29 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

30 Chris Evans, University of Illinois, Bugwood.org Thank you! Questions?